Heating device, method for controlling the heating device, and program

Abstract

To provide a temperature raising device, a method of controlling the same, and a program capable of efficiently raising the temperature of secondary batteries.SOLUTION: A temperature raising device comprises: an AC generating circuit that has a first capacitor whose first end is connected with a positive electrode side of a power storage body having an inductance component, a second capacitor whose first end is connected with a negative electrode side of the power storage body, a parallel switch part that connects the first capacitor and the second capacitor in parallel with the power storage body, and a series switch part that connects the first capacitor and the second capacitor in series with the power storage body; and a controller that alternately switches between a first state where the parallel switch part is made to be in a conduction state and the series switch part is made to be in a non-conduction state and a second state where the parallel switch part is made to be in the non-conduction state and the series switch part is made to be in the conduction state.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a temperature raising device, a control method for a temperature raising device, and a program. [Background technology]

[0002] Efforts to reduce adverse effects on the global environment (e.g., reduction of NOx, SOx, and CO2) are underway. For this reason, in recent years, from the viewpoint of improving the global environment, and in order to reduce CO2, there has been growing interest in electric vehicles that run at least by electric motors driven by power supplied from batteries (secondary batteries), such as hybrid electric vehicles (HEVs) and plug-in hybrid electric vehicles (PHEVs). The use of lithium-ion secondary batteries as batteries for in-vehicle use is being considered. In these electric vehicles, it is important to fully utilize the performance of the secondary batteries. It is known that the charge and discharge performance of secondary batteries decreases when the temperature during use falls below a moderate range. The decrease in the charge and discharge performance of secondary batteries can be suppressed by raising the temperature to a suitable temperature during use.

[0003] In this regard, for example, Patent Document 1 discloses a technology relating to a temperature raising device for raising the temperature of a secondary battery. The temperature raising device disclosed in Patent Document 1 raises the temperature of the secondary battery by actively generating in the secondary battery a ripple current of a predetermined frequency in a frequency range where the absolute value of the impedance is relatively decreased, based on the frequency characteristics of the impedance of the secondary battery. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5293820 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the conventional technology, there are cases where the temperature of the secondary battery cannot be raised efficiently.

[0006] The present invention has been made based on the recognition of the above problems, and one of its objectives is to provide a heating device, a control method for a heating device, and a program that can improve energy efficiency by more efficiently heating a secondary battery. [Means for solving the problem]

[0007] The temperature raising device, the control method for the temperature raising device, and the program according to the present invention employ the following configuration. (1): A temperature raising device according to one embodiment of the present invention is an AC generating circuit that generates an AC current based on power stored in a power storage device having an inductance component, the AC generating circuit including: a first capacitor having a first end connected to a positive electrode side of the power storage device; a second capacitor having a first end connected to a negative electrode side of the power storage device; a parallel switch unit that connects a second end of the first capacitor to the first end of the second capacitor and connects the first end of the first capacitor to the second end of the second capacitor, thereby connecting the first capacitor and the second capacitor in parallel to the power storage device; and a parallel switch unit that connects the second end of the first capacitor to the second end of the second capacitor, thereby connecting the first capacitor and the second capacitor in parallel to the power storage device. and a control unit that alternates between a first state in which the parallel switch unit is made conductive and the series switch unit is made non-conductive and a second state in which the parallel switch unit is made non-conductive and the series switch unit is made conductive, wherein, when changing the parallel switch unit from a non-conductive state to a conductive state, the control unit changes the parallel switch unit from the non-conductive state to the conductive state after changing the parallel switch unit from the conductive state to the non-conductive state, and when changing the series switch unit from the non-conductive state to a conductive state, the control unit changes the parallel switch unit from the conductive state to the non-conductive state after changing the parallel switch unit from the conductive state to the non-conductive state.

[0008] (2): In the above aspect (1), each of the parallel switch section and the series switch section includes at least one semiconductor switch section in which a semiconductor switching element and a diode, the on / off state of which is controlled by the control section, are connected in parallel with each other.

[0009] (3): In the above aspect (2), either or both of the parallel switch section and the series switch section include two of the semiconductor switch sections connected in series, and the diodes of the two semiconductor switch sections are oriented in opposite directions.

[0010] (4): In the above aspect (2), the parallel switch section and the series switch section include a first semiconductor switch section and a second semiconductor switch section which are the semiconductor switch sections connected in series, and the diodes of the first semiconductor switch section and the second semiconductor switch section are oriented in opposite directions.

[0011] (5): In the above aspect (4), when switching from a state in which the first capacitor and the second capacitor are connected in parallel to the power storage unit with the parallel switch unit in a conductive state to a state in which the first capacitor and the second capacitor are connected in series to the power storage unit, the control unit, after bringing one of the first semiconductor switch unit and the second semiconductor switch unit included in the series switch unit into a conductive state so that a current flowing through the parallel switch unit can be returned, connects the first capacitor and the second capacitor in series to the power storage unit while keeping one of the first semiconductor switch unit and the second semiconductor switch unit included in the parallel switch unit in a conductive state. state, and with the series switch unit in a conductive state, when switching from a state in which the first capacitor and the second capacitor are connected in series to a state in which the first capacitor and the second capacitor are connected in parallel to the power storage unit, one of the first semiconductor switch unit and the second semiconductor switch unit included in the parallel switch unit is brought into a conductive state so that a current flowing through the series switch unit can return, and then, while keeping one of the first semiconductor switch unit and the second semiconductor switch unit included in the series switch unit in a conductive state, the first capacitor and the second capacitor are switched into a state in which they are connected in parallel to the power storage unit.

[0012] (6): In any one of the above aspects (1) to (5), the control unit controls the conductive state and the non-conductive state of the parallel switch unit and the series switch unit based on a voltage value of the first capacitor or a voltage value of the second capacitor.

[0013] (7): In any one of the above aspects (1) to (6), the control unit controls the conductive state and non-conductive state of the parallel switch unit and the series switch unit based on the voltage values ​​of the positive and negative electrodes of the storage unit.

[0014] (8): In any one of the above aspects (1) to (7), the control unit controls the conductive state and non-conductive state of the parallel switch unit and the series switch unit based on the voltage value across both ends of the parallel switch unit or the series switch unit, which is in a non-conductive state.

[0015] (9): In any one of the above aspects (1) to (8), the control unit controls the conductive state and the non-conductive state of the parallel switch unit and the series switch unit based on a current value of the AC current flowing through the parallel switch unit or the series switch unit.

[0016] (10): In any one of the above aspects (1) to (9), the control unit controls the conductive state and the non-conductive state of the parallel switch unit and the series switch unit at a predetermined timing based on the AC current.

[0017] (11): In the above aspect (10), the predetermined timing is determined based on a period or a duty ratio of the AC current.

[0018] (12): A control method for a temperature raising device according to one embodiment of the present invention includes an AC generating circuit that generates an AC current based on power stored in a power storage body having an inductance component, the AC generating circuit including: a first capacitor having a first end connected to a positive electrode side of the power storage body; a second capacitor having a first end connected to a negative electrode side of the power storage body; a parallel switch unit that connects a second end of the first capacitor to the first end of the second capacitor and connects the first end of the first capacitor to the second end of the second capacitor, thereby connecting the first capacitor and the second capacitor in parallel to the power storage body; and a parallel switch unit that connects the second end of the first capacitor to the second end of the second capacitor, thereby connecting the first capacitor and the second capacitor in series to the power storage body. a control unit that alternately switches between a first state in which the parallel switch unit is in a conductive state and a non-conductive state and a second state in which the parallel switch unit is in a non-conductive state and the series switch unit is in a conductive state, wherein a computer of the control unit, when changing the parallel switch unit from a non-conductive state to a conductive state, changes the parallel switch unit from the non-conductive state to the conductive state after changing the series switch unit from the conductive state to the non-conductive state, and, when changing the series switch unit from the non-conductive state to a conductive state, changes the parallel switch unit from the conductive state to the non-conductive state after changing the series switch unit from the conductive state to the non-conductive state.

[0019] (13): A control method for a temperature raising device according to one embodiment of the present invention includes an AC generating circuit that generates an AC current based on power stored in a power storage body having an inductance component, the AC generating circuit including a first capacitor having a first terminal connected to a positive electrode side of the power storage body, a second capacitor having a first terminal connected to a negative electrode side of the power storage body, a second terminal of the first capacitor being connected to the first terminal of the second capacitor, and a second terminal of the first capacitor being connected to the second terminal of the second capacitor, thereby connecting the first capacitor and the second capacitor in parallel to the power storage body. a control unit that alternates between a first state in which the parallel switch unit is in a conductive state and the series switch unit is in a non-conductive state and a second state in which the parallel switch unit is in a non-conductive state and the series switch unit is in a conductive state, each of the parallel switch unit and the series switch unit includes at least one semiconductor switch unit in which a semiconductor switching element and a diode are connected in parallel to each other, the on state and the off state of which are controlled by the control unit, the parallel switch unit and the series switch unit include a first semiconductor switch unit and a second semiconductor switch unit that are connected in series, the first semiconductor switch unit and the second semiconductor switch unit being connected in opposite directions, when changing the series switch unit from a conductive state to a non-conductive state after changing the series switch unit from a non-conductive state to a conductive state, and when changing the series switch unit from a non-conductive state to a conductive state after changing the parallel switch unit from a conductive state to a non-conductive state, when changing the series switch unit from a conductive state to a non-conductive state after changing the parallel switch unit from a non-conductive state to a conductive state, and when switching from a state in which the first capacitor and the second capacitor are connected in parallel to the power storage unit to a state in which the first capacitor and the second capacitor are connected in series to the power storage unit,After bringing one of the first semiconductor switch unit and the second semiconductor switch unit included in the series switch unit into a conductive state so that the current flowing through the parallel switch unit can be returned, the first capacitor and the second capacitor are switched to a state in which they are connected in series to the power storage unit while keeping one of the first semiconductor switch unit and the second semiconductor switch unit included in the parallel switch unit in a conductive state, and the series switch unit is brought into a conductive state to switch the first capacitor and the second capacitor from a state in which they are connected in series to the power storage unit to a state in which they are connected in series to the power storage unit. When switching the first capacitor and the second capacitor to a state in which they are connected in parallel to the power storage unit, one of the first semiconductor switch unit and the second semiconductor switch unit included in the parallel switch unit is brought into a conductive state so that a current flowing through the series switch unit can be returned, and then the first capacitor and the second capacitor are switched to a state in which they are connected in parallel to the power storage unit while keeping one of the first semiconductor switch unit and the second semiconductor switch unit included in the series switch unit in a conductive state.

[0020] (14): A program according to one aspect of the present invention is an AC generating circuit that generates an AC current based on power stored in a power storage device having an inductance component, the program including: a first capacitor having a first end connected to a positive electrode side of the power storage device; a second capacitor having a first end connected to a negative electrode side of the power storage device; a parallel switch unit that connects a second end of the first capacitor to the first end of the second capacitor and connects the first end of the first capacitor to the second end of the second capacitor, thereby connecting the first capacitor and the second capacitor in parallel to the power storage device; and a parallel switch unit that connects the second end of the first capacitor to the second end of the second capacitor, thereby connecting the first capacitor and the second capacitor in series to the power storage device. and a control unit that alternately switches between a first state in which the parallel switch unit is in a conductive state and a non-conductive state and a second state in which the parallel switch unit is in a non-conductive state and the series switch unit is in a conductive state, wherein the program causes a computer of the control unit to, when changing the parallel switch unit from a non-conductive state to a conductive state, change the parallel switch unit from the conductive state to the non-conductive state after changing the parallel switch unit from the conductive state to the non-conductive state, and, when changing the series switch unit from the non-conductive state to a conductive state, change the parallel switch unit from the conductive state to the non-conductive state after changing the series switch unit from the conductive state to the non-conductive state.

[0021] (15): A program according to one aspect of the present invention is an AC generating circuit that generates an AC current based on power stored in a power storage body having an inductance component, the program including: a first capacitor having a first terminal connected to a positive electrode side of the power storage body; a second capacitor having a first terminal connected to a negative electrode side of the power storage body; and a parallel switch that connects the first capacitor and the second capacitor in parallel to the power storage body by connecting a second terminal of the first capacitor to the first terminal of the second capacitor and connecting the first terminal of the first capacitor to the second terminal of the second capacitor. a parallel switch unit that alternates between a first state in which the parallel switch unit is in a conductive state and a non-conductive state and a second state in which the parallel switch unit is in a non-conductive state and the series switch unit is in a conductive state, wherein each of the parallel switch unit and the series switch unit includes at least one semiconductor switch unit in which a semiconductor switching element and a diode are connected in parallel to each other, the on state and the off state of which are controlled by the control unit, the parallel switch unit and the series switch unit include a first semiconductor switch unit and a second semiconductor switch unit that are connected in series, the diodes of the first semiconductor switch unit and the second semiconductor switch unit being oriented in opposite directions, the program for controlling a temperature raising device comprising: an AC generating circuit having a parallel switch unit and a series switch unit that connects the first capacitor and the second capacitor in series to the power storage unit; and a control unit that alternates between a first state in which the parallel switch unit is in a conductive state and a non-conductive state and a second state in which the parallel switch unit is in a non-conductive state and the series switch unit is in a conductive state, when changing the parallel switch unit from a non-conductive state to a conductive state after changing the series switch unit from a conductive state to a non-conductive state, and when changing the series switch unit from a non-conductive state to a conductive state after changing the parallel switch unit from a conductive state to a non-conductive state, when changing the parallel switch unit from a conductive state to a non-conductive state, and when changing the parallel switch unit from a conductive state to a non-conductive state, and when switching from a state in which the first capacitor and the second capacitor are connected in parallel to the power storage unit to a state in which the first capacitor and the second capacitor are connected in series to the power storage unit,In order to allow the current flowing through the parallel switch unit to return, one of the first semiconductor switch unit and the second semiconductor switch unit included in the series switch unit is brought into a conductive state, and then, while keeping one of the first semiconductor switch unit and the second semiconductor switch unit included in the parallel switch unit in a conductive state, the first capacitor and the second capacitor are switched to a state in which they are connected in series to the power storage unit, and the series switch unit is brought into a conductive state, and the first capacitor and the second capacitor are switched from a state in which they are connected in series to the power storage unit, and when switching to a state in which the first capacitor and the second capacitor are connected in parallel to the power storage unit, one of the first semiconductor switch unit and the second semiconductor switch unit included in the parallel switch unit is brought into a conductive state so that a current flowing through the series switch unit can be returned, and then, while keeping one of the first semiconductor switch unit and the second semiconductor switch unit included in the series switch unit in a conductive state, the program switches to a state in which the first capacitor and the second capacitor are connected in parallel to the power storage unit. Effect of the Invention

[0022] According to the above aspects (1) to (15), the temperature of the secondary battery can be increased more efficiently, thereby improving the energy efficiency. [Brief description of the drawings]

[0023] [Figure 1] 1 is a diagram showing an example of the configuration of a vehicle in which a heating device according to an embodiment is employed; [Diagram 2] 2 is an example of an equivalent circuit of a battery provided in a vehicle. [Diagram 3] 2 is a diagram showing an example of the configuration of an AC generating circuit included in the temperature raising device according to the first embodiment. FIG. [Figure 4] 4A to 4C are diagrams illustrating an example of the control of a control unit and an operation waveform of an AC generating circuit according to the first embodiment. [Diagram 5]2 is a diagram showing an example of a path of an AC current flowing in the AC generating circuit of the first embodiment. FIG. [Figure 6] 5 is a diagram illustrating another example of the control of the control unit and the operation waveform of the AC generating circuit in the first embodiment. FIG. [Figure 7] FIG. 4 is a diagram illustrating another example of a path of an AC current flowing in the AC generating circuit of the first embodiment. [Figure 8] FIG. 11 is a diagram showing an example of the configuration of an AC generating circuit included in a temperature raising device according to a second embodiment. [Figure 9] 13A and 13B are diagrams illustrating an example of the control of a control unit and an operation waveform of an AC generating circuit according to a second embodiment. [Figure 10] FIG. 11 is a diagram illustrating an example of a path of an AC current flowing in an AC generating circuit according to a second embodiment. [Figure 11] FIG. 11 is a diagram showing an example of the configuration of an AC generating circuit included in a temperature raising device according to a third embodiment. [Figure 12] 13A and 13B are diagrams illustrating an example of the control of a control unit and operation waveforms of an AC generating circuit according to a third embodiment. [Figure 13] FIG. 11 is a diagram illustrating an example of a path of an AC current flowing in an AC generating circuit according to a third embodiment. [Figure 14] 10 is a diagram comparing characteristics of the amplitude of AC current generated by an AC generating circuit. FIG. [Figure 15] FIG. 13 is a diagram showing an example of the configuration of an AC generating circuit included in a temperature raising device according to a fourth embodiment. [Figure 16] 13A and 13B are diagrams illustrating an example of the control of a control unit and operation waveforms of an AC generating circuit according to a fourth embodiment. [Figure 17] FIG. 13 is a diagram showing an example of a path of an AC current flowing in an AC generating circuit according to a fourth embodiment. [Figure 18] 10 is a diagram comparing characteristics of the amplitude of AC current generated by an AC generating circuit. FIG. [Figure 19] 13 is a diagram illustrating another example of the control of the control unit and the operation waveform of the AC generating circuit according to the fourth embodiment. FIG. [Figure 20] FIG. 13 is a diagram showing an example of the configuration of an AC generating circuit included in a temperature raising device according to a fifth embodiment. [Figure 21]13A and 13B are diagrams illustrating an example of control by a control unit and operation waveforms of an AC generating circuit according to the fifth embodiment. [Figure 22] FIG. 13 is a diagram illustrating an example of a path of an AC current flowing in an AC generating circuit according to a fifth embodiment. [Diagram 23] 1 is a diagram comparing the amplitude characteristics and losses of AC currents generated by AC generating circuits. [Figure 24] FIG. 4 is a circuit diagram showing an example of a circuit configuration of a control unit. [Diagram 25] 4 is an example of a timing chart showing timings of gate signals generated by a control unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Hereinafter, embodiments of a temperature raising device, a control method for a temperature raising device, and a program according to the present invention will be described with reference to the drawings.

[0025] [Vehicle configuration] FIG. 1 is a diagram showing an example of the configuration of a vehicle in which a temperature raising device according to an embodiment is adopted. The vehicle 1 is a hybrid electric vehicle (HEV) (hereinafter, simply referred to as "vehicle") that runs by combining driving of an electric motor by electric power supplied from a battery (secondary battery) for running, or driving of an internal combustion engine using fuel such as a diesel engine or a gasoline engine as an energy source. The vehicle to which the present invention is applied may be, for example, not only a four-wheeled vehicle, but also a saddle-type two-wheeled vehicle, a three-wheeled vehicle (including a vehicle with one front wheel and two rear wheels, as well as a vehicle with two front wheels and one rear wheel), and even an assisted bicycle, or any other vehicle that runs by an electric motor driven by electric power supplied from a battery for running. The vehicle 1 may be, for example, an electric vehicle (EV) that runs by driving only an electric motor.

[0026] The vehicle 1 includes, for example, an engine 10, a motor 12, a reduction gear 14, drive wheels 16, a PDU (Power Drive Unit) 20, a battery 30, a battery sensor 32, a heating device 40, a driving operator 70, a vehicle sensor 80, and a control device 100.

[0027] The engine 10 is an internal combustion engine that outputs power by operating (rotating) through the combustion of fuel such as diesel or gasoline stored in a fuel tank (not shown) of the vehicle 1. The engine 10 is, for example, a reciprocating engine equipped with a cylinder and pistons, an intake valve, an exhaust valve, a fuel injection device, an ignition plug, a connecting rod, a crankshaft, and the like. The engine 10 may be a rotary engine. The rotational power of the engine 10 is transmitted to a reduction gear 14.

[0028] The motor 12 is a rotating electric machine for propelling the vehicle 1. The motor 12 is, for example, a three-phase AC motor. A rotor of the motor 12 is connected to the reduction gear 14. The motor 12 is driven (rotated) by power supplied from the battery 30 via the PDU 20. The rotational power of the motor 12 is transmitted to the reduction gear 14. The motor 12 may generate power by operating as a regenerative brake using kinetic energy when the vehicle 1 decelerates. The motor 12 may include a power generating motor. The power generating motor generates power using the rotational power output by the engine 10, for example.

[0029] The reduction gear 14 is, for example, a differential gear. The reduction gear 14 transmits the driving force of an axis connected to the engine 10 or the motor 12, that is, the rotational power of the engine 10 or the motor 12, to an axle connected to the drive wheels 16. The reduction gear 14 may include, for example, a speed change mechanism, a so-called transmission mechanism, in which a plurality of gears and shafts are combined and the rotational speed of the engine 10 or the motor 12 is changed according to a speed ratio (gear ratio) and transmitted to the axle. The reduction gear 14 may include, for example, a clutch mechanism that directly couples or separates the rotational power of the engine 10 or the motor 12 to the axle.

[0030] The PDU 20 is, for example, an inverter, a DC-DC converter, or an AC-DC converter. The PDU 20 converts DC power supplied from the battery 30 into three-phase AC power for driving the motor 12 and outputs the converted power to the motor 12. The PDU 20 may include, for example, a VCU (Voltage Control Unit) that boosts the DC power supplied from the battery 30. The PDU 20 converts three-phase AC power generated by the motor 12 operating as a regenerative brake into DC power and outputs the DC power to the battery 30. The PDU 20 may boost or lower the voltage of the power before outputting it according to the output destination of the power. In FIG. 1, the components of the PDU 20 are shown as a single unit, but this is merely an example, and the components of the PDU 20 may be distributed in the vehicle 1.

[0031] The battery 30 is a battery for driving the vehicle 1. The battery 30 includes a secondary battery, such as a lithium ion battery, that can be repeatedly charged and discharged, as an electricity storage unit. The battery 30 may be configured to be easily detachable from the vehicle 1, such as a cassette-type battery pack, or may be configured as a stationary battery that is not easily detachable from the vehicle 1. The secondary battery included in the battery 30 is, for example, a lithium ion battery. The secondary battery included in the battery 30 may be, for example, a lead-acid battery, a nickel-metal hydride battery, a sodium ion battery, a capacitor such as an electric double layer capacitor, or a composite battery that combines a secondary battery and a capacitor, but the secondary battery may have any configuration. The battery 30 stores (charges) power introduced from a charger (not shown) external to the vehicle 1, and discharges the stored power to drive the vehicle 1. The battery 30 stores (charges) the electric power generated by the motor 12 operating as a regenerative brake and supplied via the PDU 20, and discharges the stored electric power for running (e.g., accelerating) the vehicle 1. The battery 30 has at least an inductance component.

[0032] 2 is an example of an equivalent circuit of the battery 30 included in the vehicle 1. In the battery 30, for example, a parallel circuit of a resistance Rx and a capacitance Cx, a parallel circuit of a resistance Ry and a capacitance Cy, a parallel circuit of a resistance Rz and an inductance Lz, an inductance La, and a resistance Ra are connected in series to the positive electrode side of the power storage unit Ba. The battery 30 is an example of an "electricity storage body" in the claims, and the inductance La connected to the power storage unit Ba included in the battery 30 is an example of an "inductance component" in the claims.

[0033] A battery sensor 32 is connected to the battery 30. The battery sensor 32 detects physical quantities such as the voltage, current, and temperature of the battery 30. The battery sensor 32 includes, for example, a voltage sensor, a current sensor, and a temperature sensor. The battery sensor 32 detects the voltage of the battery 30 using a voltage sensor, detects the current of the battery 30 using a current sensor, and detects the temperature of the battery 30 using a temperature sensor. The battery sensor 32 outputs information such as the detected voltage value, current value, temperature, etc. of the battery 30 (hereinafter referred to as "battery information") to the control device 100.

[0034] The temperature raising device 40 raises the temperature of the battery 30 in response to control from the control device 100. The temperature raising device 40 includes, for example, an AC generating circuit 42 and a control unit 44.

[0035] The AC generating circuit 42 includes, for example, a first capacitor connected to the positive electrode side of the battery 30, a second capacitor connected to the negative electrode side of the battery 30, a parallel switch unit that connects the first capacitor and the second capacitor in parallel to the battery 30, and a series switch unit that connects the first capacitor and the second capacitor in series to the battery 30. The AC generating circuit 42 generates an AC current by a resonance operation between the inductance La of the battery 30 and at least the first capacitor. More specifically, the AC generating circuit 42 generates an AC current based on the power stored in the battery 30 by a resonance operation that alternately exchanges magnetic energy stored in the inductance La of the battery 30 and electrostatic energy stored in at least the first capacitor. The AC generating circuit 42 applies (passes) the generated AC current to the battery 30, thereby raising the temperature of the battery 30.

[0036] The control unit 44 switches the connection of the first capacitor and the second capacitor to the battery 30 between a parallel connection and a series connection by setting each of the parallel switch unit and the series switch unit included in the AC generating circuit 42 to a conductive state or a non-conductive state. More specifically, the control unit 44 alternately switches between a state in which the first capacitor and the second capacitor are connected in parallel to the battery 30 by setting the parallel switch unit to a conductive state and the series switch unit to a non-conductive state, and a state in which the first capacitor and the second capacitor are connected in series to the battery 30 by setting the parallel switch unit to a non-conductive state and the series switch unit to a conductive state. At this time, the control unit 44 provides a period during which both the parallel switch unit and the series switch unit are set to a non-conductive state, that is, a so-called dead time, and switches the connection of the first capacitor and the second capacitor to the battery 30 from a parallel connection to a series connection or vice versa.

[0037] The state in which the first capacitor and the second capacitor are connected in parallel to the battery 30 is an example of a "first state" in the claims, and the state in which the first capacitor and the second capacitor are connected in series to the battery 30 is an example of a "second state" in the claims. The temperature raising device 40 and the components included in the temperature raising device 40 will be described in detail later.

[0038] Driving operators 70 include, for example, an accelerator pedal, a brake pedal, a shift lever, a steering wheel, an irregular steering wheel, a joystick, and other operators. Sensors are attached to driving operators 70 to detect the presence or absence of an operation of each operator by a user (driver) of vehicle 1, or the amount of operation. Driving operators 70 output the detection results of the sensors to control device 100.

[0039] The vehicle sensor 80 detects the traveling state of the vehicle 1. The vehicle sensor 80 includes, for example, a vehicle speed sensor that detects the speed of the vehicle 1 and an acceleration sensor that detects the acceleration of the vehicle 1. The vehicle sensor 80 outputs the detection results detected by each sensor to the control device 100.

[0040] The control device 100 controls the operation and behavior of the engine 10 and the motor 12 in response to the detection results output by the respective sensors provided in the driving operators 70, i.e., the operation of the respective operators by the user (driver) of the vehicle 1. In other words, the control device 100 controls the driving force of the motor 12. The control device 100 may be configured with separate control devices, such as an engine control unit, a motor control unit, a battery control unit, a PDU control unit, and a VCU control unit. The control device 100 may be replaced with a control device such as an engine ECU (Electronic Control Unit), a motor ECU, a battery ECU, a PDU-ECU, or a VCU-ECU.

[0041] When the vehicle 1 runs, the control device 100 controls the amount of AC power supplied from the battery 30 to the motor 12 and the frequency of the supplied AC power (i.e., the voltage waveform). At this time, the control device 100 controls the start of the temperature raising device 40 based on the information on the temperature of the battery 30 included in the battery information output by the battery sensor 32. That is, the control device 100 controls the start or stop of the temperature raising device 40 so as to raise (heat up) the temperature of the battery 30 to a temperature suitable for use in order to suppress a decrease in the charge / discharge performance of the battery 30. The control device 100 may be replaced with, for example, the control unit 44 included in the temperature raising device 40. That is, the control device 100 may be configured to directly control, as the control unit 44, each of the parallel switch unit and the series switch unit of the AC generating circuit 42 included in the temperature raising device 40 to a conductive state or a non-conductive state.

[0042] The control device 100 operates by, for example, a hardware processor such as a CPU (Central Processing Unit) executing a program (software). The control device 100 may be realized by hardware (including circuitry) such as an LSI (Large Scale Integration), an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a GPU (Graphics Processing Unit), or may be realized by cooperation between software and hardware. The control device 100 may be realized by a dedicated LSI. The program may be stored in advance in a storage device (storage device having a non-transient storage medium) such as an HDD (Hard Disk Drive) or a flash memory provided in the vehicle 1, or may be stored in a removable storage medium (non-transient storage medium) such as a DVD or a CD-ROM, and installed in the HDD or flash memory provided in the vehicle 1 by mounting the storage medium in a drive device provided in the vehicle 1.

[0043] First Embodiment [Configuration of AC generating circuit in heating device] FIG. 3 is a diagram showing an example of the configuration of an AC generating circuit 42 (hereinafter, referred to as an "AC generating circuit 42-1") included in the temperature raising device 40 according to the first embodiment. FIG. 3 also shows a battery 30 related to the AC generating circuit 42-1. However, in FIG. 3, an inductance La of the battery 30 is omitted. The AC generating circuit 42-1 includes, for example, a capacitor C1, a capacitor C2, a switching element S1, a switching element S2, a switching element S3, a diode D1, a diode D2, and a diode D3. The capacitor C1 and the capacitor C2 are capacitors having the same capacitance. The switching element S1, the switching element S2, and the switching element S3 are, for example, semiconductor switching elements such as N-channel metal oxide semiconductor field effect transistors (MOSFETs).

[0044] The switching element S1 and the diode D1 are connected in parallel to each other to form a semiconductor switch section. In the following description, the semiconductor switch section formed by the switching element S1 and the diode D1 is also referred to as the "semiconductor switch section SW1". More specifically, in the semiconductor switch section SW1, the drain terminal of the switching element S1 and the cathode terminal of the diode D1 are connected to each other on the first terminal side, and the source terminal of the switching element S1 and the anode terminal of the diode D1 are connected to each other on the second terminal side. The gate terminal of the switching element S1 is controlled (a control voltage or a control current is applied) by a gate signal G1 output by the control section 44. That is, the semiconductor switch section SW1 is controlled to either an on or off state by the gate signal G1 output by the control section 44. In the semiconductor switch section SW1, the diode D1 functions as a freewheel diode that freewheels the current flowing through the switching element S1. Although a parasitic diode (so-called body diode) may exist in the switching element S1 due to its configuration, the semiconductor switch section SW1 can return current more efficiently by the connected diode D1 than by the parasitic diode.

[0045] The same is true for switching element S2 and diode D2, and for switching element S3 and diode D3. In the following description, the semiconductor switch section formed by switching element S2 and diode D2 is also referred to as "semiconductor switch section SW2," and the semiconductor switch section formed by switching element S3 and diode D3 is also referred to as "semiconductor switch section SW3."

[0046] In the AC generating circuit 42-1, a first end of the capacitor C1 is connected to the positive electrode side of the battery 30, and a first end of the capacitor C2 is connected to the negative electrode side of the battery 30. Furthermore, in the AC generating circuit 42-1, a first terminal of the semiconductor switch section SW2 is connected to the first end of the capacitor C1, and a second terminal of the semiconductor switch section SW1 is connected to the first end of the capacitor C2. In the AC generating circuit 42-1, a first terminal of the semiconductor switch section SW1 and a second terminal of the semiconductor switch section SW3 are connected to the second end of the capacitor C1, and a second terminal of the semiconductor switch section SW2 and a first terminal of the semiconductor switch section SW3 are connected to the second end of the capacitor C2.

[0047] With this configuration, in the AC generating circuit 42-1, the capacitors C1 and C2 are connected in parallel or in series between the positive and negative sides of the battery 30 in response to control from the control unit 44. More specifically, the control unit 44 outputs a gate signal G1 to the switching element S1 included in the semiconductor switch unit SW1 to turn it on, outputs a gate signal G2 to the switching element S2 included in the semiconductor switch unit SW2 to turn it on, and outputs a gate signal G3 to the switching element S3 included in the semiconductor switch unit SW3 to turn it off, thereby connecting the capacitors C1 and C2 in parallel between the positive and negative sides of the battery 30. On the other hand, the control unit 44 outputs a gate signal G1 to the switching element S1 provided in the semiconductor switch unit SW1 to turn it off, outputs a gate signal G2 to the switching element S2 provided in the semiconductor switch unit SW2 to turn it off, and outputs a gate signal G3 to the switching element S3 provided in the semiconductor switch unit SW3 to turn it on, thereby connecting the capacitors C1 and C2 in series between the positive and negative sides of the battery 30.

[0048] In the AC generating circuit 42-1, the capacitor C1 is an example of a "first capacitor" in the claims, and the capacitor C2 is an example of a "second capacitor" in the claims. In the AC generating circuit 42-1, the combination of the semiconductor switch unit SW1 and the semiconductor switch unit SW2 is an example of a "parallel switch unit" in the claims, and the semiconductor switch unit SW3 is an example of a "series switch unit" in the claims. In each semiconductor switch unit, the on state of the switching element is an example of a "conductive state" in the claims, and the off state of the switching element is an example of a "non-conductive state" in the claims. In the AC generating circuit 42-1, the state in which the capacitors C1 and C2 are connected in parallel between the positive and negative sides of the battery 30 is an example of a "first state" in the claims, and the state in which the capacitors C1 and C2 are connected in series between the positive and negative sides of the battery 30 is an example of a "second state" in the claims.

[0049] [Operation of the heating device] Next, an operation of generating an AC current in the AC generating circuit 42-1, that is, the control of each semiconductor switch unit in the control unit 44 will be described. Fig. 4 is a diagram showing an example of the control of the control unit 44 and the operation waveforms (simulation waveforms) of the AC generating circuit 42-1 in the first embodiment. Fig. 5 is a diagram showing an example of the path of the AC current flowing in the AC generating circuit 42-1 in the first embodiment.

[0050] 4 shows gate signals G1, G2, and G3 output by the control unit 44 to the respective semiconductor switch units. In FIG. 4, the "High" level of the gate signals G1, G2, and G3 indicates the ON state of the corresponding switching element, and the "Low" level indicates the OFF state of the corresponding switching element. In the following description, setting the gate signal to the "High" level is referred to as "setting the semiconductor switch unit to a conductive state," and setting the gate signal to the "Low" level is referred to as "setting the semiconductor switch unit to a non-conductive state." As shown in FIG. 4, the control unit 44 provides a period (dead time) during which all the semiconductor switch units are set to a non-conductive state between a period during which the semiconductor switch units are set to a conductive state and a period during which the semiconductor switch units are set to a non-conductive state.

[0051] Fig. 4 shows an example of changes in the voltage Vbatt across the battery 30 (including inductance La) and the voltage Vcap across the capacitor C1, which change as a result of the control unit 44 controlling the gate signals G1, G2, and G3. Fig. 4 also shows an example of changes in the current Is3 flowing through the semiconductor switch unit SW3, the current Is1 flowing through the semiconductor switch unit SW1, the current Icap flowing through the capacitor C1, and the current Ibatt flowing through the battery 30 (including inductance La), which change as a result of the control unit 44 controlling the gate signals G1, G2, and G3.

[0052] Since the temperature raising device 40 periodically repeats its operation once started by the control device 100, in the following description, the operation of the AC generating circuit 42-1 from time t1 shown in FIG. 4 will be described with reference to FIG. 5 as appropriate.

[0053] In the AC generating circuit 42-1, immediately before time t1, the current Is3 and the current Icap flow from the battery 30 through the path shown in FIG. 5(d) in the direction of charging the capacitors C1 and C2, respectively. When the control unit 44 sets the gate signal G3 to the “High” level to put the semiconductor switch unit SW3 in the conductive state at time t1 when the semiconductor switch unit SW1 and the semiconductor switch unit SW2 are in the non-conductive state, the capacitors C1 and C2 are connected in series to the battery 30. As a result, in the AC generating circuit 42-1, the current Is3 and the current Icap flow from the battery 30 through the path shown in FIG. 5(a) in the direction of charging the capacitors C1 and C2, respectively. As a result, in the AC generating circuit 42-1, the voltage Vcap rises and the current Ibatt decreases toward 0A.

[0054] Then, when the voltage Vcap reaches a positive peak voltage at time t2, the direction of the current Ibatt is reversed. At this time, the semiconductor switch units SW1 and SW2 are still non-conductive. Therefore, in the AC generating circuit 42-1, the capacitors C1 and C2 each start discharging, and the currents Is3 and Icap flow in the direction of charging the battery 30 through the path shown in FIG. 5(b). As a result, in the AC generating circuit 42-1, the current Ibatt continues to increase in the direction of charging the battery 30, and the voltage Vcap starts to decrease.

[0055] After that, at time t3, the control unit 44 first sets the gate signal G3 to a “Low” level to put the semiconductor switch unit SW3 in a non-conductive state, thereby cutting off the path of the current Is3 in the AC generating circuit 42-1, and the current Is3 becomes 0 A.

[0056] Thereafter, the control unit 44 sets the gate signal G1 and the gate signal G2 to a "High" level, and sets the semiconductor switch unit SW1 and the semiconductor switch unit SW2 to a conductive state. As a result, in the AC generating circuit 42-1, the capacitors C1 and C2 are connected in parallel to the battery 30. As a result, in the AC generating circuit 42-1, the capacitors C1 and C2 are discharged, and a current (current Is1) that charges the battery 30 flows through the path shown in FIG. 5(c). Then, in the AC generating circuit 42-1, the current Ibatt starts to decrease, and the voltage Vcap continues to decrease.

[0057] Then, when the current Ibatt becomes 0 A at time t4, the direction of the current Ibatt is reversed. At this time, the semiconductor switch units SW1 and SW2 are still in the conductive state. Therefore, in the AC generating circuit 42-1, a current (current Icap) flows from the battery 30 through the path shown in FIG. 5(d) in a direction to charge the capacitors C1 and C2. As a result, in the AC generating circuit 42-1, the current Ibatt continues to increase in a direction to discharge the battery 30, and the voltage Vcap continues to rise.

[0058] After that, at time t5, the control unit 44 first sets the gate signal G1 and the gate signal G2 to a "Low" level to make the semiconductor switch unit SW1 and the semiconductor switch unit SW2 non-conductive. As a result, in the AC generating circuit 42-1, the path of the current Icap becomes the path (return path) passing through the diode D1 of the semiconductor switch unit SW1, and the path of the current from the capacitor C2 becomes the path (return path) passing through the diode D2 of the semiconductor switch unit SW2, but the current (current Icap) continues to flow from the battery 30 in the direction of charging each of the capacitors C1 and C2, similar to the path shown in FIG. 5(d).

[0059] Thereafter, the control unit 44 sets the gate signal G3 to a "High" level to turn on the semiconductor switch unit SW3. The operation of the AC generating circuit 42-1 in this case is the same as the operation at time t1 described above. Thereafter, the AC generating circuit 42-1 and the control unit 44 each periodically repeat the above-mentioned operation in the same manner.

[0060] In this manner, in the temperature raising device 40, the control unit 44 controls the conductive and non-conductive states of the respective semiconductor switches to switch the connection of the capacitors C1 and C2 to the battery 30 between a series connection and a parallel connection, thereby generating a current Ibatt (AC current) to be passed through the battery 30 by a resonance operation between the inductance La of the battery 30 and at least the capacitor C1. As a result, the temperature of the battery 30 is raised by the current Ibatt.

[0061] At this time, the control unit 44 controls the semiconductor switch units, that is, switches the connection between the capacitors C1 and C2, by first turning the conductive semiconductor switch units into a non-conductive state and then turning the other non-conductive semiconductor switch units into a conductive state, as described at times t3 and t5 in Fig. 4. In other words, the control unit 44 causes the current flowing through the switching elements of the respective semiconductor switch units to flow back to the diodes, and then controls the respective semiconductor switch units to switch the connection between the capacitors C1 and C2.

[0062] Here, the control unit 44 may determine the timing (for example, the timing of time t3 or time t5 shown in FIG. 4) at which the control unit 44 controls the semiconductor switch unit by measuring (monitoring) the current value or voltage value of the components included in the AC generating circuit 42-1 or the battery 30, or may determine the timing based on the operating state of the AC generating circuit 42-1. For example, when determining the timing by monitoring the current value or voltage value, the control unit 44 monitors the current value (current Icap) or voltage value (voltage Vcap) of the capacitor C1, the current value or voltage value of the capacitor C2, the current value (current Ibatt) or voltage values ​​(voltage Vbatt) of the battery 30, or the current value (current Is1 or current Is3) or voltage values ​​at both ends of one or more semiconductor switch units (for example, semiconductor switch units in a conductive state). In this case, a current sensor for detecting a current or a voltage sensor for detecting a voltage is disposed in the AC generating circuit 42-1 at a position where the control unit 44 monitors the current value or voltage value. This allows the control unit 44 to determine that it is time to control the semiconductor switch unit, such as time t3 or time t5 shown in FIG. 4. For example, when determining the timing based on the operating state of the AC generating circuit 42-1, the control unit 44 determines a predetermined timing based on the AC current as the timing to control the semiconductor switch unit. The predetermined timing based on the AC current is a time (e.g., a predetermined time before) that can be determined (determined) from the period or duty ratio of the AC current, such as the timing when the AC current decreases to 0 A or the timing when the AC current increases to 0 A. This allows the control unit 44 to determine the timing to control the semiconductor switch unit, such as time t3 or time t5 shown in FIG. 4, based on the characteristics of the AC current that is generated and applied (flowed) to the battery 30.

[0063] Thus, in the temperature raising device 40 of the first embodiment, the AC generating circuit 42-1 utilizes a resonant operation that alternately exchanges the magnetic energy stored in the inductance La of the battery 30 and the electrostatic energy stored at least in the capacitor C1 to generate an AC current based on the power stored in the battery 30, thereby making it possible to raise the temperature of the battery 30 more efficiently.

[0064] Incidentally, in the AC generating circuit 42-1, since each semiconductor switch section is provided with a return diode, it is assumed that the current may flow through an unintended path depending on conditions such as the magnitude, period, and duty ratio of the AC current to be generated. For example, when the frequency of the AC current generated by the AC generating circuit 42-1 is higher than the resonant frequency, the amplitude of the AC current becomes narrower, and the amplitude of the voltage between the terminals of the capacitors C1 and C2 also becomes narrower. In this case, in the AC generating circuit 42-1, as shown in FIG. 4, the voltages (for example, the voltage Vcap) of the capacitors C1 and C2 always have positive voltage values. However, when the frequency of the AC current generated by the AC generating circuit 42-1 is brought closer to the resonant frequency, the amplitude of the AC current becomes wider, and the amplitude of the voltage between the terminals of the capacitors C1 and C2 also becomes wider. In this case, in the AC generating circuit 42-1, for example, as in the period from time t2 to time t3 shown in FIG. 4, when the capacitors C1 and C2 are connected in series and the battery 30 is being charged, the voltages of the capacitors C1 and C2 (for example, the voltage Vcap) may become negative. Then, in the AC generating circuit 42-1, the voltages of the switching elements of the semiconductor switch unit become reverse biased due to the negative voltage values ​​of the capacitors C1 and C2, and a current path (unintended path) that does not pass through the capacitors C1 and C2 is formed. In this case, in the AC generating circuit 42-1, the energy exchanged between the inductance La and the capacitor C1 during the resonant operation is reduced, and the amplitude of the AC current is narrowed. As a result, the efficiency of raising the temperature of the battery 30 is reduced in the AC generating circuit 42-1.

[0065] Here, an example of a case where a current flows through an unintended path in the AC generating circuit 42-1 will be described. FIG. 6 is a diagram showing another example of the control of the control unit 44 and the operation waveforms (simulation waveforms) of the AC generating circuit 42-1 in the first embodiment. FIG. 7 is a diagram showing another example of the path of the AC current flowing through the AC generating circuit 42-1 in the first embodiment. FIG. 6 shows an example of a case where the amplitude of the AC current becomes narrower due to a current flowing through an unintended path when the capacitors C1 and C2 are connected in series and charged in the AC generating circuit 42-1. In the following description, the operation of the AC generating circuit 42-1 when a current flows through an unintended path will be described with reference to FIG. 7, focusing on the operation when a current flows through an unintended path.

[0066] In the AC generating circuit 42-1, during a period P1 in which the capacitors C1 and C2 are connected in series to the battery 30, the capacitors C1 and C2 each discharge, and the currents Is3 and Icap flow through paths similar to those shown in FIG. 5(b), the voltage Vcap decreases, and the current Ibatt increases.

[0067] After that, when the voltage Vcap becomes negative from 0V, the current Is3 and the current Icap flow from the battery 30 in a direction to charge the capacitors C1 and C2. At this time, the current should flow unchanged from the same path as the path shown in FIG. 5(b), but the inductance La of the battery 30 continues to draw the current, forming an unintended current path as shown in FIG. 7. More specifically, the current flows through the semiconductor switch unit SW1, the semiconductor switch unit SW3, and the semiconductor switch unit SW2 in that order, forming a path in which the current does not pass through the capacitors C1 and C2. As a result, in the AC generating circuit 42-1, the semiconductor switch unit SW1 and the semiconductor switch unit SW3 are in a non-conducting state during the period P2, so that the current Is1, which should not flow (0 A), increases, and the current Icap for charging the capacitors C1 and C2 decreases as shown in FIG. 7. In other words, the electrostatic energy exchanged with the inductance La of the battery 30 to perform the resonant operation decreases. As a result, in the AC generating circuit 42-1, the voltage Vcap stops decreasing, the current Ibatt does not increase sufficiently, and starts to flow in a decreasing direction, narrowing the amplitude of the AC current.

[0068] Thereafter, the control unit 44 connects the capacitors C1 and C2 in parallel to the battery 30, but during the period P2, the current path remains the same as the path shown in FIG.

[0069] After that, when the current Ibatt becomes 0 A, the direction of the current Ibatt is reversed, and since the capacitors C1 and C2 are connected in parallel to the battery 30, in the period P3, a current flows through each of the capacitors C1 and C2 along a path similar to the path shown in Fig. 5(d). As a result, in the AC generating circuit 42-1, the amount of charge in the capacitors C1 and C2 increases, and the voltage Vcap starts to rise.

[0070] Thereafter, when the control unit 44 sets the gate signal G1 and the gate signal G2 to a "Low" level to put the semiconductor switch unit SW1 and the semiconductor switch unit SW2 in a non-conductive state, a current flows through a path similar to the path shown in FIG. 5(a) during period P4. Thereafter, the control unit 44 sets the gate signal G3 to a "High" level to put the semiconductor switch unit SW3 in a conductive state. At this time, the current path in the AC generating circuit 42-1 does not change, but the direction of the current Ibatt is then reversed, and the current path returns to the same path as in period P1 (the path shown in FIG. 5(b)). Thereafter, the above-mentioned operation is repeated periodically in the same manner.

[0071] In this way, in the temperature raising device 40 of the first embodiment, the current Ibatt (AC current) to be passed through the battery 30 is generated by a resonance operation between the inductance La of the battery 30 and at least the capacitor C1. However, in the temperature raising device 40 of the first embodiment, if a current flows through an unintended path due to conditions such as the magnitude, period, and duty ratio of the generated AC current, the amplitude of the generated AC current may become narrow, and the efficiency of raising the temperature of the battery 30 may decrease.

[0072] <Second embodiment> [Configuration of AC generating circuit in heating device] FIG. 8 is a diagram showing an example of the configuration of an AC generating circuit 42 (hereinafter, referred to as "AC generating circuit 42-2") included in the temperature raising device 40 according to the second embodiment. FIG. 8 also shows a battery 30 (however, illustration of an inductance La is omitted) related to the AC generating circuit 42-2. The AC generating circuit 42-2 is configured to avoid the formation of an unintended path assumed in the AC generating circuit 42-1 of the first embodiment. The AC generating circuit 42-2 includes, for example, a capacitor C1, a capacitor C2, a switching element S1a, a switching element S1b, a switching element S2a, a switching element S2b, a switching element S3, a diode D1a, a diode D1b, a diode D2a, a diode D2b, and a diode D3.

[0073] In the AC generating circuit 42-2, a first semiconductor switch section consisting of a switching element S1a and a diode D1a and a second semiconductor switch section consisting of a switching element S1b and a diode D1b are connected in series with the diodes facing in opposite directions to form one bidirectional semiconductor switch section. In the following description, this semiconductor switch section is also referred to as a "bidirectional semiconductor switch section SW1-2." The gate terminals of the switching element S1a and the switching element S1b are controlled to be in either an on or off state by a gate signal G1 output by the control section 44. In the bidirectional semiconductor switch section SW1-2, the diodes D1a and D1b function as return diodes that return currents in opposite directions to each other.

[0074] The semiconductor switch section configured with the switching element S2a, the switching element S2b, the diode D2a, and the diode D2b is similar to the bidirectional semiconductor switch section SW1-2. In the following description, the semiconductor switch section having this configuration is also referred to as the "bidirectional semiconductor switch section SW2-2."

[0075] The connections of the capacitor C1, the capacitor C2, the bidirectional semiconductor switch section SW1-2, the bidirectional semiconductor switch section SW2-2, and the semiconductor switch section SW3 in the AC generating circuit 42-2 are equivalent to those in the AC generating circuit 42-1 of the first embodiment.

[0076] With this configuration, in the AC generating circuit 42-2 as well, similar to the AC generating circuit 42-1, the capacitors C1 and C2 are connected in parallel or in series between the positive and negative terminals of the battery 30 in accordance with control from the control unit 44.

[0077] In the AC generating circuit 42-2, a configuration in which the bidirectional semiconductor switch unit SW1-2 and the bidirectional semiconductor switch unit SW2-2 are combined is an example of a “parallel switch unit” in the claims, and the semiconductor switch unit SW3 is an example of a “series switch unit” in the claims.

[0078] [Operation of the heating device] Next, an operation of generating an AC current in the AC generating circuit 42-2 will be described. Fig. 9 is a diagram showing an example of the control of the control unit 44 and the operation waveforms (simulation waveforms) of the AC generating circuit 42-2 in the second embodiment. Fig. 10 is a diagram showing an example of a path of an AC current flowing in the AC generating circuit 42-2 in the second embodiment. In the following description, the operation of the AC generating circuit 42-2 shown in Fig. 9 will be described with appropriate reference to Fig. 10.

[0079] The control unit 44 controls each semiconductor switch unit for the AC generating circuit 42-2 in the same manner as for the AC generating circuit 42-1. More specifically, the control unit 44 first turns a conductive semiconductor switch unit to a non-conductive state, and then turns other non-conductive semiconductor switch units to a conductive state, thereby causing the current flowing through the switching element provided in each semiconductor switch unit to flow back to the diode once, and then controls each semiconductor switch unit to switch the capacitor C1 and the capacitor C2 to a series connection or a parallel connection.

[0080] In the AC generating circuit 42-2, during a period P1 in which the capacitors C1 and C2 are connected in series to the battery 30, the capacitors C1 and C2 are each discharged, and the currents Is3 and Icap flow in the direction to charge the battery 30 through the path shown in Fig. 10(a). As a result, in the AC generating circuit 42-2, the voltage Vcap also decreases, and the current Ibatt reverses after reaching a peak voltage in the direction to charge the battery 30, and decreases toward 0 A.

[0081] After that, the voltage Vcap goes from 0V to a negative region, but since the bidirectional semiconductor switch section SW1-2 and the bidirectional semiconductor switch section SW2-2 are in a non-conducting state in the AC generating circuit 42-2, even if the inductance La of the battery 30 continues to draw a current, it is possible to operate without forming an unintended current path as shown in FIG. 7. More specifically, each of the bidirectional semiconductor switch section SW1-2 and the bidirectional semiconductor switch section SW2-2 (more specifically, the second semiconductor switch section) does not pass the current Ibatt from the battery 30 as shown in FIG. 7, and the current path does not change from the path shown in FIG. 10(a). As a result, in the AC generating circuit 42-2, the current Is1 does not change from 0A, and the voltage Vcap continues to drop, and the electrostatic energy exchanged with the inductance La of the battery 30 to perform a resonant operation does not decrease, and the voltage Vcap drops sufficiently. In other words, the AC generating circuit 42-2 can ensure a wide amplitude of the AC current.

[0082] Then, when the current Ibatt becomes 0 A, the direction of the current Ibatt is reversed. At this time, in the AC generating circuit 42-2, the bidirectional semiconductor switch section SW1-2 and the bidirectional semiconductor switch section SW2-2 are still in the non-conductive state, so that in the period P2, the current Is3 and the current Icap flow from the battery 30 in the direction to charge the capacitors C1 and C2 through the path shown in Fig. 10(b). As a result, in the AC generating circuit 42-2, the current Ibatt continues to increase in the direction to discharge the battery 30, and the voltage Vcap begins to rise.

[0083] Thereafter, the control unit 44 connects the capacitors C1 and C2 in parallel to the battery 30, so that in the AC generating circuit 42-2, the current Ibatt from the battery 30 flows through the capacitors C1 and C2 via the path shown in Fig. 10(c) during the period P3. Then, in the AC generating circuit 42-2, the capacitors C1 and C2 continue to be charged, and the voltage Vcap continues to rise.

[0084] In FIG. 9, at the beginning of the period P3, a positive current is temporarily generated in the current Is3, but this is due to the reverse recovery operation of the semiconductor switch section SW3 and settles in a short time.

[0085] Then, when the voltage Vcap becomes a positive peak voltage, this time the direction of the current (current Icap) in the capacitors C1 and C2 is reversed. At this time, the bidirectional semiconductor switch section SW1-2 and the bidirectional semiconductor switch section SW2-2 are still in the conductive state, so in the AC generating circuit 42-2, during the period P4, a current (current Icap) flows from each of the capacitors C1 and C2 through the path shown in Fig. 10(d) in the direction to charge the battery 30. As a result, in the AC generating circuit 42-2, the current Ibatt continues to increase in the direction to charge the battery 30, and the voltage Vcap starts to fall.

[0086] Thereafter, the control unit 44 connects the capacitors C1 and C2 in series to the battery 30, so that in the AC generating circuit 42-2, the current path returns to the same path as in the period P1 (the path shown in FIG. 10(a)). Thereafter, the above-mentioned operation is repeated periodically in the same manner.

[0087] In this way, in the temperature raising device 40 of the second embodiment, the semiconductor switch section SW1 and the semiconductor switch section SW2 included in the AC generating circuit 42-1 of the first embodiment are replaced with the bidirectional semiconductor switch section SW1-2 and the bidirectional semiconductor switch section SW2-2, which are composed of two semiconductor switch sections connected in series with their diodes facing in the opposite directions, in the AC generating circuit 42-2. As a result, in the temperature raising device 40 of the second embodiment, when the capacitors C1 and C2 are connected in series and the respective capacitors are charged, even if the inductance La of the battery 30 continues to draw a current and the voltage of the switching element included in the semiconductor switch section in the non-conductive state becomes reverse bias, the bidirectional semiconductor switch section SW1-2 and the bidirectional semiconductor switch section SW2-2 maintain the non-conductive state. For this reason, in the temperature raising device 40 of the second embodiment, it is possible to operate the AC generating circuit 42-2 without forming an unintended current path (see FIG. 7) like the AC generating circuit 42-1. As a result, in the temperature raising device 40 of the second embodiment, the AC generating circuit 42-2 can generate an AC current of sufficient amplitude (wider amplitude than that of the AC generating circuit 42-1) by maintaining a resonant operation with the inductance La of the battery 30. As a result, in the temperature raising device 40 of the second embodiment, the generated AC current can raise the temperature of the battery 30 more efficiently.

[0088] <Third embodiment> [Configuration of AC generating circuit in heating device] FIG. 11 is a diagram showing an example of the configuration of an AC generating circuit 42 (hereinafter, referred to as "AC generating circuit 42-3") included in the temperature raising device 40 according to the third embodiment. FIG. 11 also shows a battery 30 (however, illustration of inductance La is omitted) related to the AC generating circuit 42-3. The AC generating circuit 42-3 is also configured to avoid the formation of an unintended path assumed in the AC generating circuit 42-1 of the first embodiment, similar to the AC generating circuit 42-2 of the second embodiment. The AC generating circuit 42-3 includes, for example, a capacitor C1, a capacitor C2, a switching element S1, a switching element S2, a switching element S3a, a switching element S3b, a diode D1, a diode D2, a diode D3a, and a diode D3b.

[0089] The AC generating circuit 42-3 is configured such that the semiconductor switch section SW3 of the AC generating circuit 42-1 is a bidirectional semiconductor switch section (hereinafter referred to as "bidirectional semiconductor switch section SW3-2") similar to the bidirectional semiconductor switch section SW1-2 and bidirectional semiconductor switch section SW2-2 of the AC generating circuit 42-2. In the AC generating circuit 42-3, the bidirectional semiconductor switch section SW1-2 and bidirectional semiconductor switch section SW2-2 of the AC generating circuit 42-2 are not bidirectional semiconductor switch sections, but remain unidirectional semiconductor switch sections. The gate terminals of the switching element S3a and the switching element S3b constituting the bidirectional semiconductor switch section SW3-2 are controlled to be in either an on or off state by the gate signal G3 output by the control section 44. In the bidirectional semiconductor switch section SW3-2, the diodes D3a and D3b also function as return diodes that return currents in opposite directions to each other.

[0090] The connections of the capacitor C1, the capacitor C2, the semiconductor switch section SW1, the semiconductor switch section SW2, and the bidirectional semiconductor switch section SW3-2 in the AC generating circuit 42-3 are equivalent to those in the AC generating circuit 42-1 of the first embodiment.

[0091] With this configuration, in the AC generating circuit 42-3, like the AC generating circuit 42-1 and the AC generating circuit 42-2, the capacitors C1 and C2 are connected in parallel or in series between the positive and negative sides of the battery 30 in response to control from the control unit 44.

[0092] In the AC generating circuit 42-3, the combination of the semiconductor switch unit SW1 and the semiconductor switch unit SW2 is an example of a “parallel switch unit” in the claims, and the bidirectional semiconductor switch unit SW3-2 is an example of a “series switch unit” in the claims.

[0093] [Operation of the heating device] Next, an operation of generating an AC current in the AC generating circuit 42-3 will be described. Fig. 12 is a diagram showing an example of the control of the control unit 44 and the operation waveforms (simulation waveforms) of the AC generating circuit 42-3 in the third embodiment. Fig. 13 is a diagram showing an example of a path of an AC current flowing in the AC generating circuit 42-3 in the third embodiment. In the following description, the operation of the AC generating circuit 42-3 shown in Fig. 12 will be described with appropriate reference to Fig. 13.

[0094] As with the AC generating circuits 42-1 and 42-2, the control unit 44 also switches the conductive semiconductor switch units in the AC generating circuit 42-3 to a non-conductive state first to allow the flowing current to flow back once, and then switches the other non-conductive semiconductor switch units to a conductive state to switch the connection between the capacitors C1 and C2 to a series connection or a parallel connection.

[0095] In the AC generating circuit 42-3, during a period P1 in which the capacitors C1 and C2 are connected in series to the battery 30, currents Is1 and Icap flow from the battery 30 through the path shown in (a) of Figure 13 in the direction of charging the capacitors C1 and C2, the voltage Vcap increases, and the current Ibatt decreases toward 0 A.

[0096] Thereafter, when the voltage Vcap reaches a positive peak voltage, the current Ibatt is reversed, and during period P2, a current (current Icap) flows from each of the capacitors C1 and C2 in the direction of charging the battery 30 through the path shown in (b) of Figure 13, the current Ibatt continues to increase in the direction of charging the battery 30, and the voltage Vcap begins to decrease.

[0097] Thereafter, the control unit 44 connects the capacitors C1 and C2 in parallel to the battery 30, so that in the AC generating circuit 42-3, during the period P3, the current Ibatt from the battery 30 flows through the capacitors C1 and C2 via the path shown in FIG. 13(c), and the voltage Vcap becomes a negative voltage value. At this time, in the AC generating circuit 42-3, the bidirectional semiconductor switch unit SW3-2 is in a non-conductive state, so that it is possible to operate without forming a current path (unintended path) that does not pass through the capacitors C1 and C2, as shown in FIG. 7. More specifically, when the voltage Vcap goes from 0V to the negative region, in the AC generating circuit 42-3, the potential of the second terminal side of the semiconductor switch unit SW2 (the source terminal of the switching element S2) becomes lower than the potential of the first terminal side of the semiconductor switch unit SW1 (the drain terminal of the switching element S1). However, even in this case, in the AC generating circuit 42-3, the bidirectional semiconductor switch section SW3-2 (more specifically, the second semiconductor switch section) does not pass the current Icap from the semiconductor switch section SW1 side, and the current path does not change from the path shown in Fig. 13(c). As a result, in the AC generating circuit 42-3, the current Is3 does not change from 0A, the voltage Vcap continues to drop, and the electrostatic energy exchanged with the inductance La of the battery 30 to perform the resonance operation does not decrease, so the current Ibatt continues to decrease toward 0A and the voltage Vcap continues to drop.

[0098] Then, when the voltage Vcap becomes a negative peak voltage, the direction of the current (current Icap) in the capacitors C1 and C2 is reversed. At this time, the bidirectional semiconductor switch section SW3-2 is still in a non-conductive state, so in the AC generating circuit 42-3, during the period P4, the current Is1 and the current Icap flow from the battery 30 through the path shown in (d) of Fig. 13 in the direction of charging the capacitors C1 and C2, the current Ibatt continues to increase in the direction of discharging the battery 30, and the voltage Vcap starts to rise.

[0099] Thereafter, the control unit 44 connects the capacitors C1 and C2 in series to the battery 30, so that the current path in the AC generating circuit 42-3 also returns to the same path as in the period P1 (the path shown in FIG. 13(a)). Thereafter, the above-mentioned operation is repeated periodically in the same manner.

[0100] In this way, in the temperature raising device 40 of the third embodiment, the semiconductor switch unit SW3 included in the AC generating circuit 42-1 of the first embodiment is replaced with the bidirectional semiconductor switch unit SW3-2 in the AC generating circuit 42-3. As a result, in the temperature raising device 40 of the third embodiment, when the capacitors C1 and C2 are connected in parallel and each capacitor is charged, even if the voltage Vcap goes from 0V to a negative region, the bidirectional semiconductor switch unit SW3-2 maintains a non-conductive state. In other words, in the temperature raising device 40 of the third embodiment, even if the voltage Vcap goes from 0V to a negative region and the potentials of the semiconductor switch unit SW1 and the semiconductor switch unit SW2 become unbalanced, the bidirectional semiconductor switch unit SW3-2 maintains a non-conductive state. Therefore, in the temperature raising device 40 of the third embodiment, the AC generating circuit 42-3 can be operated without forming an unintended current path (see FIG. 7) like that of the AC generating circuit 42-1, and can generate an AC current of sufficient amplitude (wider amplitude than that of the AC generating circuit 42-1) by maintaining a resonant operation with the inductance La of the battery 30. As a result, the temperature raising device 40 of the third embodiment can also raise the temperature of the battery 30 more efficiently by the generated AC current.

[0101] Here, the difference in characteristics of the AC current generated by each of the AC generating circuit 42-1 of the first embodiment, the AC generating circuit 42-2 of the second embodiment, and the AC generating circuit 42-3 of the third embodiment will be described. FIG. 14 is a diagram comparing characteristics of the amplitude of the AC current generated by the AC generating circuit 42 (the AC generating circuit 42-1, the AC generating circuit 42-2, and the AC generating circuit 42-3). FIG. 14 shows the characteristics of the effective value (rms value) of the current value representing the amplitude of the AC current generated by each of the AC generating circuits 42 when the duty ratio is the same and the frequency is changed. As shown in FIG. 14, in the AC generating circuit 42-1, the current value of the generated AC current does not change in the frequency band FB1. This is because, in the AC generating circuit 42-1, when the voltage Vcap becomes a negative region from 0V, an unintended current path as shown in FIG. 7 is formed, and the energy exchanged between the inductance La and the capacitor C1 in the resonance operation is reduced. In contrast, in the AC generating circuit 42-2 and the AC generating circuit 42-3, the current value of the generated AC current changes over the entire frequency band, and although the frequency bands are different between the AC generating circuit 42-2 and the AC generating circuit 42-3, the effective value is higher than that of the AC generating circuit 42-1. This also shows that the AC generating circuit 42-2 and the AC generating circuit 42-3 can be operated without forming an unintended current path as shown in Fig. 7, and can be operated without causing a decrease in the energy exchanged between the inductance La and the capacitor C1 during resonant operation.

[0102] <Fourth embodiment> [Configuration of AC generating circuit in heating device] In the AC generating circuit 42-2 of the second embodiment, the semiconductor switch unit SW1 and the semiconductor switch unit SW2 included in the AC generating circuit 42-1 are replaced with a bidirectional semiconductor switch unit, and in the AC generating circuit 42-3 of the third embodiment, the semiconductor switch unit SW3 included in the AC generating circuit 42-1 is replaced with a bidirectional semiconductor switch unit. However, the semiconductor switch unit replacing the bidirectional semiconductor switch unit in the AC generating circuit 42 does not have to be either one of the semiconductor switch unit SW1 and the semiconductor switch unit SW2, or the semiconductor switch unit SW3, that is, either one of the parallel switch unit and the series switch unit, and both the parallel switch unit and the series switch unit may be replaced with bidirectional semiconductor switch units.

[0103] FIG. 15 is a diagram showing an example of the configuration of an AC generating circuit 42 (hereinafter, referred to as "AC generating circuit 42-4") included in the temperature raising device 40 according to the fourth embodiment. FIG. 15 also shows a battery 30 (however, illustration of inductance La is omitted) related to the AC generating circuit 42-4. The AC generating circuit 42-4 is configured to avoid the formation of an unintended path assumed in the AC generating circuit 42-1 of the first embodiment, similar to the AC generating circuit 42-2 of the second embodiment and the AC generating circuit 42-3 of the third embodiment. The AC generating circuit 42-4 includes, for example, a capacitor C1, a capacitor C2, a switching element S1a, a switching element S1b, a switching element S2a, a switching element S2b, a switching element S3a, a switching element S3b, a diode D1a, a diode D1b, a diode D2a, a diode D2b, a diode D3a, and a diode D3b.

[0104] The AC generating circuit 42-4 has a configuration in which all the semiconductor switch units provided in the AC generating circuit 42-1 are replaced with the bidirectional semiconductor switch units provided in the AC generating circuit 42-2 and the AC generating circuit 42-3. The connections of the capacitor C1, capacitor C2, bidirectional semiconductor switch unit SW1-2, bidirectional semiconductor switch unit SW2-2, and bidirectional semiconductor switch unit SW3-2 in the AC generating circuit 42-4 are equivalent to those in the AC generating circuit 42-1 of the first embodiment.

[0105] With this configuration, in the AC generating circuit 42-4, similar to the AC generating circuits 42 of the first to third embodiments, the capacitors C1 and C2 are connected in parallel or series between the positive and negative sides of the battery 30 in response to control from the control unit 44.

[0106] In the AC generating circuit 42-4, a configuration in which the bidirectional semiconductor switch unit SW1-2 and the bidirectional semiconductor switch unit SW2-2 are combined is an example of a “parallel switch unit” in the claims, and the bidirectional semiconductor switch unit SW3-2 is an example of a “series switch unit” in the claims.

[0107] [Operation of the heating device] Next, an operation of generating an AC current in the AC generating circuit 42-4 will be described. Fig. 16 is a diagram showing an example of the control of the control unit 44 and the operation waveforms (simulation waveforms) of the AC generating circuit 42-4 in the fourth embodiment. Fig. 17 is a diagram showing an example of a path of an AC current flowing in the AC generating circuit 42-4 in the fourth embodiment. In the following description, the operation of the AC generating circuit 42-4 shown in Fig. 16 will be described with appropriate reference to Fig. 17.

[0108] Similarly to the AC generating circuit 42 of the first to third embodiments, the control unit 44 also first turns the bidirectional semiconductor switch unit in a conductive state to a non-conductive state to allow the flowing current to flow once, and then turns the other bidirectional semiconductor switch units in a non-conductive state to a conductive state to switch the connection between the capacitor C1 and the capacitor C2 to a series connection or a parallel connection. At this time, the control unit 44 turns the bidirectional semiconductor switch unit in a non-conductive state to a conductive state when the AC current generated by the AC generating circuit 42-4 becomes approximately 0 A. In other words, the control unit 44 can perform ZCS (Zero Current Switching) control on the AC generating circuit 42-4.

[0109] At time t1 when the current Ibatt becomes approximately 0 A, the control unit 44 turns on the bidirectional semiconductor switch unit SW3-2 to connect the capacitors C1 and C2 in series to the battery 30. As a result, in the AC generating circuit 42-4 as well, during period P1, the capacitors C1 and C2 are each discharged, and the currents Is3 and Icap flow in the direction to charge the battery 30 through the path shown in Fig. 17(a). As a result, in the AC generating circuit 42-4 as well, the voltage Vcap decreases, and the current Ibatt increases in the direction to charge the battery 30.

[0110] After that, at time t2, the voltage Vcap goes from 0V to a negative region, but in the AC generating circuit 42-4, the bidirectional semiconductor switch section SW1-2 and the bidirectional semiconductor switch section SW2-2 are in a non-conducting state, so that it is possible to operate without forming an unintended current path as shown in Fig. 7, and as shown in Fig. 17(b), the current path does not change from the path shown in Fig. 17(a). As a result, in the AC generating circuit 42-4 as well, during period P2, the current Is1 does not change from 0A, and the voltage Vcap continues to drop. As a result, in the AC generating circuit 42-4 as well, the current Ibatt flows in a direction that sufficiently increases in the direction of charging the battery 30 and then decreases, so that a wide amplitude of the AC current can be secured.

[0111] Thereafter, the control unit 44 brings the bidirectional semiconductor switch unit SW3-2 into a non-conductive state when the current Ibatt becomes approximately 0 A, and thereafter, at time t3, brings the bidirectional semiconductor switch unit SW1-2 and the bidirectional semiconductor switch unit SW2-2 into a conductive state, thereby connecting the capacitors C1 and C2 in parallel to the battery 30. As a result, in the AC generating circuit 42-4 as well, during period P3, the current Is1 and the current Icap flow from the battery 30 through the path shown in Fig. 17(c) in the direction of charging the capacitors C1 and C2, the current Ibatt continues to increase in the direction of discharging the battery 30, and the voltage Vcap begins to rise.

[0112] After that, at time t4, the voltage Vcap goes from 0V to the positive region, and the voltage Vcap further rises, but in the AC generating circuit 42-4, the bidirectional semiconductor switch SW3-2 is in a non-conductive state, so that it is possible to operate without forming an unintended current path as shown in Fig. 7, and as shown in Fig. 17(d), the current path does not change from the path shown in Fig. 17(c). As a result, in the AC generating circuit 42-4, the current Is3 does not change from 0A during the period P4, and the voltage Vcap continues to rise. As a result, in the AC generating circuit 42-4, the current Ibatt flows in a direction that sufficiently increases and then decreases in a direction that discharges the battery 30, and a wide amplitude of the AC current can be secured.

[0113] Thereafter, at time t5 when the current Ibatt becomes approximately 0 A, the control unit 44 connects the capacitors C1 and C2 in series to the battery 30, so that the current path in the AC generating circuit 42-4 also returns to the same path as in the period P1 (the path shown in FIG. 17(a)). Thereafter, the above-mentioned operation is repeated periodically in the same manner.

[0114] In this way, in the temperature rise device 40 of the fourth embodiment, all the semiconductor switch sections included in the AC generation circuit 42-1 of the first embodiment are replaced with the bidirectional semiconductor switch section in the AC generation circuit 42-4. As a result, in the temperature rise device 40 of the fourth embodiment, when the bidirectional semiconductor switch section SW1-2 and the bidirectional semiconductor switch section SW2-2 are in a non-conductive state (when the capacitor C1 and the capacitor C2 are connected in series to charge the battery 30), even if the voltage Vcap goes from 0V to a negative region, the bidirectional semiconductor switch section SW1-2 and the bidirectional semiconductor switch section SW2-2 maintain the non-conductive state. Furthermore, in the temperature rise device 40 of the fourth embodiment, when the bidirectional semiconductor switch section SW3-2 is in a non-conductive state (when the capacitor C1 and the capacitor C2 are connected in parallel to charge each capacitor), even if the voltage Vcap goes from 0V to a positive region, the bidirectional semiconductor switch section SW3-2 maintains the non-conductive state. That is, in the temperature raising device 40 of the fourth embodiment, in the AC generating circuit 42-4, no current flows through the bidirectional semiconductor switch unit that is in a non-conductive state, in other words, a current flows only through the bidirectional semiconductor switch unit that is in a conductive state. As a result, in the temperature raising device 40 of the fourth embodiment, the AC generating circuit 42-4 can be operated without forming an unintended current path (see FIG. 7) like the AC generating circuit 42-1, and a resonance operation with the inductance La of the battery 30 can be maintained to generate an AC current of sufficient amplitude (wider amplitude than that of the AC generating circuit 42-1). As a result, the temperature raising device 40 of the fourth embodiment can also raise the temperature of the battery 30 more efficiently by the generated AC current.

[0115] Here, the difference in characteristics of the AC current generated by each of the AC generating circuits 42 of the first to third embodiments and the AC generating circuit 42-4 of the fourth embodiment will be described. FIG. 18 is a diagram comparing characteristics of the amplitude of the AC current generated by the AC generating circuits 42 (AC generating circuits 42-1, 42-2, 42-3, and 42-4). As in FIG. 14, FIG. 18 also shows characteristics of the effective value (rms value) of the current value representing the amplitude of the AC current generated by each of the AC generating circuits 42 when the duty ratio is the same and the frequency is changed. FIG. 18 shows characteristics of the amplitude of the AC current generated by the AC generating circuit 42-4 of the fourth embodiment superimposed on the characteristics of the amplitude of the AC current generated by the AC generating circuit 42 of the first to third embodiments shown in FIG. 14. As shown in FIG. 18, in the AC generating circuit 42-4, the effective value of the generated AC current changes higher (wider amplitude) than in the AC generating circuits 42 of the first to third embodiments. From this, it is understood that the AC generating circuit 42-4 of the fourth embodiment can generate an AC current with a higher temperature increasing effect than the AC generating circuits 42 of the first to third embodiments.

[0116] Incidentally, in the operation of the AC generating circuit 42-4 described with reference to Figs. 16 and 17, ZCS control is performed to make the non-conductive bidirectional semiconductor switch unit conductive when the AC current generated by the AC generating circuit 42-4 becomes approximately 0 A. Then, as described above, the control unit 44 first makes the conductive bidirectional semiconductor switch unit non-conductive to once circulate the current flowing therethrough, and then makes the non-conductive bidirectional semiconductor switch unit conductive. For this reason, it is assumed that the ZCS control is not suitable, for example, when adjusting the amount of AC current generated by the AC generating circuit 42-4. For example, if the conductive bidirectional semiconductor switch unit is made non-conductive at a timing when the AC current generated by the AC generating circuit 42-4 is away from approximately 0 A, the inductance La of the battery 30 will cut off the current while it is flowing. Then, in the AC generating circuit 42-4, a surge voltage is generated in the voltage Vbatt, and a load such as heat is applied to the switching element of the bidirectional semiconductor switch unit. In this case, the loss of the generated AC current becomes large.

[0117] Here, an example of a case where a surge voltage occurs in the AC generating circuit 42-4 will be described. FIG. 19 is a diagram showing another example of the control of the control unit 44 of the fourth embodiment and the operation waveforms (simulation waveforms) of the AC generating circuit 42-4. FIG. 19 shows an example of a case where a surge voltage occurs when the bidirectional semiconductor switch unit is switched from a conductive state to a non-conductive state in the AC generating circuit 42-4. Even if a surge voltage occurs in the operation of the AC generating circuit 42-4 shown in FIG. 19, the path of the current is the same as the path shown in FIG. 17. In the following description, the operation of the AC generating circuit 42-4 when a surge voltage occurs will be described with reference to FIG. 17 as appropriate.

[0118] When the control unit 44 switches the bidirectional semiconductor switch unit SW1-2 and the bidirectional semiconductor switch unit SW2-2 from a conductive state to a non-conductive state and switches the bidirectional semiconductor switch unit SW3-2 from a non-conductive state to a conductive state, the current path switches from the path shown in Fig. 17(d) to the path shown in Fig. 17(a). At this time, during a period P5 in which the bidirectional semiconductor switch unit SW1-2, the bidirectional semiconductor switch unit SW2-2, and the bidirectional semiconductor switch unit SW3-2 are all in a non-conductive state, a surge voltage is generated by the current (current before becoming 0 A) that passed through the bidirectional semiconductor switch unit SW1-2 and the bidirectional semiconductor switch unit SW2-2 through the path shown in Fig. 17(d). The surge voltage generated here is absorbed by the bidirectional semiconductor switch unit SW3-2 becoming conductive, but there is a concern that the surge voltage before being absorbed may increase loss.

[0119] When the control unit 44 switches the bidirectional semiconductor switch unit SW3-2 from a conductive state to a non-conductive state and switches the bidirectional semiconductor switch unit SW1-2 and the bidirectional semiconductor switch unit SW2-2 from a non-conductive state to a conductive state, the current path switches from the path shown in Fig. 17(b) to the path shown in Fig. 17(c). At this time, during a period P6 in which the bidirectional semiconductor switch unit SW1-2, the bidirectional semiconductor switch unit SW2-2, and the bidirectional semiconductor switch unit SW3-2 are all in a non-conductive state, a surge voltage is generated by the current (current before becoming 0 A) that passed through the bidirectional semiconductor switch unit SW3-2 via the path shown in Fig. 17(b). The surge voltage generated here is absorbed by the bidirectional semiconductor switch unit SW1-2 and the bidirectional semiconductor switch unit SW2-2 becoming conductive, but there is a concern that the surge voltage before being absorbed may increase loss.

[0120] As described above, in the temperature raising device 40 of the fourth embodiment, if a surge voltage occurs due to the timing of switching the bidirectional semiconductor switch unit, the loss of the generated AC current may become large.

[0121] <Fifth embodiment> [Configuration of AC generating circuit in heating device] FIG. 20 is a diagram showing an example of the configuration of an AC generating circuit 42 (hereinafter, referred to as an "AC generating circuit 42-5") included in the temperature raising device 40 according to the fifth embodiment. FIG. 20 also shows a battery 30 (however, illustration of an inductance La is omitted) related to the AC generating circuit 42-5. The AC generating circuit 42-5 is configured to avoid the occurrence of a surge voltage assumed in the AC generating circuit 42-4 of the fourth embodiment. The AC generating circuit 42-5 includes, for example, a capacitor C1, a capacitor C2, a switching element S1a, a switching element S1b, a switching element S2a, a switching element S2b, a switching element S3a, a switching element S3b, a diode D1a, a diode D1b, a diode D2a, a diode D2b, a diode D3a, and a diode D3b.

[0122] The AC generating circuit 42-5 has the same components as the AC generating circuit 42-4. The connections of the capacitor C1, the capacitor C2, the bidirectional semiconductor switch unit SW1-2, the bidirectional semiconductor switch unit SW2-2, and the bidirectional semiconductor switch unit SW3-2 in the AC generating circuit 42-5 are equivalent to those in the AC generating circuit 42-4, that is, equivalent to those in the AC generating circuit 42-1 of the first embodiment. However, in the AC generating circuit 42-5, the control unit 44 controls the on / off of the first semiconductor switch unit and the second semiconductor switch unit constituting each of the bidirectional semiconductor switch units at different timings.

[0123] In the following description, the first semiconductor switch section composed of the switching element S1a and the diode D1a is also referred to as the "semiconductor switch section SW1a," and the second semiconductor switch section composed of the switching element S1b and the diode D1b is also referred to as the "semiconductor switch section SW1b." Furthermore, the first semiconductor switch section composed of the switching element S2a and the diode D2a is also referred to as the "semiconductor switch section SW2a," and the second semiconductor switch section composed of the switching element S2b and the diode D2b is also referred to as the "semiconductor switch section SW2b." Furthermore, the first semiconductor switch section composed of the switching element S3a and the diode D3a is also referred to as the "semiconductor switch section SW3a," and the second semiconductor switch section composed of the switching element S3b and the diode D3b is also referred to as the "semiconductor switch section SW3b."

[0124] When changing the bidirectional semiconductor switch section SW1-2 and the bidirectional semiconductor switch section SW2-2 from a conductive state to a non-conductive state, the control section 44 controls one of the first and second semiconductor switch sections constituting the bidirectional semiconductor switch section to a non-conductive state while maintaining the conductive state of the other, so that the current flowing through each bidirectional semiconductor switch section can be sufficiently returned. Similarly, when changing the bidirectional semiconductor switch section SW3-2 from a conductive state to a non-conductive state, the control section 44 controls one of the first and second semiconductor switch sections constituting the bidirectional semiconductor switch section SW3-2 to a non-conductive state while maintaining the conductive state of the other, so that the current flowing through the bidirectional semiconductor switch section SW3-2 can be sufficiently returned.

[0125] More specifically, when the control unit 44 changes the bidirectional semiconductor switch unit SW1-2 and the bidirectional semiconductor switch unit SW2-2 from a conductive state to a non-conductive state, it changes the semiconductor switch unit on the side of the terminal to which the higher applied voltage value is brought into a non-conductive state while maintaining the conductive state of the semiconductor switch unit on the side of the terminal to which the lower applied voltage value is applied. Similarly, when the control unit 44 changes the bidirectional semiconductor switch unit SW3-2 from a conductive state to a non-conductive state, it changes the semiconductor switch unit on the side of the terminal to which the higher applied voltage value is brought into a non-conductive state while maintaining the conductive state of the semiconductor switch unit on the side of the terminal to which the lower applied voltage value is applied.

[0126] For example, consider a case where the bidirectional semiconductor switch unit SW1-2 and the bidirectional semiconductor switch unit SW2-2 are changed from a conductive state to a non-conductive state when the voltage values ​​of the capacitors C1 and C2 are positive voltage values. In this case, the control unit 44 changes the second semiconductor switch unit included in the bidirectional semiconductor switch unit SW3-2 from a non-conductive state to a conductive state, and then changes the first semiconductor switch unit included in the bidirectional semiconductor switch unit SW1-2 and the bidirectional semiconductor switch unit SW2-2 from a conductive state to a non-conductive state while maintaining the conductive state of the second semiconductor switch unit included in the bidirectional semiconductor switch unit SW1-2 and the bidirectional semiconductor switch unit SW2-2. For example, consider a case where the bidirectional semiconductor switch unit SW3-2 is changed from a conductive state to a non-conductive state when the voltage values ​​of the capacitors C1 and C2 are negative voltage values. In this case, the control unit 44 changes the first semiconductor switch units included in the bidirectional semiconductor switch unit SW1-2 and the bidirectional semiconductor switch unit SW2-2 from a non-conductive state to a conductive state, and then changes the second semiconductor switch unit included in the bidirectional semiconductor switch unit SW3-2 from a conductive state to a non-conductive state while maintaining the conductive state of the first semiconductor switch unit included in the bidirectional semiconductor switch unit SW3-2.

[0127] With this configuration, in the AC generating circuit 42-5, similar to the AC generating circuits 42 of the first to fourth embodiments, the capacitors C1 and C2 are connected in parallel or series between the positive and negative sides of the battery 30 in response to control from the control unit 44.

[0128] In the AC generating circuit 42-5, the combination of the bidirectional semiconductor switch unit SW1-2 and the bidirectional semiconductor switch unit SW2-2 is an example of a "parallel switch unit" in the claims, and the bidirectional semiconductor switch unit SW3-2 is an example of a "series switch unit" in the claims. In each of the bidirectional semiconductor switch units, the semiconductor switch unit SW1a, the semiconductor switch unit SW2a, and the semiconductor switch unit SW3a are an example of a "first semiconductor switch unit" in the claims. In each of the bidirectional semiconductor switch units, the semiconductor switch unit SW1b, the semiconductor switch unit SW2b, and the semiconductor switch unit SW3b are an example of a "second semiconductor switch unit" in the claims.

[0129] [Operation of the heating device] Next, an operation of generating an AC current in the AC generating circuit 42-5 will be described. FIG. 21 is a diagram showing an example of the control of the control unit 44 of the fifth embodiment and an operation waveform (simulation waveform) of the AC generating circuit 42-5. FIG. 22 is a diagram showing an example of a path of an AC current flowing through the AC generating circuit 42-5 of the fifth embodiment. In FIG. 22, the ON state of the switching elements provided in each semiconductor switch unit is indicated by a "circle" and the OFF state is indicated by a "cross". When the temperature raising device 40 is started by the control device 100, it periodically repeats the operation, so in the following description, the operation of the AC generating circuit 42-5 from time t1 shown in FIG. 21 will be described with appropriate reference to FIG. 22.

[0130] As shown in (a) of Fig. 22, the control unit 44 sets the semiconductor switch unit SW3a in a non-conductive state, the semiconductor switch unit SW3b in a conductive state, the semiconductor switch unit SW1a and the semiconductor switch unit SW2a in a conductive state, and the semiconductor switch unit SW1b and the semiconductor switch unit SW2b in a conductive state. In this state, at time t1 before the current Ibatt flowing from the battery 30 in the direction to charge the capacitors C1 and C2 becomes 0 A, the control unit 44 sets the gate signal G1a and the gate signal G2a to a "Low" level to set the semiconductor switch unit SW1a and the semiconductor switch unit SW2a in a non-conductive state. At this time, the semiconductor switch unit SW3b is in a conductive state, so that a current based on the current Ibatt flows through a path passing through the bidirectional semiconductor switch unit SW3-2 (more specifically, the diode D3a provided in the semiconductor switch unit SW3b and the semiconductor switch unit SW3a) as shown in (b) of Fig. 22. Furthermore, the control unit 44 sets the gate signal G3a to a "High" level to bring the semiconductor switch unit SW3a into a conductive state, as shown in Fig. 22(c). As a result, in the AC generating circuit 42-5, a surge voltage is not generated during the period P1 by the current (current before becoming 0 A) based on the current Ibatt that passed through the bidirectional semiconductor switch units SW1-2 and SW2-2 along the path shown in Fig. 22(a). In the AC generating circuit 42-5, the current Ibatt continues to flow in a direction that discharges the battery 30, and the voltage Vcap also continues to rise.

[0131] Then, when the voltage Vcap reaches a positive peak voltage at time t2, in the AC generating circuit 42-5, the direction of the current (current Icap) in the capacitors C1 and C2 is reversed, the capacitors C1 and C2 are discharged, and the currents Is3 and Icap flow in the direction opposite to the path shown in Fig. 22(c) and in the direction to charge the battery 30. As a result, in the AC generating circuit 42-5, during period P2, the voltage Vcap starts to decrease and the current Ibatt continues to increase and then starts to decrease.

[0132] At a predetermined timing during the period P2, for example, at time t3 when the voltage Vcap becomes 0V, the control unit 44 sets the gate signal G1b and the gate signal G2b to a "Low" level to put the semiconductor switch unit SW1b and the semiconductor switch unit SW2b in a non-conductive state. Furthermore, the control unit 44 sets the gate signal G1a and the gate signal G2a to a "High" level to put the semiconductor switch unit SW1a and the semiconductor switch unit SW2a in a conductive state. As a result, in the AC generating circuit 42-5, the currents (current Is3 and current Icap) discharged from the capacitor C1 and the capacitor C2 respectively continue to flow in a direction to charge the battery 30 through the path shown in FIG. 22(d).

[0133] Thereafter, at time t4 before the current Is3 flowing through the bidirectional semiconductor switch unit SW3-2 becomes 0 A, the control unit 44 sets the gate signal G3b to the "Low" level to put the semiconductor switch unit SW3b in a non-conductive state. At this time, the semiconductor switch unit SW3a is in a conductive state, so that a current based on the current Ibatt continues to flow through the paths that pass through the capacitors C1 and C2, and the diodes D3b of the semiconductor switch unit SW3a and the semiconductor switch unit SW3b, as shown in (e) of Fig. 22. As a result, no surge voltage is generated during the period P3 until time t5.

[0134] Furthermore, as shown in FIG. 22(f), the control unit 44 sets the gate signal G1b and the gate signal G2b to a "High" level to turn on the semiconductor switch unit SW1b and the semiconductor switch unit SW2b. Then, a reverse voltage is applied to the diode D3b through which a forward current had been flowing. Therefore, a current flows temporarily in the diode D3b during the reverse recovery time, but this temporary current quickly converges. Then, in the AC generating circuit 42-5, the current Ibatt continues to decrease, the direction of the current changes to the direction of discharging the battery 30, and the voltage Vcap starts to rise.

[0135] At a predetermined timing during the period P4, for example, at time t6 when the voltage Vcap becomes 0V, the control unit 44 sets the gate signal G3a to a "Low" level to put the semiconductor switch unit SW3a in a non-conductive state. Furthermore, the control unit 44 sets the gate signal G3b to a "High" level to put the semiconductor switch unit SW3b in a conductive state. As a result, the AC generating circuit 42-5 returns to the same path as in the period P1 (the path shown in FIG. 22(a)). Thereafter, the above-mentioned operation is repeated periodically in the same manner.

[0136] In this way, in the temperature rise device 40 of the fifth embodiment, the on / off of the first semiconductor switch unit and the second semiconductor switch unit constituting each bidirectional semiconductor switch unit included in the AC generating circuit 42-4 of the fourth embodiment is controlled at different timings. More specifically, in the AC generating circuit 42-5, when a bidirectional semiconductor switch unit in a conductive state is made non-conductive, one of the first semiconductor switch unit and the second semiconductor switch unit constituting the other bidirectional semiconductor switch unit is made conductive beforehand so that the current flowing through the bidirectional semiconductor switch unit can be sufficiently returned, and then the bidirectional semiconductor switch unit in a conductive state is made non-conductive. As a result, in the temperature rise device 40 of the fifth embodiment, even if the control for making the bidirectional semiconductor switch unit in a conductive state non-conductive is not performed by ZCS control, that is, even if the AC current is switched at a timing away from approximately 0 A, it is possible to avoid the occurrence of a surge voltage expected in the voltage Vbatt. As a result, in the temperature raising device 40 of the fifth embodiment, it is possible to suppress an increase in loss of the AC current generated by the AC generating circuit 42-5, and the temperature of the battery 30 can be raised more efficiently by the generated AC current.

[0137] Here, the characteristics of the AC current generated by each of the AC generating circuit 42-4 of the fourth embodiment and the AC generating circuit 42-5 of the fifth embodiment and the loss of the generated AC current will be described. FIG. 23 is a diagram comparing the characteristics of the amplitude of the AC current generated by the AC generating circuit 42 (the AC generating circuit 42-4 and the AC generating circuit 42-5) and the loss. FIG. 23(a) shows the characteristics of the effective value (rms value) of the current value representing the amplitude of the AC current generated by each of the AC generating circuit 42-4 and the AC generating circuit 42-5 when the duty ratio is the same and the frequency is changed. FIG. 23(b) shows the magnitude of the circuit loss (Watt) when each of the AC generating circuit 42-4 and the AC generating circuit 42-5 generates an AC current. As shown in FIG. 23(a), the change in the amplitude (current value) of the generated AC current is almost the same in the AC generating circuit 42-4 and the AC generating circuit 42-5. 23(b), the circuit loss is lower in the AC generating circuit 42-5 than in the AC generating circuit 42-4 over the entire frequency band of the generated AC current. This shows that the AC generating circuit 42-5 can generate an AC current of the same amplitude as the AC generating circuit 42-4 with less circuit loss.

[0138] 21, the control unit 44 has been described as bringing one of the first and second semiconductor switch units constituting the other bidirectional semiconductor switch unit into a conductive state in advance when the voltage Vcap becomes 0V. However, the timing at which the control unit 44 brings one of the semiconductor switch units into a conductive state in advance may be any timing as long as it is before the timing at which the bidirectional semiconductor switch unit in a conductive state is brought into a non-conductive state. In other words, as long as the logic at the time of bringing the bidirectional semiconductor switch unit in a conductive state into a non-conductive state is guaranteed, the control unit 44 may make the determination by measuring (monitoring) the components included in the AC generating circuit 42 and the current value and voltage value of the battery 30, as in the AC generating circuits 42 of the first to fourth embodiments, or may make the determination based on the operating state of the AC generating circuit 42.

[0139] In this manner, in the temperature raising device 40 of the fifth embodiment, the respective semiconductor switch units constituting the bidirectional semiconductor switch unit provided in the AC generating circuit 42-5 are controlled at different timings. As a result, in the temperature raising device 40 of the fifth embodiment, there is no concern about the formation of an unintended current path (see FIG. 7) as in the AC generating circuit 42-1, or an increase in loss due to the generation of a surge voltage as in the AC generating circuit 42-4, and it is possible to maintain a resonant operation with the inductance La of the battery 30 and generate an AC current of sufficient amplitude (wider amplitude than that of the AC generating circuit 42-1). As a result, the temperature raising device 40 of the fifth embodiment can also more efficiently raise the temperature of the battery 30 by the generated AC current.

[0140] Here, an example of the case where the control unit 44 is realized by a logic circuit will be described. Fig. 24 is a circuit diagram showing an example of the circuit configuration of the control unit 44. The control unit 44 includes, for example, a comparator 441, a logical negation circuit (NOT circuit or inverter circuit) 442, and four logical sum circuits (OR circuits) 443 to 446. With this configuration, the control unit 44 realizes the logical operation formula of the following formula (1).

[0141] PLS-P = Vcap == 0 PLS-N = ~PLS-P G1a = G2a ​​= PLS-A ∨ PLS-N G1b = G2b = PLS-A ∨ PLS-P G3a = PLS-B ∨ PLS-N G3b = PLS-B ∨ PLS-P ···(1)

[0142] In the above formula (1), the pulse signal PLS-A is a control signal representing that the capacitors C1 and C2 are connected in parallel. The pulse signal PLS-B is a control signal representing that the capacitors C1 and C2 are connected in series. The pulse signal PLS-P is a control signal representing that the voltage Vcap (i.e., the capacitor C1) has a positive voltage value. The pulse signal PLS-N is a control signal representing that the voltage of the capacitor C1 has a negative voltage value. The pulse signals PLS-A and PLS-B may be output by the control device 100 to the control unit 44, or may be generated by a pulse generator (not shown) included in the control unit 44, such as a clock generator, based on information on the period (frequency) and duty ratio of the AC current instructed by the control device 100.

[0143] Fig. 25 is an example of a timing chart showing the timing of gate signals generated by the control unit 44. Fig. 25 shows the timing of generating the gate signals G1a, G1b, G2a, G2b, G3a, and G3b by the control unit 44 realized by the logic circuit shown in Fig. 24 in association with an example of the operation waveforms (simulation waveforms) of the AC generating circuit 42-5 shown in Fig. 21. The control unit 44 outputs the gate signals having the timings shown in Fig. 25 based on the input periodically changing pulse signals PLS-A and PLS-B, the pulse signal PLS-P obtained by comparing the level of the voltage Vcap with the level of the ground (earth) by the comparator 441, and the pulse signal PLS-P obtained by inverting the pulse signal PLS-P and outputting it by the logical negation circuit 442.

[0144] 25, the voltage Vcap has a negative voltage value during periods P1 and P3, and a positive voltage value during period P2. Therefore, the comparator 441 outputs a pulse signal PLS-P that is at a "Low" level during periods P1 and P3, and at a "High" level during period P2. The logical NOT circuit 442 outputs a pulse signal PLS-N that is an inversion of the pulse signal PLS-P output by the comparator 441. Each of the logical OR circuits 443 to 446 outputs a signal that is the logical OR of the input pulse signals as the respective gate signals.

[0145] In the logic circuit configuration and operation timing of the control unit 44 described with reference to FIG. 24 and FIG. 25, a logic circuit configuration is shown in which the voltage value of the voltage Vcap is monitored and each gate signal is generated depending on whether the voltage Vcap is a positive voltage value or a negative voltage value. However, as described above, the control unit 44 may generate a gate signal by monitoring the current value or voltage value of any of the components included in the AC generating circuit 42-5. In this case, the logic circuit configuration and operation timing of the control unit 44 may be equivalent to the logic circuit configuration shown in FIG. 24 and the timing chart shown in FIG. 25. Furthermore, the control unit 44 is not limited to being realized by a logic circuit. In other words, the operation of the control unit 44 may be realized by a hardware processor such as a CPU included in the control unit 44 (which may be the control device 100) executing a program. In this case, the program may be, for example, a program that realizes an operation equivalent to the logical operation formula of the above formula (1).

[0146] As described above, according to the temperature raising device 40 of each embodiment, the connection of the capacitor C1 and the capacitor C2 of the AC generating circuit 42 to the battery 30 is switched between a series connection and a parallel connection, and an AC current based on the power stored in the battery 30 is generated by utilizing a resonance operation in which the magnetic energy stored in the inductance La of the battery 30 and the electrostatic energy stored at least in the capacitor C1 are alternately exchanged. As a result, the temperature raising device 40 of each embodiment can raise the temperature of the battery 30 more efficiently by the generated AC current. As a result, in the vehicle 1 in which the temperature raising device 40 of each embodiment is adopted, the battery 30 can be used in a state in which it has been heated to a suitable temperature, and a decrease in the charge / discharge performance of the battery 30 can be suppressed.

[0147] According to the temperature raising device 40 of each embodiment described above, the AC generating circuit 42 generates an AC current based on power stored in the battery 30 having an inductance La, and includes a capacitor C1 having a first terminal connected to the positive electrode side of the battery 30, a capacitor C2 having a first terminal connected to the negative electrode side of the battery 30, a parallel switch unit that connects the second terminal of the capacitor C1 to the first terminal of the capacitor C2 and connects the first terminal of the capacitor C1 to the second terminal of the capacitor C2, thereby connecting the capacitors C1 and C2 in parallel to the battery 30, and a series switch unit that connects the second terminal of the capacitor C1 to the second terminal of the capacitor C2, thereby connecting the capacitors C1 and C2 in series to the battery 30. The control unit 44 is provided with an AC generating circuit 42 and a parallel connection state in which the parallel switch unit is in a conductive state and the series switch unit is in a non-conductive state, and a series connection state in which the parallel switch unit is in a non-conductive state and the series switch unit is in a conductive state, and when the parallel switch unit is changed from a non-conductive state to a conductive state, the control unit 44 changes the parallel switch unit from a non-conductive state to a conductive state after changing the series switch unit from a conductive state to a non-conductive state, and when the series switch unit is changed from a non-conductive state to a conductive state, the control unit 44 changes the parallel switch unit from a conductive state to a non-conductive state after changing the parallel switch unit from a conductive state to a non-conductive state, and when the series switch unit is changed from a non-conductive state to a conductive state, the control unit 44 changes the parallel switch unit from a conductive state to a non-conductive state after changing the series switch unit from a non-conductive state to a conductive state, thereby making it possible to more efficiently heat up the battery 30 for driving mounted on the vehicle 1. As a result, in the vehicle 1 in which the heating device 40 of each embodiment is adopted, the battery 30 can be used in a state in which it has been heated to a suitable temperature, and a decrease in the charging and discharging performance of the battery 30 can be suppressed. As a result, in the vehicle 1 in which the heating device 40 of each embodiment is mounted, it is possible to improve the marketability of the vehicle 1, such as by improving durability. For these reasons, the vehicle 1 equipped with the heating device 40 of each embodiment is expected to improve energy efficiency and contribute to reducing adverse effects on the global environment.

[0148] In each of the above-described embodiments, the configuration in which the control device 100 provided in the vehicle 1 controls the operation of the temperature rise device 40 has been described. That is, in each of the above-described embodiments, the case in which the control device that controls the operation of the temperature rise device 40 is configured in the control device 100 provided in the vehicle 1 has been described. However, the control of the operation of the temperature rise device 40 may be performed by the control unit 44 provided in the temperature rise device 40. In this case, the control unit 44 provided in the temperature rise device 40 can control the operation of the temperature rise device 40 in each of the above-described embodiments by acquiring battery information (particularly, information on the temperature of the battery 30) directly from the battery sensor 32 connected to the battery 30 or via the control device 100 provided in the vehicle 1. In this case, the configuration, operation, and processing of the temperature rise device 40 and the control unit 44 may be equivalent to the configuration, operation, and processing of the temperature rise device 40 and the control device 100 in each of the above-described embodiments.

[0149] The above-described embodiment can be expressed as follows. An AC generating circuit that generates an AC current based on electric power stored in a power storage device having an inductance component, a first capacitor having a first terminal connected to the positive electrode side of the power storage unit; a second capacitor having a first terminal connected to the negative electrode side of the power storage unit; a parallel switch unit that connects the second end of the first capacitor to the first end of the second capacitor and connects the first end of the first capacitor to the second end of the second capacitor, thereby connecting the first capacitor and the second capacitor in parallel to the power storage unit; and a series switch section that connects the second end of the first capacitor and the second end of the second capacitor to each other, thereby connecting the first capacitor and the second capacitor in series to the power storage unit; An AC generating circuit having A temperature increasing device including: a control unit that alternates between a first state in which the parallel switch unit is in a conductive state and the series switch unit is in a non-conductive state, and a second state in which the parallel switch unit is in a non-conductive state and the series switch unit is in a conductive state, The control unit: A hardware processor; A storage device storing a program, The hardware processor reads and executes the program stored in the storage device, when changing the parallel switch unit from a non-conductive state to a conductive state, changing the series switch unit from a conductive state to a non-conductive state, and then changing the parallel switch unit from a non-conductive state to a conductive state; when changing the series switch unit from a non-conductive state to a conductive state, changing the parallel switch unit from a conductive state to a non-conductive state, and then changing the series switch unit from a non-conductive state to a conductive state. The heating device is configured as follows.

[0150] The above describes the form for carrying out the present invention using an embodiment, but the present invention is not limited to such an embodiment, and various modifications and substitutions can be made within the scope that does not deviate from the gist of the present invention. [Explanation of symbols]

[0151] 1. Vehicle 10. Engine 12. Motor 14...Reducer 16... Drive wheel 20···PDU 30. Battery 32 Battery sensor 40. Heating device 42, 42-1, 42-2, 42-3, 42-4, 42-5...AC generating circuit 44 Control section 70 Driving controls 80 Vehicle sensor 100... Control device C1 Capacitor C2: Capacitor S1, S1a, S1b, S2, S2a, S2b, S3, S3a, S3b...Switching elements D1, D1a, D1b, D2, D2a, D2b, D3, D3a, D3b...Diodes SW1, SW2, SW3: Semiconductor switch section SW1-2, SW2-2, SW3-2: Bidirectional semiconductor switch

Claims

1. An AC generating circuit that generates an AC current based on electric power stored in a power storage device having an inductance component, a first capacitor having a first terminal connected to the positive electrode side of the power storage unit; a second capacitor having a first terminal connected to the negative electrode side of the power storage unit; a parallel switch unit that connects the second end of the first capacitor to the first end of the second capacitor and connects the first end of the first capacitor to the second end of the second capacitor, thereby connecting the first capacitor and the second capacitor in parallel to the power storage unit; and a series switch unit that connects the second end of the first capacitor and the second end of the second capacitor to connect the first capacitor and the second capacitor in series to the power storage unit; An AC generating circuit having a control unit that alternates between a first state in which the parallel switch unit is in a conductive state and the series switch unit is in a non-conductive state and a second state in which the parallel switch unit is in a non-conductive state and the series switch unit is in a conductive state, Each of the parallel switch unit and the series switch unit includes at least one semiconductor switch unit in which a semiconductor switching element and a diode, the on / off state of which are controlled by the control unit, are connected in parallel with each other, the parallel switch section and the series switch section each include a first semiconductor switch section and a second semiconductor switch section which are the semiconductor switch sections connected in series, and the orientations of the diodes of the first semiconductor switch section and the second semiconductor switch section are opposite to each other; The control unit is when changing the parallel switch unit from a non-conductive state to a conductive state, changing the series switch unit from a conductive state to a non-conductive state, and then changing the parallel switch unit from a non-conductive state to a conductive state; when changing the series switch unit from a non-conductive state to a conductive state, changing the parallel switch unit from a conductive state to a non-conductive state, and then changing the series switch unit from a non-conductive state to a conductive state; When the parallel switch unit is brought into a conductive state to switch from a state in which the first capacitor and the second capacitor are connected in parallel to the power storage unit to a state in which the first capacitor and the second capacitor are connected in series to the power storage unit, after bringing one of the first semiconductor switch unit and the second semiconductor switch unit included in the series switch unit into a conductive state so that the current flowing through the parallel switch unit can return, while keeping one of the first semiconductor switch unit and the second semiconductor switch unit included in the parallel switch unit in a conductive state, the first capacitor and the second capacitor are switched to a state in which they are connected in series to the power storage unit; When the series switch unit is brought into a conductive state to switch from a state in which the first capacitor and the second capacitor are connected in series to a state in which the first capacitor and the second capacitor are connected in parallel to the power storage unit, after bringing one of the first semiconductor switch unit and the second semiconductor switch unit included in the parallel switch unit into a conductive state so that the current flowing through the series switch unit can return, while keeping one of the first semiconductor switch unit and the second semiconductor switch unit included in the series switch unit in a conductive state, the first capacitor and the second capacitor are switched to a state in which they are connected in parallel to the power storage unit; Heating device.

2. An AC generating circuit that generates an AC current based on electric power stored in a power storage device having an inductance component, a first capacitor having a first terminal connected to the positive electrode side of the power storage unit; a second capacitor having a first terminal connected to the negative electrode side of the power storage unit; a parallel switch unit that connects the second end of the first capacitor to the first end of the second capacitor and connects the first end of the first capacitor to the second end of the second capacitor, thereby connecting the first capacitor and the second capacitor in parallel to the power storage unit; and a series switch unit that connects the second end of the first capacitor and the second end of the second capacitor to connect the first capacitor and the second capacitor in series to the power storage unit; An AC generating circuit having a control unit that alternates between a first state in which the parallel switch unit is in a conductive state and the series switch unit is in a non-conductive state and a second state in which the parallel switch unit is in a non-conductive state and the series switch unit is in a conductive state, when changing the parallel switch unit from a non-conductive state to a conductive state, changing the series switch unit from a conductive state to a non-conductive state, and then changing the parallel switch unit from a non-conductive state to a conductive state; a control unit that changes the series switch unit from a non-conductive state to a conductive state after changing the parallel switch unit from a conductive state to a non-conductive state when changing the series switch unit from a non-conductive state to a conductive state; Equipped with the control unit controls a conductive state and a non-conductive state of each of the parallel switch unit and the series switch unit based on a voltage value of the first capacitor or a voltage value of the second capacitor. Heating device.

3. An AC generating circuit that generates an AC current based on electric power stored in a power storage device having an inductance component, a first capacitor having a first terminal connected to the positive electrode side of the power storage unit; a second capacitor having a first terminal connected to the negative electrode side of the power storage unit; a parallel switch unit that connects the second end of the first capacitor to the first end of the second capacitor and connects the first end of the first capacitor to the second end of the second capacitor, thereby connecting the first capacitor and the second capacitor in parallel to the power storage unit; and a series switch unit that connects the second end of the first capacitor and the second end of the second capacitor to connect the first capacitor and the second capacitor in series to the power storage unit; An AC generating circuit having a control unit that alternates between a first state in which the parallel switch unit is in a conductive state and the series switch unit is in a non-conductive state and a second state in which the parallel switch unit is in a non-conductive state and the series switch unit is in a conductive state, when changing the parallel switch unit from a non-conductive state to a conductive state, changing the series switch unit from a conductive state to a non-conductive state, and then changing the parallel switch unit from a non-conductive state to a conductive state; a control unit that changes the series switch unit from a non-conductive state to a conductive state after changing the parallel switch unit from a conductive state to a non-conductive state when changing the series switch unit from a non-conductive state to a conductive state; Equipped with the control unit controls a conductive state and a non-conductive state of the parallel switch unit and the series switch unit based on voltage values ​​of the positive and negative electrodes of the power storage unit. Heating device.

4. An AC generating circuit that generates an AC current based on electric power stored in a power storage device having an inductance component, a first capacitor having a first terminal connected to the positive electrode side of the power storage unit; a second capacitor having a first terminal connected to the negative electrode side of the power storage unit; a parallel switch unit that connects the second end of the first capacitor to the first end of the second capacitor and connects the first end of the first capacitor to the second end of the second capacitor, thereby connecting the first capacitor and the second capacitor in parallel to the power storage unit; and a series switch unit that connects the second end of the first capacitor and the second end of the second capacitor to connect the first capacitor and the second capacitor in series to the power storage unit; An AC generating circuit having a control unit that alternates between a first state in which the parallel switch unit is in a conductive state and the series switch unit is in a non-conductive state and a second state in which the parallel switch unit is in a non-conductive state and the series switch unit is in a conductive state, when changing the parallel switch unit from a non-conductive state to a conductive state, changing the series switch unit from a conductive state to a non-conductive state, and then changing the parallel switch unit from a non-conductive state to a conductive state; a control unit that changes the series switch unit from a non-conductive state to a conductive state after changing the parallel switch unit from a conductive state to a non-conductive state when changing the series switch unit from a non-conductive state to a conductive state; Equipped with the control unit controls the conductive state and the non-conductive state of the parallel switch unit and the series switch unit based on a voltage value across both ends of the parallel switch unit or the series switch unit in a non-conductive state. Heating device.

5. An AC generating circuit that generates an AC current based on electric power stored in a power storage device having an inductance component, a first capacitor having a first terminal connected to the positive electrode side of the power storage unit; a second capacitor having a first terminal connected to the negative electrode side of the power storage unit; a parallel switch unit that connects the second end of the first capacitor to the first end of the second capacitor and connects the first end of the first capacitor to the second end of the second capacitor, thereby connecting the first capacitor and the second capacitor in parallel to the power storage unit; and a series switch unit that connects the second end of the first capacitor and the second end of the second capacitor to connect the first capacitor and the second capacitor in series to the power storage unit; An AC generating circuit having a control unit that alternates between a first state in which the parallel switch unit is in a conductive state and the series switch unit is in a non-conductive state and a second state in which the parallel switch unit is in a non-conductive state and the series switch unit is in a conductive state, when changing the parallel switch unit from a non-conductive state to a conductive state, changing the series switch unit from a conductive state to a non-conductive state, and then changing the parallel switch unit from a non-conductive state to a conductive state; a control unit that changes the series switch unit from a non-conductive state to a conductive state after changing the parallel switch unit from a conductive state to a non-conductive state when changing the series switch unit from a non-conductive state to a conductive state; Equipped with the control unit controls a conductive state and a non-conductive state of each of the parallel switch unit and the series switch unit based on a current value of the AC current flowing through the parallel switch unit or the series switch unit. Heating device.

6. Each of the parallel switch unit and the series switch unit includes at least one semiconductor switch unit in which a semiconductor switching element and a diode, the on / off states of which are controlled by the control unit, are connected in parallel with each other. The temperature raising device according to any one of claims 2 to 5.

7. Either or both of the parallel switch unit and the series switch unit include two of the semiconductor switch units connected in series, and the diodes of the two semiconductor switch units are oriented in opposite directions. The temperature raising device according to claim 6.

8. The parallel switch unit and the series switch unit each include a first semiconductor switch unit and a second semiconductor switch unit which are the semiconductor switch units connected in series, and the orientation of the diodes of the first semiconductor switch unit and the second semiconductor switch unit are opposite to each other. The temperature raising device according to claim 6.

9. The control unit is When the parallel switch unit is brought into a conductive state to switch from a state in which the first capacitor and the second capacitor are connected in parallel to the power storage unit to a state in which the first capacitor and the second capacitor are connected in series to the power storage unit, after bringing one of the first semiconductor switch unit and the second semiconductor switch unit included in the series switch unit into a conductive state so that the current flowing through the parallel switch unit can return, while keeping one of the first semiconductor switch unit and the second semiconductor switch unit included in the parallel switch unit in a conductive state, the first capacitor and the second capacitor are switched to a state in which they are connected in series to the power storage unit; When the series switch unit is brought into a conductive state to switch from a state in which the first capacitor and the second capacitor are connected in series to a state in which the first capacitor and the second capacitor are connected in parallel to the power storage unit, after bringing one of the first semiconductor switch unit and the second semiconductor switch unit included in the parallel switch unit into a conductive state so that the current flowing through the series switch unit can return, while keeping one of the first semiconductor switch unit and the second semiconductor switch unit included in the series switch unit in a conductive state, the first capacitor and the second capacitor are switched to a state in which they are connected in parallel to the power storage unit; The temperature raising device according to claim 8.

10. the control unit controls a conductive state and a non-conductive state of each of the parallel switch unit and the series switch unit based on a voltage value of the first capacitor or a voltage value of the second capacitor. The temperature raising device according to any one of claims 1 to 9.

11. the control unit controls a conductive state and a non-conductive state of the parallel switch unit and the series switch unit based on voltage values ​​of the positive and negative electrodes of the power storage unit. The temperature raising device according to any one of claims 1 to 10.

12. the control unit controls the conductive state and the non-conductive state of the parallel switch unit and the series switch unit based on a voltage value across both ends of the parallel switch unit or the series switch unit in a non-conductive state. The temperature raising device according to any one of claims 1 to 3 and claims 5 to 11.

13. the control unit controls a conductive state and a non-conductive state of each of the parallel switch unit and the series switch unit based on a current value of the AC current flowing through the parallel switch unit or the series switch unit. The temperature raising device according to any one of claims 1 to 4 and claims 6 to 12.

14. the control unit controls a conductive state and a non-conductive state of each of the parallel switch unit and the series switch unit at a predetermined timing based on the AC current. The temperature raising device according to any one of claims 1 to 13.

15. The predetermined timing is determined based on a period or a duty ratio of the AC current. The heating device according to claim 14.

16. An AC generating circuit that generates an AC current based on electric power stored in a power storage device having an inductance component, a first capacitor having a first terminal connected to the positive electrode side of the power storage unit; a second capacitor having a first terminal connected to the negative electrode side of the power storage unit; a parallel switch unit that connects the second end of the first capacitor to the first end of the second capacitor and connects the first end of the first capacitor to the second end of the second capacitor, thereby connecting the first capacitor and the second capacitor in parallel to the power storage unit; and a series switch unit that connects the second end of the first capacitor and the second end of the second capacitor to connect the first capacitor and the second capacitor in series to the power storage unit; An AC generating circuit having A control unit that alternates between a first state in which the parallel switch unit is in a conductive state and the series switch unit is in a non-conductive state and a second state in which the parallel switch unit is in a non-conductive state and the series switch unit is in a conductive state, The computer of the control unit when changing the parallel switch unit from a non-conductive state to a conductive state, changing the series switch unit from a conductive state to a non-conductive state, and then changing the parallel switch unit from a non-conductive state to a conductive state; when changing the series switch unit from a non-conductive state to a conductive state, changing the parallel switch unit from a conductive state to a non-conductive state, and then changing the series switch unit from a non-conductive state to a conductive state; a conductive state and a non-conductive state of the parallel switch unit and the series switch unit are controlled based on a voltage value across both ends of the parallel switch unit or the series switch unit in a non-conductive state. A method for controlling a heating device.

17. An AC generating circuit that generates an AC current based on electric power stored in a power storage device having an inductance component, a first capacitor having a first terminal connected to the positive electrode side of the power storage unit; a second capacitor having a first terminal connected to the negative electrode side of the power storage unit; a parallel switch unit that connects the second end of the first capacitor to the first end of the second capacitor and connects the first end of the first capacitor to the second end of the second capacitor, thereby connecting the first capacitor and the second capacitor in parallel to the power storage unit; and a series switch unit that connects the second end of the first capacitor and the second end of the second capacitor to connect the first capacitor and the second capacitor in series to the power storage unit; An AC generating circuit having a control unit that alternates between a first state in which the parallel switch unit is in a conductive state and the series switch unit is in a non-conductive state and a second state in which the parallel switch unit is in a non-conductive state and the series switch unit is in a conductive state, Each of the parallel switch unit and the series switch unit includes at least one semiconductor switch unit in which a semiconductor switching element and a diode, the on / off state of which are controlled by the control unit, are connected in parallel with each other, The parallel switch unit and the series switch unit include a first semiconductor switch unit and a second semiconductor switch unit that are connected in series, and the diodes of the first semiconductor switch unit and the second semiconductor switch unit are oriented in opposite directions. The computer of the control unit when changing the parallel switch unit from a non-conductive state to a conductive state, changing the series switch unit from a conductive state to a non-conductive state, and then changing the parallel switch unit from a non-conductive state to a conductive state; when changing the series switch unit from a non-conductive state to a conductive state, changing the parallel switch unit from a conductive state to a non-conductive state, and then changing the series switch unit from a non-conductive state to a conductive state; When the parallel switch unit is brought into a conductive state to switch from a state in which the first capacitor and the second capacitor are connected in parallel to the power storage unit to a state in which the first capacitor and the second capacitor are connected in series to the power storage unit, after bringing one of the first semiconductor switch unit and the second semiconductor switch unit included in the series switch unit into a conductive state so that the current flowing through the parallel switch unit can return, while keeping one of the first semiconductor switch unit and the second semiconductor switch unit included in the parallel switch unit in a conductive state, the first capacitor and the second capacitor are switched to a state in which they are connected in series to the power storage unit; When the series switch unit is brought into a conductive state to switch from a state in which the first capacitor and the second capacitor are connected in series to a state in which the first capacitor and the second capacitor are connected in parallel to the power storage unit, after bringing one of the first semiconductor switch unit and the second semiconductor switch unit included in the parallel switch unit into a conductive state so that the current flowing through the series switch unit can return, while keeping one of the first semiconductor switch unit and the second semiconductor switch unit included in the series switch unit in a conductive state, the first capacitor and the second capacitor are switched to a state in which they are connected in parallel to the power storage unit; A method for controlling a heating device.

18. An AC generating circuit that generates an AC current based on electric power stored in a power storage device having an inductance component, a first capacitor having a first terminal connected to the positive electrode side of the power storage unit; a second capacitor having a first terminal connected to the negative electrode side of the power storage unit; a parallel switch unit that connects the second end of the first capacitor to the first end of the second capacitor and connects the first end of the first capacitor to the second end of the second capacitor, thereby connecting the first capacitor and the second capacitor in parallel to the power storage unit; and a series switch unit that connects the second end of the first capacitor and the second end of the second capacitor to connect the first capacitor and the second capacitor in series to the power storage unit; An AC generating circuit having a control unit that alternates between a first state in which the parallel switch unit is in a conductive state and the series switch unit is in a non-conductive state and a second state in which the parallel switch unit is in a non-conductive state and the series switch unit is in a conductive state, The computer of the control unit when changing the parallel switch unit from a non-conductive state to a conductive state, changing the series switch unit from a conductive state to a non-conductive state, and then changing the parallel switch unit from a non-conductive state to a conductive state; when changing the series switch unit from a non-conductive state to a conductive state, changing the parallel switch unit from a conductive state to a non-conductive state, and then changing the series switch unit from a non-conductive state to a conductive state; a conductive state and a non-conductive state of the parallel switch unit and the series switch unit are controlled based on a voltage value across both ends of the parallel switch unit or the series switch unit in a non-conductive state. program.

19. An AC generating circuit that generates an AC current based on electric power stored in a power storage device having an inductance component, a first capacitor having a first terminal connected to the positive electrode side of the power storage unit; a second capacitor having a first terminal connected to the negative electrode side of the power storage unit; a parallel switch unit that connects the second end of the first capacitor to the first end of the second capacitor and connects the first end of the first capacitor to the second end of the second capacitor, thereby connecting the first capacitor and the second capacitor in parallel to the power storage unit; and a series switch unit that connects the second end of the first capacitor and the second end of the second capacitor to connect the first capacitor and the second capacitor in series to the power storage unit; An AC generating circuit having a control unit that alternates between a first state in which the parallel switch unit is in a conductive state and the series switch unit is in a non-conductive state and a second state in which the parallel switch unit is in a non-conductive state and the series switch unit is in a conductive state, Each of the parallel switch unit and the series switch unit includes at least one semiconductor switch unit in which a semiconductor switching element and a diode, the on / off state of which are controlled by the control unit, are connected in parallel with each other, The parallel switch unit and the series switch unit include a first semiconductor switch unit and a second semiconductor switch unit which are connected in series, and the diodes of the first semiconductor switch unit and the second semiconductor switch unit are opposite in orientation. The computer of the control unit when changing the parallel switch unit from a non-conductive state to a conductive state, changing the series switch unit from a conductive state to a non-conductive state, and then changing the parallel switch unit from a non-conductive state to a conductive state; when changing the series switch unit from a non-conductive state to a conductive state, changing the parallel switch unit from a conductive state to a non-conductive state, and then changing the series switch unit from a non-conductive state to a conductive state; When switching from a state in which the first capacitor and the second capacitor are connected in parallel to the power storage unit by bringing the parallel switch unit into a conductive state to a state in which the first capacitor and the second capacitor are connected in series to the power storage unit, after bringing one of the first semiconductor switch unit and the second semiconductor switch unit included in the series switch unit into a conductive state so that the current flowing through the parallel switch unit can return, while keeping one of the first semiconductor switch unit and the second semiconductor switch unit included in the parallel switch unit in a conductive state, switching the first capacitor and the second capacitor into a state in which they are connected in series to the power storage unit; When switching from a state in which the first capacitor and the second capacitor are connected in series to the power storage unit by bringing the series switch unit into a conductive state to a state in which the first capacitor and the second capacitor are connected in parallel to the power storage unit, after bringing one of the first semiconductor switch unit and the second semiconductor switch unit included in the parallel switch unit into a conductive state so that the current flowing through the series switch unit can return, while keeping one of the first semiconductor switch unit and the second semiconductor switch unit included in the series switch unit in a conductive state, the first capacitor and the second capacitor are switched to a state in which they are connected in parallel to the power storage unit; program.

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