Alternating current generation circuit and temperature raising device

Abstract

This invention provides an AC generating circuit and a heating device capable of improving energy efficiency by heating a secondary battery more efficiently. The AC generating circuit includes: a first capacitor, the first end of which is connected to the positive terminal of a storage cell having an inductive component; a second capacitor, the second end of which is connected to the negative terminal of the storage cell; a parallel switch unit that connects the first and second capacitors in parallel to the storage cell; a series switch unit that connects the first and second capacitors in series to the storage cell; a first inductor connected between the positive terminal of the storage cell and the first terminal of the first capacitor; a second inductor connected between the second terminal of the second capacitor and the negative terminal of the storage cell; a third capacitor connected between the second terminal of the first capacitor and the negative terminal of the storage cell; and a fourth capacitor connected between the positive terminal of the storage cell and the first terminal of the second capacitor.

Description

Technical Field

[0001] This invention relates to an AC generating circuit and a heating device. Background Technology

[0002] Efforts to mitigate the adverse effects on the Earth's environment (e.g., reductions in NOx and SOx, and CO2) are progressing steadily. Therefore, in recent years, from the perspective of improving the Earth's environment and reducing CO2, there has been increasing interest in electric vehicles, such as hybrid electric vehicles (HEVs) and plug-in hybrid electric vehicles (PHEVs), which are powered by electric motors supplied with electricity from batteries (secondary batteries). Furthermore, the use of lithium-ion secondary batteries for vehicle applications is being researched. In these electric vehicles, it is important to maximize the performance of the secondary batteries. It is known that the charge and discharge performance of secondary batteries decreases when the operating temperature drops below a suitable range. Moreover, by raising the operating temperature of the secondary battery, the decrease in charge and discharge performance can be suppressed.

[0003] Relatedly, for example, Japanese Patent No. 5293820 discloses a technology related to a heating device for heating a secondary battery. In the heating device disclosed in Japanese Patent No. 5293820, the secondary battery is heated by actively generating a ripple current of a predetermined frequency in a frequency range with a relatively low absolute value of impedance based on the frequency characteristics of the secondary battery's impedance.

[0004] However, previous technologies sometimes failed to heat up the secondary battery efficiently. Summary of the Invention

[0005] This invention was made based on the above-mentioned problem understanding, and one of its objectives is to provide an AC generating circuit and heating device that can improve energy efficiency by making the secondary battery heat up more efficiently.

[0006] Solution for solving the problem

[0007] The AC generating circuit and heating device involved in this invention adopt the following structure.

[0008] (1): An AC generating circuit according to one aspect of the present invention heats up the energy storage body by generating an AC current based on the power stored in the energy storage body having an inductive component. The AC generating circuit includes: a first capacitor, the first end of which is connected to the positive terminal of the energy storage body; a second capacitor, the second end of which is connected to the negative terminal of the energy storage body; and a parallel switch unit, which connects the second terminal of the first capacitor to the second terminal of the second capacitor and connects the first terminal of the first capacitor to the first terminal of the second capacitor, so that the first capacitor and the second capacitor are connected in parallel to the energy storage body. The battery includes a series switch section, which connects the first capacitor and the second capacitor in series in the energy storage body by connecting the second terminal of the first capacitor to the first terminal of the second capacitor; a first inductor connected between the positive terminal of the energy storage body and the first terminal of the first capacitor; a second inductor connected between the second terminal of the second capacitor and the negative terminal of the energy storage body; a third capacitor connected between the second terminal of the first capacitor and the negative terminal of the energy storage body; and a fourth capacitor connected between the positive terminal of the energy storage body and the first terminal of the second capacitor.

[0009] (2): Based on the above (1) scheme, the inductance of the first inductor, the inductance of the second inductor, the capacitance of the first capacitor, the capacitance of the second capacitor, the capacitance of the third capacitor and the capacitance of the fourth capacitor are adjusted based on the relationship containing the inductance component so that the current waveform of the alternating current is close to a sine wave.

[0010] (3): Based on the above (2) scheme, the relationship is as follows: Adjust the inductance of the first inductor, the inductance of the second inductor, the capacitance of the first capacitor, the capacitance of the second capacitor, the capacitance of the third capacitor and the capacitance of the fourth capacitor so that the frequency of the alternating current in the parallel state of the first capacitor and the second capacitor connected in parallel to the energy storage body is consistent with the frequency of the alternating current in the series state of the first capacitor and the second capacitor connected in series to the energy storage body.

[0011] (4): Based on the above (3) scheme, the inductance of the first inductor and the inductance of the second inductor are equal.

[0012] (5): Based on the above scheme (4), the capacitance of the first capacitor is equal to the capacitance of the second capacitor.

[0013] (6): Based on the above scheme (5), the capacitance of the third capacitor is equal to the capacitance of the fourth capacitor, which is the second capacitance.

[0014] (7): Based on the above (1) scheme, the inductance component includes the inductance component of the wiring portion between the energy storage body and the AC generation circuit.

[0015] (8): Based on the above (1) scheme, the parallel switch section has a first switch and a second switch. The first terminal of the first switch is connected to the second terminal of the first capacitor, and the second terminal of the first switch is connected to the second terminal of the second capacitor. The first terminal of the second switch is connected to the first terminal of the first capacitor, and the second terminal of the second switch is connected to the first terminal of the second capacitor. The series switch section has a third switch. The first terminal of the third switch is connected to the first terminal of the second capacitor, and the second terminal of the third switch is connected to the second terminal of the first capacitor. The first switch and the second switch are simultaneously controlled to be in a conducting state or a non-conducting state by a first control signal. The third switch is controlled to be in a conducting state or a non-conducting state by a second control signal. The period during which the first control signal makes the first switch and the second switch in a conducting state and the period during which the second control signal makes the third switch in a conducting state are non-overlapping periods.

[0016] (9): Based on the above (8) scheme, the energy storage body includes a first energy storage body and a second energy storage body connected in series with the first energy storage body. The AC generating circuit is connected to the first energy storage body, and the second AC generating circuit with the same structure as the AC generating circuit is connected to the second energy storage body. The first control signal and the second control signal are input in a way that gives a predetermined phase difference between the AC current generated by the AC generating circuit and the AC current generated by the second AC generating circuit, i.e., the second AC current.

[0017] (10): A heating device according to one aspect of the present invention includes: an AC generating circuit of the above-described (9) aspect; and a control unit, which outputs a first control signal and a second control signal, and alternately switches between a parallel state and a series state through the first control signal and the second control signal. The parallel state refers to a state in which the first switch and the second switch are turned on and the third switch is turned off, so that the first capacitor and the second capacitor are connected in parallel to the energy storage body. The series state refers to a state in which the first switch and the second switch are turned off and the third switch is turned on, so that the first capacitor and the second capacitor are connected in series to the energy storage body.

[0018] Invention Effects

[0019] According to the schemes (1) to (10) above, energy efficiency can be improved by making the secondary battery heat up more efficiently. Attached Figure Description

[0020] Figure 1 This is a diagram illustrating an example of the structure of a vehicle employing the heating device described in the embodiment.

[0021] Figure 2 This is a diagram illustrating an example of the structure of the AC generation circuit included in the heating device according to the embodiment.

[0022] Figure 3 This is an example of an equivalent circuit with series and parallel connections in the AC generation circuit of the implementation method.

[0023] Figure 4 This is a diagram illustrating an example of the structure of an AC generating circuit for a comparative example.

[0024] Figure 5 This is an example of the equivalent circuit of the AC generating circuit in the comparative example.

[0025] Figure 6 This is an example of an equivalent circuit used to illustrate the resonant frequency of the alternating current generated in the alternating current generation circuit of the embodiment.

[0026] Figure 7 This is a diagram illustrating an example of the frequency characteristics of the alternating current generated in the alternating current generation circuit of the embodiment.

[0027] Figure 8 This is a diagram illustrating the structure and operating waveform of a heating device employing a comparative example of an AC generating circuit.

[0028] Figure 9This is a diagram illustrating another example of the operating waveform of a heating device employing the AC generating circuit of the comparative example.

[0029] Figure 10 This is a diagram illustrating an example of the structure and operating waveform of a heating device employing an AC generating circuit according to an embodiment.

[0030] Figure 11 This is a diagram illustrating an example of another structure of a heating device employing the AC generating circuit of the embodiment. Detailed Implementation

[0031] Hereinafter, embodiments of the AC generating circuit and heating device of the present invention will be described with reference to the accompanying drawings.

[0032] [Vehicle Structure]

[0033] Figure 1 This diagram illustrates an example of the structure of a vehicle employing the heating device described in the embodiment. Vehicle 1 is a hybrid electric vehicle (HEV) (hereinafter simply referred to as "vehicle") that travels by a combination of driving an electric motor (electric motor) powered by electricity supplied from a driving battery (secondary battery) or by driving an internal combustion engine that uses fuel as its energy source, such as a diesel engine or a gasoline engine. Vehicles to which the present invention is applicable may include not only four-wheeled vehicles, but also two-wheeled straddle-type vehicles, three-wheeled vehicles (including vehicles with two front wheels and one rear wheel in addition to the front wheel and two rear wheels), and auxiliary bicycles, etc., all vehicles that travel by an electric motor powered by electricity supplied from a driving battery. Vehicle 1 may also be an electric vehicle (EV) that travels by driving only an electric motor (electric motor).

[0034] Vehicle 1 includes, for example, an engine 10, a motor 12, a reducer 14, drive wheels 16, a PDU (Power Drive Unit) 20, a battery 30, a battery sensor 32, a heating device 40, driving controls 70, vehicle sensors 80, and a control device 100.

[0035] Engine 10 is an internal combustion engine that outputs power by burning fuel such as light oil or gasoline stored in a fuel tank (not shown) in vehicle 1. Engine 10 is, for example, a reciprocating engine equipped with cylinders and pistons, intake valves, exhaust valves, a fuel injection device, spark plugs, connecting rods, a crankshaft, etc. Engine 10 may also be a rotary engine. The rotational power of engine 10 is transmitted to reduction gear 14.

[0036] Motor 12 is a rotary electric motor used for driving vehicle 1. Motor 12 is, for example, a three-phase AC motor. The rotor of motor 12 is connected to reducer 14. Motor 12 is driven (rotated) by power supplied from battery 30 via PDU 20. The rotational power of motor 12 is transmitted to reducer 14. Motor 12 can also generate electricity by operating as a regenerative brake that uses the kinetic energy of vehicle 1 during deceleration. Motor 12 may also include a generator. The generator uses, for example, the rotational power output from engine 10 to generate electricity.

[0037] The reducer 14 is, for example, a differential gear. The reducer 14 transmits the driving force, i.e., the rotational power of the engine 10 and motor 12, connected to the shafts of the engine 10 and motor 12 to the axle connected to the drive wheel 16. The reducer 14 may also include, for example, a transmission mechanism that combines multiple gears and shafts and transmits the rotational speed of the engine 10 and motor 12 to the axle according to the gear ratio (gear ratio), a so-called transmission mechanism. The reducer 14 may also include, for example, a clutch mechanism that directly connects or disconnects the rotational power of the engine 10 and motor 12 from the axle.

[0038] PDU 20 is, for example, an inverter, a DC-DC converter, or an AC-DC converter. PDU 20 converts the DC power supplied from battery 30 into three-phase AC power to drive motor 12 and outputs it to motor 12. PDU 20 may also include a VCU (Voltage Control Unit) that boosts the DC power supplied from battery 30. PDU 20 converts the three-phase AC power generated by motor 12, which operates as a regenerative brake, into DC power and outputs it to battery 30. PDU 20 may also boost or buck the output voltage according to the destination of the power output. Figure 1 In the diagram, the components of PDU20 are shown as a structure that is brought together into one, but this is only one example. The various components of PDU20 can also be distributed and configured in the vehicle 1.

[0039] Battery 30 is the battery used for driving vehicle 1. Battery 30 may be a secondary battery, such as a lithium-ion battery, capable of repeated charging and discharging, serving as an energy storage unit. Battery 30 may be a box-type battery enclosure or a structure that allows for easy installation and removal from vehicle 1, or it may be an installation structure that makes installation and removal from vehicle 1 more difficult. The secondary battery included in battery 30 may be a lithium-ion battery. As for the secondary battery included in battery 30, in addition to lead-acid batteries, nickel-metal hydride batteries, and sodium-ion batteries, capacitors such as double-layer capacitors or composite batteries combining secondary batteries and capacitors may also be considered, and the structure of the secondary battery may be arbitrary. Battery 30 stores (charges) electricity from an external charger (not shown) of vehicle 1 and releases the stored electricity to drive vehicle 1. Battery 30 stores (charges) electricity generated by motor 12, which operates as a regenerative brake and is supplied via PDU 20, and releases the stored electricity to drive vehicle 1 (e.g., accelerate). The storage battery 30 has at least an inductive component.

[0040] The storage battery 30 is an example of an "energy storage body". The inductive component of the storage battery 30 (the inductive component connected to the energy storage section of the storage battery 30) is an example of an "inductive component".

[0041] A battery sensor 32 is connected to the battery 30. The battery sensor 32 detects physical quantities such as 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 the voltage sensor, the current of the battery 30 using the current sensor, and the temperature of the battery 30 using the temperature sensor. The battery sensor 32 outputs the detected voltage, current, and temperature information of the battery 30 (hereinafter referred to as "battery information") to the control device 100.

[0042] The heating device 40 raises the temperature of the battery 30 according to the control from the control device 100. The heating device 40 includes, for example, an AC generation circuit 42 and a control unit 44.

[0043] The AC generating circuit 42 includes, for example, a capacitor connected to the positive terminal of the battery 30, a capacitor connected to the negative terminal of the battery 30, a series switch unit connecting each capacitor in series with the battery 30, and a parallel switch unit connecting each capacitor in parallel with the battery 30. The AC generating circuit 42 generates alternating current (ripple current) through the resonant operation between the inductive component of the battery 30 and at least the capacitor connected to the positive terminal. More specifically, the AC generating circuit 42 generates alternating current based on the electricity stored in the battery 30 through a resonant operation that alternately transforms the magnetic energy stored in the inductive component of the battery 30 with the electrostatic energy stored in at least the capacitor connected to the positive terminal. The AC generating circuit 42 raises the temperature of the battery 30 by applying (flowing) the generated alternating current to the battery 30.

[0044] The control unit 44 switches the connection of each capacitor to the battery 30 to either a series connection or a parallel connection by turning on or off the series and parallel switches of the AC generating circuit 42. More specifically, the control unit 44 alternately switches between a state where the series switches are on and the parallel switches are off, resulting in a series connection between the capacitors and the battery 30, and a state where the series switches are off and the parallel switches are on, resulting in a parallel connection between the capacitors and the battery 30. In this case, the control unit 44 may also switch the connection of each capacitor to the battery 30 from a series connection to a parallel connection, or vice versa, to prevent the periods when both the series and parallel switches are on from overlapping. In other words, the control unit 44 can also be set to a period of so-called dead time during which both the series switch and the parallel switch are in a non-conducting state, and switch the connection of each capacitor to the battery 30 from series connection to parallel connection, or vice versa.

[0045] The state in which the capacitors are connected in series with the battery 30 is an example of a "series state," and the state in which the capacitors are connected in parallel with the battery 30 is an example of a "parallel state." Details regarding the heating device 40 and the constituent elements of the heating device 40 will be described later.

[0046] The driving control unit 70 includes, for example, an accelerator pedal, a brake pedal, a gear shift lever, a steering wheel, a custom steering wheel, a joystick, and other control components. Sensors are installed in the driving control unit 70 to detect whether the user (driver) of the vehicle 1 operates any of the control components, or the amount of operation. The driving control unit 70 outputs the sensor detection results to the control device 100.

[0047] Vehicle sensor 80 detects the driving status of vehicle 1. Vehicle sensor 80 includes, for example, a speed sensor to detect the speed of vehicle 1 and an acceleration sensor to detect the acceleration of vehicle 1. Vehicle sensor 80 outputs the detection results detected by each sensor to control device 100.

[0048] The control device 100 controls the operation and movement of the engine 10 and the motor 12 based on the detection results output by the various sensors on the driving control unit 70, i.e., the operation of the various control units 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 composed of 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 also be replaced by control devices such as an engine ECU (Electronic Control Unit), a motor ECU, a battery ECU, a PDU-ECU, and a VCU-ECU.

[0049] When the vehicle 1 is in motion, the control device 100 controls the amount and frequency (i.e., voltage waveform) of the AC power supplied from the battery 30 to the motor 12. At this time, the control device 100 controls the activation of the heating device 40 based on the battery temperature information contained in the battery information output by the battery sensor 32. That is, in order to suppress the degradation of the charging and discharging performance of the battery 30, the control device 100 controls the activation or deactivation of the heating device 40 so that the temperature of the battery 30 rises (heats) to a suitable temperature during use.

[0050] The control device 100 operates by executing a program (software) through a hardware processor such as a CPU (Central Processing Unit). The control device 100 can also be implemented using hardware (including the circuitry) such as an LSI (Large Scale Integration), ASIC (Application Specific Integrated Circuit), FPGA (Field-Programmable Gate Array), or GPU (Graphics Processing Unit), or through a combination of software and hardware. The control device 100 can also be implemented using a dedicated LSI. The program can be pre-stored in a storage device such as an HDD (Hard Disk Drive) or flash memory (a storage device with non-transitory storage media) provided by the vehicle 1, or it can be stored in a removable storage medium such as a DVD or CD-ROM (a non-transitory storage medium), and installed in the HDD or flash memory provided by the vehicle 1 by assembling the storage medium into the drive unit provided by the vehicle 1.

[0051] [The structure of the AC generation circuit in the heating device]

[0052] Figure 2 This diagram illustrates an example of the structure of the AC generation circuit 42 included in the heating device 40 according to the embodiment. Figure 2 Also shown is the battery 30 associated with the AC generating circuit 42. For example, a resistor Ra and an inductor La are connected in series on the positive terminal side of the battery 30, specifically to the energy storage section Ba. The inductor La connected to the energy storage section Ba of the battery 30 is an example of an "inductive component".

[0053] The AC generating circuit 42 includes, for example, capacitors C10, C11, C20, and C21, switches S11, S12, and S13, inductors L10 and L20.

[0054] The first terminal of capacitor C10 is connected to the positive terminal of battery 30 via inductor L10. More specifically, the first terminal of capacitor C10 is connected to the second terminal of inductor L10, and the first terminal of inductor L10 is connected to the positive terminal of battery 30. Furthermore, the first terminal of capacitor C10 is connected to the first terminal of switch S12. The second terminal of capacitor C10 is connected to the first terminal of capacitor C11. Furthermore, the second terminal of capacitor C10 is connected to the first terminal of switch S11 and the second terminal of switch S13. The second terminal of capacitor C11 is connected to the negative terminal of battery 30. The second terminal of capacitor C20 is connected to the negative terminal of battery 30 via inductor L20. More specifically, the second terminal of capacitor C20 is connected to the first terminal of inductor L20, and the second terminal of inductor L20 is connected to the negative terminal of battery 30. That is, the second terminals of capacitor C11 and inductor L20 are connected to the negative terminal of battery 30. Furthermore, the second terminal of capacitor C20 is connected to the second terminal of switch S11. The first terminal of capacitor C20 is connected to the second terminal of capacitor C21. Also, the first terminal of capacitor C20 is connected to the second terminal of switch S12 and the first terminal of switch S13. The first terminal of capacitor C21 is connected to the positive terminal of battery 30. That is, the first terminal of inductor L10 and the first terminal of capacitor C21 are connected to the positive terminal of battery 30.

[0055] Capacitors C10 and C20 are capacitors that switch between being connected in series with the battery 30 (series connection) and being connected in parallel with the battery 30 (parallel connection), respectively. By switching between these two states, capacitors C10 and C20 generate alternating current (ripple current) through resonance with the inductive component of the battery 30. Capacitors C10 and C20 are capacitors with equal capacitance. Capacitors C11 and C21, inductors L10 and L20 are used to adjust the overall impedance of the AC generating circuit 42 so that the overall impedance is the same regardless of whether capacitors C10 and C20 are connected in series or in parallel with the battery 30. Capacitors C11 and C21 are capacitors with equal capacitance. Inductors L10 and L20 are inductors with equal inductance.

[0056] Switches S11, S12, and S13 are controlled by the control signal output from the control unit 44 to either a conducting state (closed state) connecting the terminals of both sides, or a non-conducting state (open state) disconnecting the terminals of both sides. Switches S11 and S12 are controlled by the control unit 44 to connect capacitors C10 and C20 in parallel to the parallel connection section of the battery 30. Switch S13 is controlled by the control unit 44 to connect capacitors C10 and C20 in series to the series connection section of the battery 30.

[0057] Switches S11, S12, and S13 can each be, for example, an N-channel metal-oxide-semiconductor field-effect transistor (MOSFET), which can be controlled to be in any state of being on or off. In this case, a diode that functions as a return current device can also be connected in parallel. When switches S11, S12, and S13 are each composed of semiconductor switching elements, the control unit 44 outputs a gate signal that turns the semiconductor switching elements on or off, as a control signal that controls switches S11, S12, and S13 to be in a conducting or non-conducting state, respectively.

[0058] In the following description, the control signal output by the control unit 44 that controls switch S11 to a conducting or non-conducting state is called "control signal CS11", the control signal that controls switch S12 to a conducting or non-conducting state is called "control signal CS12", and the control signal that controls switch S13 to a conducting or non-conducting state is called "control signal CS13". When switches S11 and S12 are controlled simultaneously as parallel switches, the control unit 44 may also output control signals CS11 and CS12 as the same control signal CS.

[0059] Using this structure, in the AC generating circuit 42, capacitors C10 and C20 are connected in series or in parallel between the positive and negative terminals of the battery 30 according to the control from the control unit 44. More specifically, the control unit 44 outputs a control signal CS11 to switch S11 to de-conduct, a control signal CS12 to switch S12 to de-conduct, and a control signal CS13 to switch S13 to conduct, thereby connecting capacitors C10 and C20 in series between the positive and negative terminals of the battery 30. On the other hand, the control unit 44 outputs a control signal CS11 to switch S11 to conduct, a control signal CS12 to switch S12 to conduct, and a control signal CS13 to switch S13 to de-conduct, thereby connecting capacitors C10 and C20 in parallel between the positive and negative terminals of the battery 30.

[0060] In the AC generating circuit 42, capacitor C10 is an example of a "first capacitor," capacitor C20 is an example of a "second capacitor," capacitor C11 is an example of a "third capacitor," and capacitor C21 is an example of a "fourth capacitor." In the AC generating circuit 42, switch S11 is an example of a "first switch," switch S12 is an example of a "second switch," and switch S13 is an example of a "third switch." In the AC generating circuit 42, inductor L10 is an example of a "first inductor," and inductor L20 is an example of a "second inductor." The control signal CS11 output by control unit 44 to switch S11 and the control signal CS12 output to switch S12 are examples of "first control signals," and the control signal CS13 output by control unit 44 to switch S13 is an example of a "second control signal." The state in which control unit 44 makes both switches S11 and S12 in a conducting state through control signals CS11 and CS12 is an example of a "first state." The state in which the control unit 44 turns on switch S13 via control signal CS13 is an example of a "second state". The state in which the control unit 44 turns both switches S11 and S12 off via control signals CS11 and CS12, and turns on switch S13 via control signal CS13, is an example of a "series state". The state in which the control unit 44 turns both switches S11 and S12 on via control signals CS11 and CS12, and turns on switch S13 via control signal CS13, is an example of a "parallel state".

[0061] [Operation of the AC generating circuit]

[0062] Here, the frequency of the alternating current generated by the alternating current generating circuit 42 is taken into consideration. In order for the battery 30 to be heated efficiently by the heating device 40, the current waveform of the alternating current generated by the alternating current generating circuit 42 is preferably a sine wave.

[0063] However, as mentioned above, in the AC generating circuit 42, capacitors C10 and C20 are capacitors with equal capacitance. Therefore, in the AC generating circuit 42, the overall capacitance differs depending on whether capacitors C10 and C20 are connected in series with the battery 30 or in parallel, considering them as a single capacitor. More specifically, when capacitors C10 and C20 are connected in series, the overall capacitance of the AC generating circuit 42 is the sum of the reciprocals of the capacitances of each capacitor, i.e., half the capacitance. On the other hand, when capacitors C10 and C20 are connected in parallel, the overall capacitance of the AC generating circuit 42 is the sum of the capacitances of each capacitor, i.e., twice the capacitance. In other words, the overall capacitance of the AC generating circuit 42 differs by a factor of four depending on whether capacitors C10 and C20 are connected in series with the battery 30 or in parallel. Therefore, in the AC generating circuit 42, the frequency of the generated AC current is twice as different when capacitors C10 and C20 are connected in series with the battery 30 and in parallel.

[0064] Here, we will explain the difference between the case in which capacitors C10 and C20 are connected in series with the battery 30 and the case in which they are connected in parallel in the AC generating circuit 42. Figure 3 This is an example of the equivalent circuit of series and parallel connections in the AC generation circuit 42 of the embodiment. Figure 3 In (a), an equivalent circuit is shown where capacitors C10 and C20 are connected in series with the battery 30. Figure 3 (b) shows the equivalent circuit when capacitors C10 and C20 are connected in parallel to the battery 30. Figure 3 (a) and Figure 3 (b) shows that Figure 2 The equivalent circuit of the AC generating circuit 42 shown, where switches S11, S12, and S13 are either in the on or off state. Figure 3 (a) and Figure 3 In (b), the inductive component of the inductance La of the battery 30 is designated as "Ls", and the resistive component of the resistor Ra is designated as "Rs". Furthermore, in Figure 3 (a) and Figure 3In (b), the capacitance of capacitors C10 and C20 is "Cx", the capacitance of capacitors C11 and C21 is "Cy", and the inductance of inductors L10 and L20 is "Lx".

[0065] The capacitance Cx of capacitors C10 and C20 is an example of "first capacitance", and the capacitance Cy of capacitors C11 and C21 is an example of "second capacitance".

[0066] like Figure 3 As shown in (a), in the AC generating circuit 42, when capacitors C10 and C20 are connected in series with the battery 30, an inductor L10 is inserted in series between capacitor C10 and the positive terminal of the battery 30, a capacitor C11 is inserted in series between capacitor C10 and the negative terminal of the battery 30, an inductor L20 is inserted in series between capacitor C20 and the negative terminal of the battery 30, and a capacitor C21 is inserted in series between capacitor C20 and the positive terminal of the battery 30. In contrast, as... Figure 3 As shown in (b), in the AC generating circuit 42, when capacitors C10 and C20 are connected in parallel to the battery 30, a parallel circuit of capacitor C21 and inductor L10 is inserted in series between capacitors C10 and C20 and the positive terminal of the battery 30, and a parallel circuit of capacitor C11 and inductor L20 is inserted in series between capacitors C10 and C20 and the negative terminal of the battery 30. Thus, in the AC generating circuit 42, depending on the different connections of capacitors C11, C21, L10, and L20 when capacitors C10 and C20 are connected in series and in parallel, the frequency of the generated AC current can be made consistent in both the series and parallel connections of capacitors C10 and C20. Furthermore, in the AC generating circuit 42, the current waveform of the generated AC current can be made closer to a sine wave in both the series and parallel connections of capacitors C10 and C20.

[0067] <Comparative Example>

[0068] [Structure of the AC generation circuit in the comparative example]

[0069] In order to explain the effect of the structure of AC generating circuit 42, firstly, we will explain the AC generating circuit of the comparative example (hereinafter referred to as "AC generating circuit 42C") that does not have capacitor C11, capacitor C21, inductor L10 and inductor L20. Figure 4 This is a diagram illustrating an example of the structure of the AC generating circuit 42C in the comparative example.

[0070] The AC generating circuit 42C includes, for example, capacitor C1, capacitor C2, switch S1, switch S2, and switch S3. Capacitor C1 and capacitor C2 are capacitors with equal capacitance. Switches S1, S2, and S3, for example, control the terminals of both sides to be in a conducting or non-conducting state according to the control signal CS output from the control unit 44. In the following description, the control signal output from the control unit 44 that controls switch S1 to be in a conducting or non-conducting state is called "control signal CS1", the control signal that controls switch S2 to be in a conducting or non-conducting state is called "control signal CS2", and the control signal that controls switch S3 to be in a conducting or non-conducting state is called "control signal CS3".

[0071] The first terminal of capacitor C1 is connected to the positive terminal of battery 30. Furthermore, the first terminal of capacitor C1 is connected to the first terminal of switch S2. The second terminal of capacitor C1 is connected to both the first terminal of switch S1 and the second terminal of switch S3. The second terminal of capacitor C2 is connected to the negative terminal of battery 30. Furthermore, the second terminal of capacitor C2 is connected to the second terminal of switch S1. The first terminal of capacitor C2 is connected to both the second terminal of switch S2 and the first terminal of switch S3.

[0072] In AC generating circuit 42C, capacitor C1 is equivalent to capacitor C10 in AC generating circuit 42, and capacitor C2 is equivalent to capacitor C20 in AC generating circuit 42. In AC generating circuit 42C, switch S1 is equivalent to switch S11 in AC generating circuit 42, and switch S2 is equivalent to switch S12 in AC generating circuit 42. In AC generating circuit 42C, switch S3 is equivalent to switch S13 in AC generating circuit 42. Therefore, AC generating circuit 42C is a structure obtained by omitting capacitors C11 and C21, inductor L10, and inductor L20 from AC generating circuit 42.

[0073] Figure 5 This is an example of the equivalent circuit of the comparative AC generating circuit 42C. Figure 5 In (a), an equivalent circuit is shown in which capacitor C1 and capacitor C2 are connected in series with the battery 30 in the AC generating circuit 42C. Figure 5 (b) shows the equivalent circuit in which capacitor C1 and capacitor C2 are connected in parallel to the battery 30 in the AC generating circuit 42C. Figure 5 In, also with Figure 3 (a) and Figure 3Similarly, in the equivalent circuit of AC generating circuit 42 shown in (b), the inductive component of the inductance La of the battery 30 is "Ls", and the resistive component of the resistor Ra is "Rs". Moreover, the capacitance of capacitors C1 and C2 is "Cx".

[0074] Here, refer to Figure 5 This explains the frequency of the alternating current generated by the alternating current generating circuit 42C. In the alternating current generating circuit 42C, as... Figure 5 The impedance Z of capacitor C1 and capacitor C2 connected in series as shown in (a) can be obtained by the following equation (1).

[0075]

[0076] Furthermore, the angular frequency, i.e. the resonant frequency ωs, when capacitors C1 and C2 are connected in series in the AC generating circuit 42C can be obtained as follows (2).

[0077]

[0078] On the other hand, in the AC generation circuit 42C, such as Figure 5 The impedance Z of capacitor C1 and capacitor C2 connected in parallel as shown in (b) can be obtained by the following equation (3).

[0079]

[0080] Furthermore, the angular frequency, i.e. the resonant frequency ωp, when capacitors C1 and C2 are connected in parallel in the AC generating circuit 42C can be obtained as follows (4).

[0081]

[0082] In the AC generating circuit 42C, the ratio of the resonant frequency ωs when capacitor C1 and capacitor C2 are connected in series and the resonant frequency ωp when capacitor C1 and capacitor C2 are connected in parallel is expressed by the following formula (5).

[0083] ωs:ωp=2:1···(5)

[0084] That is, in the AC generating circuit 42C, the resonant frequency ω differs depending on the difference in the overall capacitance between the series connection and the parallel connection of capacitors C1 and C2. More specifically, the resonant frequency ωs when capacitors C1 and C2 are connected in series is twice the resonant frequency ωp when they are connected in parallel. Therefore, the AC current waveform generated in the AC generating circuit 42C is not sinusoidal; the AC current waveform is asymmetrical between positive (+) and negative (-) current values. Consequently, the AC current generated in the AC generating circuit 42C mostly contains high-order harmonic components, releasing a large amount of noise when the battery 30 is heated.

[0085] Therefore, the efficiency of the AC generation circuit 42C decreases when the battery 30 installed in the vehicle 1 is a combination of multiple batteries 30, for example, when the battery 30 is a combination of two batteries 30. For example, considering a structure where the battery 30 is a combination of two batteries 30, the AC generation circuit 42C is connected to each battery 30, and a predetermined phase difference is imposed between the current waveforms of the AC current generated by each AC generation circuit 42C, thereby aiming to reduce the overall voltage fluctuation (so-called voltage waveform ripple) when the battery 30's temperature rises. That is, it is considered that the phase of the current waveform of the AC current generated by each AC generation circuit 42C is offset by a predetermined phase between each AC generation circuit 42C, thereby aiming to reduce the overall voltage fluctuation when the battery 30's temperature rises. However, in the AC generation circuit 42C, the current waveform of the AC current is asymmetrical, therefore, the overall voltage fluctuation cannot be sufficiently reduced. Therefore, the heating device (hereinafter referred to as "heating device 40C") using AC generation circuit 42C cannot efficiently raise the temperature of battery 30.

[0086] return Figure 3 This describes the frequency of the alternating current generated by the alternating current generating circuit 42. First, consider... Figure 3 The angular frequency, i.e. the resonant frequency, is shown in (a) when capacitors C10 and C20 are connected in series.

[0087] In the AC generation circuit 42, when capacitors C10 and C20 are connected in series, the impedance Zs can be determined according to... Figure 3 The equivalent circuit shown in (a) is obtained as follows (6).

[0088]

[0089] Based on the above equation (6), the impedance Zs in the AC generating circuit 42 when capacitor C10 and capacitor C20 are connected in series can be expressed as follows (7).

[0090]

[0091] That is, the impedance Zs can be obtained as follows (8).

[0092]

[0093] Therefore, the resonant point of the AC current generated when capacitors C10 and C20 are connected in series in the AC generating circuit 42 is the point where the first term on the right side of the above equation (8) becomes zero. That is, the point where the impedance Zs is equal to the resistive component Rs of the resistance Ra of the battery 30 (as shown in the following equation (9)) is the resonant point of the AC current generated when capacitors C10 and C20 are connected in series in the AC generating circuit 42.

[0094] Zs=Rs...(9)

[0095] Therefore, in order to satisfy the above equation (9), the denominator of the first term on the right side of the above equation (8) must not be zero, as expressed by the following equation (10), the numerator of the first term on the right side of the above equation (8) must be zero.

[0096] ω 4 LsLxCxCy-ω 2 (2LxCx+Ls(Cy+Cx))+2=0…(10)

[0097] Therefore, when capacitor C10 and capacitor C20 are connected in series in AC generation circuit 42, the resonant frequency ωs that satisfies the above equation (9) can be expressed by the following equation (11).

[0098]

[0099] Here, the inductance Lx of inductors L10 and L20 included in equation (11) above is replaced with the ratio between the inductance component Ls of the inductance La of the storage battery 30, and the capacitance Cx of capacitors C10 and C20 is replaced with the ratio between the capacitance Cy of capacitors C11 and C21. That is, as in equation (12) below, the inductance Lx is replaced with the value obtained by multiplying the inductance component Ls by a coefficient a, and the capacitance Cx is replaced with the value obtained by multiplying the capacitance Cy by a coefficient b. Thus, equation (11) above is expressed as equation (13) below.

[0100]

[0101]

[0102] The solution to the quadratic equation represented by the above equation (13) is the resonant frequency ωs when capacitor C10 and capacitor C20 are connected in series in the AC generating circuit 42.

[0103] Next, consider Figure 3 The angular frequency, i.e. the resonant frequency ωp, is shown in (b) when capacitors C10 and C20 are connected in parallel.

[0104] In the AC generation circuit 42, when capacitors C10 and C20 are connected in parallel, the impedance Zp can be determined according to... Figure 3 The equivalent circuit shown in (b) is obtained as follows (14).

[0105]

[0106] Based on the above equation (14), the impedance Zp in the AC generating circuit 42 when capacitor C10 and capacitor C20 are connected in parallel can be expressed as follows (15).

[0107]

[0108] That is, the impedance Zp can be obtained as follows (16).

[0109]

[0110] Therefore, the resonant point of the AC current generated in the AC generating circuit 42 when capacitors C10 and C20 are connected in parallel becomes, by the same consideration as when capacitors C10 and C20 are connected in series, the point where the first term on the right side of the above equation (16) becomes zero. That is, the point where the impedance Zp is equal to the resistive component Rs of the resistance Ra of the battery 30 (as shown in equation (17)) is the resonant point of the AC current generated in the AC generating circuit 42 when capacitors C10 and C20 are connected in parallel.

[0111] Zp=Rs…(17)

[0112] Therefore, in order to satisfy the above equation (17), the denominator of the first term on the right side of the above equation (16) must not be zero, as expressed by the following equation (18), the numerator of the first term on the right side of the above equation (16) must be zero.

[0113] 2ω 2 LsCxCyLx-ω 2 (4LxCx+CyLx+2LsCx)+1=0…(18)

[0114] Therefore, when capacitor C10 and capacitor C20 are connected in parallel in AC generating circuit 42, the resonant frequency ωp that satisfies the above equation (17) can be expressed by the following equation (19).

[0115]

[0116] Here, similar to the case where capacitor C10 and capacitor C20 are connected in series, when the inductance Lx and capacitance Cx contained in the above equation (19) are replaced as in the above equation (12), the above equation (19) is expressed as the following equation (20).

[0117]

[0118] The solution to the quadratic equation represented by the above equation (20) is the resonant frequency ωp when capacitor C10 and capacitor C20 are connected in parallel in the AC generating circuit 42.

[0119] Therefore, in the AC generating circuit 42, in order to make the resonant frequency ωs when capacitor C10 and capacitor C20 are connected in series equal to the resonant frequency ωp when capacitor C10 and capacitor C20 are connected in parallel (as shown in equation (21)), based on equation (13) and equation (20) above, equation (22) can be made to hold.

[0120]

[0121] Here, when calculating the above equation (22), it becomes the following equation (23), and when further calculated, it becomes the following equation (24).

[0122]

[0123]

[0124]

[0125]

[0126]

[0127]

[0128]

[0129]

[0130]

[0131] Moreover, based on the above equation (24), we can obtain the following equation (25).

[0132]

[0133] If equation (25) holds true, then equation (21) holds true in AC generating circuit 42, so that the resonant frequency ωs when capacitor C10 and capacitor C20 are connected in series and the resonant frequency ωp when capacitor C10 and capacitor C20 are connected in parallel become equal (consistent).

[0134] Here, when the above equation (25) is further expanded, the square of the left side of the above equation (25) becomes the following equation (26), and the square of the right side of the above equation (25) becomes the following equation (27).

[0135]

[0136]

[0137] Moreover, when the relationship between coefficients a and b is obtained when the squares of both sides of equation (25) (equations (26) and (27)) are equal, as shown in equation (28), the following equation (29) can be obtained.

[0138]

[0139]

[0140] 24a 2 b+8a 2 -20a-24b+8=0

[0141] 6a 2 b+2a 2 -5a-6b+2=0

[0142] (6b+2)a 2 -5a-(6b-2)=0 …(28)

[0143]

[0144] In the above equation (29), the numerator on the right is sometimes "+ (positive)" and "- (negative)", so it can be divided into two categories: the relationship between coefficient a1 and coefficient b1 when the numerator on the right is "+ (positive)" (equation (30) below) and the relationship between coefficient a2 and coefficient b2 when the numerator on the right is "- (negative)" (equation (31) below).

[0145]

[0146]

[0147] Furthermore, regarding the relationship between coefficients a and coefficient b, if any of the relationships in equations (30) and (31) above hold, then in the AC generating circuit 42, the resonant frequency ωs when capacitors C10 and C20 are connected in series and the resonant frequency ωp when capacitors C10 and C20 are connected in parallel become equal (as shown in equation (32) below).

[0148] ωs=ωp…(32)

[0149] However, although the value of coefficient a1 in the above equation (30) is always positive, the value of coefficient a2 in the above equation (31) can sometimes be negative. When the value of coefficient a2 is negative, the operation of AC generating circuit 42 is not valid. Therefore, in order to make coefficient a2 positive (as shown in equation (33)), the numerator on the right side of above equation (31) needs to be positive. That is, for the range of coefficient b2 in the above equation (31), specific conditions need to be determined by the range represented by below equation (34). However, even if the above equation (31) does not hold in the relationship between coefficients a and b, as long as the above equation (30) holds, the resonant frequency ωs when capacitors C10 and C20 are connected in series and the resonant frequency ωp when capacitors C10 and C20 are connected in parallel in AC generating circuit 42 will be consistent in at least one case (as shown in equation (32)).

[0150] a2>0…(33)

[0151]

[0152]

[0153]

[0154]

[0155] Based on this, the solution of the quadratic equation represented by the above equation (13), that is, the resonant frequency ωs when capacitor C10 and capacitor C20 are connected in series in the AC generating circuit 42, can be divided into two cases as shown in the following equation (35): the resonant frequency ωs1 when the numerator on the right is "+ (positive)" and the resonant frequency ωs2 when the numerator on the right is "- (negative)".

[0156]

[0157]

[0158]

[0159] In this case, a resonant frequency ωs1 must also exist. However, if the relationship between coefficients a and b is the relationship of the following equation (36), and the following equation (37) in the numerator on the right side of the above equation (35) holds, then the numerator on the right side of the above equation (35) becomes the following equation (38) and a resonant frequency ωs2 exists. That is, if the following equation (38) holds in the numerator on the right side of the above equation (35), then it becomes the following equation (39). In the case where capacitors C10 and C20 are connected in series in the AC generating circuit 42, the resonant frequency ωs has two cases: resonant frequency ωs1 and resonant frequency ωs2.

[0160] ab>0…(36)

[0161] (2ab+1+b) 2 -8ab>0…(37)

[0162] (2ab+1+b) 2 >(2ab+1+b) 2 -8ab

[0163]

[0164] ωs2 2 >0…(39)

[0165] On the other hand, the solution of the quadratic equation represented by the above equation (20), that is, the resonant frequency ωp when capacitor C10 and capacitor C20 are connected in parallel in the AC generating circuit 42, can be obtained by dividing it into two cases as shown in the following equation (40): the resonant frequency ωp1 when the numerator on the right is "+ (positive)" and the resonant frequency ωp2 when the numerator on the right is "- (negative)".

[0166]

[0167]

[0168]

[0169] In this case, a resonant frequency ωp1 must also exist. However, similar to the case where capacitors C10 and C20 are connected in series, if the following equation (41) in the numerator on the right side of equation (40) holds because the relationship between coefficients a and b is the same as in equation (36), then the numerator on the right side of equation (40) becomes equation (42) and a resonant frequency ωp2 exists. That is, in the case where capacitors C10 and C20 are connected in parallel in the AC generating circuit 42, if the following equation (41) holds in the numerator on the right side of equation (40), then it becomes equation (43), and the resonant frequency ωp exists in two cases: resonant frequency ωp1 and resonant frequency ωp2.

[0170] (4ab+a+2b) 2 -8ab>0…(41)

[0171] (4ab+a+2b) 2 >(4ab+a+2b) 2 -8ab

[0172]

[0173] ωp2 2 >0…(43)

[0174] [An example of the resonant frequency of alternating current]

[0175] Here, we illustrate an example of the resonant frequency ω of the alternating current generated by the alternating current generating circuit 42. Figure 6 This is an example of an equivalent circuit used to illustrate the resonant frequency ω of the alternating current generated in the alternating current generation circuit 42 of the embodiment. Figure 6 In this diagram, an equivalent circuit is shown where a predetermined AC voltage is supplied from the AC power source E1 to the AC generating circuit 42, replacing the energy storage unit Ba in the battery 30. Figure 6 In (a), the equivalent circuit is shown when capacitor C10 and capacitor C20 are connected in series. Figure 6 (b) shows the equivalent circuit when capacitor C10 and capacitor C20 are connected in parallel.

[0176] Here, it is explained that... Figure 6 The resonant frequency ω of the alternating current generated in each of the equivalent circuits shown is, more specifically, an example where the resonant frequency ωs1 and resonant frequency ωp1 of the generated alternating current are 200 kHz. Here, the resistive component Rs of the resistor Ra and the inductive component Ls of the inductor La of the battery 30 are assumed to be, for example, the values ​​shown in equation (44). Moreover, it is assumed that the coefficient b is set to the value shown in equation (45).

[0177] Rs = 0.1Ω

[0178] Ls=300nH…(44)

[0179] b = 2.5…(45)

[0180] In this case, the coefficient a can be obtained based on the above equation (30) as shown in the following equation (46).

[0181]

[0182] Therefore, the inductance Lx of inductors L10 and L20 can be obtained from the above equation (12) as shown in the following equation (47).

[0183] Lx = aLs

[0184] =310.1nH…(47)

[0185] Furthermore, the capacitance Cy of capacitors C11 and C21 can be calculated based on the above equation (35) and then by the following equation (48). The capacitance Cy can also be calculated based on the above equation (40).

[0186]

[0187] Furthermore, the capacitance Cx of capacitors C10 and C20 can be calculated based on the above equation (12) as shown in the following equation (49).

[0188] Cx = bCy

[0189] =16.39uF…(49)

[0190] In this way, the values ​​(parameters) of coefficient a, inductance Lx, capacitance Cy, and capacitance Cx can be obtained based on the assumed coefficient b (here, coefficient b = 2.5). Furthermore, the AC generating circuit 42 is constructed from the constituent elements (capacitor C10, capacitor C11, capacitor C20, capacitor C21, inductor L10, inductor L20) that are adjusted (determined) to the obtained values. Thus, at least an AC generating circuit 42 can be realized where the resonant frequency ωs1 generated when capacitors C10 and C20 are connected in series and the resonant frequency ωp1 generated when capacitors C10 and C20 are connected in parallel are equal (consistent). More specifically, the following AC generating circuit 42 can be implemented, which generates resonant frequencies ωs1 and ωs2 that can be calculated based on the above equation (35) and the following equation (50) when capacitor C10 and capacitor C20 are connected in series, and generates resonant frequencies ωp1 and ωp2 that can be calculated based on the above equation (40) and the following equation (51).

[0191] In the calculations of equations (50) and (51) below, the angular frequencies represented as the resonant frequency ω in the various formulas of equations (35) and (40) above are represented as the usual frequency f in equations (52) and (53) below.

[0192]

[0193]

[0194]

[0195]

[0196]

[0197]

[0198] From the calculation results of equations (50) and (51) above, it can be seen that when capacitors C10 and C20 are connected in series, there are two types of resonant frequencies ω: ωs1 (=frequency fs1) ​​and ωs2 (=frequency fp2). When capacitors C10 and C20 are connected in parallel, there are two types of resonant frequencies ω: ωp1 (=frequency fp1) and ωp2 (=frequency fp2). In this case, both =frequency fs1 and =frequency fp1 are 200[kHz] and equal. That is, the resonant frequency ωs when capacitors C10 and C20 are connected in series and the resonant frequency ωp when capacitors C10 and C20 are connected in parallel are consistent in at least one of the following cases.

[0199] Figure 7 This is a diagram illustrating an example of the frequency characteristics (simulation characteristics) of the alternating current generated in the alternating current generation circuit 42 of the embodiment. Figure 7 An example of the frequency response shown is Figure 6 This is an example where the constituent elements of each equivalent circuit shown are adjusted to the values ​​calculated by equations (44) to (49) above. Figure 7 The diagram shows an example of the amplitude of the alternating current when an alternating voltage of 1 [V] is supplied from an alternating power source E1. Figure 7 In (a), an example of the frequency characteristics is shown when capacitor C10 and capacitor C20 are connected in series. Figure 7 (b) shows an example of the frequency characteristics when capacitor C10 and capacitor C20 are connected in parallel. Figure 7 (a) and Figure 7 In (b), the horizontal axis represents the frequency, and the vertical axis represents the value of the generated alternating current. The vertical axis represents the amplitude of the generated alternating current.

[0200] like Figure 7 (a) and Figure 7 As shown in (b), in both the case where capacitors C10 and C20 are connected in series and in parallel, there are two locations where the current value reaches its peak at the resonant point. Therefore, the resonant frequency ω has two distinct cases. More specifically, in Figure 7 In an example of the frequency characteristics shown in (a) where capacitors C10 and C20 are connected in series, it can be seen that there are resonant points where the current value peaks at the respective frequencies fs1 and fs2 calculated as in equation (50) above. On the other hand, in Figure 7In example of the frequency characteristics shown in (b) where capacitors C10 and C20 are connected in parallel, it can be seen that there are resonant points where the current value becomes the peak value in each of the frequencies fp1 and fp2 calculated as in equation (51) above. It can also be seen that by constructing each component that is adjusted (determined) to the values ​​calculated by equations (44) to (49) above, an AC generating circuit 42 can be realized in which the resonant frequency ω exists in two different cases.

[0201] Thus, capacitors C10, C11, C20, and C21, along with inductors L10 and L20, constitute an AC generating circuit 42, with the values ​​(parameters) of coefficient a, inductance Lx, capacitance Cy, and capacitance Cx respectively, derived from the assumed coefficient b. This allows for a structure in the AC generating circuit 42 where the frequency f is equal (consistent) in at least one of the following cases: when capacitors C10 and C20 are connected in series, and when capacitors C10 and C20 are connected in parallel, the frequency fp1 is also equal.

[0202] In the AC generation circuit 42, for example, when the battery 30 installed in the vehicle 1 is a structure obtained by combining multiple batteries 30, the AC generation circuit 42 is connected to each battery 30, and a predetermined phase difference is given between the current waveforms of the AC current generated by each AC generation circuit 42, thereby reducing the overall voltage fluctuation when the temperature of the battery 30 rises. That is, by shifting the phase of the current waveforms of the AC current generated by each AC generation circuit 42 by a predetermined phase, the overall voltage fluctuation when the temperature of the battery 30 rises can be reduced. For example, when the battery 30 installed in the vehicle 1 is a structure obtained by combining two batteries 30, the phase of the current waveforms of the AC current generated by each AC generation circuit 42 connected to each battery 30 is shifted by 180°, thereby reducing the overall voltage fluctuation when the temperature of each battery 30 rises. For example, when the battery 30 installed in vehicle 1 is a combination of three batteries 30, by shifting the phase of the current waveform of the AC current generated by each AC generating circuit 42 connected to each battery 30 by 120°, it is possible to reduce the overall voltage fluctuation when the temperature of each battery 30 rises. This is because the current waveform of the AC current generated by each AC generating circuit 42 is similar to a symmetrical sine wave at both positive (+) and negative (-) current values. Therefore, the temperature of the battery 30 can be raised efficiently in the heating device 40.

[0203] [Operation of the heating device]

[0204] Next, an example of the operation of the heating device 40 will be described. Here, we will describe a case where the battery 30 installed in vehicle 1 is a combination of two batteries 30 (battery 30a and battery 30b). In this case, an AC generating circuit 42 is connected to each battery 30, and an AC current is applied (flowing) to raise the temperature. At this time, the control unit 44 controls the phase of the AC current generated in each AC generating circuit 42 to be offset by a predetermined phase (here, 180° phase offset), thereby reducing the overall voltage fluctuation (so-called voltage waveform ripple) output from the combination of the two batteries 30. In other words, the control unit 44 inputs to each AC generating circuit 42 at different times to make each AC generating circuit 42 operate in opposite directions, thereby reducing the overall voltage fluctuation when the temperature of the two batteries 30 rises. Battery 30a is an example of a "first battery", and battery 30b is an example of a "second battery".

[0205] [Operation of the heating device in the comparative example]

[0206] First, to explain the operation used in comparison with the heating device 40, Figure 4 The operation of the heating device (hereinafter referred to as "heating device 40C") of the AC generating circuit 42C shown in the comparative example. Figure 8 This is a diagram illustrating an example of the structure and operating waveform (simulation waveform) of the heating device 40C using the AC generating circuit 42C of the comparative example. Figure 8 This is an example where the resonant frequency ω of the AC current generated by the AC generating circuit 42C is 200 kHz.

[0207] exist Figure 8 In (a), the connection of the AC generating circuit 42C (AC generating circuit 42Ca and AC generating circuit 42Cb) corresponding to each battery 30 is shown, as well as the AC current flowing in each battery 30 connected to the respective AC generating circuit 42C. Figure 8 In (b), an example is shown of the control signals output by the control unit 44 to each switch, as well as the changes in AC current and output voltage within each battery 30. Figure 8 In the figures, the “a” at the end of each figure indicates that it corresponds to AC generation circuit 42Ca, and the “b” indicates that it corresponds to AC generation circuit 42Cb.

[0208] like Figure 8As shown in (a), in the case of a structure combining two batteries 30, one battery 30a is connected to an AC generating circuit 42Ca, and the other battery 30b is connected to an AC generating circuit 42Cb. Furthermore, the control unit 44 outputs control signals to the switches of each AC generating circuit 42C, causing the phase of the AC current generated by each AC generating circuit 42C to be offset by 180°. Figure 8 In (a), an example is shown where the control unit 44 controls each switch via a control signal, thereby changing the voltage measurement position and the direction of current flow in each battery 30. More specifically, as an example of voltage and current corresponding to the AC generating circuit 42Ca, the voltages V1-V0 between the terminals of the battery 30a (including inductor Laa) and the currents I-E1a flowing in the battery 30a (including inductor Laa) are shown. Furthermore, as an example of voltage and current corresponding to the AC generating circuit 42Cb, the voltages V2-V1 between the terminals of the battery 30b (including inductor Lab) and the currents I-E1b flowing in the battery 30b (including inductor Lab) are shown. Moreover, in Figure 8 In (a), the voltage of the entire combination of batteries 30a and 30b is shown as the voltage between the negative terminal (V0) of battery 30a in AC generation circuit 42Ca and the positive terminal (V2) of battery 30b in AC generation circuit 42Cb.

[0209] exist Figure 8 In (b), an example is shown of the control signals CS used by the control unit 44 to control the various AC generation circuits 42C, and the changes in current and voltage in AC generation circuits 42Ca and 42Cb. Figure 8 In (b), the control unit 44 sets each control signal CS to a "high" level, thereby turning on the corresponding switch, and sets it to a "low" level, thereby turning off the corresponding switch. Figure 8 In (b), the control unit 44 outputs a control signal CS to each switch with a duty cycle of 1:1, i.e., a duty cycle of 50%. As described above, the control unit 44 can also set an idle time between the period when the switch is in the conducting state and the period when the switch is in the non-conducting state, during which all switches are in the non-conducting state. Figure 8 (b) shows the case where the control unit 44 controls each switch without setting an idle time.

[0210] exist Figure 8In (b), an example is shown of the changes in voltage V1-V0 and current I-E1a caused by the control unit 44 controlling control signals CS1a, CS2a, and CS3a to the AC generating circuit 42Ca. Furthermore, in Figure 8 In (b), an example is shown of the changes in voltage V2-V1 and current I-E1b caused by the control unit 44 controlling control signals CS1b, CS2b, and CS3b to the AC generating circuit 42Cb. Furthermore, in Figure 8 In (b), an example of the change in voltage V2-V0 is shown.

[0211] like Figure 8 As shown in (b), during period P1, control unit 44 sets control signals CS1a and CS2a of AC generation circuit 42Ca to a "low" level and control signal CS3a to a "high" level. Consequently, in AC generation circuit 42Ca, capacitors C1a and C2a are connected in series with battery 30a, and current I-E1a flows primarily towards the positive region. Therefore, the voltages V1-V0 of AC generation circuit 42Ca primarily decrease from the positive peak voltage towards the negative peak voltage. Afterwards, as... Figure 8 As shown in (b), during period P2, control unit 44 sets control signals CS1a and CS2a of AC generation circuit 42Ca to "high" level and control signal CS3a to "low" level. Consequently, in AC generation circuit 42Ca, capacitors C1a and C2a are connected in parallel to battery 30a, and current I-E1a flows primarily into the negative region. Therefore, the voltages V1-V0 of AC generation circuit 42Ca primarily increase from negative peak voltages towards positive peak voltages.

[0212] like Figure 8 As shown in (b), in the AC generating circuit 42Cb, the control unit 44 controls control signals CS1b, CS2b, and CS3b during periods P1 and P2. Consequently, in the AC generating circuit 42Cb, current I-E1b flows similarly to that in the AC generating circuit 42Ca. However, as described above, the control unit 44 outputs each control signal CS to shift the phase of the AC current generated by each AC generating circuit 42C by 180°. Therefore, the current I-E1b flowing in the battery 30b connected to the AC generating circuit 42Cb is phase-shifted by 180° compared to the current I-E1a flowing in the battery 30a connected to the AC generating circuit 42Ca. Consequently, the voltages V2-V1 of the AC generating circuit 42Cb are also phase-shifted by 180° compared to the voltages V1-V0 of the AC generating circuit 42Ca.

[0213] Thus, in the heating device 40C, the control unit 44 outputs control signals CS to each switch, thereby... Figure 8 As shown in (b), the voltage V2-V0 is obtained by adding the voltage V1-V0 of the AC generating circuit 42Ca to the voltage V2-V1 of the AC generating circuit 42Cb. However, from Figure 8 As shown in (b), the voltage waveform V2-V0 shows that although its amplitude is narrower than that of voltages V1-V0 and V2-V1, its voltage waveform is not close to a sine wave. This is because the control unit 44 switches the connection of capacitors C1 and C2 to the battery 30 to a series connection or a parallel connection. However, at this time, the current waveforms of the AC currents (currents I-E1a and I-E1b) generated by each AC generating circuit 42C are not sine waves, and the amplitudes are different in the positive and negative regions of the AC current, i.e., they are asymmetrical. As a result, the overall voltage fluctuation (voltage waveform ripple) when the temperature of the battery 30 rises cannot be sufficiently reduced.

[0214] However, in the AC generating circuit 42C, as described above, the resonant frequency ωs when capacitors C1 and C2 are connected in series is twice the resonant frequency ωp when capacitors C1 and C2 are connected in parallel. Therefore, in the AC generating circuit 42C, it is advisable for the control unit 44 to set the duty cycle to 1:2, switching the connection of capacitors C1 and C2 in each AC generating circuit 42C to the battery 30 to either a series connection or a parallel connection.

[0215] [Other operations of the heating device in the comparative example]

[0216] Figure 9 This is a diagram illustrating an example of another operating waveform (simulation waveform) of the heating device 40C using the AC generating circuit 42C of the comparative example. Figure 9 Is Figure 8 In the case shown in (a), the control unit 44 switches between series connection and parallel connection of capacitors C1 and C2 in each AC generation circuit 42C to the battery 30 with a duty cycle of 1:2. Figure 9 This is also an example where the resonant frequency ω of the AC current generated by the AC generating circuit 42C is 200 kHz.

[0217] exist Figure 9 In, with Figure 8 (b) also shows an example of the control signals CS used by the control unit 44 to control the various AC generating circuits 42C, as well as the changes in current and voltage in AC generating circuits 42Ca and 42Cb. Figure 9In the diagram, the "a" at the end of each figure's reference numeral indicates that it is related to... Figure 8 The AC generating circuit 42Ca shown in (a) corresponds to the circuit shown in (b), and "b" indicates the circuit with AC power generation. Figure 8 The AC generating circuit 42Cb shown in (a) corresponds to this.

[0218] like Figure 9 As shown, during the period PSA, the control unit 44 sets the control signals CS1a and CS2a of the AC generating circuit 42Ca to a "low" level and the control signal CS3a to a "high" level. Therefore, in the AC generating circuit 42Ca, capacitors C1a and C2a are connected in series with the battery 30a, and the current I-E1a and... Figure 8 Similarly, (b) mainly flows to the positive region. Therefore, the voltage V1-V0 of the AC generating circuit 42Ca is similar to... Figure 8 Similarly, (b) mainly decreases from the positive peak voltage towards the negative peak voltage. Then, during this period PPa, the control unit 44 sets the control signals CS1a and CS2a of the AC generating circuit 42Ca to the "high" level and the control signal CS3a to the "low" level. Thus, in the AC generating circuit 42Ca, capacitors C1a and C2a are connected in parallel to the battery 30a, and... Figure 8 Similarly, in (b), the current I-E1a mainly flows to the negative region. Therefore, the voltage V1-V0 of the AC generating circuit 42Ca is... Figure 8 Similarly, (b) mainly rises from negative peak voltage toward positive peak voltage.

[0219] like Figure 9 As shown, in the AC generating circuit 42Cb, the control unit 44 controls control signals CS1b, CS2b, and CS3b during PSb and PPb. Therefore, in the AC generating circuit 42Cb, the current I-E1b flows in the same manner as in the AC generating circuit 42Ca. At this time, the control unit 44 outputs each control signal CS as described above, so that the phase of the AC current generated by each AC generating circuit 42C is shifted by 180°. Therefore, with... Figure 8 Similarly, in (b), the current I-E1b flowing in battery 30b connected to AC generation circuit 42Cb is 180° out of phase with the current I-E1a flowing in battery 30a connected to AC generation circuit 42Ca. Consequently, the voltage V2-V1 of AC generation circuit 42Cb is also out of phase with... Figure 8 Similarly, (b) is 180° out of phase with the voltage V1-V0 of the AC generating circuit 42Ca.

[0220] Thus, in the heating device 40C, the control unit 44 outputs control signals CS to each switch with a duty cycle of 1:2, thereby interacting with... Figure 8 Similarly, in (b), voltage V2-V0 is obtained by adding voltage V1-V0 from AC generating circuit 42Ca and voltage V2-V1 from AC generating circuit 42Cb. However, from Figure 9 The waveforms of voltages V2-V0 shown also indicate that the voltage waveforms are similar to... Figure 8 Similarly, (b) is not close to a sine wave. This is because: even if the control unit 44 switches the connection of capacitors C1 and C2 to the battery 30 with a duty cycle of 1:2 to a series connection or a parallel connection so that the resonant frequency ωs is aligned with the resonant frequency ωp, the current waveforms of the currents I-E1a and I-E1b generated by each AC generating circuit 42C are not sine waves, and the amplitude of the AC current is still different in the positive and negative regions (positive and negative asymmetry). Therefore, as Figure 9 As shown, even if the control unit 44 sets the duty cycle to 1:2 and switches the connection of capacitors C1 and C2 in each AC generating circuit 42C to the battery 30 to a series connection or a parallel connection, it cannot sufficiently reduce the overall voltage fluctuation (voltage waveform ripple) when the temperature of the battery 30 rises.

[0221] Next, the operation of the heating device 40 will be explained. Figure 10 This is a diagram illustrating an example of the structure and operating waveform (simulation waveform) of the heating device 40 using the AC generation circuit 42 of the embodiment. Figure 10 It involves adjusting the values ​​(parameters) of each component of the AC generating circuit 42 to the values ​​calculated by equations (44) to (49) above, and then... Figure 8 The example shown is an example of the operating waveform of the AC generating circuit 42C in the comparative example, and it is also an example where the resonant frequency ω of the AC current generated by the AC generating circuit 42 is 200 [kHz].

[0222] exist Figure 10 In (a), the connection of the AC generating circuits 42 (AC generating circuits 42a and 42b) corresponding to each battery 30 is shown, as well as the AC current flowing in each battery 30 connected to the AC generating circuits 42. Figure 10 In (b), an example is shown of the control signals output by the control unit 44 to each switch, as well as the changes in AC current and output voltage within each battery 30. Figure 10In the accompanying figures, the "a" at the end indicates a correspondence with AC generating circuit 42a, and the "b" indicates a correspondence with AC generating circuit 42b. AC generating circuit 42a is an example of an "AC generating circuit," and AC generating circuit 42b is an example of a "second AC generating circuit." The AC current generated by AC generating circuit 42a is an example of "AC current," and the AC current generated by AC generating circuit 42b is an example of "second AC current."

[0223] like Figure 10 As shown in (a), in the structure obtained by combining two batteries 30, one battery 30a is connected to AC generating circuit 42a, and the other battery 30b is connected to AC generating circuit 42b. Furthermore, the control unit 44 outputs control signals to the switches of each AC generating circuit 42, so that the phase of the AC current generated by each AC generating circuit 42 is shifted by 180°. Figure 10 In (a), an example is shown where the control unit 44 controls each switch via a control signal, thereby changing the voltage measurement position and the direction of current flow in each battery 30. More specifically, as an example of voltage and current corresponding to the AC generating circuit 42a, the voltages V1-V0 between the terminals of the battery 30a (including inductor Laa) and the currents I-E1a flowing in the battery 30a (including inductor Laa) are shown. Furthermore, as an example of voltage and current corresponding to the AC generating circuit 42b, the voltages V2-V1 between the terminals of the battery 30b (including inductor Lab) and the currents I-E1b flowing in the battery 30b (including inductor Lab) are shown. Moreover, in Figure 10 In (a), the voltage of the entire combination of batteries 30a and 30b is shown as the voltage between the negative terminal (V0) of battery 30a in AC generation circuit 42a and the positive terminal (V2) of battery 30b in AC generation circuit 42b.

[0224] exist Figure 10 In (b), an example is shown of the control signals CS used by the control unit 44 to control the various AC generation circuits 42, as well as the changes in current and voltage in AC generation circuits 42a and 42b. Figure 10In (b), the control unit 44 sets each control signal CS to a "high" level to turn on the corresponding switch, and sets it to a "low" level to turn it off. In the AC generation circuit 42, as described above, the resonant frequency ωs when capacitors C10 and C20 are connected in series is equal to the resonant frequency ωp when capacitors C10 and C20 are connected in parallel. Therefore, in Figure 10 In (b), the control unit 44 sets the duty cycle to 1:1, that is, a duty cycle of 50%, and outputs a control signal CS to each switch. As described above, the control unit 44 can also set an idle time between the period when the switch is in the on state and the period when the switch is in the off state, so that all switches are in the off state. Figure 10 (a) shows the case where the control unit 44 controls each switch without setting an idle time.

[0225] exist Figure 10 In (b), an example is shown where the voltages V1-V0 and current I-E1a change as a result of the control unit 44 controlling the AC generating circuit 42a with control signals CS11a, CS12a, and CS13a. Furthermore, in Figure 10 In (b), an example is shown where the voltages V2-V1 and currents I-E1b change as a result of the control unit 44 controlling the AC generating circuit 42b with control signals CS11b, CS12b, and CS13b. Furthermore, in Figure 10 An example of the change in voltage V2-V0 is also shown in (b).

[0226] like Figure 10 As shown in (b), during period P1, control unit 44 sets control signals CS11a and CS12a of AC generation circuit 42a to a "low" level and control signal CS13a to a "high" level. Consequently, in AC generation circuit 42a, capacitors C10a and C20a are connected in series with battery 30a, and current I-E1a flows primarily to the negative region. Consequently, the voltages V1-V0 of AC generation circuit 42a primarily rise from negative peak voltages to positive peak voltages. On the other hand, during period P1, control unit 44 sets control signals CS11b and CS12b of AC generation circuit 42b to a "high" level and control signal CS13b to a "low" level. Consequently, in AC generation circuit 42b, capacitors C10b and C20b are connected in parallel with battery 30a, and current I-E1b flows primarily to the positive region. Therefore, the voltage V2-V1 of the AC generating circuit 42b decreases mainly from the positive peak voltage to the negative peak voltage.

[0227] After that, as Figure 10 As shown in (b), during period P2, control unit 44 sets control signals CS11a and CS12a of AC generating circuit 42a to "high" level and control signal CS13a to "low" level. Consequently, in AC generating circuit 42a, capacitors C10a and C20a are connected in parallel to battery 30a, and current I-E1a flows primarily in the positive region. Consequently, the voltages V1-V0 of AC generating circuit 42a decrease primarily from the positive peak voltage towards the negative peak voltage. On the other hand, during period P2, control unit 44 sets control signals CS11b and CS12b of AC generating circuit 42b to "low" level and control signal CS13b to "high" level. Consequently, in AC generating circuit 42b, capacitors C10b and C20b are connected in series to battery 30a, and current I-E1b flows primarily in the negative region. Therefore, the voltage V2-V1 of the AC generating circuit 42b mainly rises from a negative peak voltage to a positive peak voltage.

[0228] Thus, the control unit 44 outputs control signals CS as described above, causing the phase of the AC current generated by each AC generating circuit 42 to be offset by 180°. Consequently, the phase of the current I-E1a flowing in the battery 30a connected to the AC generating circuit 42a is offset by 180° with the phase of the current I-E1b flowing in the battery 30b connected to the AC generating circuit 42b. Consequently, the phase of the voltages V1-V0 of the AC generating circuit 42a and V2-V1 of the AC generating circuit 42b is also offset by 180°.

[0229] Thus, in the heating device 40, the control unit 44 outputs a control signal CS with a duty cycle of 50% to each switch, and switches the connection of capacitors C10 and C20 to the battery 30 to a series connection or a parallel connection. As a result, current I-E1a flows in the battery 30a connected to the AC generation circuit 42a, and current I-E1b flows in the battery 30b connected to the AC generation circuit 42b. Furthermore, due to… Figure 10 The waveforms of currents I-E1a and I-E1b shown in (b) also indicate that the waveforms of each alternating current are similar to those in... Figure 8 The current waveforms of the alternating currents (currents I-E1a and I-E1b) generated by each AC generating circuit 42 in the heating device 40C shown are more sinusoidal than those of a sine wave. Therefore, in the heating device 40, the voltages V1-V0 of AC generating circuit 42a and V2-V1 of AC generating circuit 42b are symmetrical, positive and negative respectively. Consequently, in the heating device 40, the voltage waveform of voltage V2-V0 obtained by adding voltage V2-V1 to voltage V1-V0 is... Figure 10The waveform of voltage V2-V0 shown in (b) can also be seen to be similar to... Figure 8 The voltage V2-V0 in the heating device 40C shown exhibits very little variation compared to voltage waveform ripple. In other words, the voltage V2-V0 in the heating device 40 hardly changes, reaching a level of characteristic that can be described as flat.

[0230] Thus, in the heating device 40, when the battery 30 installed in the vehicle 1 is a combination of two batteries 30 (here, battery 30a and battery 30b), the control unit 44 outputs a control signal CS with a duty cycle of 50% to each switch, switching the connection of capacitors C10 and C20 to the battery 30 between series connection and parallel connection. In other words, the control unit 44 controls the output of the control signal CS by shifting the phase of the control signal CS by a predetermined phase (here, 180° phase shift), so that the AC generating circuit 42 corresponding to each battery 30 operates in the opposite direction. Therefore, the AC generating circuit 42... Figure 10 As shown in (b), the variation in the overall voltage V2-V0 obtained by combining the two batteries 30 can be reduced. In other words, the AC generation circuit 42 can generate an AC current that reduces high-order harmonic components, thereby reducing noise emitted when the batteries 30 are heated. Therefore, when the batteries 30 installed in the vehicle 1 are a combination of two batteries 30, the AC generation circuit 42 is more easily adapted to a structure that increases the temperature by applying (flowing) AC current to each battery 30 and reduces the variation in the overall voltage output from the combination of the two batteries 30 (so-called voltage waveform ripple).

[0231] [Other structures of the heating device]

[0232] Figure 10 (a) shows an example of the structure of the heating device 40 when the battery 30 mounted on the vehicle 1 is a combination of two batteries 30 (here, battery 30a and battery 30b), but as mentioned above, the battery 30 mounted on the vehicle 1 can also be a combination of three batteries 30. Figure 11 This is a diagram illustrating another example of the structure of the heating device 40 employing the AC generation circuit 42 of the embodiment. Figure 11 This is an example of a configuration in which the battery 30 mounted on vehicle 1 is a combination of three batteries 30 (battery 30a, battery 30b and battery 30c).

[0233] like Figure 11As shown, in the configuration obtained by combining three batteries 30, the first battery 30a is connected to the AC generation circuit 42a, the second battery 30b is connected to the AC generation circuit 42b, and the third battery 30c is connected to the AC generation circuit 42c. Furthermore, the control unit 44 outputs control signals to the switches of each AC generation circuit 42, so that the phase of the AC current generated by each AC generation circuit 42 is shifted by 120°.

[0234] In this case, the control of each AC generation circuit 42 in the control unit 44 (the output timing of each control signal CS) and its use Figure 10 The control unit 44, which controls each AC generation circuit 42 (output timing of each control signal CS) in the case where the battery 30 is a structure obtained by combining two batteries 30, is equivalent to this. Therefore, the operation (changes in current and voltage) of each AC generation circuit 42 can be adjusted according to the user's needs. Figure 10 The operation (changes in current and voltage) of each AC generating circuit 42 is explained and is therefore easy to understand. Therefore, [the following is omitted]. Figure 11 A detailed explanation of the control of each AC generating circuit 42 by the control unit 44 in the structure shown, and the operation of each AC generating circuit 42.

[0235] As described above, according to the embodiment of the heating device 40, the AC generating circuit 42 includes, for example, capacitors C10, C11, C20, and C21, switches S11, S12, and S13, inductors L10 and L20. Furthermore, in the embodiment of the heating device 40, an AC current based on the electricity stored in the battery 30 is generated by a resonant operation in which the connection of capacitors C10 and C20 in the AC generating circuit 42 to the battery 30 is switched between series and parallel connections, thereby alternating the magnetic energy stored in the inductor La of the battery 30 with the electrostatic energy stored in the capacitor C10. At this time, in the AC generation circuit 42 of the embodiment, the values ​​(parameters) of the constituent elements of capacitors C10, C11, C20, C21, inductors L10 and L20 are adjusted (determined) to values ​​calculated based on the relationship (Equation (12), Equations (29) to (31), Equation (35), Equation (40) above) that includes the inductance component Ls of the inductance La of the battery 30. Therefore, in the heating device 40 of the embodiment, in each AC generation circuit 42, whether capacitors C10 and C20 are connected in series with the battery 30 or in parallel, the resonant frequency ω of the AC current is equal (consistent), and an AC current with a current waveform closer to a sine wave can be generated. Therefore, in the heating device 40 of the embodiment, the AC current with a current waveform closer to a sine wave generated by the AC generation circuit 42 can heat the battery 30 more efficiently. Therefore, in the vehicle 1 employing the heating device 40 of the embodiment, the battery 30 can be heated to a suitable temperature, and the reduction in the charging and discharging performance of the battery 30 can be suppressed. Furthermore, in the vehicle 1 employing the heating device 40 of the embodiment, the alternating current generated by the alternating current generation circuit 42 contains fewer high-order harmonic components, thus reducing the noise emitted when heating the battery 30.

[0236] However, in the heating device 40 of the above embodiment, it is explained that the capacitance Cx of capacitor C10 in AC generating circuit 42 is equal to the capacitance Cx of capacitor C20, the capacitance Cy of capacitor C11 is equal to the capacitance Cy of capacitor C21, and the inductance Lx of inductor L10 is equal to the inductance Lx of inductor L20. Furthermore, it is explained that the inductance component of inductor La in battery 30 is inductance component Ls, and the values ​​(parameters) of capacitance and inductance of each component are adjusted (determined) based on the relationships expressed by equations (12), (29) to (31), (35), and (40) above. However, it is envisioned that even if the capacitance and inductance of each component are identical, their characteristics may differ. Furthermore, it is also envisioned that the wiring connecting AC generating circuit 42 and battery 30 also includes an inductance component. Therefore, in the heating device 40 of the embodiment, the values ​​(parameters) of the capacitance and inductance of each component of the AC generating circuit 42 can be made to take into account the deviations in the characteristics of each component, the deviations in the inductance component Ls of the inductance La of the battery 30, and the inductance component included in the wiring portion connecting the AC generating circuit 42 and the battery 30. That is, in the heating device 40 of the embodiment, as long as the current waveform of the AC current generated by the AC generating circuit 42 can be considered as a sine wave (the range in which a substantial effect can be obtained), there can be a certain degree of leeway relative to the values ​​of capacitance Cx of capacitor C10 and capacitance Cx of capacitor C20, capacitance Cy of capacitor C11 and capacitance Cy of capacitor C21, and inductance Lx of inductor L10 and inductor Lx of inductor L20. In other words, in the heating device 40 of the embodiment, the values ​​can be within the range where the capacitance Cx of capacitor C10 is equal to the capacitance Cx of capacitor C20, the capacitance Cy of capacitor C11 is equal to the capacitance Cy of capacitor C21, and the inductance Lx of inductor L10 is equal to the inductance Lx of inductor L20.

[0237] In the heating device 40 of the above-described embodiment, the case where the duty cycle of the control signal CS output by the control unit 44 to each switch is 50% is described. However, as described above, the control unit 44 may also control the switches by setting an idle time between the period when the switches are in the conducting state and the period when the switches are in the non-conducting state, so that all switches are in the non-conducting state. For example, in the heating device 40 of the embodiment, the control unit 44 may set the idle time by setting the duty cycle of the control signal CS output to each switch to a value that can be considered approximately 50% (for example, a specified value between 45% and 55%), and output the control signal CS to each switch, thereby switching the connection of capacitors C10 and C20 to the battery 30 from a parallel connection to a series connection, or vice versa.

[0238] According to the heating device 40 of the embodiment described above, the AC generating circuit 42 heats the battery 30 by generating an AC current based on the power stored in the battery 30 having an inductance La. The AC generating circuit 42 includes: a capacitor C10, the first end of which is connected to the positive terminal of the battery 30; a capacitor C20, the second end of which is connected to the negative terminal of the battery 30; a parallel switching unit (e.g., switches S11 and S12), which connects the capacitors C10 and C20 in parallel with the battery 30 by connecting the second terminal of the capacitor C10 to the second terminal of the capacitor C20 and connecting the first terminal of the capacitor C10 to the first terminal of the capacitor C20; and a series connection. A series switch (e.g., switch S13) is used to connect capacitors C10 and C20 in series with the battery 30 by connecting the second terminal of capacitor C10 to the first terminal of capacitor C20; an inductor L10 is connected between the positive terminal of the battery 30 and the first terminal of capacitor C10; an inductor L20 is connected between the second terminal of capacitor C20 and the negative terminal of the battery 30; a capacitor C11 is connected between the second terminal of capacitor C10 and the negative terminal of the battery 30; and a capacitor C21 is connected between the positive terminal of the battery 30 and the first terminal of capacitor C20. This allows the battery 30 used in the vehicle 1 to be heated more efficiently. Therefore, in the vehicle 1 using the heating device 40 of this embodiment, the battery 30 can be used at a suitable temperature, and the reduction in the charging and discharging performance of the battery 30 can be suppressed. Therefore, in the vehicle 1 equipped with the heating device 40 of the embodiment, the product quality of the vehicle 1, such as durability, can be improved. Thus, in the vehicle 1 equipped with the heating device 40 of the embodiment, energy efficiency can be improved, and it is expected to contribute to mitigating the adverse effects on the Earth's environment.

[0239] The above embodiments describe a structure where the control device 100 controls the start-up or stop of the heating device 40, and the control unit 44 controls the switches of the AC generating circuit 42 to be in an on or off state. The operation of the control unit 44 can also be implemented by a program executed by a hardware processor such as a CPU included in the control unit 44. The function of the control device 100 may also include the function of the control unit 44 described above. In this case, the control unit 44 may be omitted from the heating device 40. In this case, the control device 100 becomes an example of a "control unit".

[0240] The above description illustrates specific embodiments of the present invention, but the present invention is not limited to such embodiments in any way, and various modifications and substitutions can be made without departing from the spirit of the present invention.

Claims

1. An AC generating circuit that heats the energy storage medium by generating an alternating current based on the electricity stored in the energy storage medium having an inductive component, wherein, The AC generating circuit includes: The first capacitor has its first end connected to the positive terminal of the energy storage body; The second capacitor has its second end connected to the negative terminal side of the energy storage body; The parallel switching section connects the first capacitor and the second capacitor in parallel to the energy storage body by connecting the second terminal of the first capacitor to the second terminal of the second capacitor and connecting the first terminal of the first capacitor to the first terminal of the second capacitor. A series switch section connects the first capacitor and the second capacitor in series with the energy storage body by connecting the second terminal of the first capacitor to the first terminal of the second capacitor. A first inductor is connected between the positive terminal of the energy storage body and the first terminal of the first capacitor; A second inductor is connected between the second terminal of the second capacitor and the negative terminal side of the energy storage body; A third capacitor is connected between the second terminal of the first capacitor and the negative terminal side of the energy storage body; as well as A fourth capacitor is connected between the positive terminal of the energy storage device and the first terminal of the second capacitor. The inductance of the first inductor, the inductance of the second inductor, the capacitance of the first capacitor, the capacitance of the second capacitor, the capacitance of the third capacitor, and the capacitance of the fourth capacitor are adjusted based on a formula that includes the inductance component so that the current waveform of the alternating current approximates a sine wave. The relationship is as follows: Adjust the inductance of the first inductor, the inductance of the second inductor, the capacitance of the first capacitor, the capacitance of the second capacitor, the capacitance of the third capacitor, and the capacitance of the fourth capacitor so that the frequency of the alternating current in the parallel state of the first capacitor and the second capacitor connected in parallel to the energy storage body is consistent with the frequency of the alternating current in the series state of the first capacitor and the second capacitor connected in series to the energy storage body.

2. The AC generating circuit according to claim 1, wherein, The inductance of the first inductor is equal to the inductance of the second inductor.

3. The AC generating circuit according to claim 2, wherein, The capacitance of the first capacitor is equal to the capacitance of the second capacitor.

4. The AC generating circuit according to claim 3, wherein, The capacitance of the third capacitor is equal to the capacitance of the fourth capacitor, which is the second capacitance.

5. The AC generating circuit according to claim 1, wherein, The inductive component is included in the inductive component of the wiring portion between the energy storage element and the AC generating circuit.

6. The AC generating circuit according to claim 1, wherein, The parallel switching section includes a first switch and a second switch. The first terminal of the first switch is connected to the second terminal of the first capacitor, and the second terminal of the first switch is connected to the second terminal of the second capacitor. The first terminal of the second switch is connected to the first terminal of the first capacitor, and the second terminal of the second switch is connected to the first terminal of the second capacitor. The series switch section includes a third switch, the first terminal of which is connected to the first terminal of the second capacitor, and the second terminal of which is connected to the second terminal of the first capacitor. The first switch and the second switch are simultaneously controlled to be in a conducting state or a non-conducting state via a first control signal. The third switch is controlled to be in a conducting or non-conducting state by a second control signal. The periods during which the first control signal puts the first and second switches into a conducting state, and the periods during which the second control signal puts the third switch into a conducting state, are non-overlapping periods.

7. The AC generating circuit according to claim 6, wherein, The energy storage device includes a first energy storage device and a second energy storage device connected in series with the first energy storage device. The AC generating circuit is connected to the first battery. A second AC generating circuit, with the same structure as the AC generating circuit, is connected to the second battery. The first control signal and the second control signal are input in such a way that a predetermined phase difference is assigned between the AC current generated by the AC generating circuit and the AC current generated by the second AC generating circuit, i.e., the second AC current.

8. A heating device, wherein, The heating device includes: The AC generating circuit as described in claim 7; and Control Department The control unit outputs the first control signal and the second control signal, and alternately switches between parallel and series states through the first control signal and the second control signal. The parallel connection state refers to a state in which the first switch and the second switch are in a conducting state, and the third switch is in a non-conducting state, such that the first capacitor and the second capacitor are connected in parallel to the energy storage body. The series connection state refers to a state in which the first switch and the second switch are in a non-conducting state, and the third switch is in a conducting state, so that the first capacitor and the second capacitor are connected in series with the energy storage body.

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