Insulated power source unit, power source system, and power source control program

Abstract

To provide an insulated power source unit capable of suppressing noise so as to meet standards, a power source system, and a power control program.SOLUTION: A switching power source 40 supplying power to a gate drive circuit DR of upper and lower arm switches Sp and Sn has an input winding 61 connected to a low voltage battery 21, an output winding 62 which can be magnetic-coupled to the input winding 61 through a core, a controlling switch circuit 50 feeding power from the low voltage battery 21 to the input winding 61 when it is turned ON and stopping feeding from the low voltage battery 21 to the input winding 61 when it is turned OFF, and a power source IC 41 controlling ON / OFF of the controlling switch circuit 50. The power source IC 41, when an operation state switching signal indicating that a power source system is in external charging is input, controls ON / OFF at a switching speed made to be later than in normal case.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to an isolated power supply device, a power supply system, and a power supply control program. [Background technology]

[0002] When an external power supply provided outside the power supply system charges an electric storage device, the voltage of the external power supply may be applied to the load driving device as well as the electric storage device. In this case, parasitic capacitance may be generated in the load driving device, which may cause the load driving device to operate unintentionally. To avoid such a situation, a switching element that cuts off the power supply to the load driving device during external charging may be controlled to an off state.

[0003] In this case, a power supply is required to supply drive power for operating the switching element during external charging. If this power supply is configured as a switching power supply, noise will be generated from the switching power supply during external charging. It is preferable to reduce such noise during external charging.

[0004] In view of this, a power supply system has been devised that reduces noise by intermittently operating a switching power supply during external charging. Such a power supply system is described in, for example, Patent Document 1. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2022-118417 Summary of the Invention [Problem to be solved by the invention]

[0006] However, when a switching power supply is operated intermittently to reduce noise, it is possible to reduce noise in a specific frequency band, but it is not possible to reduce noise in other frequency bands. Therefore, there are cases where it is not possible to meet a predetermined noise standard in frequency bands other than the specific frequency band.

[0007] The present invention has been made to solve the above-mentioned problems, and its main object is to provide an isolated power supply device, a power supply system, and a power supply control program that can suppress noise so as to meet standards. [Means for solving the problem]

[0008] A first means for solving the above problem is an isolated power supply device that supplies power to a drive circuit of a semiconductor device, the device comprising: a primary winding connected to a DC power supply; a secondary winding that can be magnetically coupled to the primary winding via a core; a control switch circuit that supplies power from the DC power supply to the primary winding when turned on and stops the power supply from the DC power supply to the primary winding when turned off; and a switch control unit that controls the on and off of the control switch circuit, wherein when an operating state switching signal is input, the switch control unit performs on and off control by making a switching frequency different from that in normal times and by making the switching speed slower than normal, or by performing either one of these.

[0009] As a result, by inputting the operation state switching signal during external charging, it is possible to suppress noise, or to shift the frequency of noise so as to satisfy the criteria.

[0010] The second means is a power supply system capable of performing external charging for charging a power storage device from an external power supply, the power supply system comprising: an inverter provided in a power supply path between a motor and the power storage device; a drive circuit for a semiconductor switching element constituting the inverter; an isolated power supply device that supplies power to the drive circuit; and a power supply control device that controls the isolated power supply device, the isolated power supply device comprising: a primary winding connected to a DC power supply; a secondary winding that can be magnetically coupled to the primary winding via a core; and a control circuit that, when turned on, supplies power from the DC power supply to the primary winding and, when turned off, stops the supply of power from the DC power supply to the primary winding. and a switch circuit for controlling the control switch circuit to be turned on and off, and during external charging, the semiconductor switching element of the inverter is turned on and off, so that power of the external power supply is converted by the motor and the inverter and supplied to the power storage device, and the power supply control device inputs an operation state switching signal to the switch control section during external charging, and when the operation state switching signal is input, the switch control section performs on / off control by making a switching frequency different from that in normal times and by making the switching speed slower than that in normal times, or by performing either one of these.

[0011] As a result, by inputting the operation state switching signal during external charging, it is possible to suppress noise, or to shift the frequency of noise so as to satisfy the criteria.

[0012] A third means is a power supply control program executed by an isolated power supply device that supplies power to a drive circuit of a semiconductor device, the isolated power supply device comprising: a primary winding connected to a DC power supply; a secondary winding magnetically coupleable with the primary winding via a core; a control switch circuit that supplies power from the DC power supply to the primary winding when turned on and stops power supply from the DC power supply to the primary winding when turned off; and a switch control unit that controls the on and off of the control switch circuit, and when an operating state switching signal is input to the isolated power supply device, causes the switch control unit to perform on and off control by changing a switching frequency from normal and by making the switching speed slower than normal, or by executing either one of them.

[0013] As a result, by inputting the operation state switching signal during external charging, it is possible to suppress noise, or to shift the frequency of noise so as to satisfy the criteria. [Brief description of the drawings]

[0014] [Figure 1] A diagram of the power supply system. [Diagram 2] FIG. [Diagram 3] A diagram of a switching power supply. [Figure 4] 4 is a flowchart of a power supply process. [Diagram 5] FIG. 1 is a diagram showing the relationship between noise magnitude and frequency. [Figure 6] FIG. 5 is a configuration diagram of a switching power supply according to a second embodiment. [Figure 7] 10 is a flowchart of a power supply process according to a second embodiment. [Figure 8] FIG. 11 is a graph showing the relationship between noise magnitude and frequency in the second embodiment. [Figure 9] 13 is a flowchart of a power supply process according to a third embodiment. [Figure 10] FIG. 11 is a graph showing the relationship between noise magnitude and frequency in the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of an insulated power supply device, a power supply system, and a power supply control program according to the present disclosure will be described with reference to the drawings. In the following embodiments and modifications, the same or equivalent parts are denoted by the same reference numerals in the drawings, and the explanations of the same reference numerals are incorporated herein. The insulated power supply device of this embodiment is mounted on the power supply system of a mobile body, including, for example, an electric vehicle or a hybrid vehicle.

[0016] First Embodiment As shown in Fig. 1, the power supply system 10 includes a motor 11 as a rotating electric machine, an inverter 12 as a power conversion device, a high-voltage battery 20 as a power storage device, and a control device 30. The motor 11 is connected to the inverter 12 and serves as a main engine of a moving body. The inverter 12 is a three-phase inverter and is connected to the high-voltage battery 20. The control device 30 controls the motor 11 by controlling the inverter 12. This will be described in detail below.

[0017] The motor 11 is a three-phase synchronous machine, and includes star-connected U-, V-, and W-phase armature windings 11a-11c, and a rotor (not shown). The armature windings 11a-11c of each phase are arranged with an electrical angle of 120°. The motor 11 is, for example, a permanent magnet synchronous machine. The rotor is capable of transmitting power to, for example, a driving wheel of a mobile object. Therefore, the motor 11 serves as a source of torque for propelling the mobile object.

[0018] The inverter 12 is a three-phase full-bridge inverter having three phases of series connections (legs) of upper arm switches Sp and lower arm switches Sn, which are connected in parallel. An upper arm diode Dp, which is a freewheel diode, is connected in anti-parallel (reverse polarity) to the upper arm switch Sp, and a lower arm diode Dn, which is a freewheel diode, is connected in anti-parallel to the lower arm switch Sn. In this embodiment, each switch Sp, Sn is a semiconductor switch element (semiconductor device), for example, an IGBT, but may also be a MOSFET. Note that the upper arm switch Sp and the lower arm switch Sn may be collectively referred to as upper and lower arm switches Sp, Sn below.

[0019] The inverter 12 includes a smoothing capacitor 13. A high-potential terminal of the smoothing capacitor 13 is connected to the positive power supply path H1. A low-potential terminal of the smoothing capacitor 13 is connected to the negative power supply path L1. The smoothing capacitor 13 may be provided outside the inverter 12.

[0020] In each phase, first ends of the armature windings 11a to 11c are connected to a connection point between the emitter, which is the low potential terminal of the upper arm switch Sp, and the collector, which is the high potential terminal of the lower arm switch Sn, via a conductive member 14 such as a bus bar. Second ends of the armature windings 11a to 11c of each phase are connected to each other at a neutral point.

[0021] The collector of the upper arm switch Sp of each phase is connected to the positive power supply path H1. The emitter of the lower arm switch Sn of each phase is connected to the negative power supply path L1. This connects the inverter 12 to the high-voltage battery 20 via the positive power supply path H1 and the negative power supply path L1.

[0022] The positive power supply path H1 and the negative power supply path L1 are provided with a main switch SMR that switches between energization and deenergization in the power supply paths H1, L1. The main switch SMR is a mechanical relay switch, but may be a semiconductor switch.

[0023] The high-voltage battery 20 serves as a power supply source for rotating the rotor of the motor 11. The high-voltage battery 20 is an assembled battery configured as a series connection of battery cells, which are single batteries. The positive terminal of the high-voltage battery 20 is connected to a positive power supply path H1, and the negative terminal is connected to a negative power supply path L1. The inter-terminal voltages (e.g., rated voltages) of the battery cells constituting the assembled battery are set to be the same, for example. The battery cells are secondary batteries such as lithium-ion batteries.

[0024] The power supply system 10 also includes an external charging mechanism 80 for connection to an external charger 100 as an external power supply. The external charging mechanism 80 includes an inlet 82 and a relay 81. The inlet 82 is connected to a power supply path H1, L1 between the high-voltage battery 20 and the inverter 12 via the relay 81. The inlet 82 is configured to supply power from the external charger 100 to the high-voltage battery 20 during external charging in which the main switch SMR and the relay 81 are in the on state (closed state, energized state). Note that, as shown in FIG. 1, the inlet 82 may be connected to the neutral point of the motor 11 to enable neutral point charging.

[0025] External charging is performed when the vehicle is connected to an external charger 100. The external charger 100 includes a connector 110, and the connector 110 is configured to be connectable to an inlet 82 of the vehicle. The external charger 100 is, for example, a DC power supply, but may be an AC power supply. In this case, an AC / DC converter or the like is required in the external charger 100 or the power supply system 10. When an AC / DC converter is provided in the power supply system 10, some of the circuit elements constituting the motor 11 and the inverter 12 may be used. That is, the system may be configured so that charging power is supplied to the inverter 12 via the motor 11, the inverter 12 is operated, and the power is converted by the motor 11 and the inverter 12 to be charged into the high-voltage battery 20.

[0026] 2, the control device 30 is mainly configured with a microcomputer 31 (microcontroller: microcontroller unit) and is driven by power supplied from a low-voltage battery 21 serving as a direct current power source. The microcomputer 31 has a CPU. The functions provided by the microcomputer 31 can be provided by software recorded in a physical memory device and a computer that executes the software, only the software, only the hardware, or a combination of these.

[0027] For example, when a microcomputer is provided by an electronic circuit, which is hardware, it can be provided by a digital circuit including a large number of logic circuits, or an analog circuit. For example, the microcomputer executes a program stored in a non-transitory tangible storage medium serving as a storage unit included in the microcomputer. The execution of the program results in the execution of a method corresponding to the program. The storage unit is, for example, a non-volatile memory. The program stored in the storage unit can be updated via a communication network such as the Internet, for example, over the air (OTA).

[0028] The microcomputer 31 operates the inverter 12 to control the torque of the motor 11 to a command torque Trq* based on detection values ​​of various sensors (not shown, such as a voltage sensor, a current sensor, and a rotation angle sensor). In detail, the control device 30 generates an operation signal to turn on and off each of the switches Sp, Sn constituting the inverter 12, and outputs the operation signal to a gate drive circuit DR (drive circuit) of each of the switches Sp, Sn via the interface unit 32.

[0029] The low-voltage battery 21 is a storage battery, such as a lead-acid battery, whose output voltage is lower than the output voltage of the high-voltage battery 20. In this embodiment, the low-voltage battery 21 corresponds to a "DC power supply."

[0030] The interface unit 32 has a function of transmitting signals between a high-voltage area including the motor 11, the inverter 12, and the high-voltage battery 20 and a low-voltage area including the control device 30 and the low-voltage battery 21 while electrically insulating these systems. The interface unit 32 is, for example, a photocoupler.

[0031] Next, a switching power supply 40 as an isolated power supply device will be described with reference to Figures 2 and 3. The switching power supply 40 has a function of supplying drive power to a gate drive circuit DR that drives each switch Sp, Sn while insulating between a high voltage region and a low voltage region. In this embodiment, the switching power supply 40 is a flyback type switching power supply.

[0032] As shown in Fig. 3, the switching power supply 40 includes a power supply IC 41 and a control switch circuit 50. The power supply IC 41 and the control switch circuit 50 are provided in a low-voltage region. The power supply IC 41 controls the control switch circuit 50 to be turned on and off by a switching signal. Therefore, the power supply IC 41 is a switch control unit. The control switch circuit 50 supplies power from the low-voltage battery 21 to each transformer 60 when turned on, and stops the power supply from the low-voltage battery 21 to each transformer 60 when turned off. The configuration of the control switch circuit 50 will be described later.

[0033] Next, a configuration of the transformer 60 will be described. The switching power supply 40 includes a transformer 60 that supplies power to the gate drive circuits DR of the switches Sp and Sn. The transformer 60 may be provided for each gate drive circuit DR, or a part or all of the transformer 60 may be shared.

[0034] The transformer 60 has an input winding 61 which is a primary winding, and an output winding 62 and a feedback winding 63 which are secondary windings. The transformer 60 has a common core around which the windings 61, 62, and 63 are wound, and the windings 61, 62, and 63 are magnetically coupled by the common core. The input winding 61 and the feedback winding 63 are provided in a low voltage region. The output winding 62 is provided in a high voltage region.

[0035] The transformer 60 is provided with a plurality of terminals. The output terminals of the transformer 60 are connected to corresponding output windings 62. The first terminal T1 of the transformer 60 is connected to the second terminal T2 of the transformer 60 via the input winding 61. The third terminal T3 of the transformer 60 is connected to the fourth terminal T4 of the transformer 60 via the feedback winding 63. When the potential of the first terminal T1 relative to the second terminal T2 of the transformer 60 becomes higher, an induced voltage is generated in the feedback winding 63 such that the potential of the fourth terminal T4 of the transformer 60 becomes higher than the third terminal T3.

[0036] An output terminal of the transformer 60 is connected to the gate drive circuit DR via an output diode 64 and an output capacitor 65. A first terminal T1 of the transformer 60 is connected to the positive terminal of the low-voltage battery 21 via a wire. The negative terminal of the low-voltage battery 21 is connected to ground. A second terminal T2 of the transformer 60 is connected to the control switch circuit 50 via a wire.

[0037] A third terminal T3 of the transformer 60 is connected to an anode of a feedback diode 71. A cathode of the feedback diode 71 is connected to ground via a feedback capacitor 72. In addition, a fourth terminal T4 of the transformer 60 is connected to ground via a wiring.

[0038] Next, the control switch circuit 50 will be described with reference to Fig. 3. The control switch circuit 50 includes a control switch 51. The control switch 51 is a voltage-controlled semiconductor switch, specifically an N-channel MOSFET. The drain of the control switch 51 is connected to the second terminal T2 of the transformer 60. The source of the control switch 51 is connected to ground.

[0039] The gate of the control switch 51 is connected to the power supply IC 41 via an electric path L10, and a switching signal for controlling on / off switching can be input to the gate from the power supply IC 41 via the electric path L10. In addition, a resistance circuit 52 is provided in the electric path L10 to change the switching speed when the switching signal switches from a high level state to a low level state or from a low level state to a high level state.

[0040] The resistor circuit 52 is configured to be able to change its resistance value. To explain in detail, the resistor circuit 52 includes a first resistor R11 as a first resistor element, a first switch SW11 connected in series to the first resistor R11, a second resistor R12 as a second resistor element, and a second switch SW12 connected in series to the first resistor R11. The series connection of the first resistor R11 and the first switch SW11 is provided on the electric path L10, and the series connection of the second resistor R12 and the second switch SW12 is connected in parallel to the series connection of the first resistor R11 and the first switch SW11. The resistance value of the first resistor R11 and the resistance value of the second resistor R12 are different, and specifically, the resistance value of the second resistor R12 is larger than the resistance value of the first resistor R11.

[0041] The power supply IC 41 outputs a switching signal by turning on either the first switch SW11 or the second switch SW12. Therefore, when the second switch SW12 is turned on, it is possible to slow down the switching speed of the switching signal input to the control switch 51 compared to when the first switch SW11 is turned on.

[0042] In the control switch circuit 50, a snubber circuit 55 is connected in parallel to the control switch 51. The snubber circuit 55 is configured to be able to change its time constant. To explain in detail, the snubber circuit 55 is configured by connecting a first snubber circuit 53 and a second snubber circuit 54 in parallel. The first snubber circuit 53 and the second snubber circuit 54 are each an RC snubber circuit for absorbing a transient high voltage generated when the switch is turned off.

[0043] More specifically, the first snubber circuit 53 is configured with a series connection of a first snubber resistor R21 and a first snubber capacitor C21. A high potential side terminal (a terminal on the first snubber resistor R21 side) of the first snubber circuit 53 is connected to the high potential side terminal side (drain side) of the control switch 51. On the other hand, a low potential side terminal (a terminal on the first snubber capacitor C21 side) of the first snubber circuit 53 is connected to the low potential side terminal side (source side, i.e., ground) of the control switch 51.

[0044] The second snubber circuit 54 is composed of a series connection of a second snubber resistor R22 and a second snubber capacitor C22. The high potential side terminal (terminal on the second snubber resistor R22 side) of the second snubber circuit 54 is connected to the high potential side terminal (drain side) of the control switch 51. On the other hand, the low potential side terminal (terminal on the second snubber capacitor C22 side) of the second snubber circuit 54 is connected to the low potential side terminal (source side, i.e., ground) of the control switch 51 via a third switch SW13 serving as a snubber changeover switch.

[0045] That is, the third switch SW13 is connected in series to the second snubber circuit 54, and when the third switch SW13 is turned on, it is electrically connected to the control switch 51, and when the third switch SW13 is turned off, it is disconnected. The power supply IC 41 is capable of controlling the on / off of this third switch SW13, and when the third switch SW13 is turned on, it is possible to make the time constant of the snubber circuit 55 larger and the switching speed slower than when the third switch SW13 is off.

[0046] If the time constant of the snubber circuit 55 increases when the third switch SW13 is turned on, the resistance value of the first snubber resistor R21, the resistance value of the second snubber resistor R22, the capacitance of the first snubber capacitor C21, and the capacitance of the second snubber capacitor C22 may be set arbitrarily. For example, the resistance value of the second snubber resistor R22 may be set larger than the resistance value of the first snubber resistor R21, and the capacitance of the second snubber capacitor C22 may be set larger than the capacitance of the first snubber capacitor C21.

[0047] The power supply IC 41 is an integrated circuit, and the functions provided by the power supply IC 41, like the microcontroller 31, can be provided by software recorded in a physical memory device and a computer that executes the software, by software alone, by hardware alone, or a combination of these.

[0048] For example, the power supply IC 41 controls the on / off of the control switch circuit 50 according to a predetermined power supply control program. Specifically, the power supply IC 41 controls the on / off of the control switch circuit 50 to supply power from the low-voltage battery 21 to the gate drive circuit DR while electrically insulating the low-voltage battery 21 from the gate drive circuit DR.

[0049] In this embodiment, the power supply IC 41 sets a duty ratio Ton / Tsw where one switching period in the control switch circuit 50 is Tsw and the on-time is Ton. Then, the power supply IC 41 outputs a switching signal according to the set duty ratio to the control switch circuit 50. In this embodiment, the power supply IC 41 corresponds to a "switch control unit." When a switching signal is input to the control switch circuit 50, the control switch 51 is controlled to be turned on and off according to the switching signal input to its gate.

[0050] When the control switch 51 is turned on, power is supplied to the input winding 61 from the low-voltage battery 21. During this time, an induced voltage is generated in the feedback winding 63 such that the potential of the fourth terminal T4 of the transformer 60 becomes higher than the potential of the third terminal T3. In this case, the feedback diode 71 prevents a current from flowing through the feedback winding 63, and magnetic energy is stored in the transformer 60. As in the case of the feedback winding 63, the output diode 64 prevents a current from flowing through the output winding 62.

[0051] On the other hand, when the control switch 51 is turned off, the power supply from the low-voltage battery 21 to the input winding 61 is stopped. During this time, an induced voltage is generated in the feedback winding 63 such that the potential of the third terminal T3 of the transformer 60 becomes higher than the potential of the fourth terminal T4. This causes a current to flow through the feedback winding 63. Also, in the same manner as in the feedback winding 63, a current flows through the output winding 62, and drive power is supplied to the gate drive circuit DR.

[0052] Meanwhile, the power supply system 10 is connected to an external charger 100 and configured to be externally chargeable. When external charging is performed, if the charging voltage of the external charger 100 is applied to the motor 11 as well as the high-voltage battery 20, a parasitic capacitance is generated in the motor 11, which may cause the motor 11 to operate unintentionally. To avoid such a situation, it is necessary to control the upper and lower arm switches Sp and Sn constituting the inverter 12 to the off state so as to cut off the current supply to the motor 11 during external charging. In addition, during external charging, it is possible that the upper and lower arm switches Sp and Sn constituting the inverter 12 are complementarily on-off controlled, for example, to convert the AC current supplied from the external charger 100 into a DC current using the inverter 12 or the like.

[0053] In these cases, the switching power supply 40 needs to supply the gate drive circuit DR with drive power for operating the upper and lower arm switches Sp, Sn during external charging. However, the switching power supply 40 generates noise during operation due to switching. It is preferable to reduce such noise during external charging. Specifically, a noise threshold Th is set for each frequency band, and laws and regulations require that noise not exceed the noise threshold Th. In particular, when the moving body is stopped, that is, during external charging, the requirements become stricter, and it is generally necessary to suppress noise more than when the moving body is moving. Therefore, the switching power supply 40 of this embodiment executes the following process during external charging. This will be described in detail below.

[0054] As shown in Fig. 1 and Fig. 2, when a start switch (ignition switch, power switch, etc.) is turned on, a host control device 200 such as a host ECU or a battery control ECU notifies the control device 30 of that fact. When the start switch is turned on, the microcomputer 31 of the control device 30 outputs a drive instruction signal to the power supply IC 41 of the switching power supply 40. Furthermore, when the external charger 100 is connected and external charging is in progress (or an external chargeable state) is entered, the host control device 200 notifies the control device 30 that external charging is in progress. During external charging, the microcomputer 31 of the control device 30 outputs an operation state switching signal to the power supply IC 41. Therefore, the microcomputer 31 has a function as a power supply control device.

[0055] When the drive instruction signal is input, the power supply IC 41 performs the power supply process shown in Fig. 4 at predetermined intervals. First, the power supply IC 41 judges whether or not an operation state switching signal is input, that is, whether or not external charging is in progress (step S101). If the judgment result is negative, the power supply IC 41 turns on the first switch SW11 and turns off the second and third switches SW12 and SW13 (step S102). In addition, the power supply IC 41 sets a duty ratio Ton / Tsw when one switching period in the control switch circuit 50 is Tsw and the on time is Ton (step S103).

[0056] Then, the power supply IC 41 outputs a switching signal according to the duty ratio set in step S103 to the control switch circuit 50 while keeping the first switch SW11 on (step S104). As a result, the switching signal is input to the gate of the control switch 51, and the control switch 51 is turned on and off in accordance with the switching signal. Then, when the control switch 51 is turned on and off, as described above, driving power is supplied to the gate drive circuit DR.

[0057] On the other hand, if the determination result in step S101 is positive, the power supply IC 41 turns off the first switch SW11 and turns on the second and third switches SW12 and SW13 (step S105).The power supply IC 41 also sets a duty ratio Ton / Tsw where Tsw is one switching period in the control switch circuit 50 and Ton is the on-time (step S106).

[0058] Then, the power supply IC 41 outputs a switching signal according to the duty ratio set in step S106 to the control switch circuit 50 (step S107) while keeping the second and third switches SW12 and SW13 on. As a result, similar to step S104, the control switch 51 is turned on and off, and drive power is supplied to the gate drive circuit DR.

[0059] At this time, the second and third switches SW12 and SW13 are turned on, and the power supply IC 41 outputs a switching signal. As a result, in the resistor circuit 52, the resistor R12 having a larger resistance value than the first resistor R11 is switched to the second resistor R12, and the resistance value of the resistor circuit 52 becomes larger than the normal value (the resistance value of the first resistor R11). In addition to the first snubber circuit 53, the second snubber circuit 54 is also connected to the control switch 51, and the time constant of the snubber circuit 55 becomes larger than the normal value (the time constant of only the first snubber circuit 53). Therefore, the switching speed can be slowed down. As a result, the speed at which the control switch 51 switches from on to off or from off to on can be slowed down.

[0060] Next, the operation and effects of the first embodiment will be described.

[0061] FIG. 5 shows noise generated from the switching power supply 40 during operation of the switching power supply 40. The vertical axis shows the noise magnitude [dBμV], and the horizontal axis shows the noise frequency [MHz]. FIG. 5 also shows the noise threshold Th determined by laws and regulations for each frequency band. The noise threshold Th is a threshold when the moving object is stopped, that is, during external charging. As shown in FIG. 5, the frequency range in which the noise threshold Th is set has upper and lower limits. The noise threshold Th differs for each frequency band. For example, the noise threshold Th1 in the low frequency band is larger than the noise threshold Th2 in the high frequency band. That is, even if the noise is larger in the low frequency band than in the high frequency band, it is acceptable.

[0062] In FIG. 5, the noise when the operation state switching signal is not input (i.e., when external charging is not occurring) is shown by a dashed line, and the noise when the operation state switching signal is input (i.e., when external charging is occurring) is shown by a solid line.

[0063] As shown in Fig. 5, when external charging is not in progress, that is, during normal operation, noise based on the operation of the switching power supply 40 may exceed the noise threshold Th depending on the frequency band. On the other hand, when external charging is in progress, the power supply IC 41 slows down the switching speed of the control switch 51 to turn the control switch 51 on and off. As a result, as shown in Fig. 5, the magnitude of the noise can be suppressed so as not to exceed the noise threshold Th. .

[0064] Incidentally, even if the switching power supply 40 is operated intermittently, it is possible to reduce noise in a specific frequency band. However, it is not possible to reduce noise in other frequency bands. That is, the noise level cannot be suppressed overall, and there is a possibility that the noise may exceed the noise threshold Th depending on the frequency band. On the other hand, the switching power supply 40 of the first embodiment suppresses the noise level overall by slowing down the switching speed. That is, it is possible to reduce the noise level evenly in all frequency bands, and it is easy to reduce the noise level below the noise threshold Th.

[0065] In normal operation when the operation state switching signal is not input, the power supply IC 41 switches the resistance value of the resistor circuit 52 to a predetermined normal value and inputs a switching signal for controlling the on / off switching to the control switch 51. On the other hand, when the operation state switching signal is input, the power supply IC 41 switches the resistance value of the resistor circuit 52 to a value larger than the normal value and inputs a switching signal to the control switch 51, thereby slowing down the switching speed. More specifically, in normal operation, the power supply IC 41 turns on the first switch SW11 and inputs a switching signal to the control switch 51 via the first resistor R11. On the other hand, when the operation state switching signal is input, the power supply IC 41 turns on the second switch SW12 and inputs a switching signal via the second resistor R12. This makes it possible to slow down the switching speed with a simple circuit configuration.

[0066] The power supply IC 41 normally switches the time constant in the snubber circuit 55 to a predetermined normal value and inputs a switching signal for controlling on / off switching to the control switch 51. On the other hand, when an operation state switching signal is input, the power supply IC 41 switches the time constant in the snubber circuit 55 to a value larger than the normal value and inputs a switching signal to the control switch 51. That is, the power supply IC 41 normally inputs a switching signal to the control switch 51 with the first snubber circuit 53 connected in parallel to the control switch 51. Then, when an operation state switching signal is input, the power supply IC 41 inputs a switching signal with the first snubber circuit 53 and the second snubber circuit 54 connected in parallel to the control switch 51. This makes it possible to slow down the switching speed with a simple circuit configuration.

[0067] <Second embodiment> Next, a second embodiment in which the configuration of the switching power supply 40 in the first embodiment is modified will be described.

[0068] As shown in Fig. 6, the switching power supply 140 of the second embodiment differs from the switching power supply 40 of the first embodiment in that it does not have a configuration for slowing down the switching speed, specifically, the second resistor R12 and the second snubber circuit 54. That is, as shown in Fig. 6, the power supply IC 41 is connected to the gate of the control switch 51 via the first resistor R11, but does not have the second resistor R12 and cannot be switched. In addition, only the first snubber circuit 53 is connected in parallel to the control switch 51, and the second snubber circuit 54 is not added and connected in parallel.

[0069] On the other hand, the power supply IC 41 is configured to be able to change the switching frequency. More specifically, when the power supply IC 41 of the second embodiment receives a drive instruction signal, it performs the power supply process shown in FIG. 7 at predetermined intervals. First, the power supply IC 41 determines whether or not an operation state switching signal is received (step S201). If the determination result is negative, the power supply IC 41 sets the switching frequency (operating frequency) to a predetermined first frequency f1 (step S202). Then, the power supply IC 41 specifies a switching period Tsw1 from the first frequency f1 and sets a duty ratio Ton1 / Tsw1 (step S203).

[0070] Then, the power supply IC 41 outputs a switching signal according to the duty ratio set in step S203 to the control switch circuit 50 (step S204). At this time, the switching signal is operated at the switching frequency (first frequency f1) set in step S202. As a result, the switching signal is input to the gate of the control switch 51, and the control switch 51 is turned on and off in accordance with the switching signal. Then, when the control switch 51 is turned on and off, as described above, driving power is supplied to the gate drive circuit DR.

[0071] On the other hand, if the determination result in step S201 is positive, the power supply IC 41 sets the switching frequency to a second frequency f2 different from the first frequency f1 (step S205). The second frequency f2 is a lower frequency than the first frequency f1. Then, the power supply IC 41 specifies a switching period Tsw2 from the second frequency f2 and sets a duty ratio Ton2 / Tsw2 (step S206). Then, the power supply IC 41 outputs a switching signal according to the duty ratio set in step S206 to the control switch circuit 50 (step S207). At this time, the switching signal is operated at the switching frequency (second frequency f2) set in step S205. As a result, the control switch 51 is turned on and off, and drive power is supplied to the gate drive circuit DR.

[0072] The operation and effects of the switching power supply 140 of the second embodiment will be described.

[0073] Similar to FIG. 5, FIG. 8 shows noise based on the operation of the switching power supply 140 of the second embodiment. As shown in FIG. 8, the frequency range for which the noise threshold Th is set has upper and lower limits. In addition, the noise threshold Th differs for each frequency band. For example, the noise threshold Th1 in the low frequency band is larger than the noise threshold Th2 in the high frequency band. That is, even if the noise is larger in the low frequency band than in the high frequency band, it is allowed.

[0074] Therefore, the power supply IC 41 of the second embodiment sets the second frequency f2, which is lower than the first frequency f1 during normal operation, as the switching frequency during external charging. That is, the power supply IC 41 lowers the switching frequency (operating frequency) during external charging to shift the noise frequency to the lower frequency side (left side) as a whole. This allows the noise present in the high frequency band to be moved to the low frequency band and to fall below the noise threshold Th. Alternatively, the noise is moved to a low frequency band where the noise threshold Th is not set (a frequency band lower than the lower limit of the threshold Th) to satisfy the noise requirement.

[0075] In the second embodiment, since the switching speed is not slowed down, heat generation that accompanies a decrease in switching speed can be suppressed, and power consumption can be reduced.

[0076] <Third embodiment> Next, a third embodiment in which the configuration of the switching power supply 40 in the first embodiment is modified will be described.

[0077] The circuit configuration of the switching power supply 140 of the third embodiment is the same as that of the second embodiment (see FIG. 6), and therefore the description thereof will be omitted. Similarly to the second embodiment, the power supply IC 41 of the third embodiment is configured to be able to change the switching frequency.

[0078] More specifically, when a drive instruction signal is input, the power supply IC 41 of the third embodiment performs the power supply process shown in Fig. 9 at predetermined intervals. In the power supply process shown in Fig. 9, the processes of steps S301 to S304 are the same as steps S201 to S204, and therefore will be omitted.

[0079] On the other hand, if the determination result in step S301 is positive, the power supply IC 41 sets the switching frequency to a third frequency f3 different from the first frequency f1 (step S305). The third frequency f3 is a higher frequency than the first frequency f1. Then, the power supply IC 41 specifies a switching period Tsw3 from the third frequency f3 and sets a duty ratio Ton3 / Tsw3 (step S306). Then, the power supply IC 41 outputs a switching signal according to the duty ratio set in step S306 to the control switch circuit 50 (step S307). At this time, the switching signal is operated at the switching frequency (third frequency f3) set in step S305. As a result, the control switch 51 is turned on and off, and drive power is supplied to the gate drive circuit DR.

[0080] The operation and effects of the switching power supply 140 of the third embodiment will be described.

[0081] Similar to Fig. 5 and Fig. 8, Fig. 10 shows noise based on the operation of the switching power supply 40 of the second embodiment. The power supply IC 41 of the third embodiment sets the switching frequency to a third frequency f3 higher than the first frequency f1 in normal operation during external charging. That is, the power supply IC 41 of the third embodiment increases the switching frequency (operating frequency) during external charging to shift the noise frequency to the higher frequency side (right side) as a whole. At that time, the noise Ns1 that exceeds the noise threshold Th in normal operation is shifted so as to deviate from the upper limit of the frequency range in which the noise threshold Th is set. This satisfies the noise requirement.

[0082] In the third embodiment, since the switching speed is not slowed down, heat generation that accompanies a decrease in switching speed can be suppressed, and power consumption can be reduced.

[0083] (Modification) A modification in which a part of the configuration of the power supply system of the above embodiment is changed will be described.

[0084] In the above embodiment, the power supply IC 41 may receive a current value from the feedback winding 63 and perform feedback control based on the current value.

[0085] In the above embodiment, the feedback winding 63 does not need to be provided.

[0086] The first and second embodiments may be combined. That is, the power supply IC 41 may turn on the second and third switches SW12 and SW13 to slow down the switching speed and lower the switching frequency (operating frequency).

[0087] The first and third embodiments may be combined. That is, the power supply IC 41 may turn on the second and third switches SW12 and SW13 to slow down the switching speed and increase the switching frequency.

[0088] In the first embodiment, only one of the second resistor R12 and the second snubber circuit 54 may be provided. The switching speed can be slowed down by using only one of them.

[0089] In the above embodiment, the switching speed is slowed down by switching to the second resistor R12. However, the circuit configuration of the resistor circuit 52 may be changed as desired if the resistance value is changeable.

[0090] In the above embodiment, the switching speed is slowed down by connecting the second snubber circuit 54. However, the circuit configuration of the snubber circuit 55 may be changed as desired if the time constant is changeable.

[0091] The control unit and the method described in the present disclosure may be realized by a special-purpose computer provided by configuring a processor and a memory programmed to execute one or more functions embodied in a computer program. Alternatively, the control unit and the method described in the present disclosure may be realized by a special-purpose computer provided by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control unit and the method described in the present disclosure may be realized by one or more special-purpose computers configured by a combination of a processor and a memory programmed to execute one or more functions and a processor configured with one or more hardware logic circuits. In addition, the computer program may be stored in a computer-readable non-transitory tangible recording medium as instructions executed by a computer.

[0092] Characteristic configurations extracted from each of the above-described embodiments will be described below. [Configuration 1] In an isolated power supply device (40) that supplies power to a drive circuit (DR) of a semiconductor device (Sp, Sn), A primary winding (61) connected to a DC power source; a secondary winding (62) capable of being magnetically coupled to the primary winding via a core; a control switch circuit (50) that, when turned on, supplies power from the DC power source to the primary winding and, when turned off, stops the supply of power from the DC power source to the primary winding; a switch control unit (41) that controls the on / off of the control switch circuit, When an operation state switching signal is input, the switch control unit performs on / off control by making a switching frequency different from that in normal times and by making the switching speed slower than that in normal times, or by performing either one of these operations. [Configuration 2] The control switch circuit includes: a control switch (51) connected to the primary winding and switching between supplying power to the primary winding and stopping the supply of power; a resistance circuit (52) provided in an electrical path between the gate of the control switch and the switch control section, the resistor circuit is configured so that its resistance value can be changed; The switch control unit is During normal operation when the operation state switching signal is not input, the resistance value of the resistor circuit is switched to a predetermined normal value, and a switching signal for controlling on / off switching is input to the control switch. 2. The isolated power supply device according to configuration 1, wherein, when the operation state switching signal is input, a resistance value in the resistor circuit is switched to a value larger than the normal value, and the switching speed is slowed down by inputting the switching signal to the control switch. [Configuration 3] The control switch circuit includes: a control switch (51) connected to the primary winding and switching between supplying power to the primary winding and stopping the supply of power; a snubber circuit (55) configured with a series connection of a capacitor and a resistor and connected in parallel to the control switch, The snubber circuit is configured so that its time constant can be changed, The switch control unit is During normal operation when the operation state switching signal is not input, a time constant in the snubber circuit is switched to a predetermined normal value, and a switching signal for controlling on / off switching is input to the control switch. 3. The isolated power supply device according to claim 1, wherein, when the operation state switching signal is input, a time constant in the snubber circuit is switched to a value larger than a normal value, and the switching speed is slowed down by inputting the switching signal to the control switch. [Configuration 4] The insulated power supply device is mounted on a power supply system (10) capable of performing external charging for charging an electricity storage device (20) from an external power supply (100), the semiconductor device is a semiconductor switching element constituting an inverter (12) that converts electric power from the power storage device and supplies the electric power to a motor, the drive circuit is a gate drive circuit that inputs an operation signal to a gate of the semiconductor switching element of the inverter, 4. The isolated power supply device according to any one of configurations 1 to 3, wherein the operation state switching signal is input to the switch control unit during external charging. [Configuration 5] the inverter is provided in a power supply path between the motor (11) and the power storage device, 5. The isolated power supply device according to configuration 4, wherein during external charging, the semiconductor switching element of the inverter is turned on and off, so that power of the external power supply is converted by the motor and the inverter and supplied to the power storage device. [Configuration 6] A power supply system (10) capable of performing external charging for charging a power storage device (20) using an external power supply (100). an inverter (12) provided in a power supply path between a motor (11) and the power storage device; A drive circuit (DR) for semiconductor switching elements (Sp, Sn) constituting the inverter; an isolated power supply device (40) for supplying power to the drive circuit; a power supply control device (31) that controls the insulated power supply device, The isolated power supply device comprises: A primary winding (61) connected to a DC power source (21); a secondary winding (62) capable of being magnetically coupled to the primary winding via a core; a control switch circuit (50) that, when turned on, supplies power from the DC power source to the primary winding and, when turned off, stops the supply of power from the DC power source to the primary winding; a switch control unit (41) that controls the on / off of the control switch circuit, During external charging, the semiconductor switching element of the inverter is turned on and off, whereby power from the external power supply is converted by the motor and the inverter and supplied to the power storage device; The power supply control device inputs an operation state switching signal to the switch control unit during external charging, The switch control unit, when the operation state switching signal is input, performs on / off control by making a switching frequency different from that in normal times and by making the switching speed slower than that in normal times, or by performing either one of these operations. [Configuration 7] A power supply control program executed by an insulated power supply device (40) that supplies power to a drive circuit (DR) of a semiconductor device (Sp, Sn), The isolated power supply device comprises: A primary winding (61) connected to a DC power source; a secondary winding (62) capable of being magnetically coupled to the primary winding via a core; a control switch circuit (50) that, when turned on, supplies power from the DC power source to the primary winding and, when turned off, stops the supply of power from the DC power source to the primary winding; a switch control unit (41) that controls the on / off of the control switch circuit, a power supply control program that, when an operating state switching signal is input to the isolated power supply device, causes the switch control unit to perform on / off control by making a switching frequency different from that in normal times and by making the switching speed slower than that in normal times, or by executing either one of these. [Explanation of symbols]

[0093] 10...power supply system, 11...motor, 12...inverter, 20...high-voltage battery, 21...low-voltage battery, 31...microcontroller, 40, 140...switching power supply, 41...power supply IC, 50...control switch circuit, 51...control switch, 61...input winding, 62...output winding, 100...external charger, DR...gate drive circuit.

Claims

1. In an isolated power supply device (40, 140) that supplies power to a drive circuit (DR) of a semiconductor device (Sp, Sn), a primary winding (61) connected to a DC power supply, a secondary winding (62) magnetically coupled to the primary winding via a core, a control switch circuit (50) that, when turned on, supplies power from the DC power supply to the primary winding and, when turned off, stops the power supply from the DC power supply to the primary winding, a switch control unit (41) that on-off controls the control switch circuit, and the isolated power supply device is mounted on a power system (10) capable of performing external charging for charging a power storage device (20) by an external power supply (100), the semiconductor device is a semiconductor switching element that constitutes an inverter (12) that converts power from the power storage device and supplies it to a motor, the drive circuit is a gate drive circuit that inputs an operation signal to the gate of the semiconductor switching element of the inverter, the inverter is provided in a power path between a motor (11) and the power storage device, during external charging, when the semiconductor switching element of the inverter is turned on and off, the power of the external power supply is converted by the motor and the inverter and supplied to the power storage device, the switch control unit is configured to receive an operation state switching signal during external charging, the switch control unit, when an operation state switching signal is input, performs on-off control by making the switching frequency different from the normal time and / or making the switching speed slower than the normal time, or performs either one of them, for the isolated power supply device.

2. The control switch circuit includes a control switch (51) connected to the primary winding and switching the power supply to and the power supply stop from the primary winding, and a resistance circuit (52) provided in an electrical path between the gate of the control switch and the switch control unit, the resistance circuit is configured to be able to change its resistance value, the switch control unit in normal times when the operation state switching signal is not input, switches the resistance value in the resistance circuit to a predetermined normal value and inputs a switching signal for controlling the on-off switching of the control switch, while When the operation state switching signal is input, the resistance value in the resistance circuit is switched to a value larger than the normal value, and the switching speed is reduced by inputting the switching signal to the control switch in the insulated power supply device according to claim 1.

3. The control switch circuit includes a control switch (51) connected to the primary winding and switching power supply to and power supply stop to the primary winding, a snubber circuit (55) composed of a series connection of a capacitor and a resistor and connected in parallel to the control switch, the snubber circuit is configured to be able to change its time constant, The switch control unit In the normal state where the operation state switching signal is not input, the time constant in the snubber circuit is switched to a predetermined normal value, and while inputting a switching signal for controlling on / off switching to the control switch, When the operation state switching signal is input, the time constant in the snubber circuit is switched to a value larger than the normal value, and the switching speed is reduced by inputting the switching signal to the control switch in the insulated power supply device according to claim 1.

4. In a power system (10) capable of performing external charging for charging a power storage device (20) by an external power supply (100), an inverter (12) provided in a power path between a motor (11) and the power storage device, a drive circuit (DR) of semiconductor switching elements (Sp, Sn) constituting the inverter, an insulated power supply device (40, 140) for supplying power to the drive circuit, and a power supply control device (31) for controlling the insulated power supply device. The insulated power supply device a primary winding (61) connected to a DC power supply (21), a secondary winding (62) magnetically coupled to the primary winding via a core, a control switch circuit (50) that supplies power from the DC power supply to the primary winding when turned on and stops power supply from the DC power supply to the primary winding when turned off, and a switch control unit (41) for on / off control of the control switch circuit. During external charging, when the semiconductor switching elements of the inverter are turned on and off, the power of the external power supply is converted by the motor and the inverter and supplied to the power storage device. The power supply control device inputs an operation state switching signal to the switch control unit during external charging. When the operation state switching signal is input, the switch control unit performs on-off control by making the switching frequency different from the normal time and / or making the switching speed slower than the normal time, or performs on-off control by executing either one of them. A power supply system.

5. A power supply system (10) capable of performing external charging for charging a power storage device (20) by an external power supply (100), An inverter (12) provided in a power supply path between a motor (11) and the power storage device, A drive circuit (DR) of semiconductor switching elements (Sp, Sn) constituting the inverter, Isolated power supply devices (40, 140) for supplying power to the drive circuit, In a power control program to be implemented in the isolated power supply device of the power supply system including a power control device (31) for controlling the isolated power supply device, The isolated power supply device, A primary winding (61) connected to a DC power supply, A secondary winding (62) magnetically coupled to the primary winding via a core, A control switch circuit (50) that supplies power from the DC power supply to the primary winding when turned on and stops supplying power from the DC power supply to the primary winding when turned off, A switch control unit (41) for performing on-off control of the control switch circuit, During external charging, when the semiconductor switching elements of the inverter are turned on and off, the power of the external power supply is converted by the motor and the inverter and supplied to the power storage device, The power control device is configured to input an operation state switching signal to the isolated power supply device during the external charging, When an operation state switching signal is input to the isolated power supply device, a power control program for causing the switch control unit to perform on-off control by making the switching frequency different from the normal time and / or making the switching speed slower than the normal time, or performing on-off control by executing either one of them.

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