Power supply, program, control method

Abstract

To provide a power supply and a program that can continue to supply power from a switching power supply to a drive circuit while suppressing the effects of noise generated by the switching control of the switching power supply.SOLUTION: A PCU 30 includes a power supply IC 70 and an insulated power supply 100 that supplies power to a drive circuit 62 for a switch SA of an inverter by switching control performed by the power supply IC 70. The drive circuit 62 has a function to operate by receiving power from the insulated power supply 100 and monitoring the state of the switch SA. The power supply IC 70 changes the switching mode of the insulated power supply 100 in a first state, such as during external charging, from the switching mode of the insulated power supply 100 in a second state in which switching control of the switch SA is performed to drive a rotating electric machine.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a power supply device applied to a system including a power storage unit, an inverter connected to the power storage unit, and a drive circuit that drives a switch included in the inverter. 、 Program and control method It relates to.

Background Art

[0002] As this type of power supply device, as described in Patent Document 1, during external charging control for charging a power storage unit from an external power supply, a switching power supply that supplies power to a drive circuit is intermittently operated. This is to reduce noise generated during the switching control of the switching power supply.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the switching power supply is intermittently operated, the period during which power supply from the switching power supply to the drive circuit is stopped becomes longer. During the power supply stop period, the drive circuit cannot be operated, and the drive circuit may not be able to monitor the state of the switch included in the inverter (for example, an overcurrent state or an overheat state).

[0005] The main object of the present disclosure is to provide a power supply device that can continue to supply power from a switching power supply to a drive circuit while suppressing the influence of noise. 、 Program and control method It aims to do.

Means for Solving the Problems

[0006] This disclosure relates to the energy storage unit and An inverter connected to the aforementioned energy storage unit, A rotating electric machine having an armature winding connected to the inverter, The inverter has a drive circuit that drives a switch, In a power supply device applied to a system comprising: It includes a power supply control unit and a switching power supply that supplies power to the drive circuit by switching control of the power supply control unit, The drive circuit operates by being powered by the switching power supply and has a function to monitor the state of the switch. The power control unit performs a change operation to change the switching mode of the switching power supply in the first state, which is a state in which the power storage unit is being charged from an external power supply via the inverter or in a state in which the switching control of the switch is stopped, from the switching mode of the switching power supply in the second state, which is a state in which the switching control of the switch for driving the rotating electric machine is performed.

[0007] According to the power supply device disclosed herein, it is possible to continue supplying power from the switching power supply to the drive circuit while suppressing the effects of noise.

[0008] The power supply device disclosed herein can be materialized, for example, as follows:

[0009] The power supply control unit, The switching frequency of the switching power supply in the second state is set to a frequency within a specific frequency range. As part of the modification process, the switching frequency of the switching power supply in the first state is shifted to a frequency outside the specified frequency range.

[0010] It may be required that the level of noise in a specific frequency range be below an acceptable level in the first state. This requirement may be, for example, a legal or regulatory requirement.

[0011] Therefore, as a change process, the power supply control unit performs a process of shifting the switching frequency of the switching power supply in the first state to a frequency outside the specific frequency range. Thereby, while the level of noise is made below the allowable value in the specific frequency range, power supply from the switching power supply to the drive circuit can be continued.

Brief Description of the Drawings

[0012] [Figure 1] The figure which shows the whole structure of the vehicle and external charging device which concern on 1st Embodiment. [Figure 2] The figure which shows the structure of an in - vehicle system. [Figure 3] The figure which shows the structure of PCU. [Figure 4] The flowchart of the change instruction process of the switching frequency which a microcomputer performs. [Figure 5] The flowchart of the switching control process of the control switch which a power supply control part performs. [Figure 6] The figure which shows typically the effect by the fall of a switching frequency. [Figure 7] The figure which shows the structure of PCU which concerns on 2nd Embodiment. [Figure 8] The flowchart of the change process of the target voltage which a microcomputer performs. [Figure 9] The flowchart of the switching control process of the control switch which a power supply control part performs. [Figure 10] The figure which shows typically the effect by the fall of a target voltage. [Figure 11] The figure which shows the structure of PCU which concerns on 3rd Embodiment. [Figure 12] The figure which shows an example of a gate switching circuit. [Figure 13] The flowchart of the change process of the gate resistance value which a microcomputer performs. [Figure 14] The flowchart of the switching control process of the control switch which a power supply control part performs. [Figure 15] The figure which shows the structure of PCU which concerns on 4th Embodiment. [Figure 16]A flowchart illustrating the process by which a microcontroller processes instructions to change the switching frequency. [Figure 17] A diagram showing the configuration of the PCU according to the fifth embodiment. [Figure 18] A flowchart illustrating the process by which a microcontroller processes instructions to change the switching frequency. [Figure 19] A diagram showing the configuration of the PCU according to the sixth embodiment. [Figure 20] A flowchart illustrating the process by which a microcontroller processes instructions to change the switching frequency. [Modes for carrying out the invention]

[0013] Multiple embodiments will be described with reference to the drawings. In multiple embodiments, functionally and / or structurally corresponding and / or related parts may be given the same reference numeral, or reference numerals that differ by hundreds or more digits. For corresponding and / or related parts, refer to the descriptions of other embodiments.

[0014] <First Embodiment> The following describes a first embodiment of the power supply device described herein with reference to the drawings. The power supply device of this embodiment is installed in an electric vehicle or a hybrid vehicle or the like.

[0015] As shown in Figure 1, the vehicle 10 includes, as an on-board system, wheels 11, a high-voltage battery 20 (corresponding to the "energy storage unit"), a low-voltage battery 21, a power control unit (hereinafter referred to as PCU) 30, and a higher-level control unit (hereinafter referred to as higher-level ECU) 60. The high-voltage battery 20 is a rechargeable secondary battery and has a terminal voltage of, for example, 100V or more. The high-voltage battery 20 is, for example, a lithium-ion battery or a nickel-metal hydride battery. The low-voltage battery 21 is a rechargeable battery having a lower output voltage (specifically, a rated voltage) than the high-voltage battery 20, and is, for example, a lead-acid battery. The low-voltage battery 21 has an output voltage of, for example, 1 / 10 or less of the output voltage of the high-voltage battery 20.

[0016] The high-voltage battery 20 can be charged externally by an external charging device 15 (corresponding to an "external power source") located outside the vehicle 10. The external charging device 15 is, for example, a stationary device.

[0017] Next, we will explain the PCU30 and the configuration related to external charging using Figure 2.

[0018] The PCU30 comprises a rotating electric machine 40 and an inverter 50. The rotating electric machine 40 provides rotational power to the wheels 11 (drive wheels) of the vehicle 10, causing the vehicle 10 to move. The rotating electric machine 40 in this embodiment is a synchronous machine, specifically a permanent magnet synchronous machine with a Y connection. The rotating electric machine 40 comprises a rotor 41 capable of transmitting power to the drive wheels, and U, V, and W phase windings 42U, 42V, and 42W that constitute the stator.

[0019] In this embodiment, a neutral point clamp type 3-level inverter is described as an example of the inverter 50. However, the configuration of the inverter 50 is not limited to a neutral point clamp type.

[0020] The inverter 50 includes U-phase first to fourth switches Su1 to Su4, V-phase first to fourth switches Sv1 to Sv4, W-phase first to fourth switches Sv1 to Sv4, a first capacitor 51, a second capacitor 52, and first to sixth clamp diodes Dc1 to Dc6. In this embodiment, each switch Su1 to Su4, Sv1 to Sv4, and Sw1 to Sw4 are voltage-controlled semiconductor switching elements, specifically IGBTs. Freewheel diodes Du1 to Du4, Dv1 to Dv4, and Dw1 to Dw4 are connected in antiparallel to each switch Su1 to Su4, Sv1 to Sv4, and Sw1 to Sw4.

[0021] The first capacitor 51 and the second capacitor 52 are connected in series. A high-voltage battery 20 is connected in parallel to the series connection of the first and second capacitors 51 and 52. The first capacitor 51 has the same capacitance as, for example, the second capacitor 52. In this embodiment, the connection point between the first capacitor 51 and the second capacitor 52 is referred to as the inverter neutral point O.

[0022] The U-phase first to fourth switches Su1 to Su4 are connected in series such that their emitters, which are the low-potential terminals, and their collectors, which are the high-potential terminals, are connected to each other. The collector of the U-phase first switch Su1 is connected to the positive terminal of the high-voltage battery 20, and the emitter of the U-phase fourth switch Su4 is connected to the negative terminal of the high-voltage battery 20. The first end of the U-phase winding 42U is connected to the connection point between the U-phase second switch Su2 and the U-phase third switch Su3 via the U-phase conductive path 53U. The U-phase conductive path 53U includes, for example, a conductive member such as a busbar.

[0023] The cathode of the first clamp diode Dc1 is connected to the connection point between the first U-phase switch Su1 and the second U-phase switch Su2, and the cathode of the second clamp diode Dc2 is connected to the anode of the first clamp diode Dc1. The connection point between the third U-phase switch Su3 and the fourth U-phase switch Su4 is connected to the anode of the second clamp diode Dc2.

[0024] The configuration of the V and W phases is basically the same as that of the U phase. Therefore, the configuration of the V and W phases will be explained in a simplified manner. The first end of the V phase winding 42V is connected to the connection point between the V phase second switch Sv2 and the V phase third switch Sv3 via the V phase conductive path 53V. The first end of the W phase winding 42W is connected to the connection point between the W phase second switch Sw2 and the W phase third switch Sw3 via the W phase conductive path 53W. The V phase conductive path 53V and the W phase conductive path 53W include conductive members such as busbars. The second ends of each phase winding 42U, 42V, and 42W are connected to the neutral point of the armature winding.

[0025] Next, we will explain the external charging-related components that make up the in-vehicle system.

[0026] The in-vehicle system includes a U-phase interruption switch 54U and a V-phase interruption switch 54V for electrically connecting or disconnecting the inverter 50 and the armature winding of the rotating electric machine 40. When each interruption switch 54U, 54W is turned on, it allows the flow of current in both directions, and when it is turned off, it interrupts the flow of current in both directions.

[0027] The in-vehicle system includes a vehicle-side connector 56, a negative terminal wire 55A, a positive terminal wire 55B, a first changeover switch 57A, and a second changeover switch 57B for electrically connecting the inverter 50 to the external charging device 15.

[0028] The vehicle-side connector 56 is detachably connected to the external connector 16 of the external charging device 15. When the vehicle-side connector 56 and the external connector 16 are mechanically connected, the positive terminal of the vehicle-side connector 56 is electrically connected to the positive terminal 101 of the external charging device 15, and the negative terminal of the vehicle-side connector 56 is electrically connected to the negative terminal of the external charging device 15.

[0029] The positive terminal wiring 55B connects the portion of the U-phase conductive path 53U closer to the inverter 50 than the U-phase interruption switch 54U to the positive terminal of the vehicle-side connector 56. A second changeover switch 57B is provided on the positive terminal wiring 55B. When the second changeover switch 57B is turned on, it allows the flow of current in both directions, and when it is turned off, it interrupts the flow of current in both directions.

[0030] The negative terminal wiring 55A connects the portion of the V-phase conductive path 53V closer to the inverter 50 than the V-phase interruption switch 54V to the negative terminal of the vehicle-side connector 56. The negative terminal wiring 55A is provided with a first changeover switch 57A. When the first changeover switch 57A is turned on, it allows the flow of current in both directions, and when it is turned off, it interrupts the flow of current in both directions.

[0031] The PCU30 is equipped with a current sensor 22. The current sensor 22 detects the current flowing through each conductive path 53U, 53V, and 53W. The detected value from the current sensor 22 is input to the microcontroller 61 of the PCU30.

[0032] The microcontroller 61 is a control unit of the PCU 30 and performs drive control of the rotating electric machine 40 for driving the vehicle 10, as well as external charging control.

[0033] The drive control of the rotating electric machine 40 is a control for controlling the control amount (torque in this embodiment) of the rotating electric machine 40 to a command value (command torque Trq*), and is a switching control of each switch Su1 to Sw4 of the inverter 50. When the output voltage of the high-voltage storage battery 20 is Vh and the potential of the inverter neutral point O is 0, the inverter 50 outputs one of three different potentials "Vh / 2", "0", or "-Vh / 2" to each phase of the rotating electric machine 40 by the switching control of each switch Su1 to Sw4. To explain in detail using the U phase as an example, when the U phase 1st and 2nd switches Su1 and Su2 are turned on and the U phase 3rd and 4th switches Su3 and Su4 are turned off, "Vh / 2" is output to the U phase of the rotating electric machine 40. On the one hand, when the U-phase 2nd and 3rd switches Su2 and Su3 are turned on and the U-phase 1st and 4th switches Su1 and Su4 are turned off, "0" is output to the U-phase. On the other hand, when the U-phase 3rd and 4th switches Su3 and Su4 are turned on and the U-phase 1st and 2nd switches Su1 and Su2 are turned off, "-Vh / 2" is output to the U-phase. The command torque Trq* is input from the higher-level ECU 60 to the microcontroller 61.

[0034] During drive control of the rotating electric machine 40, the higher-level ECU 60 or microcontroller 61 turns on the U-phase interruption switch 54U and the V-phase interruption switch 54V, and turns off the first changeover switch 57A and the second changeover switch 57B.

[0035] External charging control is a control for charging the high-voltage battery 20 from an external charging device 15 via an inverter 50 while the vehicle 10 is stopped, and is a switching control of each switch on the inverter 50. In this embodiment, external charging control is performed by a higher-level ECU 60. In external charging control, the higher-level ECU 60 turns off the U-phase cutoff switch 54U and the V-phase cutoff switch 54V and turns on the first changeover switch 57A and the second changeover switch 57B, either by itself or by instructing the microcontroller 61. Note that the switching control of the inverter 50 in external charging control is a known technology described in paragraphs 0067 to 0083 of Japanese Patent Application Publication No. 2021-52450, so please refer to that publication.

[0036] Incidentally, the microcontrollers in microcontroller 61 and the higher-level ECU 60 are equipped with a CPU. The functions provided by the microcontrollers in microcontroller 61 and the higher-level ECU 60 can be provided by software recorded in a physical memory device and the computer that executes it, by software only, by hardware only, or by a combination thereof. For example, if the microcontrollers in microcontroller 61 and the higher-level ECU 60 are provided by hardware electronic circuits, they can be provided by digital circuits including a large number of logic circuits, or by analog circuits. For example, the microcontrollers in microcontroller 61 and the higher-level ECU 60 execute programs stored in a non-transitory tangible storage medium that serves as their own memory. The programs include, for example, programs for the processes shown in Figures 4 and 5 described later. When the programs installed on the microcontrollers in microcontroller 61 and the higher-level ECU 60 are executed, the methods corresponding to the programs are executed. The memory is, for example, non-volatile memory. Furthermore, programs stored in the memory unit can be downloaded and updated via communication networks such as the Internet, for example, through OTA (Over The Air).

[0037] Next, using Figure 3, we will explain the drive circuit 62 that drives each of the switches Su1 to Sw4 of the inverter 50, and the isolated power supply 100 that supplies the output power of the low-voltage battery 21 to the drive circuit 62. Note that the switches Su1 to Sw4 of the inverter 50 have basically the same configuration. Therefore, in Figure 3, the switches of the inverter 50 are shown as SA.

[0038] The PCU30 includes a drive circuit 62 and an isolated power supply 100. The drive circuit 62 is composed of an integrated circuit and is individually provided for each switch Su1 to Sw4, for example. The drive command signal for switch SA is input to the drive circuit 62 from the microcontroller 61. The drive command signal is either an ON command signal or an OFF command signal.

[0039] The isolated power supply 100 in this embodiment is a flyback switching power supply. The isolated power supply 100 includes a power supply IC 70 as a "power supply control unit", a transformer 71, a control switch 72, first and second voltage divider resistors 75A and 75B, and a capacitor 76. The control switch 72 in this embodiment is an N-channel MOSFET.

[0040] The positive terminal of the low-voltage battery 21 is connected to the first end of the primary coil 71A of the transformer 71. The drain of the control switch 72 is connected to the second end of the primary coil 71A, and the ground of the low-voltage region is connected to the source of the control switch 72.

[0041] The positive terminal of the low-voltage battery 21 is connected to the power terminal LVCC of the power supply IC 70. Power is supplied from the low-voltage battery 21 to the power supply IC 70 via the power terminal LVCC, enabling the power supply IC 70 to operate.

[0042] The gate of the control switch 72 is connected to the control terminal LGP of the power supply IC 70. The ground terminal LGND of the power supply IC 70 is connected to the ground in the low-voltage region. The power supply IC 70 supplies a charging current to the gate of the control switch 72 using the input power from the power supply terminal LVCC as the power source, so that the gate-source voltage Vgs, which is the potential of the control terminal LGP relative to the potential of the ground terminal LGND, is equal to or greater than the threshold voltage of the control switch 72. This turns the control switch 72 on. On the other hand, the power supply IC 70 flows a discharge current from the gate of the control switch 72 to the ground terminal LGND so that the gate-source voltage Vgs falls below the threshold voltage. This turns the control switch 72 off.

[0043] The power supply IC 70 controls the switching of the control switch 72 based on the duty cycle. The duty cycle is the ratio of the on period Ton to one switching period Tsw of the control switch 72 (= Ton / Tsw).

[0044] The positive terminal of the low-voltage battery 21 is connected to the first end of the series connection of the first and second voltage divider resistors 75A and 75B, and the ground of the low-voltage region is connected to the second end of the series connection of the first and second voltage divider resistors 75A and 75B. The detection terminal UVLO of the power supply IC 70 is connected to the connection point of the first and second voltage divider resistors 75A and 75B.

[0045] Furthermore, if the power supply IC 70 determines that the input voltage of the detection terminal UVLO has fallen below the voltage threshold Vα, it performs an undervoltage lockout process that keeps the control switch 72 off. On the other hand, if the power supply IC 70 determines that the input voltage has exceeded a release threshold Vβ which is higher than the voltage threshold Vα and lower than the output voltage of the low-voltage storage battery 21, it stops the undervoltage lockout process and restarts the switching control of the control switch 72 to restart the operation of the isolated power supply 100.

[0046] The isolated power supply 100 includes a diode 73 and a capacitor 74. The anode of the diode 73 is connected to the first end of the secondary coil 71B of the transformer 71. The cathode of the diode 73 is connected to the first end of the capacitor 74 and to the power supply terminal HVCC of the drive circuit 62. The second end of the secondary coil 71B is connected to the second end of the capacitor 74. The drive circuit 62 becomes operational when power is supplied to it from the output side of the isolated power supply 100 via the power supply terminal HVCC.

[0047] The control system includes a low-voltage region and a high-voltage region electrically isolated from the low-voltage region. The low-voltage region includes a low-voltage battery 21, a higher-level ECU 60, and a microcontroller 61. The high-voltage region includes a high-voltage battery 20, an inverter 50, and a rotating electric machine 40. The isolated power supply 100 spans both the low-voltage and high-voltage regions. Specifically, the power supply IC 70, control switch 72, and primary coil 71A are located in the low-voltage region, while the secondary coil 71B and drive circuit 62 are located in the high-voltage region.

[0048] The gate of switch SA on inverter 50 is connected to control terminal HGP on drive circuit 62. The source of switch SA is connected to ground terminal HGND on drive circuit 62. When drive circuit 62 determines that an ON command signal has been input, it supplies a charging current to the gate of switch SA using the input power from power terminal HVCC as the power source, so that the gate-emitter voltage Vge, which is the potential of control terminal HGP relative to the potential of ground terminal HGND, is equal to or greater than the threshold voltage of switch SA. This turns switch SA ON. On the other hand, when drive circuit 62 determines that an OFF command signal has been input, it flows a discharge current from the gate of switch SA to ground terminal HGND so that the gate-emitter voltage Vge is less than the threshold voltage. This turns switch SA OFF.

[0049] The drive circuit 62 includes an overcurrent monitoring unit 62A and an overheat monitoring unit 62B. The overcurrent monitoring unit 62A acquires the detected value of a switch current sensor that detects the current flowing between the collector and emitter of the switch SA. If the overcurrent monitoring unit 62A determines that the acquired current of the switch SA exceeds a current threshold, it determines that there is an overcurrent abnormality in the switch SA and turns off the switch SA.

[0050] The overheat monitoring unit 62B acquires the detected value from the switch temperature sensor that detects the temperature of switch SA. If the overheat monitoring unit 62B determines that the acquired temperature of switch SA exceeds the temperature threshold, it determines that there is an overheating abnormality in switch SA and turns off switch SA.

[0051] The PCU30 includes a setting change unit 80 for notifying the power supply IC 70 of the drive status of the inverter 50, etc. Figure 3 shows an example in which the setting change unit 80 includes first and second resistors 81 and 82 and a changeover switch 83. The changeover switch 83 connects either the first or second resistor 81 or 82 to the setting terminal LRT of the power supply IC 70. The resistance values ​​of the first resistor 81 and the second resistor 82 are different.

[0052] The microcontroller 61 receives information from the higher-level ECU 60 indicating that external charging control is being performed, that the switching control of switches Su1 to Sw4 on the inverter 50 is stopped, and that drive control of the rotating electric machine 40 for driving the vehicle 10 is being performed. If the microcontroller 61 determines that information indicating external charging control is being performed or that switching control is stopped has been received, it operates the changeover switch 83 so that the setting terminal LRT is connected to the first resistor 81. On the other hand, if the microcontroller 61 determines that information indicating that drive control of the rotating electric machine 40 is being performed has been received, it operates the changeover switch 83 so that the setting terminal LRT is connected to the second resistor 82. The input voltage of the setting terminal LRT differs depending on whether the resistor connected to the setting terminal LRT is the first resistor 81 or the second resistor 82. The power supply IC 70 can determine, based on the input voltage of the setting terminal LRT, whether the current state is one in which external charging control is being performed or the switching control of the inverter 50 is stopped (corresponding to the "first state"), or one in which drive control of the rotating electric machine 40 for driving the vehicle 10 is being performed ("second state").

[0053] Incidentally, when external charging control is being performed or when the switching control of the inverter 50 is stopped, it is required that the level of noise (e.g., radiated noise, conducted noise) generated in conjunction with the switching control of the control switch 72 of the isolated power supply 100 be kept below the permissible value NLjde in a specific frequency range Rfjde. This requirement is, for example, a legal or regulatory requirement. Specifically, for example, this requirement is determined from the viewpoint of suppressing the influence of noise on in-vehicle electronic equipment. To achieve this requirement, the microcontroller 61 performs the processing shown in Figure 4, and the power supply IC 70 performs the processing shown in Figure 5.

[0054] Figure 4 is a flowchart of the process executed by the microcontroller 61.

[0055] In step S10, based on the information transmitted from the higher-level ECU 60, it is determined whether the current state is one in which external charging control is being performed, one in which the switching control of the inverter 50 is stopped, or one in which the drive control of the rotating electric machine 40 for driving the vehicle 10 is being performed.

[0056] In step S10, if it is determined that the current state is that drive control of the rotating electric machine 40 is being performed, the process proceeds to step S11, and the power supply IC 70 is instructed via the setting change unit 80 to set the switching frequency fsw (=1 / Tsw) of the control switch 72 to the first frequency fH (for example, 400kHz). Specifically, the changeover switch 83 is operated so that the setting terminal LRT and the first resistor 81 are connected. If the lower limit of the specific frequency range Rfjde is RL and the upper limit is RH, then the first frequency fH is a frequency within the specific frequency range Rfjde (RL≦fH≦RH), and specifically, for example, it is a frequency that is higher than the lower limit RL of the specific frequency range Rfjde and lower than the upper limit RH.

[0057] On the other hand, if in step S10 it is determined that the current state is either that external charging control is being performed or that the switching control of the inverter 50 is stopped, the process proceeds to step S12, instructing the power supply IC 70 via the setting change unit 80 to set the switching frequency fsw of the control switch 72 to a frequency lower than the lower limit RL of the specific frequency range Rfjde (for example, 40kHz). Specifically, the changeover switch 83 is operated so that the setting terminal LRT and the second resistor 82 are connected. For example, if the second frequency fL is 40kHz and the first frequency fH is 400kHz, the second frequency fL will be 1 / 10 of the first frequency fH.

[0058] The second frequency fL is, for example, a frequency that is 1 / 12 or more and 1 / 6 or less of the first frequency fH, preferably 1 / 11 or more and 1 / 7 or less of the first frequency fH, and more preferably 1 / 10.5 or more and 1 / 7.5 or less of the first frequency fH, or 1 / 10.5 or more and 1 / 8 or less of the first frequency fH.

[0059] The reason for setting the second frequency fL to a lower frequency than the first frequency fH is that, for example, the characteristics of transformer 71 (e.g., frequency characteristics of gain, phase, and impedance) do not satisfy the required characteristics in the frequency range higher than the upper limit RH of the specific frequency range Rfjde.

[0060] Furthermore, the reason for setting the second frequency fL to a lower frequency than the first frequency fH is, for example, to suppress the influence of the switching control of the control switch 72 on the electronic equipment of the in-vehicle system. Specifically, the electronic equipment includes a radio receiver and a speaker. The radio receiver includes an AM receiver and an FM receiver. An AM receiver is a device that detects and demodulates a modulated wave, in which the carrier wave is modulated by analog AM modulation, and outputs it as an audio signal to a speaker. An FM receiver is a device that detects and demodulates a frequency-modulated wave and outputs it as an audio signal to a speaker. Here, the frequency range that AM broadcasting can take is higher than the above-mentioned specific frequency range Rfjde, for example, "510 to 1720 kHz". The frequency range that FM broadcasting can take is even higher than the frequency range that AM broadcasting can take, for example, "76 to 108 MHz".

[0061] If the switching frequency fsw of the control switch 72 is shifted to a frequency higher than the upper limit RH of the specific frequency range Rfjde, the frequency of the noise generated by the switching control of the control switch 72 may fall within the AM broadcast frequency band. In this case, noise will be mixed into the audible frequencies (sound) output from the speaker, causing discomfort to the user. Therefore, the second frequency fL is shifted to a frequency lower than the first frequency fH.

[0062] Figure 5 is a flowchart of the processes performed by the power supply IC 70.

[0063] In step S20, it is determined whether the switching frequency fsw of the control switch 72 is set to the first frequency fH or the second frequency fL, based on the input voltage of the setting terminal LRT.

[0064] If it is determined in step S20 that the switching frequency fsw is instructed to be the first frequency fH, the process proceeds to step S21, and the switching control of the control switch 72 is performed so that the switching frequency fsw of the control switch 72 becomes the first frequency fH.

[0065] On the other hand, if it is determined in step S20 that the switching frequency fsw is instructed to be the second frequency fL, the process proceeds to step S22, and the switching control of the control switch 72 is performed so that the switching frequency fsw of the control switch 72 becomes the second frequency fL.

[0066] As shown in Figure 6, by shifting the switching frequency fsw to a second frequency fL that is lower than the lower limit RL of the specific frequency range Rfjde, the level of noise generated in conjunction with the switching control of the isolated power supply 100 can be reduced to below the permissible value NLjde in the specific frequency range Rfjde.

[0067] As described in detail above, according to this embodiment, the switching frequency fsw of the control switch 72 of the isolated power supply 100 is set to a frequency within a specific frequency range Rfjde when the vehicle 10 is running, and to a frequency outside the specific frequency range Rfjde when external charging is performed or when the inverter 50 is stopped. As a result, when external charging is performed or when the inverter 50 is stopped, power can be supplied from the isolated power supply 100 to each drive circuit 62 while keeping the noise level below the allowable value NLjde in the specific frequency range Rfjde. Therefore, when external charging is performed or when the inverter 50 is stopped, the overheat monitoring unit 62B can continue to monitor for overheating abnormalities of the switch SA, and the overcurrent monitoring unit 62A can continue to monitor for overcurrents of the switch SA.

[0068] Furthermore, the power consumption of the drive circuit 62 during external charging is less than that of the rotating electric machine 40 used to drive the vehicle 10. This is because, for example, the number of switching cycles of the inverter 50 per specified period during external charging is less than that of the rotating electric machine 40 used for drive control in each drive circuit 62. Therefore, even if the switching frequency fsw of the isolated power supply 100 is reduced during external charging, it is possible to suppress the occurrence of a situation where the power supplied from the isolated power supply 100 to the drive circuit 62 for driving the switch SA is insufficient.

[0069] <Modified form of the first embodiment> The switching frequency fsw of the control switch 72 may be set to a frequency higher than the upper limit RH of the specific frequency range Rfjde.

[0070] The higher-level ECU 60 does not need to send information to the microcontroller 61 indicating that the switching control of each switch Su1 to Sw4 on the inverter 50 has been stopped. In this case, in step S10 shown in Figure 4, the state in which the switching control of the inverter 50 has been stopped can be excluded from the state determination target based on the information transmitted from the higher-level ECU 60.

[0071] <Second Embodiment> The second embodiment will be described below, focusing on the differences from the first embodiment, with reference to the drawings. In this embodiment, in order to reduce the noise level in a specific frequency range Rfjde to below the allowable value NLjde, the output voltage of the isolated power supply 100 is reduced instead of the switching frequency fsw of the control switch 72.

[0072] As shown in Figure 7, the isolated power supply 100 is equipped with a feedback coil 90 as a "voltage detection coil". The feedback coil 90 detects the output voltage VCC (terminal voltage of capacitor 74) of the isolated power supply 100 and transmits the detected output voltage VCC information to the power supply IC 70. Based on the input information from the feedback coil 90, the power supply IC 70 controls the switching of the control switch 72 in order to feed back control the output voltage VCC to a target voltage Vtgt.

[0073] The drive circuit 62 performs an undervoltage lockout process to keep switch SA in the off position if it determines that the input voltage of the power supply terminal HVCC has fallen below the voltage threshold Vγ. On the other hand, if the drive circuit 62 determines that the input voltage has exceeded the release threshold Vδ, it stops the undervoltage lockout process and allows switching control of switch SA. The release threshold Vδ is set to a value greater than the voltage threshold Vγ.

[0074] Figure 8 is a flowchart of the process executed by the microcontroller 61.

[0075] In step S10, if it is determined that the current state is one in which drive control of the rotating electric machine 40 is being performed, the process proceeds to step S13, and the power supply IC 70 is instructed via the setting change unit 80 to set the target voltage Vtgt to the first voltage VH. Specifically, the changeover switch 83 is operated so that the setting terminal LRT and the first resistor 81 are connected.

[0076] On the other hand, if in step S10 it is determined that the current state is either that external charging control is being performed or that the switching control of the inverter 50 is stopped, the process proceeds to step S14, instructing the power supply IC 70 via the setting change unit 80 to set the target voltage Vtgt to the second voltage VL, which is lower than the first voltage VH. Specifically, the changeover switch 83 is operated so that the setting terminal LRT and the second resistor 82 are connected.

[0077] Furthermore, the second voltage VL only needs to be set to a value equal to or greater than the above voltage threshold Vγ. This prevents the low-voltage malfunction prevention processing from being executed in the drive circuit 62 as a result of reducing the noise level.

[0078] Figure 9 is a flowchart of the processes performed by the power supply IC 70.

[0079] In step S30, it is determined whether the target voltage Vtgt is set to the first voltage VH or the second voltage VL, based on the input voltage of the setting terminal LRT.

[0080] If it is determined in step S30 that the target voltage Vtgt is set to the first voltage VH, the process proceeds to step S31, where the target voltage Vtgt is set to the first voltage VH. Then, the switching control of the control switch 72 is performed to feed back the output voltage VCC of the isolated power supply 100 to the first voltage VH.

[0081] On the other hand, if it is determined in step S30 that the target voltage Vtgt is set to the second voltage VL, the process proceeds to step S32, where the target voltage Vtgt is set to the second voltage VL. Then, the switching control of the control switch 72 is performed to feed back the output voltage VCC of the isolated power supply 100 to the second voltage VL. In this case, the duty cycle of the control switch 72 is made smaller than in the process of step S31.

[0082] According to the embodiment described above, as shown in Figure 10, the level of noise generated in conjunction with the switching control of the isolated power supply 100 can be reduced to an acceptable value of NLjde or less in a specific frequency range Rfjde.

[0083] <Third Embodiment> The third embodiment will be described below, focusing on the differences from the first embodiment, with reference to the drawings. In this embodiment, in order to reduce the noise level in a specific frequency range Rfjde to below the allowable value NLjde, the switching speed of the control switch 72 is reduced instead of the switching frequency fsw of the control switch 72.

[0084] As shown in Figure 11, the isolated power supply 100 includes a gate switching circuit 110 for changing the switching speed of the control switch 72. The gate switching circuit 110 can employ various circuit configurations. Figure 12 shows an example of the gate switching circuit 110. The gate switching circuit 110 includes a first gate resistor 111A, a second gate resistor 111B, a first charge / discharge switch 112A, and a second charge / discharge switch 112B. The series connection of the first gate resistor 111A and the first charge / discharge switch 112A connects the control terminal LGP of the power supply IC 70 to the gate of the control switch 72. The series connection of the second gate resistor 111B and the second charge / discharge switch 112B also connects the control terminal LGP of the power supply IC 70 to the gate of the control switch 72.

[0085] The resistance value RGA of the first gate resistor 111A is smaller than the resistance value RGB of the second gate resistor 111B. The resistance value RGA of the first gate resistor 111A is, for example, "0.3 × RGB ≤ RGA ≤ 0.7 × RGB", more specifically "0.4 × RGB ≤ RGA ≤ 0.6 × RGB", and more specifically "0.45 × RGB ≤ RGA ≤ 0.55 × RGB".

[0086] Figure 13 is a flowchart of the process executed by the microcontroller 61.

[0087] In step S10, if it is determined that the current state is that drive control of the rotating electric machine 40 is being performed, the process proceeds to step S15, and the power supply IC 70 is instructed via the setting change unit 80 to set the gate resistor connected to the gate of the control switch 72 to the first gate resistor 111A. Specifically, the changeover switch 83 is operated so that the setting terminal LRT and the first resistor 81 are connected.

[0088] On the other hand, if in step S10 it is determined that the current state is either that external charging control is being performed or that the switching control of the inverter 50 is stopped, the process proceeds to step S16, instructing the power supply IC 70 via the setting change unit 80 to set the gate resistor connected to the gate of the control switch 72 to the second gate resistor 111B. Specifically, the changeover switch 83 is operated so that the setting terminal LRT and the second resistor 82 are connected.

[0089] Figure 14 is a flowchart of the processes performed by the power supply IC 70.

[0090] In step S40, it is determined whether the gate resistor connected to the gate of the control switch 72 is directed to the second gate resistor 111B or the first gate resistor 111A. If it is determined in step S40 that the first gate resistor 111A is directed to the first gate resistor, the process proceeds to step S41, where the first charge / discharge switch 112A is turned on and the second charge / discharge switch 112B is turned off. Then, the switching control of the control switch 72 is performed.

[0091] On the other hand, if it is determined in step S40 that the second gate resistor 111B is instructed to turn on, the process proceeds to step S42, where the second charge / discharge switch 112B is turned on and the first charge / discharge switch 112A is turned off. Then, the switching control of the control switch 72 is performed. In this case, the switching speed of the control switch 72 when turning on and when turning off can be reduced compared to when the process in step S41 is executed. As a result, the level of harmonic components contained in the noise is reduced, and the noise level can be reduced to below the allowable value NLjde in a specific frequency range Rfjde.

[0092] <Modified form of the third embodiment> The gate switching circuit may be configured to change the switching speed of either the turn-on or turn-off state of the control switch 72, rather than changing the switching speed of both the turn-on and turn-off states.

[0093] The circuit for changing the switching speed of the control switch 72 is not limited to a circuit for changing the resistance value of the gate resistor, but may also be a circuit for changing the power supply voltage of the gate of the control switch 72, or a circuit for changing the ground potential to which the gate charge of the control switch 72 is discharged.

[0094] <Fourth Embodiment> The fourth embodiment will now be described, focusing on the differences from the first embodiment, with reference to the drawings. In this embodiment, the switching frequency fsw is changed based on information inside the PCU 30, instead of the transmission information from the higher-level ECU 60 located outside the PCU 30. For this purpose, in this embodiment, as shown in Figure 15, the PCU 30 is configured so that the drive information of the drive circuit 62 is input to the microcontroller 61.

[0095] Figure 16 is a flowchart of the process executed by the microcontroller 61.

[0096] In step S17, it is determined whether the drive control of the rotating electric machine 40 has not been performed for a predetermined period of time, based on the drive information of the drive circuit 62. Specifically, for example, if the drive information is the gate voltage of switch SA, it is determined whether the gate voltage of switch SA has been maintained at 0 for a predetermined period of time. Note that the drive information is not limited to the gate voltage, but may also be, for example, a drive command signal input to the drive circuit 62.

[0097] If it is determined in step S17 that drive control of the rotating electric machine 40 has been performed within a predetermined period, the process proceeds to step S11. On the other hand, if it is determined in step S17 that drive control of the rotating electric machine 40 has not been performed within a predetermined period, the process proceeds to step S12.

[0098] According to the embodiment described above, the microcontroller 61 of the PCU 30 can determine the change in the switching frequency fsw without relying on the information transmitted by the higher-level ECU 60.

[0099] <Fifth Embodiment> The fifth embodiment will now be described, focusing on the differences from the fourth embodiment, with reference to the drawings. As shown in Figure 17, the microcontroller 61 changes the switching frequency fsw when it determines, based on the value detected by the current sensor 22, that a charging current has flowed from the inverter 50 to the high-voltage battery 20 due to external charging control.

[0100] Figure 18 is a flowchart of the process executed by the microcontroller 61.

[0101] In step S18, it is determined whether or not a charging current is flowing from the inverter 50 to the high-voltage battery 20 based on the value detected by the current sensor 22. For example, if the direction of current flow in the U,V phase conductive paths 53U, 53V detected by the current sensor 22 is toward the inverter 50, and the current detected by the current sensor 22 is determined to be a DC current, then it is determined that a charging current is flowing.

[0102] If it is determined in step S18 that no charging current is flowing, the process proceeds to step S11. On the other hand, if it is determined in step S18 that a charging current is flowing, the process proceeds to step S12.

[0103] According to the embodiment described above, when external charging control is performed, the microcontroller 61 of the PCU 30 can determine the change in the switching frequency fsw without relying on the information transmitted by the higher-level ECU 60.

[0104] <Sixth Embodiment> The sixth embodiment will now be described, focusing on the differences from the fourth embodiment, with reference to the drawings. As shown in Figure 19, the isolated power supply 100 of this embodiment includes an input current detection unit 120 that detects the current flowing from the low-voltage battery 21 to the primary coil 71A. The input current detection unit 120 is, for example, a shunt resistor. The power supply IC 70 determines whether to change the switching frequency fsw based on the value detected by the input current detection unit 120.

[0105] Figure 20 is a flowchart of the processes performed by the power supply IC 70.

[0106] In step S50, it is determined whether the detected current Ir of the input current detection unit 120 has fallen below the threshold Ith over the judgment period. The judgment period is set to a period longer than, for example, "1 / fL". The threshold Ith is set to a value close to 0, for example. The process in step S50 is to determine whether power is not being supplied from the low-voltage battery 21 to the primary coil 71A.

[0107] If a negative determination is made in step S50, the process proceeds to step S51, where the switching frequency fsw of the control switch 72 is set to the first frequency fH. Then, the switching control of the control switch 72 is performed so that the switching frequency fsw of the control switch 72 becomes the first frequency fH.

[0108] On the other hand, if a positive determination is made in step S50, the process proceeds to step S52, where the switching frequency fsw of the control switch 72 is set to the second frequency fL. Then, the switching control of the control switch 72 is performed so that the switching frequency fsw of the control switch 72 becomes the second frequency fL.

[0109] According to the embodiment described above, the power supply IC 70 can determine when the switching frequency fsw is changed.

[0110] <Other Embodiments> Furthermore, each of the above embodiments may be implemented with the following modifications.

[0111] In the fourth to sixth embodiments, instead of the switching frequency fsw, the output voltage may be changed as described in the second embodiment, or the switching speed may be changed as described in the third embodiment.

[0112] • The isolated power supply, which is a switching power supply, is not limited to the flyback type; it may also be of other types, such as the feedforward type.

[0113] The switches provided by the inverter are not limited to IGBTs; for example, they could be N-channel MOSFETs.

[0114] The inverter is not limited to a 3-level inverter; it may also be a multi-level inverter with 4 or more levels, or a 2-level inverter. Furthermore, the inverter and rotating electric machine are not limited to 3-phase; they may be 2-phase or have 4 or more phases.

[0115] The rotating electric machine is not limited to a star connection; a delta connection is also acceptable.

[0116] The power source for the inverter and the energy storage unit to be externally charged are not limited to rechargeable batteries, but may also be, for example, capacitors (e.g., electric double-layer capacitors), or both batteries and capacitors.

[0117] Furthermore, the energy storage unit may be, for example, a fuel cell. In this case, for example, when there is a need to monitor the state of the inverter switch while the inverter switching control is stopped during a vehicle stoppage, the power supply device of this disclosure is effective.

[0118] The mobile device on which the power supply unit is mounted is not limited to a vehicle; for example, it could be an aircraft or a ship. Furthermore, the location on which the power supply unit is mounted is not limited to a mobile device; it could be a stationary device.

[0119] The control unit and its method described herein may be implemented by a dedicated computer provided by configuring a processor and memory programmed to perform one or more functions embodied by a computer program. Alternatively, the control unit and its method described herein may be implemented by a dedicated computer provided by configuring a processor by one or more dedicated hardware logic circuits. Alternatively, the control unit and its method described herein may be implemented by one or more dedicated computers configured by a combination of a processor and memory programmed to perform one or more functions and a processor configured by one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by the computer on a computer-readable non-transitional tangible recording medium. [Explanation of Symbols]

[0120] 10...Vehicle, 20...High-voltage storage battery, 40...Rotating electric machine, 50...Inverter, 62...Drive circuit, 70...Power supply IC, 100...Isolated power supply.

Claims

1. Energy storage unit (20), An inverter (50) connected to the energy storage unit, A rotating electric machine (40) having armature windings (42U to 42W) connected to the inverter, A drive circuit (62) that drives the switches (Su1 to Sw4, SA) of the inverter, In a power supply device applied to a system comprising: The aforementioned system includes, Speakers and, An AM receiver that detects and demodulates a modulated wave whose carrier wave has been modulated by AM modulation, and outputs it as an audio signal to the speaker, It is equipped with, The system includes a power supply control unit (70) and a switching power supply (100) that supplies power to the drive circuit through switching control of the power supply control unit, The drive circuit operates by being powered by the switching power supply and has a function to monitor the state of the switch. The power control unit performs a change process to change the switching mode of the switching power supply in the first state, which is a state in which the power storage unit is being charged from an external power supply (15) via the inverter or in a state in which the switching control of the switch is stopped, from the switching mode of the switching power supply in the second state, which is a state in which the switching control of the switch for driving the rotating electric machine is performed. The power supply control unit, The switching frequency of the switching power supply in the second state is set to a frequency within a specific frequency range. As part of the modification process, the switching frequency of the switching power supply in the first state is shifted to a frequency below the lower limit (RL) of the specified frequency range so that the level of noise generated in conjunction with the switching control of the switching power supply is below the permissible value (NLjde) in the specified frequency range. A power supply device in which the frequency range that AM broadcasts received by the AM receiver can take is higher than the specified frequency range.

2. The power supply control unit, Based on the information transmitted from the external control device (60) of the power supply unit, it is determined whether the current state is the first state or the second state. The power supply device according to claim 1, which performs the modification process when it is determined that the current state is the first state.

3. The power supply control unit, Based on the drive information of the drive circuit, it is determined whether the current state is the first state or the second state. The power supply device according to claim 1, which performs the modification process when it is determined that the current state is the first state.

4. The first state is a state in which the energy storage unit is being charged from the external power supply via the inverter, The system includes a current sensor (22) that detects the charging current flowing from the inverter to the energy storage unit. The power supply control unit, Based on the value detected by the current sensor, it is determined whether the current state is the first state or the second state. The power supply device according to claim 1, which performs the modification process when it is determined that the current state is the first state.

5. The system includes an input current detection unit (120) that detects the input current of the switching power supply and outputs the detected input current to the power supply control unit, The power supply control unit, Based on the input current detection value received by the input current detection unit, it is determined whether the current state is the first state or the second state. The power supply device according to claim 1, which performs the modification process when it is determined that the current state is the first state.

6. Energy storage unit (20), An inverter (50) connected to the energy storage unit, A rotating electric machine (40) having armature windings (42U to 42W) connected to the inverter, A drive circuit (62) that drives the switches (Su1 to Sw4) of the inverter, A switching power supply (100) having a power supply control unit (70) and supplying power to the drive circuit by switching control of the power supply control unit, In a program applied to a system that includes the following features, The aforementioned system includes, Speakers and, An AM receiver that detects and demodulates a modulated wave whose carrier wave has been modulated by AM modulation, and outputs it as an audio signal to the speaker, It is equipped with, The drive circuit operates by being powered by the switching power supply and has a function to monitor the state of the switch. The aforementioned power supply control unit, A process to determine whether the current state is a first state in which the energy storage unit is being charged from an external power source (15) via the inverter or the switching control of the switch is stopped, or a second state in which the switching control of the switch for driving the rotating electric machine is being performed. If it is determined that the current state is the first state, the switching mode of the switching power supply is changed from the switching mode of the switching power supply when it is determined that the current state is the second state, and this change process is executed. When it is determined that the second state is in place, the switching mode of the switching power supply is such that the switching frequency of the switching power supply is set to a frequency within a specific frequency range. The modification process involves shifting the switching frequency of the switching power supply in the first state to a frequency below the lower limit (RL) of the specified frequency range, so that the level of noise generated in conjunction with the switching control of the switching power supply is below an acceptable value (NLjde) in the specified frequency range. A program in which the frequency range that AM broadcasts received by the AM receiver can take is higher than the specified frequency range.

7. A power storage unit (20) and An inverter (50) connected to the energy storage unit, A rotating electric machine (40) having armature windings (42U to 42W) connected to the inverter, A drive circuit (62) that drives the switches (Su1 to Sw4) of the inverter, A switching power supply (100) having a power supply control unit (70) and supplying power to the drive circuit by switching control of the power supply control unit, In a control method applied to a system comprising, The aforementioned system includes, Speakers and, An AM receiver that detects and demodulates a modulated wave whose carrier wave has been modulated by AM modulation, and outputs it as an audio signal to the speaker, It is equipped with, The drive circuit operates by being powered by the switching power supply and has a function to monitor the state of the switch. The aforementioned power supply control unit, A process to determine whether the current state is a first state in which the energy storage unit is being charged from an external power source (15) via the inverter or the switching control of the switch is stopped, or a second state in which the switching control of the switch for driving the rotating electric machine is being performed. If it is determined that the current state is the first state, the switching mode of the switching power supply is changed from the switching mode of the switching power supply when it is determined that the current state is the second state, and this change process is executed. When it is determined that the second state is in place, the switching mode of the switching power supply is such that the switching frequency of the switching power supply is set to a frequency within a specific frequency range. The modification process involves shifting the switching frequency of the switching power supply in the first state to a frequency below the lower limit (RL) of the specified frequency range, so that the level of noise generated in conjunction with the switching control of the switching power supply is below an acceptable value (NLjde) in the specified frequency range. A control method wherein the frequency range that the AM broadcast received by the AM receiver can take is higher than the specified frequency range.

Images