Power supply system and control method thereof

Abstract

A power supply system is mounted on a vehicle. The power supply system includes: a first power supply (2); a first load (41) that operates using the power supplied from the first power supply (2); a first controller (9) that controls the operation of the first load (41) through a first program; a second power supply (8) that is connected to the first power supply (2) via a converter (7); a second load (11) that operates using the power supplied from the second power supply (8); a second controller (10) that controls the operation of the second load (11) through a second program; a power cut-off device (3) that connects or disconnects the first power supply (2) and the first load (41); and a third controller (12) that controls the power cut-off device (3). When the first program is changed, the third controller (12) disconnects the first power supply (2) and the first load (41) through the power cut-off device (3) before the start of the change process of the first program.

Description

Technical Field

[0001] The present invention relates to a power supply system and a control method for the power supply system. Background Art

[0002] There is known a power supply system mounted on a vehicle (for example, Patent Document 1). This power supply system includes: a secondary battery; an electric generator and a voltage converter connected in parallel with the secondary battery; and an auxiliary equipment battery connected to the secondary battery via the voltage converter. The secondary battery discharges electricity when the electric generator functions as a motor, and is charged when the electric generator functions as a generator. The voltage converter steps down the voltage of the secondary battery and outputs the stepped-down voltage to the auxiliary equipment battery. The auxiliary equipment battery supplies power to the auxiliary equipment system load mounted on the vehicle.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2014 - 135873

[0006] Problems to be Solved by the Invention

[0007] In the power supply system described in Patent Document 1, the operation of the electric generator or the auxiliary equipment system load is sometimes controlled by a program. During the period of rewriting the control program, it is difficult to normally control the object controlled by the program. In the power supply system described in Patent Document 1, during the period of program rewriting, the secondary battery and the electric generator are in a conducting state, and therefore, there is a problem that an unexpected operation occurs in the object controlled by the program. Summary of the Invention

[0008] The problem to be solved by the present invention is to provide a power supply system and a control method for the power supply system that can suppress an unexpected operation from occurring in the object controlled by the program during the period when the program is rewritten.

[0009] The present invention includes: a first power supply; a first load that operates using the power supplied from the first power supply; a first controller that controls the operation of the first load through a first program; a second power supply connected to the first power supply via a converter; a second load that operates using the power supplied from the second power supply; a second controller that controls the operation of the second load through a second program; a power cut-off device that connects or disconnects the first power supply and the first load; and a third controller that controls the power cut-off device. Moreover, in the present invention, when the first program is changed, the third controller disconnects the first power supply and the first load through the power cut-off device before the start of the change process of the first program, thereby solving the above problem.

[0010] Advantages of the Invention

[0011] According to the present invention, before the start of the change process of the first program, the first power supply and the first load are cut off. Therefore, during the period when the program is rewritten, it is possible to suppress unexpected actions from occurring in the control object of the program. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a block diagram of the power supply system according to the first embodiment.

[0013] Figure 2 is a flowchart showing the control process executed by the vehicle controller in the power supply system according to the first embodiment.

[0014] Figure 3 is a block diagram of the power supply system according to the second embodiment.

[0015] Figure 4 is a flowchart showing the control process executed by the vehicle controller in the power supply system according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0017] (First Embodiment)

[0018] Figure 1 is a block diagram of the power supply system 100 when the power supply system 100 according to the first embodiment is mounted on an electric vehicle. As the electric vehicle, for example, an electric car having the motor 1 as a driving source for traveling can be cited. In Figure 1 example, the motor 1 is connected to an axle (not shown) of the electric vehicle and is driven by the power of the storage battery 2. In addition, the electric vehicle on which the power supply system 100 can be mounted is not limited to an electric car. The power supply system 100 can also be mounted on a hybrid vehicle having both the motor 1 and an internal combustion engine (not shown) as driving sources for traveling. Hereinafter, for convenience, the electric vehicle will be simply referred to as a vehicle for description.

[0019] As Figure 1 shown, the power supply system 100 is composed of two power systems with different voltage levels. The power system 50 is a power system composed of devices that operate at the voltage of the storage battery 2. The power system 60 is a power system composed of devices that operate at a voltage lower than that of the power system 50, that is, lower than the voltage of the storage battery 2. Hereinafter, the power system 50 will be referred to as the high-voltage power system 50, and the power system 60 will be referred to as the low-voltage power system 60.

[0020] The high-voltage power system 50 includes: a motor 1, a storage battery 2, a relay 3, a power conversion device 4, and a current sensor 5.

[0021] The electric motor 1 is a so-called three-phase induction motor. The electric motor 1 is also referred to as a three-phase motor. The electric motor 1 has coils of three phases (U phase, V phase, and W phase). As Figure 1 shown, the coils of each phase of the electric motor 1 are connected to the power conversion device 4. Current sensors 5 are provided on the wirings connecting the coils of each phase of the electric motor 1 and the power conversion device 4. The current sensors 5 detect the current of each phase output from the power conversion device 4 to the electric motor 1. The values of the current of each phase detected by the current sensors 5 are output to the motor controller 9. In addition, although not shown in Figure 1 , an angle sensor such as a resolver or an encoder is provided on the electric motor 1, and the position information of the rotor of the electric motor 1 detected by the angle sensor is output to the motor controller 9.

[0022] The storage battery 2 is a DC power source and is the driving power source of the vehicle in the present embodiment. For example, the storage battery 2 uses a secondary battery such as a lithium-ion battery. The storage battery 2 is a DC power source of a so-called high-voltage system that discharges at a DC voltage of several hundred volts (V). As will be described later, the power conversion device 4 includes an inverter 41 as a device that can operate using the voltage of the storage battery 2. In the following description, the inverter 41 may also be replaced with a high-voltage device. In addition, in the following description, the storage battery 2 may also be replaced with a high-voltage storage battery 2.

[0023] The relay 3 is a device that is driven to be opened and closed by a vehicle controller 12 described later. The storage battery 2 is connected to the power conversion device 4 via the relay 3. In addition, the storage battery 2 is connected to the DC-DC converter 7 via the relay 3.

[0024] The relay 3 is provided between the storage battery 2 and the power conversion device 4 to conduct or cut off the storage battery 2 and the power conversion device 4. In addition, the relay 3 is provided between the storage battery 2 and the DC-DC converter 7 to conduct or cut off the storage battery 2 and the DC-DC converter 7. As the relay 3, for example, a mechanical relay can be cited. In addition, the relay 3 may also use a semiconductor switching element.

[0025] As Figure 1 shown in the example, when the power conversion device 4 and the DC-DC converter 7 are connected in parallel to the storage battery 2, relays for the power conversion device 4 and relays for the DC-DC converter 7 are rarely provided separately. Generally, as Figure 1 shown in the example, the relay 3 is provided between the storage battery 2 and the power conversion device 4 and the DC-DC converter 7. In addition, in the present embodiment, the closing of the relay 3 is synonymous with the turning on of the relay 3. In addition, the opening of the relay 3 is synonymous with the turning off of the relay 3.

[0026] The power conversion device 4 performs power conversion between the electric motor 1 and the storage battery 2. As Figure 1As shown, the power conversion device 4 includes: an inverter 41, a capacitor 43, a voltage sensor 44, and a discharge circuit 45.

[0027] The inverter 41 operates using the power supplied from the storage battery 2. The inverter 41 includes a plurality of switching elements Tr1 to Tr6, a plurality of rectifying elements D1 to D6, and a gate drive circuit 42. The plurality of switching elements Tr1 to Tr6 use, for example, insulated gate bipolar transistors (IGBTs: Insulated Gate Bipolar Transistors). In addition, the plurality of switching elements Tr1 to Tr6 are not limited to IGBTs and may also use metal-oxide-semiconductor field-effect transistors (MOSFETs: Metal-Oxide-Semiconductor Field-Effect Transistors). In the present embodiment, the case where the plurality of switching elements Tr1 to Tr6 use IGBTs will be described as an example.

[0028] In the inverter 41, the emitter electrode of the switching element Tr1 is connected to the collector electrode of the switching element Tr2, and an arm circuit is formed by the switching element Tr1 and the switching element Tr2. The connection point of the switching element Tr1 and the switching element Tr2 is connected to the U-phase coil (not shown) of the motor 1. The rectifying element D1 is connected in parallel with the switching element Tr1 so that current flows in a direction opposite to the current direction of the switching element Tr1. The rectifying element D2 is connected in parallel with the switching element Tr2 so that current flows in a direction opposite to the current direction of the switching element Tr2. The rectifying elements D1 and D2 are freewheeling diodes.

[0029] In addition, as Figure 1 shown, in the inverter 41, an arm circuit is formed by the switching element Tr3 and the switching element Tr4, and an arm circuit is formed by the switching element Tr5 and the switching element Tr6. Figure 1 The three arm circuits shown are provided corresponding to the respective phases of the motor 1 and are connected in parallel between the power supply bus 6a and the power supply bus 6b. In addition, the arm circuit formed by the switching element Tr3 and the switching element Tr4 and the arm circuit formed by the switching element Tr5 and the switching element Tr6 have the same circuit structure as the arm circuit formed by the switching element Tr1 and the switching element Tr2, and thus the description already given is incorporated by reference for the circuit structure.

[0030] The gate electrodes of the plurality of switching elements Tr1 to Tr6 are each connected to the gate drive circuit 42. The plurality of switching elements Tr1 to Tr6 are turned on or off according to the gate control signal output from the gate drive circuit 42.

[0031] The gate drive circuit 42 outputs gate control signals to the gate electrodes of a plurality of switching elements Tr1 to Tr6 to turn on or off each switching element. A PWM signal (Pulse Width Modulation signal) is input from the motor controller 13 to the gate drive circuit 42. The gate drive circuit 42 includes a level shifter circuit that can shift the input voltage to a high level. The gate drive circuit 42 shifts the voltage level of the PWM signal to a voltage at which the plurality of switching elements Tr1 to Tr6 can be turned on or off. The gate drive circuit 42 shifts the voltage level of the PWM signal generated by the motor controller 13 and outputs it to the gate electrodes of the respective switching elements. Thus, each switching element of the inverter 41 is turned on or off.

[0032] The capacitor 43 is connected between the power supply bus 6a and the power supply bus 6b. The capacitor 43 is provided to smooth the power output from the storage battery 2. The voltage sensor 44 is connected in parallel with the capacitor 43. The voltage sensor 44 detects the voltage between the two terminals of the capacitor 43.

[0033] The discharge circuit 45 is connected between the power supply bus 6a and the power supply bus 6b. The discharge circuit 45 is composed of a series circuit of a discharge resistor 46 and a switching element 47. The switching element 47 uses, for example, an IGBT, a MOSFET, or the like. In the present embodiment, a control signal is input from the gate drive circuit 42 to the switching element 47. The switching element 47 is turned on or off according to the control signal input from the gate drive circuit 42.

[0034] Next, the low-voltage power system 70 will be described. As Figure 1 shown, the storage battery 2 is connected to the auxiliary equipment storage battery 8 via the DC-DC converter 7. The DC-DC converter 7 is a voltage converter that steps down the voltage of the storage battery 2. The input terminal of the DC-DC converter 7 is connected to the storage battery 2. In addition, the output terminal of the DC-DC converter 7 is connected to the auxiliary equipment storage battery 8, the motor controller 9, the auxiliary equipment controller 10, the auxiliary equipment 11, and the vehicle controller 12.

[0035] The DC-DC converter 7 outputs the stepped-down voltage of the storage battery 2 to the auxiliary equipment storage battery 8, the motor controller 9, the auxiliary equipment controller 10, the auxiliary equipment 11, and the vehicle controller 12. The auxiliary equipment storage battery 8 is charged by the voltage output from the DC-DC converter 7. In the DC-DC converter 7, a circuit structure and a control mechanism known at the time of filing the present invention application can be applied.

[0036] The auxiliary device battery 8 is a DC power source and is a driving source for driving the motor controller 9, the auxiliary device controller 10, the auxiliary device 11, and the vehicle controller 12. The auxiliary device battery 8 uses a secondary battery such as a lithium-ion battery. The auxiliary device battery 8 is a DC power source of a so-called weak power system that discharges at a DC voltage in the range of a dozen volts (V) to several dozen volts (V). The motor controller 9, the auxiliary device controller 10, the auxiliary device 11, and the vehicle controller 12 are devices that can operate using the voltage of the auxiliary device battery 8. In the following description, these devices may also be replaced with weak power devices. Additionally, in the following description, the auxiliary device battery 8 may also be replaced with the weak power battery 8. Although not shown in Figure 1 , a current sensor for detecting the current flowing through the auxiliary device battery 8 is provided in the auxiliary device battery 8. The current value of the auxiliary device battery 8 detected by the current sensor is output to the vehicle controller 12.

[0037] The motor controller 9 is a computer for controlling the operation of the motor 1. Specifically, the motor controller 9 controls the operation of the motor 1 by driving a plurality of switching elements Tr1 to Tr6 constituting the inverter 41. For example, the motor controller 9 is composed of a ROM (Read Only Memory) storing a program for controlling the operation of the motor 1, a CPU (Central Processing Unit) that executes the program stored in the ROM, and a RAM (Random Access Memory) that functions as an accessible storage device. In the motor controller 9, a PWM signal is generated based on the torque command value input from the vehicle controller 12, the position information of the rotor input from the angle sensor provided on the motor 1, and the current value input from the current sensor 5. The motor controller 9 outputs the PWM signal to the gate drive circuit 42. Thereby, the inverter 41 performs an operation corresponding to the power running or regeneration of the motor 1. Specifically, when the motor 1 performs a power running operation, the inverter 41 converts the DC voltage output from the battery 2 into an AC voltage. On the other hand, when the motor 1 performs a regeneration operation, the inverter 41 converts the AC voltage generated by the motor 1 into a DC voltage.

[0038] The motor controller 9 controls the inverter 41 as described above by executing the program stored in the ROM. The program stored in the ROM of the motor controller 9 is changed by the vehicle controller 12 described later. Specifically, the vehicle controller 12 writes the changed program into the ROM of the motor controller 9.

[0039] In addition, changes to the program include program updates (program upgrades). In addition, changes to the program are also referred to as reprogramming or re-programming (abbreviated as reprogramming). Therefore, in the following description, for the program of the motor controller 9, "change to the program" can also be replaced with "reprogramming" or "re-programming". In addition, in the following description, for convenience, the changed program will be referred to as the "changed program" for explanation.

[0040] The auxiliary device controller 10 is a computer for controlling the operation of the auxiliary device 11. For example, the auxiliary device controller 10 includes a ROM that stores a program for controlling the operation of the auxiliary device 11, a CPU that executes the program stored in the ROM, and a RAM that functions as an accessible storage device.

[0041] As Figure 1 shown, as the auxiliary device 11, for example, an audio device 111 and a navigation system 112 can be cited. The audio device 111 outputs music, etc. to the interior of the vehicle according to the operation of the vehicle occupants. The navigation system 112 indicates a route from the current position of the vehicle to the destination based on information on the current position of the vehicle and guides the vehicle occupants. In addition, Figure 1 The audio device 111 and the navigation system 112 shown are examples of the auxiliary device 11, and the auxiliary device 11 is not limited thereto. The auxiliary device 11 may include other devices or systems as long as the device or system can operate using the voltage of the auxiliary device battery 8. In the following description, the auxiliary device 11 can also be replaced with a low-voltage device.

[0042] The auxiliary device controller 10 controls the operations of the audio device 111 and the navigation system 112 by executing the program stored in the ROM. The program stored in the ROM of the auxiliary device controller 10 is also changed by the vehicle controller 12 described later, similar to the motor controller 9. Specifically, the vehicle controller 12 writes the changed program into the ROM of the auxiliary device controller 10.

[0043] In addition, regarding the program of the auxiliary device controller 10, similar to the motor controller 9, in the following description, "change to the program" can also be replaced with "reprogramming" or "re-programming". Similarly to the motor controller 9, for the auxiliary device controller 10, the changed program will also be referred to as the "changed program" for explanation.

[0044] The vehicle controller 12 is composed of a computer with hardware and software. The vehicle controller 12 is composed of a ROM that stores programs, a CPU that executes the programs stored in the ROM, and a RAM that functions as an accessible storage device. In addition, as an operation circuit, an MPU (Micro Processing Unit), a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), etc. can be used instead of or together with the CPU.

[0045] The vehicle controller 12 is connected via an in-vehicle LAN such as CAN (Controller Area Network) in order to mutually transmit and receive information between the motor controller 9 and the auxiliary equipment controller 10. In addition, the vehicle controller 12 is also connected via an in-vehicle LAN such as CAN to a communication controller (not shown) provided on the vehicle. The communication controller is a computer for controlling a communication device provided on the vehicle. CAN and other in-vehicle LANs are called in-vehicle networks. In the present embodiment, information related to the programs of the motor controller 9 and the auxiliary equipment controller 10 is transmitted and received between the respective controllers.

[0046] The vehicle controller 12 realizes a converter control function, a relay control function, a discharge control function, and a program change function by executing the programs stored in the ROM. Hereinafter, each function possessed by the vehicle controller 12 will be described.

[0047] The vehicle controller 12 controls the operation of the DC-DC converter 7 through the converter control function. Specifically, the vehicle controller 12 operates the DC-DC converter 7 according to the charge amount of the auxiliary equipment battery 8 to charge the auxiliary equipment battery 8. In addition, regarding the control method for charging the auxiliary equipment battery 8, a control method known at the time of filing this invention application can be applied to the vehicle controller 12.

[0048] The vehicle controller 12 controls the operation of the discharge circuit 45 through the discharge control function. In the present embodiment, the vehicle controller 12 outputs an instruction for operating the switching element 47 to the motor controller 9 to turn on or off the switching element 47.

[0049] For example, if the switching element 47 is turned on according to the instruction of the vehicle controller 12, the power supply bus 6a and the power supply bus 6b are connected via the discharge resistor 46. That is, the vehicle controller 12 can cause the charge stored in the capacitor 43 to start discharging. In addition, once the switching element 47 is turned on, if the switching element 47 is turned off according to the instruction of the vehicle controller 12, the power supply bus 6a and the power supply bus 6b are disconnected and become a non-conductive state. That is, the vehicle controller 12 can stop the discharge of the charge stored in the capacitor 43.

[0050] The vehicle controller 12 changes at least one of the program of the motor controller 9 and the program of the auxiliary equipment controller 10 through the program change function.

[0051] The change process of the program of the motor controller 9 and the program of the auxiliary equipment controller 10 starts, for example, according to an instruction from a server provided outside the vehicle. As the program change process of the server, for example, the server can send a request signal for requesting program change to the vehicle and then send the process of changing the program.

[0052] For example, first, a request signal for requesting program change is input to the vehicle controller 12 via the in-vehicle network. Then, a change program corresponding to the request signal is input to the vehicle controller 12. In addition, the vehicle controller 12 can identify that the request signal is a signal for changing the program of which controller. In addition, when the auxiliary equipment controller 10 controls a plurality of auxiliary equipments 11, the vehicle controller 12 can identify that the request signal is a request signal for the program for controlling which auxiliary equipment among the plurality of auxiliary equipments 11. In addition, when a plurality of change programs are input to the vehicle controller 12, the vehicle controller 12 can identify which controller the change program belongs to.

[0053] When the change program is input, the vehicle controller 12 performs a program rewriting process based on the change program on the ROM of the controller (motor controller 9, auxiliary equipment controller 10) to be changed. Thereby, the program stored in the ROM of the motor controller 9 or the ROM of the auxiliary equipment controller 10 is changed. In other words, the program of the motor controller 9 or the program of the auxiliary equipment controller 10 is reprogrammed.

[0054] Further, in the present embodiment, when at least any one of the programs of the motor controller 9 and the auxiliary equipment controller 10 is changed, the vehicle controller 12 controls the relay 3 and controls the discharge circuit 45. The case where the vehicle controller 12 controls the relay 3 and the discharge circuit 45 may also be a case other than the case where the program of the motor controller 9 or the program of the auxiliary equipment controller 10 is changed. For example, when the vehicle controller 12 switches the ignition switch of the electric vehicle from off to on by the operation of the occupant, the vehicle controller 12 may also control the relay 3 and the discharge circuit 45. In addition, regarding the control of the relay 3 and the discharge circuit 45 in this case, the control technology known at the time of filing the present invention application can be applied to the vehicle controller 12.

[0055] Figure 2 It is a flowchart showing the control process executed by the vehicle controller 12 in the power supply system 100. In addition, as Figure 2 the state of the power supply system 100 before the start of step S1 shown, the relay 3 is turned on and the switching element 47 of the discharge circuit 45 is turned off.

[0056] In step S1, the vehicle controller 12 determines whether the occupant (driver) has performed a vehicle stop operation. For example, when a signal indicating that the ignition switch is turned off is input to the vehicle controller 12, the vehicle controller 12 can determine that the vehicle is in a stopped state. This step is for determining whether the state of the vehicle is in a state where the program change process shown later can be executed. If it is determined that the vehicle stop operation has been performed, the process proceeds to step S2. On the other hand, if it is determined that the vehicle stop operation has not been performed, the process waits in step S1. In addition, the method for determining whether the vehicle stop operation has been performed is not limited to the above example, and other methods can also be used to determine whether the vehicle stop operation has been performed. In addition, not limited to the vehicle stop operation, it is also possible to determine whether the state of the vehicle is a state where the program change process can be executed based on other operations of the occupant or the state of the vehicle.

[0057] In step S2, the vehicle controller 12 determines whether a program change request has been input. For example, a program change request is input to the vehicle controller 12 from a server provided outside the vehicle via the in-vehicle network. If a change request is input to the vehicle controller 12, the process proceeds to step S3. If a change request has not been input to the vehicle controller 12, the process proceeds to step S7.

[0058] In step S2, when a change request for a program is input, the process proceeds to step S3. In step S3, the vehicle controller 12 determines whether the target program (object program) of the change request input in step S2 is a program for controlling the high-voltage device. In the present embodiment, the high-voltage device refers to a device that can operate using the voltage of the storage battery 2. For example, Figure 1 the inverter 41 shown is a high-voltage device. When it is determined that the target program of the change request is a program for controlling the high-voltage device, the process proceeds to step S4. On the other hand, when it is determined that the target program of the change request is a program other than for controlling the high-voltage device, the process proceeds to step S8.

[0059] When it is determined in step S3 that the target program of the change request is a program for controlling the high-voltage device, the process proceeds to step S4. In step S4, the vehicle controller 12 performs a disconnection process of the relay 3. For example, the vehicle controller 12 outputs a control signal for disconnecting the relay 3 to the relay 3. As a result, the relay 3 switches from the on state to the off state, and the storage battery 2 and the power conversion device 4 switch from the conductive state to the cut-off state. In addition, the storage battery 2 and the DC-DC converter 7 also switch from the conductive state to the cut-off state. Through the processing of this step, it is possible to prevent the voltage of the storage battery 2 from being input to the power conversion device 4.

[0060] In step S5, the vehicle controller 12 performs a discharge process for discharging the charge accumulated in the capacitor 43. For example, the vehicle controller 12 outputs an instruction for turning on the switching element 47 to the motor controller 9. The switching element 47 conducts according to the control signal input from the motor controller 9. As a result, the charge accumulated in the capacitor 43 flows to the discharge resistor 46, and the energy of the charge is consumed in the discharge resistor 46.

[0061] In addition, in step S5, after performing the discharge process, the vehicle controller 12 may also perform a process of confirming whether the discharge of the capacitor 43 is completed. For example, the vehicle controller 12 keeps the switching element 47 turned on for a specified period of time. After that, the vehicle controller 12 may determine whether the discharge of the capacitor 43 is completed based on the voltage between the two terminals of the capacitor 43 detected by the voltage sensor 44. Regarding the method of determining whether the discharge of the capacitor 43 is completed, a known determination method at the time of filing the present invention application can be applied to the vehicle controller 12. In addition, when it is determined that the discharge of the capacitor 43 is not completed, the vehicle controller 12 may further keep the switching element 47 turned on for a specified period of time, and then determine again whether the discharge is completed.

[0062] In step S6, the vehicle controller 12 performs a change process of the program for controlling the high-voltage device. In Figure 1In the example, the vehicle controller 12 performs a program change process on the program stored in the ROM of the motor controller 9. When the program stored in the ROM of the motor controller 9 is changed, the process proceeds to step S7.

[0063] In step S7, the vehicle controller 12 performs a sleep process of the vehicle. For example, the vehicle controller 12 performs a sleep process according to the program changed in step S6, and turns off each switching element of the inverter 41. Additionally, for example, the vehicle controller 12 turns off the switching element 47 that was turned on in step S5. When the process of this step ends, the vehicle transitions to a so-called sleep state. When the process in step S7 ends, the vehicle controller 12 ends Figure 2 the process shown.

[0064] When it is determined in step S3 that the target program of the change request is a program other than the one for controlling the high-voltage equipment, the process proceeds to step S8. In step S8, the vehicle controller 12 performs a program change process for controlling the low-voltage equipment. In Figure 1 the example, the vehicle controller 12 performs a program change process on the program stored in the ROM of the auxiliary equipment controller 10. When the program stored in the ROM of the auxiliary equipment controller 10 is changed, the process proceeds to step S9.

[0065] In step S9, the vehicle controller 12 performs a disconnection process of the relay 3. This step corresponds to step S3. For a specific example of the disconnection process of the relay 3, the description in step S3 is cited. When the process in step S9 ends, the process proceeds to step S7, and the vehicle controller 12 performs a sleep process of the vehicle.

[0066] Additionally, in Figure 2 the flowchart shown, there is no particular limitation on the timing of inputting the changed program to the vehicle controller 12. For example, the changed program of the motor controller 9 or the auxiliary equipment controller 10 may also be input to the vehicle controller 12 in step S2. Additionally, for example, in step 6, the changed program of the motor controller 9 or the auxiliary equipment controller 10 may also be input to the vehicle controller 12.

[0067] Here, the states of the motor controller 9 and the power conversion device 4 during the program change of the motor controller 9 are described. For example, in order to reduce the steadily flowing current, when no pull-up resistor or pull-down resistor is provided at the output terminal of the motor controller 9, during the period of executing the program change process of the motor controller 9, the output terminal of the motor controller 9 becomes an indeterminate state. Since an indeterminate signal is input from the motor controller 9 to the gate drive circuit 42, the gate drive circuit 42 outputs a control signal in an indeterminate state to the inverter 41 or the discharge circuit 45. Due to the control signal in the indeterminate state, unexpected operations may occur in the inverter 41 or the discharge circuit 45. For example, the upper and lower switching elements of the arm circuit constituting the inverter 41 are turned on simultaneously, and a through current may flow through the inverter 41 during the program change process. Additionally, for example, the switching element 47 of the discharge circuit 45 is turned on, and a current may continuously flow through the discharge resistor 46 during the program change process.

[0068] The power supply system 100 of the present embodiment includes: a storage battery 2; an inverter 41 that operates using the power supplied from the storage battery 2; a motor controller 9 that controls the operation of the inverter 41 through a program; an auxiliary equipment storage battery 8 connected to the storage battery 2 via a DC-DC converter 7; an auxiliary equipment 11 that operates using the power supplied from the auxiliary equipment storage battery 8; an auxiliary equipment controller 10 that controls the operation of the auxiliary equipment 11 through a program; a relay 3 that conducts or cuts off the storage battery 2 and the inverter 41; and a vehicle controller 12 that controls the relay 3. When the program of the motor controller 9 is changed, before the start of the program change process of the motor controller 9, the vehicle controller 12 cuts off the storage battery 2 and the inverter 41 through the relay 3. Thereby, during the period when the program of the motor controller 9 is rewritten, it is possible to suppress unexpected operations from occurring in the inverter 41, which is the control object of the program. For example, even if the output terminal of the motor controller 9 is in an indeterminate state during the program change process of the motor controller 9, the voltage of the storage battery 2 is not applied to the inverter 41, so it is possible to prevent a through current from flowing through the inverter 41.

[0069] In addition, in the present embodiment, the power supply system 100 includes a capacitor 43 that smoothes the output voltage of the storage battery 2, and a discharge circuit 45 that discharges the charge stored in the capacitor 43. Further, a relay 3 is provided between the storage battery 2 and the capacitor 43. When the storage battery 2 and the inverter 41 are cut off, the vehicle controller 12 discharges the charge stored in the capacitor 43 through the discharge circuit 45. Thereby, it is possible to prevent the charge stored in the capacitor 43 from flowing into the inverter 41 during the process of changing the program of the motor controller 9. As a result, even if the output terminal of the motor controller 9 is in an indeterminate state during the process of changing the program of the motor controller 9, it is possible to prevent the through-current from flowing into the inverter 41. In addition, since the charge can be discharged earlier than in the case of natural discharge, the process of changing the program of the motor controller 9 can be executed earlier than in the case of natural discharge. As a result, the time during which the relay 3 is opened, that is, the time during which the auxiliary equipment storage battery 8 cannot be charged, can be shortened. Therefore, miniaturization of the auxiliary equipment storage battery 8 can be achieved.

[0070] Furthermore, in the present embodiment, when the program of the auxiliary equipment controller 10 is changed, after the process of changing the program of the auxiliary equipment controller 10 is completed, the vehicle controller 12 cuts off the storage battery 2 and the inverter 41 through the relay 3. Thereby, during the process of changing the program of the auxiliary equipment controller 10, the auxiliary equipment storage battery 8 can be charged through the DC-DC converter 7, so that a decrease in the power supply voltage of the auxiliary equipment controller 10 can be suppressed. As a result, it is possible to suppress a situation in which the process of changing the program of the auxiliary equipment controller 10 abnormally ends due to a decrease in the power supply voltage. In addition, it is possible to suppress a situation in which the auxiliary equipment storage battery 8 excessively discharges charge to the auxiliary equipment controller 10 and the auxiliary equipment storage battery 8 becomes over-discharged during the process of changing the program of the auxiliary equipment controller 10.

[0071] (Second Embodiment)

[0072] Next, Figure 3 the power supply system 100 of the second embodiment will be described. Figure 3 is a block diagram of the power supply system 200 of the second embodiment. The power supply system 200 is mounted on an electric vehicle in the same manner as the power supply system 100 of the first embodiment. In the second embodiment, the driving method of the electric vehicle is different from that of the electric vehicle in the first embodiment. The electric vehicle in the present embodiment is a four-wheel drive vehicle. The electric vehicle is provided with a motor 1 for driving the front wheels and a motor 21 for driving the rear wheels.

[0073] As Figure 3As shown, the power supply system 200 is composed of two power systems with different voltage levels. In the high-voltage power system 150, in addition to the motor 1, battery 2, relay 3, power conversion device 4, and current sensor 5 described in the first embodiment, it also includes a motor 21, a power conversion device 24, and a current sensor 25. For the same structures as in the first embodiment, the same symbols are marked, and for the description of each structure, the description in the first embodiment is incorporated by reference. Figure 1 The same symbol as

[0074] In addition, Figure 3 The shown motor 21, power conversion device 24, and current sensor 25 correspond to the motor 1, power conversion device 4, and current sensor 5, so for these structures, the description in the first embodiment is incorporated by reference. The power conversion device 24 includes: an inverter 241, a capacitor 243, a voltage sensor 244, and a discharge circuit 245. Each structure of the power conversion device 24 corresponds to each structure of the power conversion device 4, so for these structures, the description in the first embodiment is incorporated by reference. As Figure 3 shown, in this embodiment, the power conversion device 4 and the power conversion device 24 are connected in parallel to the battery 2 via the relay 3.

[0075] Next, the low-voltage power system 160 of the second embodiment will be described. The low-voltage power system 160 of the second embodiment is the same as the low-voltage power system 60 of the first embodiment except that it has a motor controller 13 and a part of the functions of the vehicle controller 14 are different from those of the vehicle controller 12 in the first embodiment. Therefore, for the same structures as in the first embodiment, the description in the first embodiment is incorporated by reference.

[0076] The motor controller 13 is a computer for controlling the operation of the motor 21. Similar to the motor controller 9, the motor controller 13 controls the inverter 241 by executing a program stored in the ROM. The program stored in the ROM of the motor controller 13 is changed by the vehicle controller 14 described later.

[0077] The vehicle controller 14 of this embodiment, similar to the vehicle controller 12 of the first embodiment, has a converter control function, a relay control function, a discharge control function, and a program change function. Hereinafter, the controls different from those of the vehicle controller 12 in the first embodiment will be described, and for the controls the same as those of the vehicle controller 12, the description in the first embodiment is incorporated by reference.

[0078] Next, Figure 4 is used to describe the control executed by the vehicle controller 14. Figure 4 is a flowchart showing the control process executed by the vehicle controller 14 in the power supply system 200. Figure 4The processing shown is executed by the vehicle controller 14. Additionally, as Figure 4 the state of the power supply system 200 before the start of step S11 shown, the relay 3 is turned on, and the switching elements 47 of the discharge circuit 45 and the switching element 247 (not shown) of the discharge circuit 245 are turned off.

[0079] Step S11 and step S12 respectively correspond to Figure 2 step S1 and step S2 shown. Therefore, for the description of each step, the description in the first embodiment is cited. When a change request is input to the vehicle controller 14, the process proceeds to step S13. When a change request is not input to the vehicle controller 14, the process proceeds to step S24.

[0080] In step S12, when a change request for the program is input, the process proceeds to step S13. In step S13, the vehicle controller 14 determines whether the target program of the change request input in step S12 is a program for controlling the high-voltage equipment. In this embodiment, different from the first embodiment, the two devices, the inverter 41 and the inverter 241, are high-voltage equipment. When it is determined that the target program of the change request is a program for controlling the high-voltage equipment, the process proceeds to step S14. On the other hand, when it is determined that the target program of the change request is a program for controlling equipment other than the high-voltage equipment, the process proceeds to step S21.

[0081] When it is determined in step S13 that the target program of the change request is a program for controlling the high-voltage equipment, the process proceeds to step S14. Steps S14 to S16 correspond to Figure 2 step S4 to step S6 shown. Therefore, the description of these steps cites the description in the first embodiment.

[0082] Additionally, in this embodiment, the vehicle controller 14 determines whether the program changed in step S13 is a program for controlling the operation of either the motor 1 or the motor 21. When the vehicle controller 14 determines that it is a program for controlling the operation of the motor 1, in step S15, it outputs an instruction to turn on the switching element 47 to the motor controller 9. Additionally, in step S16, the vehicle controller 14 performs a program change process on the program stored in the ROM of the motor controller 9. On the other hand, when the vehicle controller 14 determines that it is a program for controlling the operation of the motor 21, in step S15, it outputs an instruction to turn on the switching element 247 to the motor controller 13. Additionally, in step S16, the vehicle controller 14 performs a program change process on the program stored in the ROM of the motor controller 13.

[0083] In step S17, the vehicle controller 14 determines whether there is an unprocessed change program. An unprocessed change program refers to a program for which change processing has not yet been performed. For example, when the change request for the program input in step S3 includes change requests for programs of multiple controllers, the vehicle controller 14 determines whether there is an unprocessed change program based on the number of times step S16 is executed. For example, when the number of times step S16 is executed is less than the number of programs with change requests, it is determined that there is an unprocessed change program. On the other hand, for example, when the number of times step S16 is executed is the same as the number of programs with change requests, it is determined that there is no unprocessed change program. When it is determined that there is an unprocessed change program, the process proceeds to step S18. On the other hand, when it is determined that there is no unprocessed change program, the process proceeds to step S24.

[0084] When it is determined in step S17 that there is an unprocessed change program, the process proceeds to step S18. In step S18, the vehicle controller 14 performs the turn-on process of the relay 3. For example, the vehicle controller 14 outputs a control signal for turning on the relay 3 to the relay 3. As a result, the relay 3 switches from the off state to the on state, and the battery 2 and the DC-DC converter 7 switch from the cut-off state to the conducting state. Through the processing of this step, the voltage of the battery 2 is input to the DC-DC converter 7. Charging of the auxiliary battery 8 can be started.

[0085] In step S19, the vehicle controller 14 performs the charging process of the auxiliary battery 8. For example, the vehicle controller 14 outputs a control signal for reducing the voltage of the battery 2 to the DC-DC converter 7. As a result, voltage is input from the DC-DC converter 7 to the auxiliary battery 8, and the auxiliary battery 8 is charged. In step S16, since the relay 3 is in the off state, during the change processing of the program, in order to supply power to the motor controller 9 or the motor controller 13, the auxiliary battery 8 discharges its charge. Therefore, when the processing of step S16 ends, the charge amount of the auxiliary battery 8 decreases compared to before the start of the processing of step S16. Through the processing of this step, the power reduced in the auxiliary battery 8 can be replenished. In other words, in step S19, the vehicle controller 14 performs the process of replenishing the charge of the auxiliary battery 8.

[0086] In addition, in step S19, the vehicle controller 14 may also perform a process of measuring the charge amount of the auxiliary device battery 8 after performing the supplementary charging process. For example, the vehicle controller 14 measures the charge amount of the auxiliary device battery 8 based on the detection results from the current sensor and voltage sensor provided in the auxiliary device battery 8. In addition, as a method of measuring the charge amount of the auxiliary device battery 8, a determination method known at the time of filing this invention application may be applied to the vehicle controller 14. When the process of step S19 ends, the process returns to step S13. For example, when the programs of the motor controller 9 and the motor controller 13 are the targets (objects) of the change request, the process re-enters step S16 to change the programs.

[0087] When it is determined in step S13 that the target program (object program) of the change request is a program other than the one for controlling the high-voltage device, the process proceeds to step S21. In step S21, the vehicle controller 14 performs a change process for the program for controlling the low-voltage device. This step corresponds to Figure 2 step S8 shown.

[0088] In step S22, the vehicle controller 14 determines whether there is an unprocessed change program. This step corresponds to step S17. If it is determined that there is an unprocessed change program, the process returns to step S13. On the other hand, if it is determined that there is no unprocessed change program, the process proceeds to step S23.

[0089] In step S23, the vehicle controller 14 performs a disconnection process for the relay 3. This step corresponds to Figure 2 step S9 shown. For a specific example of the disconnection process of the relay 3, refer to the description in the first embodiment. When the process of step S23 ends, the process proceeds to step S24.

[0090] When it is determined in step S2 that no change request for the program is input, when it is determined in step S17 that there is no unprocessed change program, or when the process of step S22 ends, the process proceeds to step S24. In step S24, the vehicle controller 14 performs a sleep process for the vehicle. This step corresponds to Figure 2 step S7 shown. When the process in step S23 ends, the vehicle controller 14 ends Figure 4 the process shown.

[0091] As described above, the power supply system 200 of the present embodiment includes: a plurality of high-power devices of the inverter 41 and the inverter 241, a motor controller 9 that controls the operation of the inverter 41, and a motor controller 13 that controls the operation of the inverter 241. In the present embodiment, when the vehicle controller 14 sequentially changes the programs of the motor controller 9 and the motor controller 13, during the period from the end of the change process of one program to the start of the change process of the next program, the battery 2 is connected to the DC-DC converter 7 through the relay 3. Thereby, it is possible to charge the auxiliary equipment battery 8 before the start of the program change process, so that it is possible to suppress the abnormal end of the program change process due to the decrease in the power supply voltage. In addition, during the program change process, it is possible to suppress the situation where the auxiliary equipment battery 8 excessively discharges charge to the motor controller 9 or the motor controller 13 and the auxiliary equipment battery 8 becomes over-discharged. Furthermore, since the capacity of the auxiliary equipment battery 8 can be minimized as much as possible, it is possible to miniaturize the auxiliary equipment battery 8.

[0092] In addition, the embodiments described above are described for the purpose of easily understanding the present invention, and are not described for the purpose of limiting the present invention. Therefore, the gist of each element disclosed in the above embodiments also includes all design changes and equivalents belonging to the technical scope of the present invention.

[0093] For example, as Figure 2 shown in step S1 and Figure 4 before the start of step S11 shown, the state of the relay 3 is described as the relay 3 being turned on, but the vehicle controller may also execute the process of turning on the relay. For example, in Figure 2 shown in step S8, the vehicle controller 12 may also connect the battery 2 to the inverter 41 through the relay 3 before the start of the change process of the program of the auxiliary equipment controller 10. Thereby, even during the program change process, it is possible to charge the auxiliary equipment battery 8 through the DC-DC converter 7, so that it is possible to suppress the decrease in the power supply voltage of the auxiliary equipment controller 10. As a result, it is possible to suppress the abnormal end of the change process of the program of the auxiliary equipment controller 10 due to the decrease in the power supply voltage. In addition, it is possible to suppress the situation where the auxiliary equipment battery 8 excessively discharges charge to the auxiliary equipment controller 10 during the change process of the program of the auxiliary equipment controller 10 and the auxiliary equipment battery 8 becomes over-discharged.

[0094] In addition, in the above-described embodiments, the structure in which the power conversion device includes a discharge circuit has been described as an example. However, the power conversion device is not limited to including a discharge circuit. The vehicle controller may also discharge the charge stored in the capacitor outside the discharge circuit. For example, the vehicle controller may also control each switching element of the inverter to cause the charge stored in the capacitor to flow to the windings of the motor. The technique of discharging using the windings of the motor can apply the techniques known at the time of filing this invention application to the vehicle controller.

[0095] In addition, in the above-described embodiments, the structure in which the vehicle controller 12 or the vehicle controller 14 has multiple functions has been described as an example. However, the functions of the vehicle controller 12 or the vehicle controller 14 may also be constituted by multiple controllers. For example, the power supply system may also be configured to include: a converter controller having a converter control function, a relay controller having a relay control function, a discharge controller having a discharge control function, and a program controller having a program change function. In addition, in the above-described first embodiment, the controller that controls the operation of the motor 1 has been described as the motor controller 9. However, since the operation control of the motor 1 is based on the operation control of the inverter 41, the controller that controls the operation of the motor 1 may also be referred to as the "inverter controller 9".

[0096] In addition, in the above-described embodiments, the structure in which the auxiliary equipment battery 8 drives each controller has been described as an example. However, as long as the auxiliary equipment battery 8 is a driving power source for the auxiliary equipment 11, the driving power source for each controller may also be a battery different from the auxiliary equipment battery 8.

[0097] Symbol Explanation

[0098] 1: Motor

[0099] 2: Battery

[0100] 3: Relay

[0101] 4: Power Conversion Device

[0102] 41: Inverter

[0103] 42: Gate Drive Circuit

[0104] 43: Capacitor

[0105] 44: Voltage Sensor

[0106] 45: Discharge Circuit

[0107] 5: Current Sensor

[0108] 6a, 6b: Power Supply Bus

[0109] 7: DC - DC Converter

[0110] 8: Auxiliary Equipment Battery

[0111] 9: Motor Controller

[0112] 10: Auxiliary Equipment Controller

[0113] 11: Auxiliary Equipment

[0114] 111: Audio Equipment

[0115] 112: Navigation System

[0116] 12: Vehicle Controller

Claims

1. A power supply system is mounted on a vehicle, wherein, the power supply system includes: a first power supply; a first load that operates using the power supplied from the first power supply; a first controller that controls the operation of the first load through a first program; a second power supply that is connected to the first power supply via a converter; a second load that operates using the power supplied from the second power supply; a second controller that controls the operation of the second load through a second program; a power cut-off device that connects or disconnects the first power supply and the first load; a third controller that controls the power cut-off device; a capacitor that smoothes the output voltage of the first power supply; a discharge circuit that discharges the charge stored in the capacitor, the power cut-off device is provided between the first power supply and the capacitor, when the first program is changed, before the start of the change process of the first program, in a state where the first power supply and the first load are disconnected by the power cut-off device, the third controller discharges the charge through the discharge circuit.

2. The power supply system according to claim 1, wherein, when the second program is changed, before the start of the change process of the second program, the third controller connects the first power supply and the first load through the power cut-off device.

3. The power supply system according to claim 1 or 2, wherein, when the second program is changed, after the end of the change process of the second program, the third controller disconnects the first power supply from the first load and the converter through the power cut-off device.

4. The power supply system according to claim 1 or 2, wherein, the power cut-off device connects or disconnects the first power supply and the converter, the first load is composed of multiple loads, the first controller is composed of multiple first controllers that respectively control the operations of the multiple loads through multiple first programs, the multiple loads and the converter are connected in parallel to the first power supply via the power cut-off device, when the multiple first programs are sequentially changed, during the period from the end of the change process of the first program to the start of the change process of the next first program, the third controller connects the first power supply and the converter through the power cut-off device.

5. A control method for a power supply system, controlling a power supply system mounted on a vehicle, wherein, the power supply system includes: a first power supply; a first load that operates using the power supplied from the first power supply; a first controller that controls the operation of the first load through a first program; a second power supply that is connected to the first power supply via a converter; a second load that operates using the power supplied from the second power supply; a second controller that controls the operation of the second load through a second program; a power cut-off device that connects or disconnects the first power supply and the first load; a third controller that controls the power cut-off device; a capacitor that smoothes the output voltage of the first power supply; A discharge circuit that discharges the charge stored in the capacitor, The power cut-off device is provided between the first power supply and the capacitor, When the first program is changed, the third controller discharges the charge through the discharge circuit in a state where the first power supply and the first load are cut off by the power cut-off device before the start of the change process of the first program.

Images