JP3911131B2 - Vehicle power supply - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electric vehicle using a power storage device as a power source, or a hybrid vehicle using a power storage device and an engine generator as a power source, and more particularly to a power supply device for an electric vehicle suitable for use in a commercial vehicle.
[0002]
[Prior art]
As a power storage device for an electric vehicle such as a hybrid vehicle, attention is focused on an application technology of an electric double layer capacitor (capacitor) that can be rapidly charged and has a long charge / discharge cycle life. When a large number of capacitor cells are connected in series and parallel to form a power storage device with the required capacity, the terminal voltage of each capacitor cell reaches a predetermined value (reference voltage) so that these capacitor cells can be charged uniformly. It is conceivable to connect working current bypass circuits in parallel. Japanese Patent Application Laid-Open No. 6-343225 discloses a device including a comparator that detects a terminal voltage of a capacitor and a current bypass circuit that operates in response to the output. Japanese Patent Laid-Open No. 7-87668 discloses a capacitor in which a constant current output of a DC-DC converter can be efficiently charged to a power source.
[0003]
[Problems to be solved by the invention]
Such a bypass circuit allows each capacitor cell to share the maximum voltage of the power storage device evenly, but there are variations among capacitor cells such as capacitance, internal resistance, and leakage current, and charging and discharging are repeated. As a result, a difference occurs between the shared voltages of the capacitor cells, which may accelerate deterioration of the capacitor cell having a large shared voltage. For this reason, it is required to periodically charge (initialize) the capacitor cell terminal voltage to the reference voltage (corresponding to the maximum voltage of the power storage device), but an external charging facility is also required. There is also the inconvenience that the charging time is taken before driving.
[0004]
An object of the present invention is to provide an effective means for solving such problems.
[0005]
[Means for Solving the Problems]
1st invention is a power supply device of a vehicle provided with the electric motor which constitutes the motor | power_engine of a vehicle, and the electrical storage apparatus which comprises the main power supply of an electric motor, In these capacitor cells which comprise an electrical storage apparatus, these shared voltages are set | placed. comprising a DC-DC converter to charge the power storage device using the onboard electrical system supply as an auxiliary power supply for equalization, the variation in the sharing voltages of the capacitor cells is higher default Vk, for equalizing the shared voltage The charging of the power storage device by the DC-DC converter is started .
[0006]
According to a second aspect of the present invention , there is provided a power supply device for a vehicle including an electric motor that constitutes a prime mover of the vehicle and a power storage device that constitutes a main power source of the motor. A DC-DC converter that charges the power storage device using an in-vehicle electrical system power supply as an auxiliary power source for equalization is detected, and the maximum voltage Vmax among these shared voltages is detected for the capacitor cell that composes the power storage device. Each shared voltage is equalized to the maximum voltage Vmax + predetermined value β .
[0007]
According to a third aspect of the present invention , there is provided a power supply device for a vehicle including an electric motor that constitutes a prime mover of the vehicle and a power storage device that constitutes a main power source of the motor. A DC-DC converter that charges the power storage device using an in-vehicle electrical system power supply as an auxiliary power source for equalization is detected, and the maximum voltage Vmax among these shared voltages is detected for the capacitor cell that composes the power storage device. Each shared voltage is equalized to the maximum voltage Vmax + predetermined value β .
[0008]
According to a fourth aspect of the present invention , there is provided a power supply device for a vehicle including an electric motor that constitutes a prime mover of the vehicle and a power storage device that constitutes a main power source of the motor. A DC-DC converter that charges the power storage device using an in-vehicle electrical system power supply as an auxiliary power source for equalization. When the main power supply of the motor is in a charge / discharge state, the DC-DC converter charges the power storage device. characterized in that it prohibited.
[0009]
According to a fifth aspect of the present invention, a DC-DC converter according to any one of the first to fourth aspects of the present invention constitutes an isolated power source for a main power circuit and an electrical system power source insulated from the main power circuit. And
[0010]
According to a sixth invention, a DC-DC converter according to any one of the first to fourth inventions is provided with a maximum voltage of the power storage device + a high voltage output of a predetermined value α and a constant current output. And
[0012]
In the first to sixth inventions , the power storage device is steadily charged (such as when the vehicle is stopped) by the DC-DC converter using the electrical system power supply, and the shared voltage of the capacitor cells can be equalized. . The equalization of the shared voltage of the capacitor is performed by a voltage alignment means that applies a current bypass circuit, and is aligned with the equalized voltage set at any time, and the standard corresponding to the maximum voltage of the power storage device without using an external charging facility It is also possible to initialize to a voltage.
[0013]
In the first aspect of the present invention, the dispersion of the shared voltage of the capacitor cell can be suppressed within the predetermined value Vk by charging the DC-DC converter .
[0014]
In the second aspect of the invention, the shared voltage of the capacitor cell is equalized to the maximum voltage + the predetermined value β by charging the DC-DC converter. Further, since the equalization voltage is the maximum voltage + the predetermined value β, the power consumption accompanying the bypass can be minimized .
[0015]
In the third invention, it is possible to easily select between steady equalization of the shared voltage and equalization to initialize the shared voltage to the reference voltage (maximum voltage of the power storage device) .
[0016]
In the fourth aspect of the invention, interference between the charging current of the DC-DC converter and the charging / discharging current of the main power supply circuit is avoided, and the reliability and durability of the system can be ensured .
[0017]
In the fifth aspect of the invention, the DC-DC converter constitutes an insulated power supply for the main power supply circuit and the electrical system power supply insulated from the main power supply circuit, thereby avoiding a short circuit between them and improving the safety of the vehicle. It can be.
[0018]
In the sixth aspect of the invention, the shared voltage of the capacitor cell is maintained in an equal state by charging from the DC-DC converter, and the shared voltage can be efficiently charged to the maximum voltage .
[0019]
DETAILED DESCRIPTION OF THE INVENTION
In FIG. 1, reference numeral 1 denotes an electric motor that constitutes a prime mover of a vehicle, and is connected to a power storage device 3 (capacitor power storage device) via an inverter 2. The inverter 2 supplies driving power to the electric motor 1 using the power storage device 3 as a power source during vehicle power running, and supplies charging power to the power storage device 3 using regenerative power generated by the electric motor 1 during vehicle braking.
[0020]
The power storage device 3 is composed of a large number of capacitor cells 3a into an assembled battery 3A having a required capacity. These cells 3a are divided into a plurality of modules 3B (capacitor cell modules), and voltage aligning means 4 (consisting of 25 to 37 in FIG. 2) for equalizing the shared voltage (terminal voltage) of the capacitor cells 3a for each module 3B. Is provided). The large number of capacitor cells 3a and the plurality of modules 3B are not limited to the series connection shown in the figure, and may be configured to use a parallel connection together.
[0021]
In power storage device 3, contactor 5 and fuse 6 are interposed between assembled battery 3 </ b> A and inverter 2 (main circuit 9), and total voltage detection amplifier 7 that monitors the total voltage of power storage device 3 is provided. The total voltage amplifier 7 detects a voltage (total voltage of the power storage device 3) from both ends of the assembled battery 3A, and the detection signal is insulated from the main circuit 9 and input to the hybrid ECU 10.
[0022]
The hybrid ECU 10 controls the entire system, and exchanges various information (detection data, control commands, etc.) between the inverter 2 of the electric motor 1 and each module 3B of the power storage device 3. 11 is built. For example, information on each module 3B is transmitted to the hybrid ECU 10 via the communication network 11, and information on the hybrid ECU 10 is also transmitted to each module 3B. Reference numerals 11 a and 11 b denote termination resistors of the communication network 11.
[0023]
The vehicle is equipped with an electrical system power supply 15 (car battery), and supplies power to each electrical component (including the ECU 10, the inverter 2, and each voltage alignment circuit 4 of the power storage device 3) via the key switch 16 during operation of the vehicle. To do. Contactor 5 of power storage device 3 is connected to electrical system power supply 15 via key switch 16 and closes main circuit 9 when energization is ON (coil excitation), and opens main circuit 9 when energization is OFF. .
[0024]
In order to perform auxiliary charging of the power storage device 3, a DC-DC converter 17 connected to the electrical system power supply 15 via the key switch 16 is provided, and a relay 18 that opens and closes the power supply to the DC-DC converter 17 is connected to the key switch 16. It is inserted between. The DC-DC converter 17 sets the power supplied from the electrical system power supply 15 via the key switch 16 and the relay 18 to a high voltage suitable for charging the power storage device 3 (maximum voltage of the power storage device 3 + predetermined value α). To be supplied to the assembled battery 3A. The main circuit 9 system power supply (power storage device 3) and the electrical system power supply 15 are insulated from each other at the ground point in order to avoid a short circuit. The DC-DC converter 17 is also configured as an insulating charging power source that is isolated from the ground point of the main circuit 9 system power source and the electrical system power source 15.
[0025]
Reference numeral 20 denotes a switch for selecting a maximum voltage alignment for initializing the power storage device 3 to the maximum voltage (an operation switch disposed in the driver's cab). When the switch 20 is ON, the maximum voltage alignment is selected and the vehicle While the vehicle is stopped, the power storage device 3 is charged using the constant current output of the DC-DC converter as a power source. On the other hand, when this switch is OFF, arbitrary voltage alignment is selected, and the constant current of the DC-DC converter is stopped when the vehicle is stopped. The power storage device 3 is charged with the output as a power source. The relay 18 that opens and closes the power supply to the DC-DC converter 17 is controlled by the hybrid ECU 10 based on information from each module 3B.
[0026]
Each module of the power storage device 3 is configured as shown in FIG. Each capacitor cell 3a (1-n) is provided with a bypass circuit 25 in parallel. The bypass circuit 25 includes a current limiting resistor 25a and a transistor 25b, and includes an OR circuit 26 that turns on and off the transistor 26b. Based on the input from the comparator 27 and the input from the bypass switching circuit 29, the OR circuit 26 turns ON (bypass operation) signal to the transistor 25b when at least one of these inputs becomes a high level signal (bypass command). Is output. The transistor 25b closes the bypass circuit 25 when the base voltage is applied by the ON signal of the OR circuit 26, and bypasses the bypass circuit 25 when the application of the base voltage is canceled by the OFF signal of the OR circuit 26. Is established.
[0027]
The comparator 27 outputs a bypass command for initializing the power storage device 3 to the maximum voltage, and the terminal voltage (cell voltage) of the capacitor cell 3 a (1 to n) corresponds to the maximum voltage of the power storage device 3. When the terminal voltage of the capacitor cell 3a (1 to n) exceeds the reference voltage as compared with the reference voltage (set in the generator 28), a bypass command is output to the OR circuit 26. The bypass switching circuit 29 outputs a bypass command for arbitrarily correcting (equalizing) variations in the shared voltage of the capacitor cells 3a (1 to n), and outputs the bypass command to the OR circuit 26 of the capacitor cell that needs to be bypassed. Outputs a bypass command.
[0028]
The voltage detection switching circuit 30 sequentially detects these shared voltages (cell voltages) for the capacitor cells 3a (1 to n), and the detection signal is insulated from the main circuit 9 system power supply by the insulation amplifier 31. The data is input to the CPU 33 via the AD converter 32. The CPU 33 exchanges various necessary information via the communication network 11 and uses it for control data stored in the RAM 34, while performing processing as described below based on a program stored in the ROM 35 ( The bypass determination of the capacitor cell 3a is executed.
[0029]
Based on the determination of the CPU 33, the target cell switching processing circuit 36 specifies the capacitor cell 3a that needs to be bypassed for the bypass switching circuit 29. The processing circuit 36 also has a function of specifying a detection target capacitor cell for the voltage detection switching circuit 30. Further, based on the determination of the CPU 33, a control command for the relay 18 that opens and closes the power supply from the communication control circuit 37 to the DC-DC converter 17 is transmitted to the hybrid ECU 10.
[0030]
FIG. 3 is a flowchart for explaining the control contents of each module 3B (main routine related to bypass determination), and is repeatedly processed at a predetermined cycle. In step 1, vehicle driving information (charge / discharge state) is acquired from the system ECU 10 via the communication network 11. In step 2, it is determined whether or not the vehicle is in a non-charge / discharge state (not a regenerative operation or a power running operation) from the vehicle operation information. If the determination in step 2 is yes, the process proceeds to step 3, while if the determination in step 2 is no, the process jumps to END.
[0031]
In step 3, it is determined whether the switch 20 is ON (selection of maximum voltage alignment). When the determination in step 3 is yes, the maximum voltage alignment (switching the open / close relay 18 of the DC-DC converter 17 to ON) is processed in step 4, while when the determination in step 3 is no, in step 5 Process any voltage alignment.
[0032]
In the maximum voltage alignment in step 4, the DC-DC converter 17 outputs a constant current with a predetermined voltage (maximum voltage of the power storage device 3 + α) by the power supplied from the electrical system power supply 15 via the key switch 16 and the relay 18. To charge the power storage device 3. When charging current flows through the capacitor cells 3a (1 to n) of each module 3B and the terminal voltage reaches the reference voltage while the relay 18 is ON, the OR circuit 26 switches the transistor 25b on the basis of the output of the comparator 27. Since the charging current flows through the bypass circuit 25 to be turned on, the shared voltage of the capacitor cells 3a (1 to n) is equalized to the reference voltage (corresponding to the maximum voltage of the power storage device 3).
[0033]
FIG. 4 illustrates the processing contents of the arbitrary voltage alignment (performed in step 5 of FIG. 3). In steps 1 to 4, the voltage of each terminal of the capacitor cell 3a (1 to n) is determined based on these terminal voltages. The minimum voltage Vmin and the maximum voltage Vmax are detected. Specifically, the detected value of the terminal voltage is compared with the lowest voltage Vmin stored in the memory for the capacitor cell of number i = 1 to be detected, and when the detected value falls below the lowest voltage Vmin, the lowest voltage of the memory While Vmin is updated to the detected value, when the detected value is equal to or higher than the minimum voltage Vmin, the minimum voltage Vmin of the memory is stored, and the detected value is compared with the maximum voltage Vmax stored in the memory. When the detected value exceeds the maximum voltage Vmax, the maximum voltage Vmax of the memory is updated to the detected value. On the other hand, when the detected value is equal to or lower than the maximum voltage Vmax, the maximum voltage Vmax of the memory is stored. This process is sequentially repeated for all the capacitor cells 3a (1 to n). When the lowest voltage Vmin and the highest voltage Vmax are determined by the end of the process of the nth capacitor cell 3a, the process proceeds to step 5.
[0034]
In step 5, a voltage difference ΔV = Vmax−Vmin between the lowest voltage Vmin and the highest voltage Vmax is calculated. In step 6, it is determined whether ΔV is equal to or greater than a predetermined value Vk (arbitrary voltage alignment is necessary). If the determination in step 6 is yes, the process proceeds to step 7. On the other hand, if the determination in step 6 is no, the process jumps to step 15 and switches the open / close relay 18 of the DC-DC converter 17 to OFF. In step 7, the equalization voltage of the capacitor cell is set to a voltage that exceeds a predetermined value β from the maximum voltage Vmax. In step 8, the open / close relay 18 of the DC-DC converter 17 is turned ON.
[0035]
As a result, the DC-DC converter 17 charges the power storage device 3 with a constant current output of a predetermined voltage (the maximum voltage of the power storage device 3 + α) by the power supplied from the electrical system power supply 15 via the key switch 16 and the relay 18. To do. Then, in equalizing the shared voltage of the capacitor cell 3a (1 to n) to the maximum voltage Vmax + β, in step 9 and step 10, the terminal voltage (voltage detection switching) of the capacitor cell 3a with the target number i = 1. The detection value of the circuit 30) is compared with the set value (maximum voltage Vmax + β) of the equalization voltage. When the terminal voltage of the capacitor cell 3a (1) is equal to or higher than the equalization voltage, the bypass operation is commanded at step 11, while when the terminal voltage of the capacitor cell 3a (1) is equal to or lower than the equalization voltage, step 12 is performed. In order to stop the bypass. This processing is sequentially repeated for all capacitor cells 3a (1 to n) until the processing of the nth capacitor cell is completed (step 10 to step 14).
[0036]
FIG. 5 is a characteristic diagram for explaining the alignment of the shared voltage. When the DC-DC converter 17 is turned on, the charging current from the DC-DC converter 17 flows to the capacitor cell 3a and the bypass circuit 25 is turned off. The terminal voltage rises. When the terminal voltage reaches the equalization voltage, the bypass circuit 25 is turned on, and the terminal voltage of the capacitor 3a is regulated to the equalization voltage.
[0037]
With such a configuration, when the switch 20 is in an arbitrary voltage alignment, if the shared voltage of the capacitor cell 3a (1 to n) varies more than the predetermined value Vk, the output of the DC-DC converter is output when the vehicle is stopped. The voltage shared by the capacitor cells 3a (1 to n) is aligned to the maximum voltage Vmax + β at that time. Therefore, variation in the shared voltage of capacitor cell 3a (1 to n) is corrected, and when initializing to the maximum voltage of the power storage device, the shared voltage of capacitor cell 3a (1 to n) reaches the reference voltage at the same time. Thus, a part of the capacitor cell 3a (1 to n) is prevented from being overcharged to a reference voltage or higher. As a result, reduction of the margin to be taken into account in setting the maximum voltage of the power storage device 3 (the reference voltage of the comparator) is possible, stored energy of the original power storage capacity of power storage device 3 (capacitor ^{Ec = C · V 2/2} C Is an electrostatic capacity, and V is a voltage).
[0038]
In the arbitrary voltage alignment, since the equalization voltage is set to the maximum voltage Vmax + β at that time, the frequency of bypassing is minimized, and the power consumption associated with the bypass can be reduced to the maximum. Of course, the equalization voltage can be set to the minimum voltage Vmin or the average value of the maximum voltage Vmax and the minimum voltage Vmin, etc. However, compared to the case of the maximum voltage Vmax + β, the bypass frequency increases as the set voltage is small. End up. Further, the power storage device 3 can be efficiently charged by the constant current (small current) output of the DC-DC converter 17. Since the output voltage of the DC-DC converter 17 is set to the maximum voltage + α of the power storage device 3, depending on the charge / discharge state during traveling, the initialization of the power storage device 3 (maximum voltage) is possible without using an external charging facility. (Alignment) is also sufficiently possible.
[0039]
In addition, when the charge amount of the power storage device 3 has a margin, it is conceivable to charge the electrical system power supply 15 from the power storage device 3 via the DC-DC converter 17. Even in this case, the shared voltage of the capacitors 3a (1 to n) can be equalized by turning the bypass circuit 25 on and off. In the above embodiment, the equalization voltage at the time of arbitrary voltage alignment is set for each module 3B of the power storage device 3, but the equalization voltage common to each module 3B of the power storage device 3 (for example, each module 3B) An equalization voltage for further averaging the equalization voltage) may be set.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a system representing an embodiment of the present invention.
FIG. 2 is a configuration diagram of the capacitor module.
FIG. 3 is a flowchart for explaining the control contents of the capacitor module.
FIG. 4 is a flowchart for explaining the control content of the capacitor module.
FIG. 5 is a characteristic diagram for explaining the control content of the capacitor module.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Electric motor 2 Inverter 3 Power storage device 3B Capacitor cell module 3a (1-n) Capacitor cell 4 Voltage alignment means 5 Contactor 7 Total voltage amplifier 9 Main circuit 10 Hybrid ECU
11 Communication network 15 Electrical system power supply 16 Key switch 17 DC-DC converter 18 Relay 20 Switch (operating switch in cab)
25 Bypass circuit 25a Limiting resistor 25b Transistor 26 OR circuit 27 Comparator 28 Reference voltage generator

Claims (6)

Assistance for equalizing these shared voltages for a plurality of capacitor cells constituting a power storage device in a vehicle power supply device comprising an electric motor that constitutes a motor for the vehicle and a power storage device that constitutes a main power source of the motor It is equipped with a DC-DC converter that charges the power storage device using an in-vehicle electrical power supply as the power source. When the dispersion of the shared voltage of the capacitor cell exceeds the preset value Vk, the DC-DC converter is used to equalize the shared voltage. A power supply device for a vehicle, which starts charging a power storage device. Assistance for equalizing these shared voltages for a plurality of capacitor cells constituting a power storage device in a power supply device for a vehicle comprising an electric motor that constitutes a prime mover of the vehicle and a power storage device that constitutes a main power source of the motor It has a DC-DC converter that charges the power storage device using an on-board electrical power supply as the power source. For the capacitor cells that compose the power storage device, the highest voltage Vmax among these shared voltages is detected, and each shared voltage is maximized. A power supply device for a vehicle, characterized by equalizing voltage Vmax + predetermined value β. Assistance for equalizing these shared voltages for a plurality of capacitor cells constituting a power storage device in a vehicle power supply device comprising an electric motor that constitutes a motor for the vehicle and a power storage device that constitutes a main power source of the motor It has a DC-DC converter that charges the power storage device using an on-board electrical power supply as the power source. For the capacitor cell that composes the power storage device, the highest voltage Vmax is detected among these shared voltages, and each shared voltage is maximized. A vehicle comprising: means for selecting between equalizing voltage Vmax + predetermined value β and equalizing each shared voltage of the capacitor cell to a reference voltage corresponding to the maximum voltage of the power storage device Power supply. Assistance for equalizing these shared voltages for a plurality of capacitor cells constituting a power storage device in a power supply device for a vehicle comprising an electric motor that constitutes a prime mover of the vehicle and a power storage device that constitutes a main power source of the motor using onboard electrical system supply as a power supply comprising a DC-DC converter for charging the power storage device, when the main power supply of the motor of the charge and discharge states and wherein the prohibiting charging of the power storage device according to the DC-DC converter A vehicle power supply device. 5. The vehicular power supply device according to claim 1 , wherein the DC-DC converter constitutes an insulated power supply for the main power supply circuit and an electrical system power supply insulated from the main power supply circuit. 6. 5. The vehicular power supply apparatus according to claim 1 , wherein the DC-DC converter includes a maximum voltage of the power storage device + a high voltage output of a predetermined value α and a constant current output. 6.

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