JP6918588B2 - Control system - Google Patents

Description

The present invention relates to a control system including a first DC / DC converter that performs a step-down operation and a second DC / DC converter that performs a step-up operation.

The power storage device has a characteristic that the terminal voltage changes depending on the temperature. Therefore, in order to stabilize the terminal voltage of the power storage device, it is necessary to control the temperature of the power storage device. In Patent Document 1, a heater driven by electric power supplied from a DC / DC converter is provided, and the temperature of the power storage device is controlled by the heat generated by the heater.

Japanese Unexamined Patent Publication No. 2016-157647

When a heater is used for temperature control of the power storage device, the electric power of the power storage device is consumed as the heater generates heat. In this case, there is a concern that the remaining capacity of the power storage device will decrease faster.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a control system capable of reducing the power consumption of the power storage device required for raising the temperature of the power storage device.

In order to solve the above problems, the first invention comprises a first DC / DC converter that performs a step-down operation, a second DC / DC converter that performs a step-up operation, an input side of the first DC / DC converter, and the second DC / DC. It is a control system including a main wiring connecting the output side of the converter and the main power storage device, and a sub wiring connecting the output side of the first DC / DC converter and the input side of the second DC / DC converter. In the first invention, the first DC / DC converter is stepped down in order to circulate a current in a loop circuit including the main wiring, the first DC / DC converter, the second DC / DC converter, and the sub wiring. The heat generated by at least one of the first DC / DC converter and the second DC / DC converter by the step-down operation and the step-up operation of the temperature rise control unit for boosting the second DC / DC converter and the step-down operation and the boost operation of the temperature rise control unit. Is provided with a heat transfer unit that transmits the above to the main power storage device.

When power conversion is performed by the first and second DC / DC converters, a part of the power is converted into thermal energy in the first and second DC / DC converters. Therefore, it is conceivable to use the converted thermal energy to raise the temperature of the main power storage device. Therefore, the first invention includes a temperature rise control unit and a heat transfer unit. Due to the step-down operation and the step-up operation of the temperature rise control unit, a current flows through the loop circuit, and heat for raising the temperature of the main power storage device is generated by the first DC / DC converter and the second DC / DC converter. The heat transfer unit transfers the heat generated by at least one of the first DC / DC converter and the second DC / DC converter to the main power storage device. As a result, the heat generated by the power conversion can be effectively used, and the power consumption of the power storage device required for raising the temperature of the power storage device can be reduced.

In the second invention, the temperature rise control unit requires the first DC / to raise the temperature of the main power storage device to the target temperature based on the deviation between the temperature of the main power storage device and the target temperature thereof. It has a command value setting unit that sets the first output current command value, which is the output current command value of the DC converter, and the second output current command value, which is the output current command value of the second DC / DC converter. The output current of the DC converter is controlled to the first output current command value, and the output current of the second DC / DC converter is controlled to the second output current command value.

In the above configuration, the output current of the first and second DC / DC converters is controlled based on the amount of temperature rise required to raise the temperature from the current temperature of the main power storage device to the target temperature, so that unnecessary thermal energy is not required. Can be prevented from increasing. As a result, it is possible to suppress an increase in power consumption during the temperature raising operation of the main power storage device.

In the third invention, a sub power storage device is connected to the sub wiring, and a power source when a step-down operation and a boost operation are performed by the temperature rise control unit based on the voltage state of the main power storage device. A selection unit for selecting either the main power storage device or the sub power storage device is provided, and the command value setting unit selects a power source for circulating a current in the loop circuit by the selection unit. The first output voltage command value, which is the output voltage command value of the first DC / DC converter, the first output current command value, and the output of the second DC / DC converter so as to be either the power storage device or the sub power storage device. The second output voltage command value and the second output current command value, which are voltage command values, are set, and the temperature rise control unit controls the output current of the first DC / DC converter to the first output current command value. The output voltage of the first DC / DC converter is controlled to the first output voltage command value, the output current of the second DC / DC converter is controlled to the second output current command value, and the second DC / DC is controlled. The output voltage of the converter is controlled to the second output voltage command value.

In the above configuration, either the main power storage device or the sub power storage device can be used as a power source for circulating a current in the loop circuit according to the voltage state of the main power storage device. Therefore, for example, when the voltage between the terminals of the main power storage device is small, the sub power storage device may be used as the power source, and the temperature raising operation can be stably continued.

In the fourth invention, the command value setting unit sets the first output voltage command value to be larger than the terminal voltage of the sub power storage device when the main power storage device is selected by the selection unit. However, the second output voltage command value is set to be smaller than the terminal voltage of the main power storage device.

Specifically, when the main power storage device is used as a power source, as in the fourth invention, the output voltage command values of the first and second DC / DC converters and the terminal voltages of the main power storage device and the sub power storage device are used. You just have to determine the relationship with.

In the fifth invention, the command value setting unit sets the first output voltage command value to be smaller than the terminal voltage of the sub power storage device when the sub power storage device is selected by the selection unit. However, the second output voltage command value is set to be larger than the terminal voltage of the main power storage device.

Specifically, when the sub power storage device is used as a power source, the output voltages of the first and second DC / DC converters and the terminal voltages of the main power storage device and the sub power storage device are set as in the fifth invention. You just have to decide.

In the sixth invention, the temperature rise control unit requires the first DC / DC to raise the temperature of the main power storage device to a predetermined temperature based on the deviation between the temperature of the main power storage device and the target temperature thereof. It has a command value setting unit that sets the first output current command value, which is the output current command value of the converter, and the second output current command value, which is the output current command value of the second DC / DC converter, and has the second DC / DC. The output current of the converter is controlled to the second output current command value.

In the above configuration, the temperature of the main power storage device can be brought close to the target temperature only by adjusting the second output current command value. Therefore, the control related to the temperature raising operation can be simplified, and the processing load of the control device can be reduced.

The block diagram of the control system which concerns on 1st Embodiment. The figure explaining the arrangement relation of each part in a power supply unit. The figure explaining the relationship between the discharge capacity of a high voltage battery and temperature. The figure explaining the loop circuit which concerns on this embodiment. The flowchart explaining the temperature raising process performed by a control device. The graph which shows the correspondence relationship between the temperature rise amount ATR and the required electric energy amount NAP. The flowchart explaining the temperature raising process which concerns on 2nd Embodiment. The flowchart explaining the process performed by the control device which concerns on 3rd Embodiment. The figure explaining the current flowing in a power supply unit. The block diagram of the control system which concerns on 4th Embodiment. The flowchart explaining the process performed by the control device which concerns on 4th Embodiment.

(First Embodiment)
Hereinafter, a first embodiment embodying the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of a control system 100 according to the first embodiment. The control system 100 is mounted on the vehicle. The vehicle on which the control system 100 is mounted is, for example, a hybrid vehicle including an engine which is an internal combustion engine and a motor for traveling as a traveling power source.

The control system 100 includes a power supply unit 40, an inverter 51, a motor 11, a device group 60, and an auxiliary battery 61. In the control system 100, the inverter 51, the device group 60, and the auxiliary battery 61, which are the targets of power supply, are supplied with power from the power supply unit 40.

The power supply unit 40 includes a high-voltage battery 50, first to sixth high-voltage lines HL1 to HL6, first and second sub-wiring SL1 and SL2, a first DC / DC converter 20, and a second DC / DC converter 30. Mainly prepared. The high-voltage battery 50 corresponds to the main power storage device.

The high voltage battery 50 functions as a main power source in the control system 100. In the present embodiment, the high-voltage battery 50 is an assembled battery in which cells of a plurality of lithium-ion storage batteries are combined. The high voltage battery 50 produces, for example, a first terminal voltage Vb1 of 200V to 400V. The high-voltage battery 50 also includes a monitoring unit that detects the remaining capacity (SOC).

The first high-voltage line HL1 is connected to the positive terminal of the high-voltage battery 50, and the second high-voltage line HL2 is connected to the negative terminal. Further, in the first and second high-voltage lines HL1 and HL2, the side opposite to the side connected to the high-voltage battery 50 is connected to the inverter 51.

A relay 53 is provided on the first high voltage line HL1. By controlling the relay 53 in the closed state, a closed circuit connecting the high-voltage battery 50 and the inverter 51 is formed, and a current flows through the closed circuit. As a result, electric power can be transmitted between the high-voltage battery 50 and the inverter 51.

The first and second DC / DC converters 20 and 30 are connected to the high voltage battery 50 through the first to sixth high voltage lines HL1 to HL6. Hereinafter, the first DC / DC converter 20 will be referred to as a first DDC 20, and the second DC / DC converter 30 will be referred to as a second DDC 30.

The first DDC 20 is a unidirectional buck converter. In the present embodiment, the first DDC 20 is an insulated conversion device in which a primary side circuit and a secondary side circuit are connected via a transformer. The first input terminal Ti1 of the first DDC 20 is connected to the first high voltage line HL1 through the third high voltage line HL3, and the second input terminal Ti2 is connected to the second high voltage line HL2 through the fourth high voltage line HL4. Further, the first output terminal To1 of the first DDC 20 is connected to the first sub-wiring SL1, and the second output terminal To2 is connected to the second sub-wiring SL2. In the present embodiment, the first and second input terminals Ti1 and Ti2 correspond to the input side of the first DDC20, and the first and second output terminals To1 and To2 correspond to the output side.

The first DDC 20 includes a plurality of semiconductor switches. The first terminal voltage Vb1 supplied from the high voltage battery 50 is input to the first input terminal Ti1 and the second input terminal Ti2. By switching the on / off of each semiconductor switch, the first terminal voltage Vb1 is stepped down and output from the first output terminal To1 and the second output terminal To2. As a result, the electric power of the high-voltage battery 50 is supplied to at least one of the equipment group 60 and the auxiliary battery 61 via the first DDC 20.

The third high-voltage line HL3 is connected to the first high-voltage line HL1 on the high-voltage battery 50 side of the relay 53. Therefore, even when the relay 53 is controlled to be in the open state, a current can flow through the closed circuit connecting the high-voltage battery 50 and the first DDC 20.

The first DDC 20 is provided with a first current sensor 21 that detects the current flowing through the first DDC 20. For example, the first current sensor 21 is connected to the primary circuit of the first DDC 20. The control device 10 constituting the control system 100 can estimate the output current output from the first DDC 20 based on the current detected by the first current sensor 21 and the turns ratio of the transformer of the first DDC 20. Hereinafter, the output current of the first DDC 20 will be referred to as the first output current Ic1r.

The second DDC 30 is a bidirectional buck-boost converter. In the present embodiment, the second DDC 30 is an insulated conversion device in which the primary side circuit and the secondary side circuit are connected via a transformer. The second DDC 30 includes a plurality of semiconductor switches, and by switching on / off of each semiconductor switch, a step-down operation or a step-up operation with respect to an input voltage is performed.

The first terminal TA of the second DDC 30 is connected to the first high voltage line HL1 through the fifth high voltage line HL5. The second terminal TB is connected to the second high voltage line HL2 through the sixth high voltage line HL6. The third terminal TC is connected to the first output terminal To1 via the first sub-wiring SL1, and the fourth terminal TD is connected to the second output terminal To2 via the second sub-wiring SL2.

Explaining the step-down operation, the second DDC 30 steps down the first terminal voltage Vb1 supplied through the first and second terminals TA and TB, and outputs the voltage from the third and fourth terminals TC and TD. Explaining the boosting operation, the second DDC 30 boosts the voltage supplied through the third and fourth terminals TC and TD, and outputs the voltage from the first and second terminals TA and TB. In the present embodiment, the third and fourth terminals TC and TD correspond to the input side of the second DDC 30, and the first and second terminals TA and TB correspond to the output side.

The fifth high-voltage line HL5 is connected to the first high-voltage line HL1 on the inverter 51 side of the relay 53. Therefore, when the relay 53 is closed, a current can flow through the closed circuit including the high-voltage battery 50, the first DDC 20, and the second DDC 30. On the other hand, when the relay 53 is opened, the closed circuit including the high voltage battery 50 and the second DDC 30 is not formed.

The second DDC 30 is provided with a second current sensor 31 that detects the current flowing through the second DDC 30. For example, the second current sensor 31 is connected to the primary circuit of the second DDC 30. The control device 10 can estimate the output current output from the second DDC 30 based on the current detected by the second current sensor 31 and the turns ratio of the transformer of the second DDC 30. Hereinafter, the output current of the second DDC 30 will be referred to as the second output current Ic2r.

FIG. 2 is a diagram for explaining the arrangement relationship of each part in the power supply unit 40. The power supply unit 40 further includes a housing 41 and a fan 42. FIG. 2 is a view showing the inside of the housing 41. Further, the air flow in the housing 41 is indicated by a broken line arrow.

Inside the housing 41, the high-voltage battery 50, the first DDC 20, the second DDC 30, and the fan 42 are arranged side by side in this order. The air blown from the fan 42 passes through the first and second DDCs 20 and 30 and then flows to the high voltage battery 50. Then, the blast flows from the opening 43 of the housing 41 to the outside of the power supply unit 40. At this time, the heat generated by the first and second DDCs 20 and 30 is transferred to the high-voltage battery 50 by blowing air from the fan 42. Therefore, in the present embodiment, the housing 41, the fan 42, and the opening 43 correspond to the heat transfer unit.

Returning to FIG. 1, the first and second sub-wiring SL1 and SL2 are connected to the device group 60 that is supplied with power through the sub-wiring SL1 and SL2 and the auxiliary battery 61 that corresponds to the sub-power storage device. The positive terminal of the device group 60 is connected to the first sub wiring SL1. Further, the negative terminal of the device group 60 is connected to the second sub wiring SL2. The device group 60 is, for example, an audio device, a navigation device, a power slide door, a power back door, a meter, or the like.

The positive terminal of the auxiliary battery 61 is connected to the first sub-wiring SL1, and the negative terminal is connected to the second sub-wiring SL2. Therefore, at least one of the output voltages V1r and V2r of the first and second DDCs 20 and 30 and the second terminal voltage Vb2 which is the terminal voltage of the auxiliary battery 61 is applied to the first and second sub-wiring SL1 and SL2. NS.

In the present embodiment, the storage capacity of the auxiliary battery 61 is smaller than the storage capacity of the high-voltage battery 50. Further, the second terminal voltage Vb2 of the auxiliary battery 61 is lower than the first terminal voltage Vb1 of the high voltage battery 50. The second terminal voltage Vb2 of the auxiliary battery 61 is, for example, 12V.

The inverter 51 converts the DC voltage supplied from the high-voltage battery 50 into an AC voltage and supplies it to the motor 11. Further, the smoothing capacitor 52 is connected in parallel to the inverter 51 between the first high voltage line HL1 and the second high voltage line HL2. The output side of the inverter 51 is connected to the motor 11.

The motor 11 is a motor for traveling the vehicle, and is driven by an AC voltage from the inverter 51. The motor 11 has a function of regenerative power generation by utilizing the kinetic energy of the vehicle while the vehicle is traveling. Further, the inverter 51 has a rectifying function for rectifying an alternating current into a direct current. The inverter 51 rectifies the alternating current output from the motor 11 by the regenerative power generation into a direct current when the vehicle is braked. The rectified direct current is supplied to the high-voltage battery 50 through the high-voltage lines HL1 and HL2 to charge the high-voltage battery 50.

The control system 100 includes a control device 10. The control device 10 calculates the command torque required to drive the motor 11 according to the accelerator operation amount of the user. The control device 10 controls the inverter 51 in order to control the torque of the motor 11 to the command torque.

Further, the control device 10 sets a duty command value that determines an on period in one switching cycle of the semiconductor switch in order to operate the first and second DDCs 20 and 30. Among the duty command values, the one that operates the semiconductor switch of the first DDC 20 is defined as the first duty command value Duty 1, and the value that operates the semiconductor switch of the second DDC 30 is defined as the second duty command value.

The control device 10 sets the first duty command value Duty1 in order to control the first output current Ic1r to the first output current command value Ic1 *. Further, the second duty command value Duty2 is set in order to control the second output current Ic2r to the second output current command value Ic2 *.

In the present embodiment, the control device 10 for driving the inverter 51 and the semiconductor switches of the first and second DDCs 20 and 30 will be described as one device, but the present invention is not limited thereto. For example, a control device for controlling the inverter 51 and a control device for driving the semiconductor switches of the first and second DDCs 20 and 30 may be separately provided.

The control system 100 includes a first voltage sensor 54, a second voltage sensor 55, and a temperature sensor 56. The first voltage sensor 54 is connected in parallel to the positive terminal and the negative terminal of the high voltage battery 50, and detects the first terminal voltage Vb1. The second voltage sensor 55 is connected in parallel to the positive terminal and the negative terminal of the auxiliary battery 61, and detects the second terminal voltage Vb2. The temperature sensor 56 detects the temperature of the high-voltage battery 50 as the battery temperature Tbat.

Next, the principle of this embodiment will be described. FIG. 3 is a diagram illustrating the relationship between the first terminal voltage Vb1 of the high-voltage battery 50 and the battery temperature Tbat. In FIG. 3, the horizontal axis is the battery temperature Tbat, and the vertical axis is the first terminal voltage Vb1.

The high-voltage battery 50 has a voltage characteristic in which the first terminal voltage Vb1 depends on the battery temperature Tbat. This voltage characteristic is such that the first terminal voltage Vb1 decreases as the battery temperature Tbat decreases. Therefore, in order to stabilize the first terminal voltage Vb1, it is necessary to manage the high-voltage battery 50 at a reference temperature (for example, 0 degrees) or higher. However, when the temperature of the high-voltage battery 50 is raised by using a heater that uses the high-voltage battery 50 as a power source, there is a concern that the power consumption of the heater accelerates the decrease in the remaining capacity of the high-voltage battery 50.

Here, in the first and second DDCs 20 and 30, a loss occurs at the time of power conversion, and a part of the power becomes thermal energy. Therefore, it is conceivable to use this thermal energy to raise the temperature of the high-voltage battery 50. At this time, if the amount of heat energy radiated by the first and second DDCs 20 and 30 can be controlled, the power consumption required for the temperature raising process can be reduced as compared with the case where the amount of heat energy is not controlled.

Therefore, the control device 10 forms a loop circuit in which a current circulates between the first DDC 20 and the second DDCs 20 and 30, and heats the high-voltage battery 50 from the first and second DDCs 20 and 30 driven on the loop circuit. A temperature raising process for raising the temperature is performed. FIG. 4 is a diagram illustrating a loop circuit according to the present embodiment. In FIG. 4, for convenience, a partial configuration of the power supply unit 40 is omitted.

In FIG. 4, a loop circuit is formed by a current path connecting the first, third, and fifth high-voltage lines HL1, HL3, HL5, the first DDC20, the first sub-wiring SL1, and the second DDC30. In this loop circuit, the first DDC 20 steps down the first terminal voltage Vb1 from the high-voltage battery 50 and outputs it to the first sub-wiring SL1. Further, the second DDC 30 boosts the output voltage V1r from the first DDC 20 and outputs it to the fifth high voltage line HL5. Therefore, the current continuously flows in the loop circuit. The first, third, and fifth high-voltage lines HL1, HL3, and HL5 correspond to the main wiring, and the first sub-wiring SL1 corresponds to the sub-wiring.

Further, the control device 10 controls the first output current Ic1r of the first DDC 20 and the second output current Ic2r of the second DDC 30 according to the battery temperature Tbat, thereby releasing heat from the first and second DDCs 20 and 30. Controls energy (calorific value). Therefore, as compared with the case where the amount of current flowing through the loop circuit is not controlled, the power consumption required for the temperature raising process is reduced, and the decrease in the remaining capacity SOC of the high-voltage battery 50 can be suppressed.

Next, the temperature rising process performed by the control device 10 will be described with reference to FIG. The process shown in FIG. 5 is repeatedly performed by the control device 10 at a predetermined cycle.

In step S11, the battery temperature Tbat, which is the temperature of the high-voltage battery 50, is acquired. In step S12, it is determined whether or not the conditions for performing the temperature raising process are satisfied based on the battery temperature Tbat. For example, if the battery temperature Tbat is less than the reference temperature Tref, it is determined that the conditions for carrying out the temperature raising process are satisfied.

If it is determined that the conditions for carrying out the temperature raising process are not satisfied, the process proceeds to step S14. In step S14, a power supply process for supplying power from the high-voltage battery 50 to the auxiliary battery 61 and the device group 60 via the first and second DDCs 20 and 30 is performed. In this power feeding process, the first DDC 20 and the second DDC 30 are stepped down to supply power to the auxiliary battery 61 and the device group 60.

If it is determined that the conditions for carrying out the temperature raising process are satisfied, the process proceeds to step S13. In steps S13 to S18, a temperature raising process for raising the temperature of the high-voltage battery 50 by the heat generated by the first and second DDCs 20 and 30 is performed. Steps S13 to S18 correspond to the temperature rise control unit.

In step S13, the temperature increase amount ATR required to raise the battery temperature Tbat to the target temperature Ttag is calculated based on the battery temperature Tbat acquired in step S11. In this embodiment, the target temperature Ttag is set to the reference temperature Tref. The temperature rise amount ATR is calculated by subtracting the battery temperature Tbat acquired in step S11 from the target temperature Ttag. Therefore, when the battery temperature Tbat is the reference temperature Tref, the temperature rise amount ATR becomes 0.

In step S15, based on the calculated temperature rise amount ATR, the required power amount NAP [Wh] indicating the power amount required to raise the battery temperature Tbat by the temperature rise amount ATR is calculated. FIG. 6 is a graph showing the correspondence between the temperature rise amount ATR and the required electric energy amount NAP as an example. In the graph of FIG. 6, the horizontal axis is the temperature rise amount ATR, and the vertical axis is the required electric energy NAP. As the temperature rise amount ATR increases, the heat energy required to raise the temperature of the high-voltage battery 50 increases, so that the required power amount NAP increases. It is desirable that the relationship between the temperature rise amount ATR and the required electric energy amount NAP is determined in consideration of the heat transfer efficiency when heat is transferred through the air, the material of the high-voltage battery 50, and the like.

For example, the map information shown in FIG. 6 may be recorded in a memory as a storage unit of the control device 10, and the required electric energy NAP corresponding to the temperature rise amount ATR may be calculated based on the recorded map information.

In step S16, the required electric energy NAP calculated in step S15 is distributed to the first DDC 20 and the second DDC 30, respectively. Hereinafter, the required power amount distributed to the first DDC 20 is referred to as the first distribution amount NA1, and the required power amount distributed to the second DDC 30 is referred to as the second distribution amount NA2. The first distribution amount NA1 and the second distribution amount NA2 can be set to different values. For example, the first DDC 20 and the second DDC 30 can be made different depending on the magnitude of the rated current. Specifically, when the rated current of the first DDC 20 is smaller than the rated current of the second DDC 30, the first distribution amount NA1 can be made smaller than the second distribution amount NA2.

In step S17, the first and second output current command values Ic1 * and Ic2 * of the first and second DDCs 20 and 30 are set according to the first and second distribution amounts NA1 and NA2 calculated in step S16. Specifically, the larger the first distribution amount NA1, the larger the first output current command value Ic1 * is set, and the larger the second distribution amount NA2, the larger the second output current command value Ic2 * is set. For example, map information that determines the relationship between the first and second distribution amounts NA1 and NA2 and the first and second output current command values Ic1 * and Ic2 * is recorded in a memory as a storage unit of the control device 10. .. Then, the first and second output current command values Ic2 * corresponding to the first and second distribution amounts NA1 and NA2 may be calculated based on the recorded map information. Step S17 corresponds to the command value setting unit.

In step S18, the first duty command value Duty1 of the first DDC20 and the second duty command value Duty2 of the second DDC30 are set according to the first and second output current command values Ic1 * and Ic2 * set in step S17. .. By setting the first duty command value Duty1 in step S18, the first DDC 20 performs a step-down operation in the directions from the first and second input terminals Ti1 and Ti2 to the first and second output terminals To1 and To2. Further, by setting the second duty command value Duty2 in step S18, the second DDC 30 performs the boosting operation in the directions from the third and fourth terminals TC and TD to the first and second terminals TA and TB.

Therefore, the high-voltage battery 50 is heated to the target temperature Ttag by the heat generated from the first and second DDCs 20 and 30. When the process of step S18 is completed, the process of FIG. 5 is temporarily terminated.

According to the present embodiment described above, the following effects are obtained.

The control device 10 steps down the first DDC 20 and boosts the second DDC 30 to form a loop circuit in which a current circulates between the first DDC 20 and the second DDC 30. Then, the calorific value of the first and second DDCs 20 and 30 is controlled by adjusting the output currents of the first and second DDCs 20 and 30 based on the temperature rise amount ATR. As a result, the heat generated by the power conversion of the first and second DDCs 20 and 30 can be effectively used, and the power consumption required for raising the temperature of the own unit in the high-voltage battery 50 can be reduced.

The control device 10 controls the output currents Ic1r and Ic2r of the first and second DDCs 20 and 30 based on the temperature rise amount ATR for bringing the battery temperature Tbat closer to the target temperature. Therefore, it is possible to prevent an increase in unnecessary heat energy. As a result, it is possible to suppress an increase in power consumption during the temperature raising process of the high-voltage battery 50.

(Second Embodiment)
In this second embodiment, a configuration different from that of the first embodiment will be mainly described. Since the parts with the same reference numerals indicate the same contents as those in the first embodiment, the description thereof will not be repeated.

In this embodiment, the rated current of the first DDC 20 is smaller than the rated current of the second DDC 30. Therefore, the first distribution amount NA1 is made smaller than the second distribution amount NA2. Further, the control device 10 adjusts the required electric energy NAP by controlling the output current Ic2r of the second DDC 30 having a large rated current without changing the output current Ic1r of the first DDC 20 having a small rated current.

The temperature rising process performed by the control device 10 will be described with reference to FIG. 7. The process shown in FIG. 7 is repeatedly executed by the control device 10 at a predetermined cycle.

In step S19, the first distribution amount NA1 is set to a predetermined fixed value. Further, in step S19, the second distribution amount NA2 is set based on the temperature rise amount ATR calculated in step S13. Specifically, the larger the temperature rise amount ATR (the lower the battery temperature Tbat with respect to the target temperature Ttag), the larger the second distribution amount NA2 is set.

In step S20, the first output current command value Ic1 * is set according to the first distribution amount NA1. Further, the second output current command value Ic2 * is set according to the second distribution amount NA2. After the process of step S20, the process proceeds to step S18.

According to the present embodiment, the closer the temperature rise amount ATR calculated in step S13 is to 0, the smaller the second output current command value Ic2 * is set.

According to the present embodiment described above, the following effects are obtained.

The control device 10 brings the temperature of the high-voltage battery 50 closer to the target temperature Ttag only by adjusting the second output current command value Ic2 *. Therefore, the control related to the temperature raising operation can be simplified, and the processing load of the control device 10 can be reduced. Further, by keeping the first output current Ic1r of the first DDC20 having a small rated current constant and controlling the output current Ic2r of the second DDC30 having a large rated current, the first DDC20 is required by a sudden temperature change of the high voltage battery 50 or the like. It is possible to prevent the first output current Ic1r from exceeding the rated current.

(Third Embodiment)
In this third embodiment, a configuration different from that of the first embodiment will be mainly described. Since the parts with the same reference numerals indicate the same contents as those in the first embodiment, the description thereof will not be repeated.

When the high-voltage battery 50 is used as a power source in the temperature raising process, if the remaining capacity SOC of the high-voltage battery 50 is low, it is assumed that the temperature raising process cannot be continued stably. In particular, when the remaining capacity SOC of the high-voltage battery 50 is near the remaining capacity indicating a predetermined over-discharged state, the remaining capacity SOC of the high-voltage battery 50 may be in the over-discharged state due to the temperature raising process. In this case, it is not desirable because it deteriorates the high voltage battery 50.

Therefore, in the present embodiment, the control device 10 is configured to switch the power source for the temperature raising process to either the high-voltage battery 50 or the auxiliary battery 61 according to the remaining capacity SOC of the high-voltage battery 50.

FIG. 8 is a flowchart illustrating a process performed by the control device 10 according to the second embodiment. The process shown in FIG. 8 is repeatedly executed by the control device 10 at a predetermined cycle.

After setting the first and second output current command values Ic1 * and Ic2 * in step S17, the process proceeds to step S30. In step S30, the remaining capacity SOC of the high-voltage battery 50 is acquired. In the present embodiment, the remaining capacity SOC is acquired from the battery monitoring unit included in the high-voltage battery 50.

In step S31, which of the high-voltage battery 50 and the auxiliary battery 61 is used as the power source in the temperature raising process is selected based on the remaining capacity SOC acquired in step S30. In the present embodiment, the power source is selected by comparing the remaining capacity SOC with the battery threshold Thb. Specifically, when the remaining capacity SOC is equal to or higher than the battery threshold Thb, the high-voltage battery 50 is selected as the power source, and when the remaining capacity SOC is less than the battery threshold Thb, the auxiliary battery 61 is used as the power source. do. The battery threshold Thb is a value indicating the remaining capacity when the high-voltage battery 50 is over-discharged. Step S31 corresponds to the selection unit.

When the high-voltage battery 50 is selected as the power source, the process proceeds to step S32. In step S32, the outputs of the first DDC 20 and the second DDC 30 are set so that the power source of the current circulating in the loop circuit is the high-voltage battery 50 and the auxiliary battery 61 is not the power source of the current circulating in the loop circuit. .. Specifically, the first output voltage command value V1 *, which is the command value of the output voltage of the first DDC 20, and the second output voltage command value V2 *, which is the command value of the output voltage of the second DDC 30 during the boosting operation, are set. do. In the present embodiment, the first output voltage command value V1 * is set to a value larger than the second terminal voltage Vb2, and the second output voltage command value V2 * is set to a value smaller than the first terminal voltage Vb1.

When the auxiliary battery 61 is selected as the power source, the process proceeds to step S33. In step S33, the power source of the current circulating in the loop circuit is the auxiliary battery 61, and the first and second output voltage command values V1 *, so that the high voltage battery 50 does not become the power source of the current circulating in the loop circuit. Set V2 *. In the present embodiment, the first output voltage command value V1 * is set to a value smaller than the second terminal voltage Vb2, and the second output voltage command value V2 * is set to a value larger than the first terminal voltage Vb1.

Step S34 is based on the first and second output current command values Ic1 * and Ic2 * set in step S17 and the first and second output voltage command values V1 * and V2 * set in step S32 or step S33. Then, the first and second duty command values Duty1 and Duty2 are set. Specifically, the first duty command value Duty1 is set so that the output power of the first DDC 20 is a multiplication value of the first output current command value Ic1 * and the first output voltage command value V1 *. Further, the second duty command value Duty2 is set so that the output power of the second DDC 30 is a multiplication value of the second output current command value Ic2 * and the second output voltage command value V2 *.

For example, map information that determines the relationship between the first output current command value Ic1 *, the first output voltage command value V1 *, and the first duty command value Duty1 is recorded in a memory as a storage unit of the control device 10. .. Further, the map information defining the relationship between the second output current command value Ic2 *, the second output voltage command value V2 *, and the second duty command value Duty2 is recorded in the memory as the storage unit of the control device 10. .. Then, based on the recorded map information, the first and first output current command values Ic1 * and Ic2 * and the first and second output voltage command values V1 * and V2 * correspond to the first and second output current command values Ic1 * and Ic2 *. 2 Duty command values Duty1 and Duty2 may be acquired.

FIG. 9 is a diagram illustrating a current flowing in the power supply unit 40 in the temperature raising process. FIG. 9A shows a loop circuit when the high voltage battery 50 is used as a power source. Due to the first output voltage command value V1 * set in step S32, the first output voltage V1r of the first DDC 20 becomes larger than the second terminal voltage Vb2 of the auxiliary battery 61. Therefore, the current from the auxiliary battery 61 does not flow through the first sub-wiring SL1.

Due to the second output voltage command value V2 * set in step S32, the second output voltage V2r of the second DDC 30 becomes smaller than the first terminal voltage Vb1 of the high voltage battery 50. Therefore, the output current of the second DDC 30 does not flow into the positive terminal side of the high-voltage battery 50, but flows into the input side of the first DDC 20. Further, the current from the high voltage battery 50 flows into the input side of the first DDC 20 via the first and third high voltage lines HL1 and HL3.

FIG. 9B shows a loop circuit when the auxiliary battery 61 is used as a power source. Due to the first output voltage command value V1 * set in step S33, the first output voltage V1r of the first DDC 20 becomes smaller than the second terminal voltage Vb2 of the auxiliary battery 61. Therefore, the output current of the first DDC 20 does not flow into the auxiliary battery 61, but flows into the input side of the second DDC 30 during the boosting operation. Further, the current from the auxiliary battery 61 flows into the input side of the second DDC 30 via the first sub-wiring SL1.

Due to the second output voltage command value V2 * set in step S33, the second output voltage V2r of the second DDC 30 becomes larger than the first terminal voltage Vb1 of the high voltage battery 50. Therefore, the current from the high-voltage battery 50 does not flow to the input side of the first DDC 20 via the first and third high-voltage lines HL1 and HL3. Further, the output current from the second DDC 30 flows into the input side of the first DDC 20 via the first, third, and fifth high voltage lines HL1, HL3, and HL5.

Therefore, the high-voltage battery 50 is heated to the target temperature Ttag by the heat generated from the first and second DDCs 20 and 30. Returning to FIG. 8, when the process of step S34 is completed, the process shown in FIG. 8 is temporarily terminated.

According to the present embodiment described above, the following effects are obtained.

The control device 10 selects either the high-voltage battery 50 or the auxiliary battery 61 as the power source during the temperature rise process, depending on the remaining capacity SOC of the high-voltage battery 50. Therefore, either the high-voltage battery 50 or the auxiliary battery 61 can be selected to continue the temperature raising operation. Further, when the remaining capacity SOC of the high-voltage battery 50 is small, deterioration of the high-voltage battery 50 due to over-discharging can be prevented by using the auxiliary battery 61 as a power source for passing a current through the loop circuit.

(Modified example of the third embodiment)
Instead of the remaining capacity SOC of the high-voltage battery 50, the first terminal voltage Vb1 of the high-voltage battery 50 may be used, and either the high-voltage battery 50 or the auxiliary battery 61 may be selected as the power source during the temperature raising process. .. In this case, when the first terminal voltage Vb1 is equal to or higher than a predetermined voltage threshold value, the high-voltage battery 50 is selected as the power source during the temperature raising process. Further, when the first terminal voltage Vb1 is less than the voltage threshold value, the auxiliary battery 61 is selected as the power source during the temperature raising process.

Using the terminal voltages Vb1 and Vb2 of both the high-voltage battery 50 and the auxiliary battery 61, either the high-voltage battery 50 or the auxiliary battery 61 may be selected as the power source.

When the control device 10 can acquire the remaining capacity SOC of the auxiliary battery 61, it uses both the remaining capacity SOCs of the high-pressure battery 50 and the auxiliary battery 61 to power one of the high-pressure battery 50 and the auxiliary battery 61. It may be the one of choice as the source. In this case, for example, in step S31, the one having the higher remaining capacity SOC may be used as the power source in the temperature raising process.

(Fourth Embodiment)
In this fourth embodiment, a configuration different from that of the first embodiment will be mainly described. Since the parts with the same reference numerals indicate the same contents as those in the first embodiment, the description thereof will not be repeated.

In the fourth embodiment, the control device 10 controls the first and second output currents Ic1r and Ic2r based on a predetermined required electric energy NAP at the time of the temperature raising process.

FIG. 10 shows the control system 100 according to the fourth embodiment. The power supply unit 40 includes a heater 70. The heater 70 is located near the high voltage battery 50. The heater 70 is connected to the first sub-wiring SL1. Therefore, the electric power from the high-voltage battery 50 is supplied to the heater 70 via the first sub-wiring SL1. In this embodiment, the control system 100 does not include the temperature sensor 56.

Next, in the fourth embodiment, the temperature raising process performed by the control device 10 will be described with reference to FIG. The process shown in FIG. 11 is repeatedly executed by the control device 10 at a predetermined cycle.

In step S40, the predetermined first and second distribution amounts NA1 and NA2 are acquired for the first and second DDCs 20 and 30. Then, in step S41, the first and second output current command values Ic1 * and Ic2 * of the first and second DDCs 20 and 30 are set based on the first and second distribution amounts NA1 and NA2 acquired in step S40. .. Further, in step S41, a temperature rise time indicating the time of the temperature rise processing by the first and second DDCs 20 and 30 is set.

In step S18, the first and second duty command values Duty1 and Duty2 are set based on the first and second distribution amounts NA1 and NA2 set in step S41.

After the process of step S18, the process proceeds to step S42. In step S42, the passage of the temperature rising time set in step S41 is counted. In step S43, the counting time measured in step S41 is compared with the time determined as the temperature rising time. If the counting time does not elapse the temperature rising time, the process of FIG. 11 is temporarily terminated.

On the other hand, in step S43, if the counting time has passed the temperature rising time, the process proceeds to step S44. In step S44, the operation of the heater 70 is started in order to raise the temperature of the high voltage battery 50. In this embodiment, open control is performed in which the heater 70 is operated for a predetermined time.

In the present embodiment, the temperature of the high-voltage battery 50 rises due to heat generated from the first and second DDCs 20 and 30. Therefore, the time required for the heater 70 to raise the temperature of the high-voltage battery 50 to the target temperature Ttag can be shortened as compared with the case where the temperature raising process is not performed. As a result, the operating time of the heater 70 can be shortened, and the power consumption of the heater 70 can be reduced.

(Other embodiments)
The power supply unit 40 may be composed of the first to sixth high voltage lines HL1 to HL6, the first and second sub wirings SL1 and SL2, the first DDC20, and the second DDC30, excluding the high voltage battery 50. In this case, the power supply unit 40 is connected to the high-voltage battery 50 to supply power from the high-voltage battery 50.

In the first to fourth embodiments described above, only the heat generated by the first DDC 20 may be used to raise the temperature of the high voltage battery 50.

Instead of using either the high-voltage battery 50 or the auxiliary battery 61 as the power source, both the high-voltage battery 50 and the auxiliary battery 61 may be used as the power source. In this case, the first output voltage command value V1 * may be set to a value smaller than the second terminal voltage Vb2, and the second output voltage command value V2 * may be set to a value smaller than the first terminal voltage Vb1.

In the first to third embodiments described above, the control system 100 may be configured to include a heater. Also in this case, since the high-voltage battery 50 is heated by the temperature raising treatment of the first and second DDCs 20 and 30, the power consumption of the heater 70 required to raise the high-voltage battery 50 to the target temperature Ttag is reduced. can do.

The heat transfer unit may be any one that transfers the heat generated at least one of the first and second DDCs 20 and 30 to the high voltage battery 50. For example, a member as a heat transfer unit is interposed between the first and second DDCs 20 and 30 and the high voltage battery 50. Then, the high-voltage battery 50 is heated by the heat transferred from the first and second DDCs 20 and 30 to the member.

10 ... Control device, 20 ... 1st DC / DC converter, 30 ... 2nd DC / DC converter, 41 ... Housing, 42 ... Fan, 43 ... Aperture, 50 ... High voltage battery, 100 ... Control system.

Claims (3)

The first DC / DC converter (20) that performs step-down operation and
The second DC / DC converter (30) that performs boosting operation and
The main wiring (HL1, HL3, HL5) connecting the input side of the first DC / DC converter, the output side of the second DC / DC converter, and the main power storage device (50),
In a control system (100) including an auxiliary wiring (SL1) connecting the output side of the first DC / DC converter and the input side of the second DC / DC converter.
The first DC / DC converter is stepped down and the second DC / DC converter is operated in order to circulate current through the loop circuit including the main wiring, the first DC / DC converter, the second DC / DC converter, and the sub wiring. A temperature rise control unit (10) that boosts the pressure of the
Heat transfer units (41, 42, 43) that transfer heat generated by at least one of the first DC / DC converter and the second DC / DC converter to the main power storage device by the step-down operation and the step-up operation of the temperature rise control unit. ) and, with a,
The temperature rise control unit
The first output current, which is the output current command value of the first DC / DC converter required to raise the temperature of the main power storage device to the target temperature based on the deviation between the temperature of the main power storage device and the target temperature thereof. It has a command value setting unit for setting a command value and a second output current command value which is an output current command value of the second DC / DC converter.
The output current of the first DC / DC converter is controlled to the first output current command value, and the output current of the second DC / DC converter is controlled to the second output current command value.
A sub power storage device (61) is connected to the sub wiring.
A selection unit for selecting either the main power storage device or the sub power storage device as a power source when the step-down operation and the step-up operation are performed by the temperature rise control unit based on the voltage state of the main power storage device is provided.
The command value setting unit of the first DC / DC converter so that the power source for circulating the current in the loop circuit is either the main power storage device or the sub power storage device selected by the selection unit. The first output voltage command value, which is the output voltage command value, the first output current command value, the second output voltage command value, which is the output voltage command value of the second DC / DC converter, and the second output current command value are set. death,
The temperature rise control unit controls the output current of the first DC / DC converter to the first output current command value, and controls the output voltage of the first DC / DC converter to the first output voltage command value. said first 2DC / DC converter output current is controlled by the second output current command value, and controls the output voltage of the first 2DC / DC converter to the second output voltage command value, the control system. The command value setting unit sets the first output voltage command value to be larger than the terminal voltage of the sub power storage device when the main power storage device is selected by the selection unit, and the second The control system according to claim 1 , wherein the output voltage command value is set to be smaller than the terminal voltage of the main power storage device. The command value setting unit sets the first output voltage command value to be smaller than the terminal voltage of the sub power storage device when the sub power storage device is selected by the selection unit, and the second output voltage command value is set to be smaller than the terminal voltage of the sub power storage device. The control system according to claim 1 or 2 , wherein the output voltage command value is set to be larger than the terminal voltage of the main power storage device.

Images