JP2012249412A - Battery temperature-increase system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery temperature-increase system capable of realizing both securing of a voltage necessary for driving an electric motor and prompt temperature increasing of a battery.SOLUTION: There is provided a battery temperature-increase system in which a control apparatus 14 calculates a driving voltage Vm necessary for driving an electric motor 30 in accordance with a running state of a vehicle while the vehicle is running, and obtains a capacitor voltage Vc charged in a power storage device 13, and then the control apparatus 14 switches between transfer of power from a battery 11 to the power storage device 13 and transfer of power from the power storage device 13 to the battery 11 so that the capacitor voltage Vc is in a range between a reference voltage Vth which is a maximum voltage necessary for driving the electric motor 30 and a driving voltage Vm necessary for driving the electric motor 30. Consequently, the system can achieve both securing of the driving voltage Vm necessary for driving the electric motor 30 and prompt temperature increasing of the battery 11.

Description

  The present invention relates to a battery temperature raising system for quickly raising a battery of a hybrid vehicle or an electric vehicle, and is particularly effective when raising the temperature while securing a voltage necessary for driving an electric motor during traveling.

  Conventionally, for example, Patent Document 1 proposes a voltage converter that is mounted on an electric vehicle such as a hybrid vehicle and rapidly raises the temperature of a rechargeable secondary battery serving as a battery. Specifically, in Patent Document 1, when the temperature of the battery detected by the temperature sensor is lower than a reference value, electric power is transferred between the battery and the power storage device by voltage conversion (step-up operation and step-down operation) of the voltage converter. There has been proposed a control device that controls the boost converter so as to repeatedly give and receive.

  Then, when the battery temperature rises to a reference value or more by the boost operation and the step-down operation of the boost converter, the control device controls the boost converter to perform a normal operation including the boost operation and / or the step-down operation. Further, the voltage stored in the power storage device is used as a drive voltage for operating an electric motor for driving the vehicle.

Japanese Patent Laying-Open No. 2005-312160

  However, in the above conventional technique, when the driving voltage supplied from the power storage device to the electric motor for starting the engine is set to a maximum voltage such as 650 V, or when the electric motor is operating such as at high speed running, the battery rises. When the temperature control is performed, the drive voltage of the electric motor is lowered during the step-down operation. For this reason, since the drive voltage of sufficient magnitude | size is not supplied to the electric motor which operate | moves based on a drive voltage, there exists a problem that the output required for driving | running | working cannot be obtained from an electric motor.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a battery temperature raising system capable of achieving both securing of a voltage necessary for driving an electric motor and rapid temperature raising of the battery.

  In order to achieve the above object, according to the invention described in claim 1, voltage conversion is performed between the rechargeable battery (11), the power storage device (13), and the battery (11) and the power storage device (13). An inverter that converts the storage voltage (Vc) charged in the power storage device (13) into an alternating voltage and supplies it to the voltage converter (12) and the electric motor (30) that rotates or regenerates as the vehicle travels When the battery temperature (Tb) of the battery (11) and the battery (11) is lower than the reference value (Tth), the battery (11) is switched between power transfer between the battery (11) and the power storage device (13). And a control device (14) for controlling the voltage converter (12) so as to raise the temperature of the battery, and is characterized by the following points.

  That is, the control device (14) calculates a drive voltage (Vm) necessary for driving the electric motor (30) according to the traveling state of the vehicle while the vehicle is traveling, and the power storage device (13) is charged. The battery voltage (Vc) is acquired, the battery voltage (Vb) of the battery (11) is acquired, and the battery (11) and the battery are stored according to the drive voltage (Vm), the battery voltage (Vc), and the battery voltage (Vb). It is characterized by switching the exchange of power with the device (13).

  Thus, the drive required for driving the electric motor (30) is switched by switching the transfer of electric power between the battery (11) and the power storage device (13) according to the driving voltage (Vm) of the electric motor (30). While ensuring the voltage (Vm), the battery (11) can be quickly heated.

  Specifically, in the invention according to claim 2, the control device (14) has a drive voltage (Vm) lower than a predetermined threshold value (Vth) which is a maximum voltage required to drive the electric motor (30). In addition, when the stored voltage (Vc) is higher than the drive voltage (Vm), power transfer is switched between the battery (11) and the power storage device (13).

  According to this, since the temperature rise control is performed so that the storage voltage (Vc) of the power storage device (13) does not fall below the drive voltage (Vm), a decrease in the drive voltage (Vm) due to power transfer can be avoided, An output required for traveling can be obtained from the electric motor (30) operating based on the drive voltage (Vm). Moreover, the temperature of the battery (11) can be quickly raised by switching the power transfer between the battery (11) and the power storage device (13). Therefore, it is possible to achieve both the securing of the drive voltage (Vm) necessary for driving the electric motor (30) and the rapid temperature rise of the battery (11).

  In the invention according to claim 3, the control device (14) acquires the battery voltage (Vb) of the battery (11), and the battery voltage (Vb) of the battery (11) rises to the upper limit voltage (Vbu). When the voltage reaches, the voltage converter (12) supplies power from the battery (11) to the power storage device (13). When the battery voltage (Vb) decreases and reaches the lower limit voltage (Vbd), the voltage converter (12) stores the power. Electric power is supplied from the device (13) to the battery (11).

  According to this, since the battery voltage (Vb) of the battery (11) does not exceed the range between the upper limit voltage (Vbu) and the lower limit voltage (Vbd), the battery (11) is prevented from being overcharged or overdischarged. can do.

  In the invention according to claim 4, when the storage voltage (Vc) rises and reaches the upper limit value (Vcu), the control device (14) causes the battery (11) from the storage device (13) in the voltage converter (12). When the storage voltage (Vc) drops and reaches the drive voltage (Vm), the voltage converter (12) switches the transmission / reception of power from the battery (11) to the storage device (13). And

  According to this, since the storage voltage (Vc) of the power storage device (13) does not exceed the range between the upper limit value (Vcu) and the lower limit value (Vcd), failure of the power storage device (13) can be prevented. it can.

  According to a fifth aspect of the present invention, in the third aspect of the present invention, the control device (14) is predetermined before the stored voltage (Vc) of the power storage device (13) rises and exceeds the upper limit value (Vcu). When the time elapses, power is transferred from the power storage device (13) to the battery (11). Thereby, it can prevent that a battery (11) will be in the state of an overdischarge by the discharge state of a battery (11) continuing.

  In the invention according to claim 6, in the invention according to claim 3 or 4, the control device (14) is configured such that before the storage voltage (Vc) of the power storage device (13) drops and drops below the drive voltage (Vm). When a predetermined time elapses, power is transferred from the battery (11) to the power storage device (13). Thereby, it can prevent that a battery (11) will be in the state of an overcharge by the charge state of a battery (11) continuing.

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim shows the correspondence with the specific means as described in embodiment mentioned later.

1 is an overall configuration diagram of a load driving device including a battery temperature raising system according to a first embodiment of the present invention. It is a timing chart of the drive signal inputted into capacitor voltage Vc, battery voltage Vb, reactor current IL, and a voltage converter. It is the flowchart which showed the content of the temperature rising control of a control apparatus. It is a figure for demonstrating the difference in the effect of the case where temperature rising control is not performed, and the case where it performs.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The battery temperature raising system shown in the present embodiment is a system for raising the temperature of a rechargeable power source early, and can be applied to an electric vehicle such as a hybrid vehicle or a plug-in hybrid vehicle.

  FIG. 1 is an overall configuration diagram of a load driving device including a battery temperature raising system according to the present embodiment. As shown in this figure, the load driving device includes a battery temperature raising system 10, an inverter 20, an electric motor 30, a first current detector 40, and a first current detector 50.

  The battery temperature raising system 10 includes a battery 11, a voltage converter 12, a power storage device 13, and a control device 14.

  The battery 11 is a battery group configured by connecting a plurality of battery cells (not shown) as a minimum unit in series. A rechargeable lithium ion secondary battery is used as the battery cell. Such a battery 11 is used as a power source for driving an electric motor 30 such as an inverter or a motor.

  A temperature detector 16 is provided in the vicinity of the battery 11, and the battery temperature detected by the temperature detector 16 is output from the temperature detector 16 to the control device 14. The battery voltage of the battery 11 is detected by a voltage detector (not shown), and the battery current flowing through the battery 11 is detected by the current detector 17. These battery voltage and battery current are output from the detectors to the control device 14, respectively. In this embodiment, the battery temperature is Tb, the battery voltage is Vb, and the battery current is Ib.

  The voltage converter 12 is a boost converter that performs voltage conversion between the battery 11 and the power storage device 13 in accordance with a command from the control device 14. That is, the voltage converter is a DC-DC converter. Such a voltage converter 12 includes a reactor 12a, switching elements 12b and 12c (Qc1 and Qc2 in FIG. 1), and diode elements 12d and 12e (D1 and D2 in FIG. 1).

  Reactor 12a has one end connected to the positive electrode side of battery 11 and the other end connected to a connection point between one switching element 12b and the other switching element 12c. The reactor current flowing through the reactor 12 a is detected by the current detector 18 and output from the current detector 18 to the control device 14. In the present embodiment, the reactor current is IL.

  Each of the switching elements 12b and 12c is an IGBT (Insulated Gate Bipolar Transistor), and is connected in series between the power line of the inverter 20 and the ground line. Specifically, the collector of one switching element 12b is connected to the power supply line of the inverter 20, and the emitter is connected to the collector of the other switching element 12c. Further, the emitter of the switching element 12 c is connected to the ground line of the inverter 20. And between the collector-emitter of each switching element 12b and 12c, the diode elements 12d and 12e which flow an electric current from the emitter side to the collector side are respectively connected. Each of the diode elements 12d and 12e is a so-called FWD (Free Wheeling Diode).

  The power storage device 13 is a capacitor that smoothes the DC voltage from the voltage converter 12 and supplies the smoothed DC voltage to the inverter 20. The power storage device 13 is provided on the input side of the inverter 20 and is connected to a power supply line and a ground line of the inverter 20. Then, the voltage across the capacitor as the power storage device 13 is detected as a capacitor voltage by a voltage detector (not shown), and is output from the voltage detector to the control device 14. In this embodiment, the capacitor voltage is Vc.

  The control device 14 outputs a drive signal to each switching element 12b, 12c of the voltage converter 12 and the inverter 20 in accordance with a command related to driving of the electric motor 30 from an ECU (Electrical Control Unit) provided outside the load drive device. This is a device that drives them. The ECU is a device that executes a predetermined function in accordance with a program stored in a ROM or the like by a microcomputer having a CPU, ROM, EEPROM, RAM, or the like (not shown).

  For this reason, the control device 14 inputs data on the accelerator opening, the shift position of the transmission, and the vehicle speed from the outside, and determines the torque, the rotation speed, and the power required for driving the motor 30. Based on these data, a driving voltage necessary for traveling of the vehicle is calculated. In the present embodiment, the phase currents are Iv and Iw, the rotation speed is N, and the drive voltage is Vm. Further, regarding the accelerator opening, the shift position, and the vehicle speed, the control device 14 may directly receive data from each sensor that detects them, or may be received from an external device such as an engine ECU.

  In addition, when the battery temperature Tb of the battery 11 is lower than the reference value, the control device 14 controls the voltage converter 12 according to the drive voltage Vm, the storage voltage Vc, and the battery voltage Vb, so that the battery 11 and the storage device 13 are controlled. The battery 11 is provided with a function of raising and lowering the temperature of the battery 11. In this embodiment, the reference value is Tth. This reference value Tth is a temperature at which the input / output characteristics of the battery 11 deteriorate, and is set, for example, below the freezing point. Thereby, the temperature of the battery 11 can be raised in the situation where the battery 11 is exposed to below freezing point. The reference value Tth is preferably set as appropriate according to the battery cells constituting the battery 11.

  When the temperature of the battery 11 rises, the control device 14 prevents the capacitor voltage Vc from exceeding the capacitor upper limit voltage, prevents it from falling below the drive voltage Vm, and further prevents the battery voltage Vb from exceeding the upper limit voltage. The voltage converter 12 is controlled so as not to fall below the lower limit voltage, and the power transfer between the battery 11 and the power storage device 13 is switched. That is, the control device 14 transmits and receives power so that the capacitor voltage Vc falls within the range between the capacitor upper limit voltage and the drive voltage Vm, and the battery voltage Vb falls within the range between the upper limit voltage and the lower limit voltage. Switch.

  When battery temperature Tb of battery 11 exceeds reference value Tth, control device 14 controls voltage converter 12 and inverter 20 to drive electric motor 30. That is, control device 14 includes voltage converter 12 and inverter 20 so as to perform a normal operation consisting of a boost operation for boosting capacitor voltage Vc of power storage device 13 and a step-down operation for lowering capacitor voltage Vc of power storage device 13. To control.

  In the present embodiment, the upper limit voltage of the battery 11 is Vbu, and the lower limit voltage of the battery 11 is Vbd. The operation of the control device 14 will be specifically described later.

  Inverter 20 is a circuit that converts the DC voltage from power storage device 13 into an AC voltage in accordance with a signal from control device 14 and drives motor 30. The inverter 20 also has a function of converting the AC voltage generated by the electric motor 30 into a DC voltage and supplying the converted DC voltage to the voltage converter 12 via the power storage device 13.

  Such an inverter 20 includes a U-phase arm 21, a V-phase arm 22, and a W-phase arm 23. These arms 21 to 23 are connected in parallel between the power supply line and the ground line.

  U-phase arm 21 is composed of switching elements 21a and 21b connected in series, V-phase arm 22 is composed of switching elements 22a and 22b connected in series, and W-phase arm 23 is a switching element connected in series. 23a and 23b. Between the collector and emitter of each switching element 21a, 21b, 22a, 22b, 23a, and 23b, diode elements 21c, 21d, 22c, 22d, 23c, and 23d that flow current from the emitter side to the collector side are respectively connected. . Each switching element 21a, 21b, 22a, 22b, 23a, 23b is, for example, an IGBT, and each diode element 21c, 21d, 22c, 22d, 23c, 23d is an FWD.

  Further, the intermediate point of each phase arm 21 to 23 is connected to each phase end of each phase coil of the three-phase motor which is the electric motor 30. That is, the motor is a three-phase permanent magnet motor, and is configured such that one end of three coils of U phase, V phase, and W phase is commonly connected to the midpoint. The other end of the U-phase coil is at the intermediate point between the switching elements 21a and 21b, the other end of the V-phase coil is at the intermediate point between the switching elements 22a and 22b, and the other end of the W-phase coil is between the switching elements 23a and 23b. Each point is connected.

  Each switching element 21a, 21b, 22a, 22b, 23a, 23b of the inverter 20 having such a configuration is subjected to switching control by the control device 14 so that each motor of the motor 30 outputs a commanded torque. The current flowing through the phase is controlled.

  The electric motor 30 is a motor for driving drive wheels of a hybrid vehicle or an electric vehicle. This motor corresponds to the load. By connecting the electric motor 30 to the engine of the hybrid vehicle, the electric motor 30 can have the function of a generator that generates electric power by the rotational force of the engine and the function of an electric motor that starts the engine. That is, the electric motor 30 rotates when the vehicle is accelerated, and performs a regenerative operation when the vehicle is decelerated.

  The first current detector 40 is a sensor that detects a phase current Iv that flows from the V-phase arm 22 to the V-phase coil of the electric motor 30. The first current detector 50 is a sensor that detects the phase current Iw that flows from the W-phase arm 23 to the W-phase coil of the electric motor 30. The data of these phase currents Iv and Iw are input to the control device 14, and the phase current Iu flowing through the U-phase coil is calculated from Iv and Iw. These Iu, Iv, and Iw are used when the controller 14 calculates the drive voltage Vm.

  The above is the overall configuration of the battery temperature raising system 10 and the load driving device according to the present embodiment.

  Next, the operation of the battery temperature raising system 10 will be described with reference to FIGS. 1 and 2. FIG. 2 is a timing chart of the capacitor voltage Vc, the battery voltage Vb, the reactor current IL, and the drive signal input to the voltage converter 12.

  First, when boosting the power storage device 13, the control device 14 turns on the switching element 12c (Qc2). Thereby, current flows through the path of battery 11 → reactor 12a → switching element 12c (Qc2), and thus energy is accumulated in reactor 12a.

  Thereafter, when control device 14 turns off switching element 12c (Qc2), a current flows through the path of battery 11 → reactor 12a → diode element 12d (D1) → power storage device 13. If the direction in which the current flows from the battery 11 to the reactor 12a is positive, the current flows in the positive direction during boosting. Thereby, since the voltage on the battery 11 side of reactor 12a becomes battery voltage Vb, the boosted voltage is charged in power storage device 13.

  As shown in FIG. 2, when the switching element 12c (Qc2) is switching-driven at a predetermined duty, the battery voltage Vb gradually decreases and the capacitor voltage Vc increases at the time of boosting. The boosted capacitor voltage Vc is represented by Vc = {1 / (1-Duty)} × Vb using Duty (= ton / (ton + toff)). Ton is the ON time of the switching element 12c (Qc2), and toff is the OFF time of the switching element 12c (Qc2). On the other hand, since the energy of the battery 11 is used for boosting the power storage device 13, the battery voltage Vb decreases. This is a boost operation.

  When power storage device 13 is stepped down, control device 14 turns on switching element 12b (Qc1). As a result, current flows through the path of power storage device 13 → switching element 12b (Qc1) → reactor 12a → battery 11, and thus energy is stored in reactor 12a.

  Thereafter, when the control device 14 turns off the switching element 12b (Qc1), a current flows through the path of the reactor 12a → the battery 11 → the diode element 12e (D2). As described above, when the direction in which the current flows from the battery 11 to the reactor 12a is positive, the current flows in the negative direction at the time of step-down. As a result, the voltage on the diode element 12e (D2) side of the reactor 12a becomes 0 V, so that the reduced voltage is charged in the battery 11.

  As shown in FIG. 2, when the switching element 12b (Qc1) is switching-driven at a predetermined duty, the capacitor voltage Vc gradually decreases and the battery voltage Vb increases at the time of step-down. The battery voltage Vb after step-down is calculated by using Duty (= ton / (ton + toff), ton: ON time of the switching element 12b (Qc1), toff: OFF time of the switching element 12b (Qc1)), Vb = Duty × Vc It is represented by On the other hand, since the energy of the power storage device 13 moves to the battery 11, the battery voltage Vb increases. This is a step-down operation.

  In FIG. 2, the drive voltage Vm is shown as a constant value. However, since the drive voltage Vm is actually a value calculated by the above parameters, the drive voltage Vm actually changes with time.

  Next, the temperature rise control of the control device 14 will be described with reference to the flowchart of FIG. First, the control device 14 inputs accelerator opening, shift position, and vehicle speed data from the outside, and further inputs phase currents Iv and Iw flowing through the electric motor 30 and the rotational speed N. Then, the torque of the electric motor 30 is determined from the accelerator opening, the shift position, and the vehicle speed. Further, the power necessary for driving the electric motor 30 is determined from the rotational speed N of the electric motor 30, and the driving voltage Vm of the electric motor 30 is calculated (S100). ). The drive voltage Vm is a minimum voltage necessary for traveling of the vehicle and is a voltage that improves the efficiency of the electric motor 30.

  Subsequently, it is determined whether or not the calculated drive voltage Vm is lower than the reference voltage Vth (S101). Here, the reference voltage Vth is a maximum voltage necessary for driving the electric motor 30, that is, a maximum value of the drive voltage Vm (for example, 650V), or a voltage (for example, 400V) that allows a sufficient current to flow during temperature increase control. When the drive voltage Vm is lower than the reference voltage Vth, the process shifts to the temperature rise control of the battery 11. On the other hand, when the drive voltage Vm is higher than the reference voltage Vth, power transfer, that is, a temperature rise operation is performed to prevent destruction of the device. Normal control (S114) is performed without performing it. The normal control is control in which the voltage converter 12 boosts the battery 11 as necessary, and travels and regenerates using the inverter 20 and the electric motor 30.

  When the drive voltage Vm is lower than the reference voltage Vth, the battery voltage Vb of the battery 11 is acquired from a voltage detector (not shown), and it is determined whether or not the battery voltage Vb is higher than a predetermined voltage (S102). Here, when the predetermined voltage is Vd, the predetermined voltage Vd is set based on the remaining capacity (State of Charge: SOC) calculated by the control device 14 from the battery voltage Vb, the battery current Ib, and the like. The predetermined voltage Vd is, for example, a voltage equivalent to 50% SOC. Thus, by returning to the normal control when the battery voltage Vb is lower than the predetermined voltage Vd, it is possible to prevent the battery voltage Vb from further decreasing due to temperature rise control and being unable to travel.

  When the battery voltage Vb is higher than the predetermined voltage Vd, the control device 14 acquires the battery temperature Tb detected by the temperature detector 16 (S103). Note that when the battery temperature Tb is higher than the reference value Tth (S104), it is not necessary to raise the temperature of the battery 11, so that the control shifts to normal control (S114).

  When the battery temperature Tb is lower than the reference value Tth (S104), the boosting operation of S105 to S108 is performed. In the boosting operation, first, the battery voltage Vb is boosted to charge the capacitor as the power storage device 13 (S105).

  Thereafter, when the battery voltage Vb decreases and reaches the lower limit voltage Vbd (S106), that is, when the battery voltage Vb falls below the lower limit voltage Vbd, the boosting operation is terminated, and the operation proceeds to the step-down operation after S109.

  On the other hand, if the battery voltage Vb has fallen and has not reached the lower limit voltage Vbd, that is, if the battery voltage Vb exceeds the lower limit voltage Vbd, it is determined whether or not the capacitor voltage Vc exceeds the upper limit value (S107). Here, the upper limit value of the capacitor voltage Vc is assumed to be Vcu. The upper limit value Vcu is set to, for example, the withstand voltage of the capacitor. This determination can prevent a failure of the power storage device 13.

  When a predetermined time elapses before the capacitor voltage Vc increases and reaches the upper limit value Vcu (S108), the operation proceeds to step-down operation after S109. This is because the current value decreases from a certain time when the capacity of the capacitor, which is the power storage device 13, becomes insufficient, and the amount of heat generation decreases, so that the temperature cannot be increased efficiently. Thereby, it is possible to prevent the electricity storage device 13 from being saturated and no current from flowing, and the amount of heat generation from being reduced. If the predetermined time has not elapsed (S108), the process returns to S105 and the boosting operation is repeated.

  As described above, control device 14 supplies power from power storage device 13 to battery 11 in voltage converter 12 when battery voltage Vb decreases and reaches lower limit voltage Vbd. Control device 14 supplies power from power storage device 13 to battery 11 in voltage converter 12 when capacitor voltage Vc increases to reach upper limit value Vcu. In this way, by monitoring the battery voltage Vb of the battery 11 and the capacitor voltage Vc of the power storage device 13 and switching the power transfer, the battery 11 can be prevented from being overdischarged.

  Subsequently, in the step-down operation, the battery 11 is charged by stepping down the power storage device 13 (S109). When the battery voltage Vb of the battery 11 increases to reach the upper limit voltage Vbu (S110), that is, when the battery voltage Vb exceeds the upper limit voltage Vbu, the step-down operation is terminated.

  Then, when the battery voltage Vb of the battery 11 has risen and has not reached the upper limit voltage Vbu, that is, when the battery voltage Vb is lower than the upper limit voltage Vbu, it is determined whether or not the capacitor voltage Vc is higher than the drive voltage Vm ( S111). As a result, when the capacitor voltage Vc decreases and reaches the drive voltage Vm, the step-down operation is terminated. Similarly to the step-up, the step-down operation is terminated when a predetermined time elapses even if the battery voltage Vb is lower than the upper limit voltage Vbu and the capacitor voltage Vc is higher than the drive voltage Vm (S112). Thereby, the electric current which flows into the electrical storage apparatus 13 becomes small, and it can prevent that the emitted-heat amount falls.

  When the step-down operation is completed, it is determined whether or not it is time to calculate the drive voltage Vm of the electric motor 30 (S113), and if it is time to calculate the drive voltage Vm, go to the step of calculating the drive voltage Vm of the electric motor 30 (S100). Transition. Here, the “timing for calculating the driving voltage Vm” is a timing for determining the torque of the motor that is the electric motor 30. This timing is set to a predetermined time interval such as several hundred msec.

  In this way, the drive voltage Vm is calculated again, and the step-up operation and the step-down operation are repeated. If it is not time to calculate the drive voltage Vm, the process proceeds to detection of the battery voltage Vb (S102). When the battery temperature Tb reaches the reference value Tth, the normal control is restored (S114).

  As described above, control device 14 supplies power from battery 11 to power storage device 13 in voltage converter 12 when battery voltage Vb of battery 11 rises and reaches upper limit voltage Vbu. Control device 14 supplies electric power from battery 11 to power storage device 13 in voltage converter 12 when capacitor voltage Vc decreases to reach drive voltage Vm. In this way, by monitoring the battery voltage Vb of the battery 11 and the capacitor voltage Vc of the power storage device 13 and switching the power transfer, the battery 11 can be prevented from being overcharged.

  Then, the effect by said temperature rising control is demonstrated with reference to FIG. FIG. 4A is a diagram showing the capacitor voltage Vc (upper column) and the battery current Ib (lower column) when the temperature rise control of the battery 11 is not performed. FIG. 4B is a diagram showing the capacitor voltage Vc (upper column) and the battery current Ib (lower column) when the temperature increase control of the battery 11 according to this embodiment is performed.

  First, when the temperature rise control of the battery 11 is not performed, as shown in the upper column of FIG. 4A, the capacitor voltage Vc is the minimum drive voltage of the electric motor 30 necessary for traveling of the vehicle according to the traveling state of the vehicle. The drive voltage Vm varies within the range of the maximum drive voltage (for example, 650 V) of the electric motor 30. In light running, the fluctuation of the capacitor voltage Vc is small, and in high speed running, the capacitor voltage Vc rises to 650 V, which is the maximum value of the drive voltage Vm.

  As shown in the lower column of FIG. 4A, the battery current Ib also varies according to the variation of the capacitor voltage Vc. However, since the battery current Ib follows the capacitor voltage Vc that varies depending on the traveling state, the battery current Ib flows greatly when the capacitor voltage Vc varies, but the variation of the battery current Ib is small during traveling when the variation of the capacitor voltage Vc is small. For this reason, the battery current Ib does not exceed -100A or + 100A.

  On the other hand, when the temperature rise control of the battery 11 is performed, as shown in the upper column of FIG. 4B, the capacitor voltage Vc is 650 V which is the driving voltage Vm and the maximum driving voltage regardless of the running state of the vehicle. The up and down pressure is repeated between. In the upper column of FIG. 4B, the capacitor voltage Vc is blacked out. Actually, as shown in the upper column of FIG. 4B, the capacitor voltage Vc is the maximum drive voltage. When it reaches (650V), it falls, and when it reaches the drive voltage Vm, it rises, and this is repeated. As described above, when the capacitor voltage Vc reaches the drive voltage Vm, the capacitor voltage Vc is charged, so that a voltage necessary for driving the electric motor 30 can be secured.

  Then, as shown in the lower column of FIG. 4B, the battery current Ib flows in accordance with the step-up / down of the capacitor voltage Vc. That is, since the battery current Ib repeatedly flows at a large value exceeding −150A or 150A, the battery 11 is heated by the battery current Ib flowing. As described above, when the temperature increase control of the battery 11 is performed, the battery current Ib flowing through the battery 11 is large and the frequency of the flow increases as compared with the case where the temperature increase control is not performed. .

  When performing the temperature rise control as described above, the portion indicated by “A” in the upper column of FIG. 4A corresponds to the case where the battery voltage Vb is higher than the reference voltage Vth. In this case, since normal control is performed without performing temperature rise control, the capacitor voltage Vc does not repeat step-up / step-down. When the period “A” elapses and the drive voltage Vm becomes lower than the reference voltage Vth, the step-up operation and the step-down operation are repeated again.

  As described above, in this embodiment, when the temperature of the battery 11 is controlled while the electric vehicle such as a hybrid vehicle is running, the capacitor voltage Vc of the capacitor serving as the power storage device 13 is equal to the drive voltage Vm and the reference voltage Vth. It is characterized in that the exchange of power is switched between the battery 11 and the power storage device 13 so as to be within the range.

  Thereby, a decrease in drive voltage Vm of power storage device 13 due to power transfer can be avoided, and drive voltage Vm necessary for traveling can be supplied to electric motor 30. Thereby, the output required for driving | running | working can be obtained from the electric motor 30 which operate | moves based on the drive voltage Vm. Of course, since the exchange of power is frequently switched between the battery 11 and the power storage device 13, the battery 11 can be quickly heated. Therefore, it is possible to achieve both the securing of the drive voltage Vm necessary for driving the electric motor 30 and the rapid temperature increase of the battery 11.

  In the present embodiment, the control device 14 supplies power from the power storage device 13 to the battery 11 in the voltage converter 12 so that the battery voltage Vb of the battery 11 falls within the range between the upper limit voltage Vbu and the lower limit voltage Vbd. ing. This prevents the battery 11 from being overcharged or overdischarged.

  Furthermore, in the present embodiment, when the capacitor voltage Vc increases and reaches the upper limit value Vcu, the voltage converter 12 switches the power transfer from the battery 11 to the power storage device 13, thereby preventing a failure of the power storage device 13. be able to.

  As for the correspondence relationship between the description of the present embodiment and the description of the claims, the reference voltage Vth corresponds to the “predetermined threshold value” of the claims, and the capacitor voltage is the “storage voltage” of the claims. ".

(Other embodiments)
The configurations of the battery temperature raising system 10 and the load driving device shown in the above embodiments are examples, and the present invention is not limited to the configurations shown above, and other configurations including the features of the present invention may be adopted. it can. For example, since the step-up operation and the step-down operation may be repeated by monitoring the battery voltage Vb and the capacitor voltage Vc regardless of the predetermined time, each processing of S108 and S113 may be omitted.

  Further, when the control device 14 acquires the phase current flowing through the electric motor 30, in the above embodiment, the control device 14 acquires two currents, that is, the phase current Iv flowing through the V-phase coil and the phase current Iw flowing through the W-phase coil. The phase current Iu flowing through the U-phase coil was calculated. However, the electric motor 30 is a three-phase motor, and if the two phase currents are detected, the remaining one phase current can be known. For this reason, it is sufficient if two currents can be detected. Therefore, the present invention is not limited to the case of detecting Iv and Iw as in the above embodiment, and the phase current may be detected by a combination of Iu and Iv and Iu and Iw.

  In the above embodiment, the battery voltage Vb of the battery 11 is monitored to switch the power transfer, but this is to prevent the battery 11 from being overdischarged. Therefore, only the capacitor voltage Vc of the power storage device 13 may be monitored, and power transfer may be switched so that the capacitor voltage Vc falls within the range between the drive voltage Vm and the reference voltage Vth.

  In addition, the drive voltage Vm is calculated from the power necessary for driving the electric motor 30, but when the temperature rise is necessary, the current may be increased to output the power, and the drive voltage Vm may be lowered.

DESCRIPTION OF SYMBOLS 11 Battery 12 Voltage converter 13 Power storage apparatus 14 Control apparatus 20 Inverter 30 Electric motor

Claims (6)

A rechargeable battery (11);
A power storage device (13);
A voltage converter (12) that performs voltage conversion between the battery (11) and the power storage device (13);
An inverter (20) for converting and supplying the accumulator voltage (Vc) charged in the accumulator (13) to an AC voltage to the electric motor (30) that performs a rotating operation or a regenerative operation according to the traveling of the vehicle;
When the battery temperature (Tb) of the battery (11) is lower than a reference value (Tth), the battery (11) is switched by switching power transfer between the battery (11) and the power storage device (13). A battery temperature raising system comprising: a control device (14) for controlling the voltage converter (12) to raise the temperature;
The control device (14) calculates a drive voltage (Vm) necessary for driving the electric motor (30) according to a running state of the vehicle during the running of the vehicle, and supplies the power storage device (13) to the power storage device (13). Acquire the charged storage voltage (Vc), acquire the battery voltage (Vb) of the battery (11), and according to the drive voltage (Vm), the storage voltage (Vc), and the battery voltage (Vb) A battery temperature raising system for switching power transfer between the battery (11) and the power storage device (13).   The control device (14) has a driving voltage (Vm) lower than a predetermined threshold (Vth) that is a maximum voltage necessary for driving the electric motor (30) and is lower than the driving voltage (Vm). 2. The battery temperature raising system according to claim 1, wherein when the power storage voltage (Vc) is high, power transfer is switched between the battery (11) and the power storage device (13).   When the battery voltage (Vb) of the battery (11) rises and reaches the upper limit voltage (Vbu), the control device (14) causes the voltage converter (12) to transfer the power storage device (13) from the battery (11). When the battery voltage (Vb) drops and reaches the lower limit voltage (Vbd), the voltage converter (12) supplies power from the power storage device (13) to the battery (11). The battery temperature raising system according to claim 1 or 2, wherein   When the storage voltage (Vc) increases and reaches the upper limit (Vcu), the control device (14) transfers power from the storage device (13) to the battery (11) in the voltage converter (12). When the storage voltage (Vc) decreases and reaches the drive voltage (Vm), the voltage converter (12) switches the transfer of power from the battery (11) to the storage device (13). The battery temperature rising system according to any one of claims 1 to 3, characterized in that:   When a predetermined time elapses before the storage voltage (Vc) of the power storage device (13) rises and exceeds the upper limit value (Vcu), the control device (14) removes the battery from the power storage device (13). The battery temperature raising system according to claim 4, wherein power is transferred to (11).   When a predetermined time elapses before the storage voltage (Vc) of the power storage device (13) drops and falls below the drive voltage (Vm), the control device (14) The battery temperature raising system according to claim 4 or 5, wherein power is transferred to the device (13).

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