JP2009254209A - Power supply control system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively control the temperature rise of a voltage converter while ensuring power supply to an auxiliary machine in a power supply control system. <P>SOLUTION: The power supply control system 10 includes: a power supply circuit 12 containing an energy storage device 14, a voltage converter 20 having a reactor 22, an upper arm side switching element 24, and a lower arm side switching element 26, an inverter unit 34, and a low voltage activate auxiliary machine 50; and a control part 60. The control part 60 is composed of a reactor temperature acquisition module 62 which acquires the temperature of the reactor 22, an energy storage device W<SB>IN</SB>and W<SB>OUT</SB>control module 64 which controls W<SB>IN</SB>and W<SB>OUT</SB>of the energy storage device 14 according to the temperature of the reactor 22, and a switching element activate control module 66 which keeps the upper arm side switching element 24 to be in ON state according to the temperature of the reactor 22. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a power supply control system, and more particularly, to a power supply control system that controls the operation of a power supply including a reactor and including a voltage converter that can step up and down between a low voltage and a high voltage.

  Some power supply devices that drive rotating electrical machines are provided with an inverter that is an orthogonal transformation circuit and a converter that performs step-up / step-down between a low voltage and a high voltage. Since these inverters and converters use switching elements to handle large electric power, they generate heat and increase in temperature as they operate. For this purpose, the temperature is monitored, and output restriction to the load, operation restriction of the converter, and the like are performed according to the temperature.

  For example, in Patent Document 1, in the power output apparatus, as a second embodiment, the temperature management of the DC / DC converter that performs the step-up / step-down operation is performed by increasing the ripple of the current flowing through the reactor according to the temperature of the reactor. It is disclosed that the temperature is increased and the ripple is reduced to suppress the temperature increase. Here, it is stated that the ripple is increased by setting the terminal voltage of the boost side capacitor of the DC / DC converter high and the switching frequency low, and suppressing the ripple by the reverse setting.

  As a converter operation control technique related to the present invention, Patent Document 2 discloses that when a boost side voltage detection sensor of a boost converter fails in a vehicle drive device, the boost side capacitor suddenly moves to the low voltage DC power source side. A configuration for preventing a surge current from flowing is disclosed. Here, it is disclosed that a current sensor is provided on the DC power supply side, and the upper arm of the boost converter is turned on only when current flows from the DC power supply to the boost converter side.

  Further, in Patent Document 3, in a voltage converter, a terminal voltage that periodically oscillates in a boost side capacitor of a boost converter when the upper arm of the boost converter is turned on is detected and boosted from the peak voltage and frequency. Determining converter failure is disclosed. Here, since the resonance circuit is constituted by the boost side capacitor C2, the upper arm NPN transistor of the boost converter, and the reactor L, the failure of C2 and the failure of L are determined from the combination of the change in peak voltage and the change in frequency. Can be distinguished.

Japanese translation of PCT publication No. 2002-065628 JP 2006-325322 A JP 2004-242375 A

  In a power supply circuit including an inverter and a converter, when the temperature of the inverter rises, for example, the drive output of a rotating electrical machine as a load or the regenerative power is limited, and the operating power of the inverter can be suppressed. Moreover, when the temperature of the converter which is a voltage converter rises in connection with this, the input / output of the electric power with respect to the secondary battery which is a low voltage electrical storage apparatus can be restrict | limited, and the electric power which flows into a voltage converter can be restrict | limited. .

  By the way, when an auxiliary machine that operates at a low voltage is connected between the low-voltage power storage device and the voltage converter, if the input / output of the power of the low-voltage power storage device is restricted, the power supplied to the auxiliary machine There may be a shortage of operating power. At this time, power is supplied from the high voltage side via the voltage converter in order to compensate for the insufficient power. That is, the inverter also performs the corresponding operation, and an alternating current also flows through the reactor of the converter. As described above, the inverter temperature also rises despite the restriction of power input / output of the low-voltage power storage device, and the reactor also rises in temperature due to eddy current loss depending on the frequency of the alternating current. End up. Thus, in the prior art, the temperature rise suppression of the inverter and the voltage converter may be insufficient.

  The objective of this invention is providing the power supply control system which makes it possible to suppress the temperature rise of a voltage converter effectively. Another object is to provide a power supply control system that can effectively suppress the temperature rise of the voltage converter while securing the power supply to the auxiliary machine.

  A power supply control system according to the present invention includes an upper arm side switching element, a lower arm side switching element, an upper arm side switching element, and a lower arm side switching element connected in series between a high voltage side positive electrode bus and a negative electrode bus. A voltage converter capable of performing step-up / step-down between a low voltage and a high voltage, and a reactor including a reactor having one side connected to a connection point between the two and the other end connected to the low voltage side positive bus And a control means for controlling ON / OFF of the upper arm side switching element and the lower arm side switching element according to the temperature of the reactor in the predetermined temperature range of the reactor. And a control means for holding the switching element in the ON state.

  Further, in the power supply control system according to the present invention, the control means preliminarily sets a temperature rising side threshold temperature when the temperature of the reactor increases and a temperature decreasing side threshold temperature when the temperature decreases, and the temperature rising side threshold temperature and the temperature decreasing side threshold temperature are determined. It is preferable to keep the upper arm side switching element in the ON state in a temperature range between the temperature.

  The power supply control system according to the present invention may further include a power storage device input / output limiting unit that limits input power and output power to the low voltage power storage device connected to the other end of the reactor according to the temperature of the reactor. preferable.

  Further, in the power supply control system according to the present invention, the control means further includes a low-voltage power storage connected to the other end of the reactor when the temperature of the reactor rises to be equal to or higher than a predetermined input / output limit threshold temperature. Means for limiting the input power and output power to the device, and when the temperature of the reactor exceeds the input / output limit threshold temperature and exceeds a predetermined temperature increase threshold temperature, the upper arm side switching element is Means for holding in the ON state, and the upper arm side switching element when the temperature is lowered in a state after the upper arm side switching element is held in the ON state, and the temperature is lower than a predetermined temperature drop side threshold temperature. And a means for releasing the holding of the ON state.

  With the above configuration, the power supply control system holds the reactor upper arm side switching element in the ON state in a predetermined reactor temperature range according to the temperature of the reactor. As a result, for example, even when the input / output of power of the low-voltage power storage device is restricted, it is possible to supply power necessary for the auxiliary machine from the high-voltage side via the reactor, and the reactor is supplied with an alternating current. Since direct current flows instead, eddy current loss is suppressed and the temperature rise of the voltage converter is suppressed.

  Also, in the power supply control system, the upper arm side switching element is maintained in the ON state in the temperature range between the temperature increase side threshold temperature and the temperature decrease side threshold temperature, so that normal control is performed when the reactor is at a low temperature. It can be carried out. As a result, it is possible to minimize a decrease in voltage controllability due to holding the upper arm side switching element in the ON state. Further, by setting the temperature increase side threshold temperature and the temperature decrease side threshold temperature to different temperatures, it is possible to cope with a response delay due to the thermal mass of the reactor, and to effectively suppress the temperature increase of the reactor.

  Further, in the power supply control system, the input power and the output power to the low voltage power storage device connected to the other end of the reactor are limited according to the temperature of the reactor, so that the temperature increase of the reactor can be suppressed.

  Also, in the power supply control system, when the temperature of the reactor rises and exceeds the input / output limit threshold temperature, the input power and output power to the low-voltage power storage device are limited, and the temperature is further increased. When the temperature is equal to or higher than the threshold temperature, the upper arm side switching element is kept in the ON state, the temperature is lowered from the temperature, and when the temperature is lower than the temperature lowering side threshold temperature, the upper arm side switching element is in the ON state. Release the hold. By performing such fine control, it is possible to effectively suppress the temperature rise of the voltage converter while securing the power supply to the auxiliary machine.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following, a motor / generator mounted on a vehicle will be described as a rotating electrical machine. However, if the vehicle is a vehicle mounted with a power circuit including an inverter and a voltage converter, a hybrid mounted with an engine and the rotating electrical machine. In addition to the vehicle, an electric vehicle not equipped with an engine, a vehicle equipped with a fuel cell, and the like may be used. The rotating electrical machine may be a stationary motor / generator, for example, other than the one mounted on the vehicle. In addition, the rotating electrical machine may simply have a function as a motor, or may simply have a function as a generator. In the following description, control of a power supply circuit including two inverters corresponding to a rotating electric machine will be described. Of course, only one inverter corresponding to one rotating electric machine may be provided. May be provided. The power supply circuit is described as having a power storage device, a system main relay, a voltage converter, a smoothing capacitor, a discharge resistor, and an inverter circuit, but these elements may be omitted as appropriate, and other elements May be added as appropriate. In addition, as auxiliary machines that operate at low voltage, a DC / DC converter, an electric control unit for air conditioning (A / C Electric Control Unit: A / C-ECU), an inverter for air conditioning (A / C inverter), a compressor for air conditioning (COMP) will be described, but other than these, for example, various low-voltage operation motors, ECUs, lamps, various on-vehicle electronic devices such as audio devices, and the like may be used.

  In the following description, a voltage of about 600 V, which is an operating voltage of an inverter that controls the rotating electrical machine, is assumed to be a high voltage, and a voltage of about 200 V to about 300 V, which is a voltage across the power storage device, is assumed to be a low voltage. These voltage values are illustrative examples, and of course other voltage values may be used. An auxiliary machine that operates at a low voltage is a device that operates directly at a voltage of about 300 V that is the voltage across the power storage device, and further reduces the voltage of about 200 V to about 300 V, for example, about Also includes various electrical devices that operate at a voltage of 12V. In that sense, an auxiliary machine that operates at a low voltage refers to all devices that operate at a voltage before boosting the voltage converter.

  In the following, similar elements are denoted by the same reference symbols in all the drawings, and redundant description is omitted. In the description in the text, the symbols described before are used as necessary.

  FIG. 1 is a diagram illustrating a configuration of a power supply control system 10 that controls a power supply circuit for a rotating electrical machine or the like mounted on a vehicle. The power supply control system 10 has a function of controlling the operation of each component of the power supply circuit mounted on the vehicle according to the running state of the vehicle. The power supply control system 10 includes a power supply circuit 12 and a control unit 60. In FIG. 1, two rotary electric machines 6 and 8 and an air conditioning compressor 4 are shown, although they are not constituent elements of the power supply control system 10.

  Of the two rotating electrical machines 6 and 8, the first rotating electrical machine (MG1) 6 is, for example, a motor / generator (MG) mounted on a vehicle, and in this case, connected to an engine (not shown). And a three-phase synchronous rotating electric machine having a function of generating electric power by the driving force of the engine. The operation of the first rotating electrical machine 6 is controlled by, for example, a first inverter (MG1 inverter) 36 that operates at a high voltage of about 600V.

  The second rotating electrical machine (MG2) 8 is a motor / generator (MG) mounted on the vehicle, which functions as an electric motor when electric power is supplied and functions as a generator during braking. Electric. The second rotating electrical machine 8 mounted on the vehicle has a function of assisting engine power transmitted to a vehicle axle (not shown) to increase driving force. Similarly to the first rotating electrical machine 6, the second rotating electrical machine 8 is also controlled by a second inverter (MG2 inverter) 38 that operates at a high voltage of about 600 V, for example.

  The air-conditioning compressor (COMP) 4 is a compressor constituting an air-conditioning device mounted on the vehicle. The air conditioning compressor 4 is controlled by an air conditioning inverter (A / C inverter) 58 that operates at a low voltage of about 200V to about 300V, for example.

  The power supply circuit 12 includes a power storage device 14, a system main relay 16, a smoothing capacitor 18 on the power storage device side, a voltage converter 20, a smoothing capacitor 30 on the inverter side, an inverter unit 34, an inverter cooling system 40, and a low-voltage operation auxiliary device 50. Consists of including.

  The power storage device 14 is a chargeable / dischargeable secondary battery. Since the power storage device 14 is disposed on the low voltage side of the voltage converter 20, it can be called a low voltage power storage device. As the power storage device 14, for example, a lithium ion assembled battery, a nickel hydride assembled battery, a capacitor, or the like having a terminal voltage of about 200V to about 300V can be used.

  The system main relay 16 is a high-power interruption device configured to include a high-power relay provided on each of the positive electrode bus and the negative electrode bus of the power storage device 14. The system main relay 16 is connected when the power supply circuit 12 enters the operating state, and is shut off when the power supply circuit 12 finishes operating. As described above, the system main relay 16 can electrically cut off the power storage device 14 from other elements when the power supply circuit 12 is not in operation, so that, for example, the vehicle body of the vehicle can be cut from about 200V. It has a function of safely cutting off from a voltage of about 300 V or a voltage of about 600 V obtained by boosting the voltage.

The smoothing capacitor 18 on the power storage device side provided between the power storage device 14 and the voltage converter 20 is a capacitor having a function of suppressing voltage fluctuation on the low voltage side. Although V _L is illustrated in FIG. 1 as the voltage across the smoothing capacitor 18, this V _L is the voltage on the low voltage side of the voltage converter 20.

  The voltage converter 20 is a step-up / step-down circuit that includes a reactor 22 and two switching elements 24 and 26. The voltage converter 20 is a circuit having a function of boosting a low voltage of about 200 V to about 300 V on the power storage device 14 side to a high voltage of, for example, about 600 V using the energy storage action of the reactor 22. Also called. In addition, the voltage converter 20 has a bidirectional function, and when the power from the first inverter 36 and the second inverter 38 constituting the inverter unit 34 is supplied to the power storage device 14 side as charging power, The high voltage on the side of the first inverter 36 and the second inverter 38 is also lowered to a low voltage suitable for the power storage device 14.

  Reactor 22 is a device that has one end connected to a positive electrode bus on the side of power storage device 14 and the other end connected to a connection point between two switching elements 24 and 26, and can store magnetic energy. The reactor 22 is used as an inductance by winding a coil around a magnetic core and passing a high-frequency signal through the coil. The reactor 22 can be used together with the switching elements 24 and 26 to constitute a step-up / step-down circuit. . When a high frequency signal is passed through the coil, the core and the coil generate heat. For example, the temperature may rise from about 100 ° C. to about 200 ° C.

The temperature sensor 28 disposed in the vicinity of the reactor 22 is a temperature detection element having a function of detecting the temperature θ _{1 of the} reactor 22 and transmitting the detection result to the control unit 60 via an appropriate signal line.

  The two switching elements 24 and 26 are high power switching transistors connected in series with each other and disposed between the positive and negative buses of the inverter unit 34. The connection point between the two switching elements 24 and 26 is connected to the other end of the reactor 22 as described above. As the switching elements 24 and 26, gate-insulated bipolar transistors (IGBT) can be used. In FIG. 1, the switching elements 24 and 26 are shown as n-channel type, but may be p-channel type due to voltage. A diode is connected to each of the two switching elements 24 and 26 in parallel.

  Of the two switching elements 24 and 26, the switching element 24 on one side has a collector terminal connected to the positive electrode bus of the inverter unit 34, an emitter terminal connected to the collector terminal of the switching element 26 on the other side, and a gate terminal. The control terminal is connected to a control signal line from the control unit 60. As described above, the switching terminal 26 on the other side has the collector terminal connected to the emitter terminal of the switching element 24 on one side, the emitter terminal connected to the negative electrode bus common to the power storage device 14 and the inverter unit 34, and the gate terminal The control terminal is connected to a control signal line from the control unit 60.

  The two switching elements 24 and 26 are distinguished from each other, with one switching element 24 connected to the positive bus side being the upper switching element and the other switching element 26 being connected to the negative bus side being the lower switching element. It can be called an arm side switching element.

  The voltage converter 20 performs step-up and step-down operations as follows under the control of the switching elements 24 and 26. In the step-up operation, power is supplied from the inverter unit 34 side to the power storage device 14 side, and in the step-down operation, power is supplied from the power storage device 14 side to the inverter unit 34 side.

In the case of the boosting operation, the switching element 24 is turned off and the switching element 26 is turned on. As a result, the connection with the inverter unit 34 is opened. On the other hand, since the other end of reactor 22 is connected to the negative electrode bus, a current flows from the positive electrode bus of power storage device 14 to negative electrode bus through reactor 22. As described above, since current flows into the reactor 22 from the power storage device 14, energy of (LI ² ) / 2 is accumulated in the reactor 22, where I is the current and L is the impedance of the reactor. As a result, the voltage at the other end of the reactor 22 rises, and when the difference from the voltage on the inverter unit 34 side becomes more than a certain level due to the action of the diode connected in parallel to the switching element 24, the energy of the inverter unit 34 is increased. Flows into the side. As a result, the voltage of the smoothing capacitor 30 on the inverter side gradually increases. In this manner, the voltage between the positive electrode bus and the negative electrode bus of the inverter unit 34 is increased and the voltage is boosted.

  In the case of the step-down operation, the switching element 26 is turned off and the switching element 24 is turned on, contrary to the step-up operation. As a result, the connection between the reactor 22 and the negative electrode bus is opened. On the other hand, since the positive electrode bus of inverter unit 34 is connected to the other end of reactor 22, the energy accumulated in inverter-side smoothing capacitor 30 flows into reactor 22 and enters smoothing capacitor 18 on power storage device 14 side. Transferred. In this way, the power on the inverter unit 34 side is stepped down and supplied to the power storage device 14 side.

  Since the voltage converter 20 performs step-up or step-down operation by the switching operation of the switching elements 24 and 26 as described above, the reactor 22 is supplied with a current whose direction changes due to switching, that is, an alternating current. The power loss of the reactor 22 includes an iron loss that depends on the switching frequency f and a copper loss that depends on the magnitude of the flowing current. Due to these power losses, the reactor 22 generates heat with the operation of the voltage converter 20, and its temperature rises.

The inverter-side smoothing capacitor 30 provided between the voltage converter 20 and the inverter unit 34 is a capacitor having a function of suppressing voltage fluctuation on the high voltage side. Although V _H is shown in FIG. 1 as the voltage across the smoothing capacitor 30, this V _H is the voltage on the high voltage side of the voltage converter 20. The discharge resistor 32 is a resistance element that is used when the operation of the power supply circuit 12 stops and the electrical energy accumulated in the smoothing capacitor 30 needs to be discharged.

  The inverter unit 34 includes two inverters 36 and 38. The two inverters 36 and 38 both convert high-voltage DC power into AC three-phase drive power and supply it to the rotating electrical machines connected thereto, and conversely, AC three-phase regenerative power from each rotating electrical machine. Is a circuit having a function of converting the power into high-voltage DC charging power. Of the two inverters 36 and 38, the one connected to the first rotating electric machine (MG1) 6 is the second one connected to the first rotating electric machine (MG1 inverter) 36 and the second rotating electric machine (MG2) 8 is the second. Inverter (MG2 inverter) 38.

  The inverters 36 and 38 have the same basic configuration, and include a plurality of switching elements and a plurality of diodes. The switching element is a high-power switching transistor similar to the switching elements 24 and 26 in the voltage converter 20, and an IGBT or the like can be used. Since these switching elements perform high-power switching, they generate heat during operation and the temperature rises.

  The inverter cooling system 40 is a cooling system for cooling the inverter unit 34. In FIG. 1, the voltage converter 20 is also cooled together with the inverter unit 34, but this is a high voltage system from the voltage converter 20 to the inverter unit 34 as one PCU (Power Control Unit). This is because they are often collected and stored in one unit case. In that sense, the inverter cooling system 40 can be said to be a cooling system for a power unit including an inverter.

  The inverter cooling system 40 circulates a coolant such as cooling water along the coolant circulation flow path 44 by the circulation pump 42, carries heat away from the inverters 36 and 38 and the voltage converter 20, and dissipates heat to the outside by an appropriate radiator 46. Cooling system.

The temperature sensor 48 disposed in the vicinity of the refrigerant circulation flow path has a function of detecting the temperature θ ₂ of the coolant that is the refrigerant and transmitting the detection result to the control unit 60 via an appropriate signal line. It is an element.

The low voltage operation auxiliary machine 50 is an electric device or the like that is operated by the voltage V _L on the low voltage side of the voltage converter 20. In FIG. 1, a DC / DC converter 52 that converts low voltage power having V _L to DC power of about 12V and supplies the DC power to a 12V battery 54, and an air conditioning ECU (A / C-ECU) that operates at a voltage of 12V 56 and an air conditioning inverter (A / C inverter) 58 that operates at _VL and controls the operation of the air conditioning compressor (COMP) 4 are shown.

  The control unit 60 is a control circuit having a function of controlling the operation of each element constituting the power supply circuit 12 as a whole. The control unit 60 operates under the instruction of an integrated control unit that controls traveling of the vehicle (not shown). Here, the control unit 60 particularly has a function of performing control for suppressing the temperature rise of the voltage converter 20. Such a control unit 60 can be configured by a computer suitable for mounting on a vehicle. This may be an independent computer, and the function of the control unit 60 may be included as part of the function of another control device mounted on the vehicle. For example, the function of the control unit 60 may be included in the overall control unit.

Control unit 60 includes a reactor temperature acquisition module 62 for acquiring the temperature theta ₁ of the reactor 22, depending on the temperature theta ₁ of the reactor 22 is the output power brought out as W _IN is the input power being brought into the electric storage device 14 power storage device W _iN to limit the W _OUT, and W _OUT limiting module 64, includes a switching element actuated limiting module 66 for limiting the operation of the switching elements 24, 26 of the voltage converter 20 according to the temperature theta ₁ of the reactor 22 Composed. Each of these functions is realized by software, and specifically can be realized by executing a power supply control program. Some of these functions may be realized by hardware.

The operation of the above configuration, in particular, each function of the control unit 60 will be described in detail with reference to FIGS. FIG. 2 is a flowchart showing a processing procedure for suppressing the temperature rise of the voltage converter 20, FIG. 3 is a diagram for explaining the state of load factor limitation of the power storage device 14, and FIG. 4 is the temperature θ _{1 of the} reactor 22. It is a figure explaining the mode of switching of operation | movement of the switching element 24 grade | etc., Of an upper arm with a change of. Each procedure in the flowchart of FIG. 2 corresponds to each processing procedure of the power supply control program.

When the power supply control program is started, the temperature θ ₁ of the reactor 22 is acquired (S10). This step is executed by the function of the reactor temperature acquisition module 62 of the control unit 60. Specifically, the temperature θ _{1 of the} reactor 22 is detected by the temperature sensor 28, and the control unit 60 acquires the detection result.

Then, it is determined whether or not the temperature θ _{1 of the} reactor 22 is equal to or higher than a predetermined temperature A ° C. (S12). The temperature A ° C. is a temperature set in advance to limit W _IN that is input power brought into the power storage device 14 and W _OUT that is output power that is taken out, and this can be referred to as an input / output limit threshold temperature. .

If the determination is affirmative in S12, W _IN and W _OUT of power storage device 14 are limited according to the temperature of reactor 22 (S14). This process is executed by the function of the W _IN and W _OUT limiting module 64 of the power storage device of the control unit 60. When there is no other device that consumes power between the power storage device 14 and the reactor 22 or when there is little power consumption, the reactor 22 is limited by limiting W _IN and W _OUT of the power storage device 14. Can be effectively suppressed, whereby the reactor 22 can be prevented from generating heat and rising in temperature.

FIG. 3 shows how W _IN and W _OUT of the power storage device 14 are limited. In FIG. 3, the horizontal axis represents the temperature θ ₁ of the reactor 22, and the vertical axis represents the normalized amount of W _IN or W _OUT of the power storage device. The normalized value of W _IN or W _OUT is ₁ when the temperature θ _{1 of the} reactor 22 is sufficiently low, and for an arbitrary temperature, the ratio to 1 is shown as the load factor. As shown in FIG. 3, when the temperature θ ₁ of the reactor 22 is less than A ° C., the load factor is 1, and the load factor is not limited. On the other hand, when the temperature θ _{1 of the} reactor 22 is equal to or higher than A ° C., the load factor becomes gradually smaller than 1 as θ ₁ becomes higher, and the load factor restriction becomes gradually larger. In this way, at θ ₁ that is equal to or higher than A ° C. that is the input / output limit threshold temperature, W _IN and W _OUT of power storage device 14 are limited according to θ ₁ . FIG. 3 also shows the relationship between temperatures B ° C. and C ° C. described later.

Returning to FIG. 2 again, it is next determined whether or not the temperature θ _{1 of the} reactor 22 is equal to or higher than a predetermined temperature C ° C. (S16). When the temperature of the reactor 22 continues to rise, the temperature C ° C. keeps the switching element 24 on the upper arm side in the ON state from the state where the switching elements 24 and 26 of the voltage converter 20 are in the normal switching control state, This temperature is set to enter an operation restriction state in which the switching element 26 on the lower arm side is held in the OFF state, and this can be called a temperature increase side threshold temperature.

  If the determination is affirmative in S16, as described above, the switching element 24 on the upper arm side is held in the ON state, and the switching element 26 on the lower arm side is held in the OFF state (S18). This state is a state in which the operation state of the switching elements 24 and 26 is limited, unlike the case where the voltage step-up / step-down operation of the voltage converter 20 is performed by switching of the switching elements 24 and 26. In this way, the operating state of the switching elements 24 and 26 is fixed to either ON or OFF from the switching control state in which ON and OFF are alternately repeated, and thus depends on the switching frequency f in the voltage converter 20. It is possible to suppress the iron loss that occurs, and to suppress the heat generation and temperature rise of the reactor 22 associated therewith. Further, since the switching element 24 on the upper arm side is held in the ON state, electric power can be supplied from the inverters 36 and 38 side to the reactor 22 side, whereby necessary electric power can be supplied to the low-voltage operation auxiliary machine 50.

Next, it is determined whether or not the temperature θ _{1 of the} reactor 22 is lower than a predetermined temperature DC ° C. (S20). The temperature D ° C. is a temperature set so that the switching elements 24 and 26 of the voltage converter 20 return from the operation restricted state of S18 to the normal switching control state when the reactor 22 falls from the state of S18. This can be referred to as a temperature-lowering threshold temperature.

  If the determination is affirmative in S20, as described above, the ON state holding of the upper arm side switching element 24 and the OFF state holding of the lower arm side switching element 26 are released, and these are returned to the normal switching control state again. Return (S22). Steps S <b> 16, S <b> 18, S <b> 20, and S <b> 22 are executed by the function of the switching element operation restriction module 66 of the control unit 60. After S22, the process returns to S10 again, and the above procedure is repeated. Similarly, when the determination is negative in S12, S16, S20, the process returns to S10 and the above procedure is repeated.

FIG. 4 is a diagram illustrating the procedure of FIG. 2 as a time-series change. In FIG. 4, the horizontal axis represents time, the vertical axis represents the temperature θ ₁ of the reactor 22, and the upper arm side switching element 24 and the lower arm side switching element 26 are associated with the temperature range of the reactor 22. It is the figure which showed the operating state of.

In FIG. 4, when the temperature θ ₁ of the reactor 22 gradually increases and reaches A ° C. or higher at time t ₁ , S 12, S 14 and W _IN and W _OUT of the power storage device 14 are limited as described in FIG. Is called. At this time, the switching elements 24 and 26 are in a normal switching control state.

Further, when the temperature θ _{1 of the} reactor 22 gradually rises and exceeds the temperature B ° C. and reaches C ° C. or higher at time t ₂ , the switching element 24 on the upper arm side remains in the ON state as described in S 16 and S 18. The switching element 26 on the lower arm side is held in the OFF state. As a result, the iron loss in the reactor 22 is reduced, and the temperature of the reactor 22 starts to decrease after a certain time delay.

When the temperature θ _{1 of the} reactor 22 gradually decreases and becomes lower than the temperature B ° C. at time t ₃ , as described in S 20 and S 22, the ON state holding of the switching element 24 on the upper arm side, and the lower arm side The holding of the OFF state of the switching element 26 is released. As a result, the switching elements 24 and 26 return to the normal switching control state. When temperature θ ₁ further decreases and becomes lower than temperature A ° C. at time t ₄ , the restrictions on W _IN and W _OUT of power storage device 14 are released.

As described above, the period in which the switching element 24 on the upper arm side is held in the ON state and the switching element 26 on the lower arm side is held in the OFF state is the temperature range on the temperature rising side in the temperature range of the reactor 22. It is in the range of C ° C. or higher and the temperature B ° C. or higher on the temperature drop side. Speaking on the time axis of FIG. 4, it is between time t ₂ and time t ₃ . As described above, since the voltage converter 20 has a limited time period outside normal switching control, it is possible to minimize the voltage controllability.

  In addition, by setting the temperature increase side threshold temperature and the temperature decrease side threshold temperature to different temperatures, it is possible to cope with a response delay due to the thermal mass of the reactor 22 and to effectively suppress the temperature increase of the reactor 22.

It is a figure which shows the structure of the power supply control system of embodiment which concerns on this invention. In embodiment which concerns on this invention, it is a flowchart which shows the process sequence which suppresses the temperature rise of a voltage converter. In embodiment which concerns on this invention, it is a figure explaining the mode of the load factor restriction | limiting of an electrical storage apparatus. In embodiment which concerns on this invention, it is a figure explaining the mode of switching of action | operations, such as a switching element of an upper arm, with the change of the temperature of a reactor.

Explanation of symbols

4 Air-conditioning compressor, 6, 8 Rotating electric machine, 10 Power supply control system, 12 Power supply circuit, 14 Power storage device, 16 System main relay, 18, 30 Smoothing capacitor, 20 Voltage converter, 22 Reactor, 24, 26 Switching element, 28 , 48 Temperature sensor, 32 Discharge resistance, 34 Inverter unit, 36, 38 Inverter, 40 Inverter cooling system, 42 Circulation pump, 44 Refrigerant circulation flow path, 46 Radiator, 50 Low voltage operation auxiliary machine, 52 DC / DC converter, 54 Battery, 60 control unit, 62 reactor temperature acquisition module, 64 power storage device W _IN , W _OUT limiting module, 66 switching element operation limiting module.

Claims (4)

One side is connected to the connection point between the upper arm side switching element and the lower arm side switching element, and the upper arm side switching element and the lower arm side switching element connected in series between the high voltage side positive electrode bus and the negative electrode bus A voltage converter capable of performing step-up / step-down between a low voltage and a high voltage, including a reactor whose other end is connected to the low-voltage-side positive bus.
Means for obtaining the temperature of the reactor;
Control means for controlling ON / OFF of the upper arm side switching element and the lower arm side switching element, and keeps the upper arm side switching element in the ON state in a predetermined reactor temperature range according to the temperature of the reactor. Control means to
A power supply control system comprising: The power supply control system according to claim 1,
The control means preliminarily sets a temperature increase side threshold temperature when the reactor heats up and a temperature decrease side threshold temperature when the reactor temperature decreases, and the upper arm side in the temperature range between the temperature increase side threshold temperature and the temperature decrease side threshold temperature. A power supply control system characterized by holding a switching element in an ON state. The power supply control system according to claim 1,
A power supply control system comprising power storage device input / output limiting means for limiting input power and output power to a low voltage power storage device connected to the other end of the reactor according to the temperature of the reactor. The power supply control system according to claim 1,
The control means further includes
Means for limiting the input power and output power to the low-voltage power storage device connected to the other end of the reactor when the temperature of the reactor rises to a predetermined input / output limit threshold temperature or higher,
Means for holding the upper arm side switching element in an ON state when the temperature of the reactor exceeds the input / output limit threshold temperature and becomes equal to or higher than a predetermined temperature increase side threshold temperature;
Means for lowering the temperature in the state after the upper arm side switching element is maintained in the ON state, and releasing the ON state holding of the upper arm side switching element when the temperature is lower than the predetermined temperature decrease side threshold temperature When,
A power supply control system comprising:

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