JP2009284735A - Vehicle power supply - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce an influence on the operability of a vehicle when malfunction is caused by noise electromagnetic wave or the like in a vehicle power supply having an inverter circuit. <P>SOLUTION: A current sensor 30 measures current that flows in each IGBT 18 and outputs measured values to a MG control unit 26. The MG control unit 26 sets a self protective signal to be output to a main control unit 22 through a signal line 32 at ON level if there is a predetermined current threshold value or more in measured current values. The main control unit 22 determines whether or not the unit makes protection control on the inverter circuit 14 in response to the length of time of the self protective signal in the signal line 32. If the unit determines that the unit performs protection control, the unit outputs a signal to make protection control to the MG control unit 26, and the MG control unit 26 makes control in response to the received signal. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicle power supply device including an inverter circuit that converts DC power into AC power and outputs the AC power to a motor generator, and converts AC power generated by the motor generator into DC power and outputs the DC power.

  An electric vehicle that travels by the driving force of a motor generator and performs regenerative braking by the motor generator during deceleration is widely used. Such an electric vehicle includes a battery that transfers power to and from a motor generator, a battery power that is converted into AC power and supplied to the motor generator, and an AC power generated by the motor generator is converted into DC power that is converted into a battery. Inverter circuit for supplying to

  In an electric vehicle, if a large amount of electric power is supplied to the motor generator, such as when a start operation is performed with the tire locked, an excessive current may flow in the inverter circuit. Electric vehicles are also equipped with other electric circuits connected to the inverter circuit. Due to the failure of the other electric circuit, an excessive current flows in the inverter circuit or an excessive voltage is applied to a specific part of the inverter circuit. May be applied. Such an excessive current or excessive voltage may shorten the life of the inverter circuit.

  Therefore, the electric vehicle includes a sensor that detects a current flowing through a predetermined path in the inverter circuit, a voltage between predetermined nodes in the inverter circuit, a temperature of the inverter circuit, and the like. The control unit that performs switching control of the inverter circuit determines whether the inverter circuit is abnormal according to the detection result of the sensor. When it is determined that there is an abnormality, the switching control of the inverter circuit is stopped regardless of the traveling state and the driver's operation.

JP 2002-235991 A JP 2006-280193 A JP 2001-37242 A JP 7-15948 A JP 2001-320894 A

  In an environment where an electric vehicle travels, there are various electric devices such as an air conditioner outdoor unit of a building, an automatic door, a traffic light, and an electric system of another vehicle. Such electric equipment may emit noise electromagnetic waves.

  When the noise electromagnetic wave induces noise in the circuit in the control unit, the control unit may stop switching control of the inverter circuit even though no abnormality has occurred in the inverter circuit. When such a malfunction occurs, there arises a problem that the operability of the vehicle is affected.

  The present invention has been made for such a problem. That is, an object of the vehicle power supply device including an inverter circuit is to reduce the influence of malfunction caused by noise electromagnetic waves or the like on the operability of the vehicle.

  The present invention converts the DC power into AC power and outputs it to the motor generator, converts the AC generator power of the motor generator into DC power and outputs it, an inverter control unit for switching the inverter circuit, A vehicle power supply apparatus comprising: an abnormality detection unit that outputs a protection signal when an abnormality of the inverter circuit is detected; and a control stop unit that stops switching control by the inverter control unit, wherein the abnormality detection unit A detection unit that detects a signal in an output signal path from the output unit, and a determination unit that determines whether to perform protection control of the inverter circuit based on a time length of the signal detected by the detection unit. The control stop unit stops switching control of the inverter circuit when the determination unit determines that protection control is to be performed. And wherein the Rukoto.

  The vehicle power supply device according to the present invention includes a boost converter circuit that adjusts power exchanged between a battery and the inverter circuit, and a converter control unit that controls the boost converter circuit. The converter control unit may control the boost converter circuit so that the torque of the motor generator converges to 0 after the determination unit starts the determination process until the determination is made. Is preferred.

  Further, in the vehicle power supply device according to the present invention, the inverter circuit is provided separately from the control stop unit, and the determination circuit starts the determination process and then performs the determination. It is preferable to provide a preliminary control stop unit for stopping the switching control.

  ADVANTAGE OF THE INVENTION According to this invention, in the vehicle electric power supply apparatus provided with an inverter circuit, the influence which malfunction by noise electromagnetic waves etc. has on the operativity of a vehicle can be reduced.

  FIG. 1 shows the configuration of an electric vehicle according to an embodiment of the present invention. The electric vehicle rotates the motor generator 16 based on the electric power supplied from the battery 10 and travels by the driving force of the motor generator 16. The acceleration / deceleration control of the electric vehicle is performed by adjusting the electric power supplied from the battery 10 to the motor generator 16. Therefore, a boost converter circuit 12 that boosts the battery voltage and adjusts the boost voltage is used in the electric vehicle. In addition, since the motor generator 16 for AC power is used, an inverter circuit 14 that converts AC power into DC power and converts DC power into AC power is used.

  Boost converter circuit 12 boosts the battery voltage based on the control of MG control unit 26 (MG is an abbreviation for Motor Generator), and outputs the boosted voltage to inverter circuit 14. The inverter circuit 14 converts the output voltage of the boost converter circuit 12 into an AC voltage based on the control of the MG control unit 26 and outputs the AC voltage to the motor generator 16.

  The inverter circuit 14 outputs a larger alternating voltage as the output voltage of the boost converter circuit 12 is larger. Further, the smaller the output voltage of the boost converter circuit 12, the smaller the AC voltage is output. Therefore, the output AC voltage of inverter circuit 14 can be adjusted by adjusting the output voltage of boost converter circuit 12.

  When the motor generator 16 is rotating at a speed corresponding to the output AC voltage of the inverter circuit 14, power is not transferred between the battery 10 and the motor generator 16, and the motor generator 16 rotates at a constant speed. . When the output voltage of boost converter circuit 12 is increased in this state, the output AC voltage of inverter circuit 14 increases, and electric power is supplied from battery 10 to motor generator 16 via boost converter circuit 12 and inverter circuit 14. Thereby, the motor generator 16 generates acceleration torque and the electric vehicle is accelerated. Further, when the output voltage of boost converter circuit 12 is lowered, the output AC voltage of inverter circuit 14 decreases, and power is recovered from motor generator 16 to battery 10 via inverter circuit 14 and boost converter circuit 12. Thereby, motor generator 16 generates a braking torque, and the electric vehicle decelerates. The deceleration of the electric vehicle can be performed by a brake mechanism provided separately in addition to the braking torque of the motor generator 16.

  The operation unit 24 includes an accelerator pedal, a brake pedal, and the like, and outputs a control command corresponding to the driving operation to the main control unit 22. The main control unit 22 obtains torque to be generated by the motor generator 16 based on the control command, and outputs a torque command value to the MG control unit 26.

  The MG control unit 26 refers to the torque of the motor generator 16 detected by the torque detector 28 and controls the boost converter circuit 12 so that the difference between the detected torque and the torque command value becomes small.

  Next, protection control of the inverter circuit 14 will be described. The inverter circuit 14 according to the present embodiment includes a plurality of IGBTs 18 (Insulated Gate Bipolar Transistors) as switching elements. As the switching element, in addition to the IGBT, a triac, a thyristor, or the like can be used. The IGBT 18 is controlled to be turned on or off between the collector terminal C and the emitter terminal E by changing the voltage between the gate terminal G and the emitter terminal E. When it is on, current flows from the collector terminal C to the emitter terminal E, and when it is off, the collector terminal C and the emitter terminal E are disconnected. According to such a principle, the collector terminal C and the emitter terminal E can be used as a switch.

  The inverter circuit 14 performs conversion from AC power to DC power or conversion from DC power to AC power by switching the IGBT 18 by the MG control unit 26.

  A diode 20 is connected between the collector terminal C and the emitter terminal E of the IGBT 18 so that the collector terminal C side is the cathode terminal K and the emitter terminal E side is the anode terminal A. The diode 20 makes the current of the motor generator 16 continuous when the on / off state of the IGBT 18 is switched. In addition, by providing the diode 20, even when the IGBT 18 is off, a current can flow from the emitter terminal E side to the collector terminal C side. Thereby, even when the switching control is stopped, the inverter circuit 14 can convert the AC power generated by the motor generator 16 into a DC voltage and output it to the boost converter circuit 12 side. Therefore, even when switching control of inverter circuit 14 is stopped, regenerative braking of the electric vehicle can be performed by flowing the regenerative current of motor generator 16 through diode 20.

  The current sensor 30 measures the current flowing through each IGBT 18 and outputs the measured value to the MG control unit 26. The MG control unit 26 sets the self-protection signal output to the main control unit 22 via the signal line 32 to the ON level when there is a current measurement value that exceeds a predetermined current threshold value. On the other hand, when all the current measurement values are less than the predetermined current threshold, the MG control unit 26 sets the level of the self-protection signal to 0. Here, of the signal paths exchanged between the main control unit 22 and the MG control unit 26, only the path of the self-protection signal is shown by the signal line 32. It is for showing that it is suitable in order to solve the problem based on the noise to be performed.

  FIG. 2 is a flowchart showing processing executed by the main control unit 22 based on the self-protection signal detected from the signal line 32.

  The main control unit 22 detects a self-protection signal input from the signal line 32 (S101). The main control unit 22 determines whether or not the self-protection signal is on level (S102). When the self-protection signal is off level, the process returns to step S102.

  On the other hand, when the self-protection signal is at the on level, the main control unit 22 sets the zero torque command signal output to the MG control unit 26 to the on level (S103). Here, the zero torque command signal is a signal indicating that the torque generated by the motor generator 16 should converge to 0 regardless of the above-described torque command value based on the operation of the operation unit 24. MG control unit 26 controls boost converter circuit 12 so that the torque generated by motor generator 16 converges to 0 in accordance with the zero torque command signal.

  After a predetermined determination time has elapsed since the execution of step S103, the main control unit 22 determines whether or not the self-protection signal has been kept on for the determination time (S104). If it is determined that it is not maintained, the zero torque command signal is turned off (S105), and the process returns to step S101.

  On the other hand, when the self-protection signal is maintained at the on level for the determination time, the main control unit 22 sets the zero torque command signal to the off level (S106) and outputs a gate cutoff command signal to be output to the MG control unit 26. The level is turned on (S107). Here, the gate cutoff command signal is a signal indicating that the switching control of the inverter circuit 14 should be stopped regardless of the above-described torque command value based on the operation of the operation unit 24. The MG control unit 26 stops the switching control of the inverter circuit 14 in accordance with the gate cutoff command signal.

  According to such processing, when the self-protection signal of the signal line 32 becomes the on level and the self-protection signal maintains the on level for a predetermined determination time, the switching control of the inverter circuit 14 is stopped. . As a result, when an abnormality occurs in the inverter circuit 14 and any one of the IGBTs 18 included in the inverter circuit 14 becomes equal to or greater than the current threshold, the current flowing through all the IGBTs 18 can be cut off. Further, the regenerative current flowing through the diode 20 can be reduced by reducing the torque generated by the motor generator 16. Thereby, it is possible to avoid the life of the inverter circuit 14 from being shortened due to an abnormality.

  As described above, there are various electric devices in the environment in which the electric vehicle travels. Such electric equipment may emit noise electromagnetic waves. The noise electromagnetic wave may induce noise in the signal line 32. According to the electric vehicle according to the present embodiment, the protection control of the inverter circuit 14 is performed when the self-protection signal on the signal line 32 maintains the on level for a predetermined determination time. Therefore, if the expected value of the time length of the noise waveform induced in the signal line 32 is measured in advance by experiments or the like, and the determination time is made longer than the assumed time length of the noise waveform, the inverter circuit 14 has an abnormality. Although it has not occurred, it is possible to avoid a malfunction in which protection control of the inverter circuit 14 is performed for a time longer than the determination time. In the hybrid vehicle under development at the time of filing this application, a simulation result is obtained that the determination time is preferably 30 ms to 70 ms, preferably 50 ms.

  Further, in the processing according to the present embodiment, when the self-protection signal of the signal line 32 becomes the on level, the motor generator 16 is generated until the determination time elapses after the detection level becomes the on level. The torque is controlled to converge to zero. As a result, the current flowing through the IGBT 18 and the diode 20 of the inverter circuit 14 can be reduced, and the life of the inverter circuit 14 can be prevented from being shortened due to an abnormality.

  During the period from when the self-protection signal is turned on until the judgment time elapses, the detection level is turned on due to noise or an overcurrent in the inverter circuit was actually detected. This is a period during which it is not determined whether or not According to the processing according to the present embodiment, the inverter circuit 14 can be protected even during a period in which the cause of the self-protection signal of the signal line 32 being at the on level is uncertain.

  FIG. 3 shows an example of a timing chart for protection control of the inverter circuit 14. FIG. 3A shows the self-protection signal P of the signal line 32, and shows that the self-protection signal P is turned on from time t1 to time t3. When the level of the self-protection signal P becomes the on level at time t1, the main control unit 22 sets the zero torque command signal q to the on level from time t1 to time t1 + τ as shown in FIG. 3B. Since the zero torque command signal q is turned on from time t1 to time t1 + τ, the generated torque qt of the motor generator 16 converges to 0 between time t1 and time t1 + τ as shown in FIG.

  The self-protection signal P remains on level even after the time t1 + τ has elapsed. Therefore, the main control unit 22 sets the gate cutoff command signal g to the on level at time t1 + τ as shown in FIG. The switching control of the inverter circuit 14 is stopped after the time t1 + τ because the gate cutoff command signal g becomes the on level after the time t1 + τ. Therefore, as shown in FIG. 3D, the generated torque qt of the motor generator 16 becomes zero.

  As shown in FIG. 3, when the self-protection signal P output from the signal line 32 to the main control unit 22 is on level for a time longer than the determination time τ, the zero torque command signal q is changed from the time t1 to the time t1 + τ. It becomes on level for a while. Then, after time t1 + τ, the gate cutoff command signal is turned on. As a result, when an abnormality occurs in the inverter circuit 14, the current flowing through any of the IGBTs 18 in the inverter circuit 14 exceeds the current threshold value, and the self-protection signal P is turned on, protection control of the inverter circuit 14 is performed. Is called.

  FIG. 4 shows another example of a timing chart of protection control of the inverter circuit 14. FIG. 4A shows that noise is induced in the signal line 32, and the level is turned on from time t1 to time t2. Here, it is assumed that the time from time t1 to time t2 is shorter than the determination time τ. When the self-protection signal P becomes the on level at time t1, the main control unit 22 sets the zero torque command signal q to the on level from time t1 to time t2, as shown in FIG. 4B. As a result, the torque generated by the motor generator 16 converges to 0 from time t1 to time t2, as shown in FIG. 4 (d).

  The self-protection signal P becomes an off level before the determination time τ elapses from the time t1. Therefore, as shown in FIG. 4C, the main control unit 22 sets the zero torque command signal q to the off level and maintains the gate cutoff command signal g at the off level after time t2. Thus, after time t2, control according to the control command output from the operation unit 24 is performed. Therefore, as shown in FIG. 4D, the generated torque qt of the motor generator 16 becomes a value corresponding to the control command output from the operation unit 24 after time t2.

  As shown in FIG. 4, when noise is induced in the signal line 32 and the time during which the noise is on level is shorter than the determination time τ, the zero torque command signal q is on level between time t1 and time t2. However, after time t2, it becomes an off level. Then, after time t2, the gate cutoff command signal does not become an on level. Therefore, since the electric vehicle is in a normal traveling state after time t2, it is possible to avoid malfunction due to noise induced in the signal line 32 and affect the operability of the electric vehicle.

  Next, a modified example of the protection control of the inverter circuit 14 will be described. FIG. 5 shows a flowchart of protection control according to the modification. The same processes as those in the flowchart shown in FIG.

  In the protection control shown in the flowchart of FIG. 2, in step S103, the torque generated by the motor generator 16 is converged to 0 and the current flowing through the inverter circuit 14 is converged to 0 by setting the zero torque command signal to the on level. On the other hand, in the protection control of the inverter circuit 14 according to the modification, the main control unit 22 sets the zero current command signal output to the MG control unit 26 to the on level in step S203. Here, the zero current command signal is a signal indicating that the current flowing through the IGBT 18 is zero regardless of the torque command value based on the operation of the operation unit 24. In the protection control based on the flowchart of FIG. 5, instead of setting the zero torque command signal to the off level in steps S105 and S106 in the flowchart of FIG. 2, the zero current command signal is set to the off level in steps S205 and S206. As a result, the control state based on the zero current command signal is released.

  FIG. 6 shows an example of a timing chart of protection control according to the modification. FIG. 6A shows the self-protection signal P of the signal line 32, and shows that the self-protection signal P input from the signal line 32 to the main control unit 22 is on level from time t1 to time t3. When the level of the self-protection signal P becomes the on level at the time t1, the main control unit 22 sets the zero current command signal I to the on level from the time t1 to the time t1 + τ as shown in FIG. 6B. . Since the zero current command signal I is turned on from time t1 to time t1 + τ, the current J flowing through the IGBT 18 of the inverter circuit 14 becomes 0 between time t1 and time t1 + τ as shown in FIG. 6 (d). Become. Here, the IGBT current is shown for a normal one of the IGBTs 18 provided in the inverter circuit 14.

  The self-protection signal P maintains the on level even after the time t1 + τ has elapsed from the time t1. Therefore, the main control unit 22 sets the gate cutoff command signal G to the on level at time t1 + τ as shown in FIG. 6 (c). Since the gate cutoff command signal G is turned on after time t1 + τ, switching control of the inverter circuit 14 is stopped after time t1 + τ. Therefore, as shown in FIG. 6D, the current J flowing through the IGBT 18 of the inverter circuit 14 becomes zero.

  As shown in FIG. 6, when the self-protection signal P output from the signal line 32 to the main control unit 22 is on level for a time longer than the determination time τ, the zero current command signal I is changed from the time t1 to the time t1 + τ. On level during Thereafter, the gate cutoff command signal G is turned on after time t1 + τ. As a result, when an abnormality occurs in the inverter circuit 14 and the current flowing through any of the IGBTs 18 in the inverter circuit 14 exceeds the current threshold, all the IGBTs 18 can be turned off, and the life of the inverter circuit 14 can be reduced. Shortening can be avoided.

  FIG. 7 shows another example of a timing chart of protection control according to the modification. FIG. 7A shows that noise is induced in the signal line 32, and the level is turned on from time t1 to time t2. When the level of the self-protection signal P becomes the on level at time t1, the main control unit 22 sets the zero current command signal I to the on level from time t1 to time t2, as shown in FIG. 7B. . As a result, the current flowing through the IGBT 18 of the inverter circuit 14 becomes 0 between time t1 and time t2, as shown in FIG. 7 (d).

  The self-protection signal P becomes an off level before the determination time τ elapses from the time t1. Therefore, as shown in FIG. 7C, the main control unit 22 sets the zero current command signal I to the off level and maintains the gate cutoff command signal G at the off level after time t2. Thus, after time t2, control according to the control command output from the operation unit 24 is performed. Therefore, as shown in FIG. 7D, the current flowing through the IGBT 18 of the inverter circuit 14 becomes a value corresponding to the control command output by the operation unit 24 after time t2.

  As shown in FIG. 7, when noise is induced in the signal line 32 and the time during which the noise is on level is shorter than the determination time τ, the zero current command signal I is on level from time t1 to time t2. However, after time t2, it becomes an off level. Then, after time t2, the gate cutoff command signal G does not become the on level. Thus, since the electric vehicle is in a normal traveling state after time t2, it is possible to avoid malfunction caused by noise induced in the signal line 32 and affect the operability of the electric vehicle.

  As described above, at least one of the zero torque command signal and the zero current command signal can be employed as the protection control for the inverter circuit 14. Therefore, protection control by these combinations is also possible.

  In the above description, the example in which the current flowing through the IGBT 18 of the inverter circuit 14 is measured by the current sensor 30 and the protection control of the inverter circuit 14 is performed based on the measured current value has been described. As a sensor for detecting an abnormality in the inverter circuit 14, a temperature sensor, a voltage sensor, or the like may be used.

  When using a temperature sensor, the temperature sensor measures the temperature of each IGBT 18 and outputs the measured value to the MG control unit 26. The MG control unit 26 sets the self-protection signal to the on level when there is a temperature measurement value that exceeds a predetermined temperature threshold. On the other hand, when all the temperature measurement values are less than the predetermined temperature threshold, the MG control unit 26 sets the level of the self-protection signal to 0.

  When a voltage sensor is used, the voltage sensor measures a voltage between nodes at which a voltage drop occurs due to the current of the IGBT 18. Then, the measurement value corresponding to each IGBT is output to the MG control unit 26. The MG control unit 26 sets the self-protection signal to the on level when there is a voltage measurement value that exceeds a predetermined voltage threshold. On the other hand, when all the voltage measurement values are less than the predetermined voltage threshold, the MG control unit 26 sets the level of the self-protection signal to 0.

It is a figure showing the composition of the electric vehicle concerning an embodiment. It is a flowchart which shows protection control of an inverter circuit. It is a timing chart of protection control when a self-protection signal is output. It is a timing chart of protection control when noise is induced. It is a flowchart which shows the protection control which concerns on a modification. It is a timing chart of protection control concerning a modification when a self-protection signal is outputted. It is a timing chart of protection control concerning a modification when noise is induced.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Battery, 12 Boost converter circuit, 14 Inverter circuit, 16 Motor generator, 18 IGBT, 20 Diode, 22 Main control unit, 24 Operation part, 26 MG control unit, 28 Torque detection part, 30 Current sensor, 32 Signal line.

Claims (3)

An inverter circuit that converts direct current power into alternating current power and outputs it to the motor generator; converts alternating current power generated by the motor generator into direct current power; and
An inverter control unit for switching control of the inverter circuit;
An abnormality detection unit that outputs a protection signal when an abnormality of the inverter circuit is detected;
A control stop unit for stopping switching control by the inverter control unit;
A vehicle power supply device comprising:
A detection unit for detecting a signal in an output signal path from the abnormality detection unit;
A determination unit that determines whether to perform protection control of the inverter circuit based on a time length of the signal detected by the detection unit;
With
The control stop unit is
A vehicular power supply device that stops switching control of the inverter circuit when the determination unit determines to perform protection control. The vehicle power supply device according to claim 1,
A step-up converter circuit that adjusts the power transferred between the battery and the inverter circuit;
A converter control unit for controlling the boost converter circuit;
With
The converter controller is
The power for a vehicle is characterized in that the boost converter circuit is controlled so that the torque of the motor generator converges to 0 after the determination unit starts processing for determination and until determination is made. Feeding device. The vehicle power supply device according to claim 1,
Provided separately from the control stop unit, and provided with a preliminary control stop unit that stops switching control of the inverter circuit from when the determination unit starts processing for determination until it makes a determination. A vehicular power supply device.

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