JP2010063244A - Device and method of controlling driving of step-up/step-down converter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device and method of driving of a step-up/step-down converter, which sufficiently supplies power to a load and sufficiently collects regeneration power from the load without damaging the step-up/step-down converter when the load requires large power and when large regeneration power is generated. <P>SOLUTION: The controller includes a main control part driving the step-up/step-down converter so that a voltage value of a DC bus between the load and the step-up/step-down converter follows a target voltage value, and a current detection part detecting current flowing in the step-up/step-down converter. The main control part stops driving of the step-up/step-down converter when the current value detected by the current detection part exceeds a first threshold, resumes driving of the step-up/step-down converter when the current value detected by the current detection part drops to a second threshold lower than the first threshold and determines that the step-up/step-down converter fails when the number of times that the current value detected by the current detection part exceeds the first threshold exceeds the predetermined value. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention includes a step-up / down converter drive control device that includes a step-up switching element and a step-down switching element, and performs control of power supply to a load and control of supply of regenerative power obtained from the load to a capacitor, and The present invention relates to a drive control method.

Conventionally, a general buck-boost converter uses a PWM (Pulse Width Modulation) signal so that the voltage value of the DC bus between the load and the buck-boost converter becomes a target value. Driving control of the switching element is performed (for example, see Patent Document 1).
JP 2005-176567 A

  By the way, when the power supplied to the load increases or when the regenerative power from the load increases, an excessive current may flow through the buck-boost converter. Such an excessive current leads to damage to internal elements of the buck-boost converter (for example, a reactor, an IGBT (Insulated Gate Bipolar Transistor), etc.), so that the buck-boost converter is stopped (off) when an overcurrent occurs. Is generally done.

  However, when the load requires a large amount of power or when a large amount of regenerative power is generated, if an overcurrent occurs, the buck-boost converter is stopped, and the power supply to the load can be sufficiently performed. There is a problem that it may not be possible, or there is a possibility that regenerative power from the load cannot be sufficiently collected by the capacitor.

  Therefore, the present invention provides a sufficient power supply to the load and a load from the load without damaging the buck-boost converter when the load requires a large amount of power or when a large amount of regenerative power is generated. It is an object of the present invention to provide a drive control device and drive control method for a buck-boost converter capable of recovering sufficient regenerative power.

  A drive control device for a buck-boost converter according to one aspect of the present invention is a drive control device for a buck-boost converter connected between a capacitor and a load that performs both power running operation and regenerative operation, wherein the load and the load A main controller that drives the buck-boost converter so that a voltage value of a DC bus between the buck-boost converter follows a target voltage value; and a current detector that detects a current flowing through the buck-boost converter; The main control unit stops driving the step-up / down converter when the current value detected by the current detection unit exceeds a first threshold, and the current value detected by the current detection unit is When lowered to a second threshold value lower than one threshold value, the driving of the buck-boost converter is resumed, and when the number of times the current value detected by the current detection unit exceeds the first threshold value is equal to or greater than a predetermined number of times, It determines that an abnormality due to the current is generated.

  The counter further includes a counter for accumulating the number of times that the current value detected by the current detection unit exceeds the first threshold, and the main control unit, when the counter is not incremented over a predetermined time, May be reset.

  A step-up / down converter drive control device according to another aspect of the present invention is a drive control device for a step-up / down converter connected between a capacitor and a load that performs both power running operation and regenerative operation, wherein the load and A main controller that drives the buck-boost converter and a current detector that detects a current flowing through the buck-boost converter so that a voltage value of a DC bus between the buck-boost converter follows a target voltage value The main control unit stops driving the step-up / down converter when the current value detected by the current detection unit exceeds a first threshold, and the current value detected by the current detection unit is The current value detected by the current detection unit after the driving of the buck-boost converter is restarted and the driving of the buck-boost converter is restarted when the second threshold lower than the first threshold is reached. Again it determines the elapsed time until more than the first threshold value is the case where less than or equal to a predetermined time, an abnormality due to overcurrent occurs.

  Further, when the main control unit determines that an abnormality due to the overcurrent has occurred, the main control unit may stop the step-up / down converter and not allow resumption of driving.

  The main control unit may determine that the buck-boost converter is a light abnormality that is lighter than the abnormality when the current value detected by the current detection unit exceeds a first threshold value. .

  A drive control method for a step-up / down converter according to one aspect of the present invention is a drive control method for a step-up / down converter connected between a storage battery and a load that performs both power running operation and regenerative operation, wherein the current detection unit When the current value detected by the first step exceeds the first threshold value, the first step of stopping the driving of the buck-boost converter, and the current value detected by the current detection unit in the first step is lower than the first threshold value. When the voltage drops to a low second threshold, the second step of resuming driving of the step-up / down converter, and when the number of times the current value detected by the current detection unit exceeds the first threshold exceeds a predetermined number, And a third step of determining that an abnormality has occurred in the converter.

  According to the present invention, when the load requires a large amount of power or when a large amount of regenerative power is generated, sufficient power supply to the load and damage from the load can be achieved without damaging the buck-boost converter. A unique effect of providing a drive control device and drive control method for a buck-boost converter capable of recovering sufficient regenerative power can be obtained.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments to which a drive control device and a drive control method for a buck-boost converter according to the present invention are applied will be described.

  FIG. 1 is a diagram schematically showing a circuit configuration of the buck-boost converter according to the present embodiment. This step-up / down converter 10 includes a reactor 11, a boosting IGBT (Insulated Gate Bipolar Transistor) 12A, a step-down IGBT 12B, a power connection terminal 14 for connecting a battery 13 as a capacitor, and an output terminal 16 for connecting a motor 15. , A smoothing capacitor 17 inserted in parallel with the pair of output terminals 16 and a reactor current detection unit 18 as a current detection unit.

  Further, the power supply connection terminal 14 and the output terminal 16 are provided with voltage detection units 14A and 16A for detecting the power supply voltage and the output voltage, respectively, and the DC terminal between the output terminal 16 of the converter 10 and the motor 15 is DC. Connected by bus 19.

  The drive control of the step-up IGBT 12A and the step-down IGBT 12B is performed by the controller 20 as a main control unit. The controller 20 performs drive control of the step-up IGBT 12A and the step-down IGBT 12B based on the power supply voltage and output voltage detected by the voltage detection units 14A and 16A and the current value detected by the reactor current detection unit 18, and DC It is an arithmetic processing unit that executes step-up / step-down control of the voltage value of the bus 19.

  Reactor 11 has one end connected to an intermediate point between boosting IGBT 12A and step-down IGBT 12B, and the other end connected to power supply connection terminal 14, so that induced electromotive force generated when ON / OFF of boosting IGBT 12A is generated. It is provided for supplying to the DC bus 9.

  The step-up IGBT 12 </ b> A and the step-down IGBT 12 </ b> B are semiconductor elements that are composed of bipolar transistors in which a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) is incorporated in a gate portion, and can perform high-power high-speed switching. The step-up IGBT 12A and the step-down IGBT 12B are driven by applying a PWM (Pulse Width Modulation) voltage to the gate terminal from a drive control device for a step-up / down converter described later. Diodes 12a and 12b, which are rectifier elements, are connected in parallel to the step-up IGBT 12A and the step-down IGBT 12B.

  The battery 13 only needs to be a chargeable / dischargeable battery so that power can be exchanged with the DC bus 19 via the buck-boost converter 10. In FIG. 1, the battery 13 is shown as a capacitor. However, instead of the battery 13, a capacitor, a chargeable / dischargeable secondary battery, or another type of power source capable of transferring power may be used as the capacitor. Good.

  The power connection terminal 14 and the output terminal 16 may be terminals that can connect the battery 13 and the motor 15. The voltage detection unit 14A disposed between the pair of power supply connection terminals 14 detects the voltage value (vbat_det) of the battery 13, and the voltage detection unit 16A disposed between the pair of output terminals 16 is The voltage of the DC bus 19 (hereinafter, DC bus voltage: vdc_det) is detected.

  The motor 15 that is a load connected to the output terminal 16 may be an electric motor capable of both power running operation and regenerative operation. For example, the motor 15 is configured by an IPM (Interior Permanent Magnetic) motor in which a magnet is embedded in the rotor. be able to. Although FIG. 1 shows a motor 15 for direct current drive, a motor driven by alternating current through an inverter may be used.

  The smoothing capacitor 17 may be any storage element that is inserted between the pair of output terminals 16 in parallel with the voltage detector 16A and can smooth the output voltage.

  The reactor current detection unit 18 may be any detection means capable of detecting the value of the current flowing through the reactor 11, and includes a current detection resistor. The reactor current detection unit 18 detects a current value (ibat_det) flowing through the battery 13. The detected current value is input to the controller 20. The battery current value (ibat_det) is positive in the direction flowing from the battery 13 to the DC bus 19.

  The controller 20 is an arithmetic processing device including a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and the like, and as described above, the power supply detected by the voltage detection units 14A and 16A. Based on the voltage and the output voltage and the current value detected by the reactor current detection unit 18, drive control of the boosting IGBT 12 </ b> A and the step-down IGBT 12 </ b> B is performed, and step-up / step-down control of the voltage value of the DC bus 19 is performed. In addition to the step-up / step-down control, the controller 20 executes a later-described process shown in FIGS.

"Buck-boost operation"
In such a step-up / step-down converter 10, when boosting the DC bus 19, a PWM voltage is applied to the gate terminal of the boosting IGBT 12A, and the boosting IGBT 12A is connected via the diode 12b connected in parallel to the step-down IGBT 12B. The induced electromotive force generated in the reactor 11 when the power is turned on / off is supplied to the DC bus 19. As a result, a positive current flows through the reactor 11 and the DC bus 19 is boosted.

  When the DC bus 19 is stepped down, a PWM voltage is applied to the gate terminal of the step-down IGBT 12B, and regenerative power generated by the motor 15 is supplied from the DC bus 19 to the battery 13 via the step-down IGBT 12B. . As a result, a negative current flows through the reactor 11, the power stored in the DC bus 19 is charged in the battery 13, and the DC bus 19 is stepped down.

  In the actual power running operation and regenerative operation of the motor 15, electric power necessary for the power running operation is supplied from the DC bus 19 to the motor 15, and electric power obtained by the regenerative operation is supplied from the motor 15 to the DC bus 19. For this reason, although the voltage value of the DC bus 19 fluctuates, the voltage value of the DC bus 19 is kept within a certain range by the step-up / step-down control using the target value of the DC bus voltage value.

  Here, when the motor 15 requires a large amount of power or when a large amount of regenerative power is generated, an excessive current exceeding the rated current may flow through the buck-boost converter 10. Such an overcurrent is particularly likely to occur when the rated current value of the motor 15 is large.

  For this reason, in general, in order to protect the internal elements of the buck-boost converter (for example, a reactor, an IGBT, etc.) from overcurrent, when the overcurrent occurs, the buck-boost converter is stopped (turned off). Has been done.

  However, if the step-up / down converter 10 is stopped, there is a case where sufficient power cannot be supplied to the motor 15 or the regenerative power of the motor 15 cannot be recovered sufficiently.

  By the way, the buck-boost converter 10 does not damage the reactor 11, the IGBTs 12A, 12B, and the like even if an overcurrent is passed in the moment.

  Therefore, in the step-up / down converter drive control device of the present embodiment, when the motor 15 requires a large amount of power or when an overcurrent is generated when a large amount of regenerative power is generated, Stop the pressure converter.

  Then, after stopping for a minute time, the step-up / step-down control of the step-up / down converter 10 is restarted (restarted), and when the current value rises again and becomes overcurrent again, the step-up / down converter is temporarily stopped again. . Further, after this temporary stop, the buck-boost converter 10 is restarted.

  Thus, if the buck-boost converter 10 is temporarily stopped when an overcurrent occurs and restarted after a minute time, an instantaneous overcurrent is allowed. The reactor 11 and the IGBTs 12A and 12B are not damaged by the overcurrent.

  In the drive control device for the buck-boost converter according to the present embodiment, it is possible to supply or recover a large amount of electric power by repeatedly allowing such an instantaneous overcurrent. In the present embodiment, it is determined that the instantaneous overcurrent is a light abnormality, and if it is less than a predetermined number of times, the instantaneous overcurrent is allowed to be supplied or recovered.

  In addition, when the buck-boost converter 10 is repeatedly restarted a predetermined number of times or more, the instantaneous overcurrent is allowed to be repeated a predetermined number of times or more. A large number of times are allowed, and the burden on the buck-boost converter 10 due to overcurrent increases.

  Therefore, in such a case, in order to protect the buck-boost converter 10 from damage, it is determined that a heavy abnormality due to overcurrent has occurred, the buck-boost converter 10 is completely stopped, and restart is not permitted. State.

  From the above, even when an overcurrent occurs when the motor 15 requires a large amount of power or when a large amount of regenerative power is generated, a large amount of power can be supplied without stopping the buck-boost converter 10 completely. When recovery is possible and the burden on the buck-boost converter 10 is increased due to overcurrent, damage to the buck-boost converter 10 can be prevented, so ensuring efficient driving of the motor 15 and securing safety. Can be compatible. Hereinafter, the details will be described with reference to FIGS.

  FIG. 2 is a diagram showing an example of operation showing the drive control processing executed by the drive control device of the buck-boost converter according to the present embodiment together with the operation of the buck-boost converter, and (a) is detected by the reactor current detector 18. (B) is the starting state of the buck-boost converter 10, (c) is the number of retries, and (d) is a diagram showing the alarm state. These are all shown as time change characteristics on the same time axis.

  As shown in FIG. 2A, an overcurrent determination value and a retry start current value are set as the current value detected by the reactor current detection unit 18.

  The overcurrent determination value is a threshold value (first threshold value) for determining whether or not the current flowing through the reactor 11 is an overcurrent. For example, the overcurrent determination value is set to the maximum current value of the step-up / down converter 10. When the current value detected by the reactor current detection unit 18 exceeds the overcurrent determination value, the controller 20 stops the buck-boost converter 10.

  The retry start current value is determined by the controller 20 after the current value detected by the reactor current detection unit 18 exceeds the overcurrent determination value and the controller 20 stops the step-up / down converter 10. It is a threshold value (second threshold value) for determining whether or not to restart the buck-boost control (restart the buck-boost converter 10). After the step-up / down converter 10 is stopped, when the current value detected by the reactor current detection unit 18 decreases to the retry start current value, the step-up / down converter 10 is restarted. The retry start current value as the second threshold is a threshold lower than the overcurrent determination value as the first threshold, and is set to a rated current value, for example.

  The activated state in FIG. 2B indicates whether the buck-boost control of the buck-boost converter 10 is on (ON) or off (OFF). When the current value detected by the reactor current detection unit 18 exceeds the overcurrent determination value, the controller 20 turns off the buck-boost converter 10, and when the current value drops to the retry start current value, the controller 20 restarts the buck-boost converter. Activated and turned on.

  The number of retries in FIG. 2C represents the number of times that the controller 20 has restarted the step-up / step-down control of the step-up / step-down converter 10. The integration of the number of retries is executed by the function of the controller 20 as a counter. Here, the controller 20 determines whether to increment or reset the number of integrations depending on whether the operation time of the buck-boost converter has reached the retry reset time. Specifically, the controller 20 increments the integrated value when the operating time does not reach the retry reset time, and resets the integrated value when the operating time reaches the retry reset time.

  Here, “operation time” refers to the time during which the buck-boost converter 10 is continuously operated. That is, when the buck-boost converter 10 is restarted, it represents the operating time from when it restarts until it stops again.

  In FIG. 2 (c), the current value detected by the reactor current detection unit 18 exceeds the overcurrent determination value, and the buck-boost converter 10 is stopped by the controller 20, and then the reactor current detection unit 18 It is the time from when the detected current value decreases to the retry start current value and the buck-boost converter 10 is restarted until the current value again exceeds the overcurrent determination value and the buck-boost converter 10 is stopped. .

  The “retry reset time” is a threshold value for determining whether or not to reset the integrated value (integrated count) of the number of restarts (retry count) of the controller 20.

  In the drive control device for the buck-boost converter according to the present embodiment, when the number of integration reaches a predetermined number (N times (N is an integer of 2 or more)), it is determined that an abnormality due to overcurrent has occurred, and the controller 20 moves up and down. The pressure converter 10 is completely stopped without allowing the restart thereof.

  This indicates the number of times the operation was restarted without reaching the retry reset time. The large number of accumulations allowed an instantaneous overcurrent in a relatively short time. In order to indicate that the number of times of the operation has been increased, when the number of integration reaches a predetermined number (N times), the burden on the buck-boost converter 10 due to overcurrent is large. For this reason, in order to prevent the buck-boost converter 10 from being damaged, the restart of the buck-boost converter 10 is not permitted but is completely stopped.

  On the other hand, if a restart is performed after the retry time has elapsed, a restart is performed after a relatively long time since the previous restart. Therefore, since the load received by the step-up / down converter 10 is small and the possibility of damage is low, the number of integrations for determining whether to stop completely is reset.

  Therefore, the retry reset time is such that the buck-boost converter 10 is not damaged even if N-1 instantaneous overcurrent flows for a relatively short predetermined time after the retry reset time has elapsed. It is necessary that the time is sufficient for the driving state of the buck-boost converter 10 to recover.

  The alarm state in FIG. 2 (d) indicates whether or not a warning or alarm has been issued. When a warning or alarm has been issued, the alarm flag is set to “1”, and the warning or alarm When none of them are issued, the alarm flag is set to “0”.

  Here, the warning is a warning due to a minor abnormality that is issued by the controller 20 when an overcurrent is detected and the buck-boost converter 10 has been stopped but the number of retries has not reached N times.

  The alarm is an alarm due to a serious abnormality that is issued by the controller 20 when the number of retries of the buck-boost converter 10 reaches N times.

  That is, the warning is treated as a minor abnormality that is less abnormal than the alarm and does not require the buck-boost converter 10 to be completely stopped immediately.

  Note that it is only necessary that the alarm is set to have a higher alerting level than the warning. For example, in the warning, a warning light is lit on the operation panel of the motor 15, and in the alarm, a warning sound is issued in addition to the warning light. Can be configured.

  The controller 20 determines the occurrence of a light abnormality or a heavy abnormality based on the number of retries of the buck-boost converter 10, and sets an alarm flag. The controller 20 sets the warning flag to “1” when a warning or alarm is issued, and sets the warning flag to “0” when neither a warning nor an alarm is issued.

  Here, the operations shown in FIGS. 2A to 2D will be described together.

  When the step-up / step-down converter 10 is turned on at time t = 0 and a boosting operation is performed by the controller 20, the current value in the positive direction is detected by the reactor current detection unit 18.

  When the current value exceeds the overcurrent determination value at time t = t1, the step-up / down converter 10 is turned off by the controller 20 (see FIG. 2B), and the step-up / step-down control is temporarily stopped. When the buck-boost converter 10 is turned off, the boosting IGBT 12A is not driven, so that the current in the positive direction starts to gradually decrease (see FIG. 2A).

  Further, when the current value exceeds the overcurrent determination value at time t = t1 and an overcurrent is detected, the alarm flag shown in FIG. 2D is set to “1”, and a warning is issued by the controller 20. Is done.

  Next, at time t = t2, since the current value detected by the reactor current detection unit 18 decreases to the retry start current value (see FIG. 2A), the controller 20 turns the buck-boost converter 10 on again. (See FIG. 2B). As the step-up / down converter 10 is restarted in this manner, the boosting operation is resumed and power is supplied from the reactor 11 to the DC bus 19, so that the current value detected by the reactor current detection unit 18 increases again. (See FIG. 2A).

  When the buck-boost converter 10 is restarted at time t = t2, the controller 20 increments the counter, and the number of retries becomes “1” (see FIG. 2C).

  When the controller 20 restarts the buck-boost converter 10 at time t = t2, the controller 20 starts measuring the operation time of the buck-boost converter 10.

  Next, at time t = t3, since the current value detected by the reactor current detection unit 18 again exceeds the overcurrent determination value (see FIG. 2A), the controller 20 turns off the step-up / down converter 10 ( As shown in FIG. 2B, the step-up / step-down control is temporarily stopped. When it is turned off, since the voltage boosting operation is not performed, the current value detected by the reactor current detection unit 18 decreases (see FIG. 2A).

  At this time, since the operation time measured by the controller 20 is shorter than the retry reset time (see FIG. 2B), the controller 20 continues the process without resetting the counter. Note that the alarm flag is held at “1”.

  Next, at time t = t4, the current value detected by the reactor current detection unit 18 decreases to the retry start current value, so the controller 20 restarts the step-up / down converter 10 (see FIG. 2B). ). As a result, the boosting operation is resumed, and the current value starts to rise again (see FIG. 2A).

  When the buck-boost converter 10 is restarted at time t = t4, the controller 20 increments the counter, and the retry count becomes “2” (see FIG. 2C).

  Next, at time t = t5, the current value detected by the reactor current detection unit 18 again exceeds the overcurrent determination value, so the controller 20 turns off the step-up / down converter 10 (see FIG. 2B), The step-up / down control is temporarily stopped. When it is turned off, since the voltage boosting operation is not performed, the current value detected by the reactor current detection unit 18 decreases (see FIG. 2A).

  At this time, since the operation time measured by the controller 20 is shorter than the retry reset time (see FIG. 2B), the controller 20 continues the process without resetting the counter. Note that the alarm flag is held at “1”.

  Next, at time t = t6, the current value detected by the reactor current detection unit 18 decreases to the retry start current value, so the controller 20 restarts the step-up / down converter 10 (see FIG. 2B). ). As a result, the boosting operation is resumed, and the current value starts to rise again (see FIG. 2A).

  When the buck-boost converter 10 is restarted at time t = t6, the controller 20 increments the counter, and the number of retries becomes “3” (see FIG. 2C).

  As a result of repeating this state, when the time t = tk (k is an integer of 7 or more), the current value detected by the reactor current detection unit 18 again exceeds the overcurrent determination value. The converter 10 is turned off (see FIG. 2B), and the buck-boost control is temporarily stopped. When it is turned off, since the voltage boosting operation is not performed, the current value detected by the reactor current detection unit 18 decreases (see FIG. 2A).

  At this time, since the operation time measured by the controller 20 is shorter than the retry reset time (see FIG. 2B), the controller 20 continues the process without resetting the counter. Note that the alarm flag is held at “1”.

  Next, at time t = tk + 1, since the current value detected by the reactor current detection unit 18 decreases to the retry start current value, the controller 20 restarts the step-up / down converter 10 (see FIG. 2B). ). As a result, the boosting operation is resumed, and the current value starts to rise again (see FIG. 2A).

  When the buck-boost converter 10 is restarted at time t = tk + 1, the controller 20 increments the counter, and the number of retries becomes “N” (see FIG. 2C).

  Thus, when the number of retries reaches the predetermined number “N”, the controller 20 completely stops the step-up / down converter 10 in order to protect the step-up / down converter 10 from damage. That is, the controller 20 does not allow the buck-boost converter 10 to be restarted even if the current value detected by the reactor current detection unit 18 decreases to the retry start current value.

  At this time, the controller 20 issues an alarm in order to notify that a serious abnormality due to overcurrent has occurred because the number of retries has reached a predetermined number N.

  The operation of the operation example shown in FIG.

  FIG. 3 is a diagram showing another example of operation showing the drive control processing executed by the drive control apparatus for the buck-boost converter according to the present embodiment together with the operation of the buck-boost converter. FIG. (B) is a starting state of the buck-boost converter 10, (c) is the number of retries, and (d) is a diagram showing an alarm state. These are all shown as time change characteristics on the same time axis. FIG. 3 differs from the operation example shown in FIG. 2 in that the number of retries is reset, and is the same as the operation example shown in FIG. 2 until time t = t6. For this reason, description of time t = 0 to t6 is omitted.

  After the time t = t6, the current value detected by the reactor current detector 18 starts to rise again.

  At time t = t7, since the operation time exceeds the retry reset time before reaching the predetermined number of times “N”, the controller 20 resets the counter to set the number of retries to “0”. Accordingly, the controller 20 sets the alarm flag to “0” and cancels the warning.

  At time t = t8, since the current value detected by the reactor current detection unit 18 exceeds the overcurrent determination value, the controller 20 turns off the step-up / down converter 10 (see FIG. 2B). When it is turned off, since the voltage boosting operation is not performed, the current value detected by the reactor current detection unit 18 decreases (see FIG. 2A).

  Next, at time t = t9, since the current value detected by the reactor current detection unit 18 decreases to the retry start current value, the controller 20 restarts the step-up / down converter 10 (see FIG. 2B). ). As a result, the boosting operation is resumed, and the current value starts to rise again (see FIG. 2A).

  When the buck-boost converter 10 is restarted at time t = t9, the controller 20 increments the counter, and the number of retries becomes “1” (see FIG. 2C).

  Thus, the operation shown in FIG. 3 is completed.

  2 and 3, the case where an overcurrent occurs when performing a step-up operation has been described. However, the processing content when an overcurrent occurs when performing a step-down operation is the current value. The processing contents are the same as those in the case where the boosting operation is performed, except that the signs of are different. For this reason, the description about the operation example at the time of step-down operation is omitted.

  FIG. 4 is a diagram illustrating a processing procedure of a drive control process executed by the drive control device for the buck-boost converter according to the present embodiment. This drive control process is a process executed by the controller 20, and generalizes the operation examples shown in FIGS. 2 and 3 and covers other process patterns. Note that the process illustrated in FIG. 4 is a process that is repeatedly executed, for example, every 10 milliseconds. For this reason, N times used as the threshold value of the number of retries can be, for example, several times.

  When starting the drive control process, the controller 20 first turns on the buck-boost converter 10 (step S1). This is to start up / down pressure control.

  Next, the controller 20 starts measurement of the operation time of the buck-boost converter 10 and starts monitoring the current value detected by the reactor current detection unit 18 (step S2). This is because the operation time and the retry reset time are compared, and the detected current value and the overcurrent determination value are compared.

  Furthermore, the controller 20 continues to measure the operation time (step S3).

  Next, the controller 20 determines whether or not the current value detected by the reactor current detection unit 18 exceeds the overcurrent determination value (step S4). This is because it is necessary to immediately stop the buck-boost converter 10 to protect it from damage when an overcurrent occurs.

  When it is determined that the current value has exceeded the overcurrent determination value (Yes in step S4), the controller 20 immediately stops the step-up / down converter 10 (step S5). This step S5 is a process performed as the first step in the drive control method for the buck-boost converter according to the present embodiment, and is executed to prevent the buck-boost converter 10 from being damaged.

  Next, the controller 20 determines whether or not a warning has been issued (step S6). This is to determine whether or not it is necessary to issue a warning in order to notify this state because a warning as a minor abnormality is not issued because an overcurrent has occurred for the first time.

  When it is determined that a warning has been issued (Yes in step S6), the controller 20 determines whether or not the operation time has reached the retry reset time (step S7). This is to determine whether to reset the number of retries.

  When it is determined that the operation time has not reached the retry reset time (Yes in step S7), the controller 20 increments the counter (step S8). As a result, the number of retries is increased by one.

  Next, the controller 20 determines whether or not the number of retries has reached N as a threshold value (step S9). This is because when it reaches N times, it is necessary to completely stop the buck-boost converter 10.

  If the controller 20 determines that the number of retries has not reached N (No in step S9), the controller 20 determines whether or not the current value detected by the reactor current detection unit 18 has decreased to the retry start current value. Determine (step S10). This is because the step-up / down converter 10 is restarted and turned on when the retry start current value is lowered. The restart of the step-up / step-down converter 10 performed in step S1 after step S10 is a process performed as the second step in the drive control method for the step-up / down converter of the present embodiment.

  If the controller 20 determines in step S4 that the current value detected by the reactor current detection unit 18 does not exceed the overcurrent determination value, the controller 20 determines whether or not a warning has been issued (step S11). This is because it is determined whether or not a warning is issued when the current value does not exceed the overcurrent determination value.

  When it is determined that a warning has been issued (Yes in step S11), the controller 20 determines whether or not the operation time has reached the retry reset time (step S12). This is for determining this because it is necessary to cancel the warning when the retry reset time has been reached.

  If the controller 20 determines that the operation time has reached the retry reset time (Yes in step S12), the controller 20 cancels the warning and resets the counter so that the number of retries is zero (step S13).

  When the process of step S13 is completed, the controller 20 returns the flow to step S3.

  On the other hand, if the controller 20 determines in step S6 that no warning has been issued (No), the controller 20 issues a warning (step S14). This is to issue a warning as a minor abnormality when an overcurrent occurs.

  After finishing the process of step S14, the controller 20 advances the flow to step S10.

  On the other hand, if the controller 20 determines in step S7 that the operation time has not reached the retry reset time (No), the controller 20 cancels the warning and resets the counter so that the number of retries is zero (step S15).

  After finishing the process of step S15, the controller 20 advances the flow to step S10.

  On the other hand, if the controller 20 determines in step S9 that the number of retries has reached N (Yes), the controller 20 completely stops the buck-boost converter 10 and issues an alarm (step S16). This is because if the drive control of the buck-boost converter 10 is continued further, the buck-boost converter 10 may be damaged. In addition, this step S16 is a process performed as a 3rd process in the drive control method of the buck-boost converter of this Embodiment.

  When step S16 ends, the controller 20 ends all drive control processes.

  As described above, according to the drive control device for the buck-boost converter according to the present embodiment, when the motor 15 requires a large amount of power or when an excessive current is generated when a large amount of regenerative power is generated. The step-up / down converter 10 is stopped for a minute time to allow an instantaneous overcurrent, and by repeating this, it is possible to supply or recover a large amount of power.

  As a result, the motor 15 can be driven more efficiently as compared with the conventional case where the buck-boost converter 10 is completely turned off only when an overcurrent occurs instantaneously once.

  Further, when the instantaneous overcurrent is repeatedly allowed for a predetermined number of times or more, the buck-boost converter is completely stopped, so that the buck-boost converter can be prevented from being damaged and the drive control can be performed safely.

  In the above, when the number of occurrences of overcurrent (that is, the number of retries) is less than N times, a warning is issued assuming that a minor abnormality has occurred, and when the number of occurrences of overcurrent reaches N times, Although it has been described that the buck-boost converter 10 is completely stopped by determining that an abnormality has occurred and an alarm is issued, a warning is not necessarily required, and the number of occurrences of overcurrent has reached N times. The alarm may be issued as an alarm indicating an abnormality when the number of occurrences of overcurrent has reached N times without issuing an alarm until the alarm is issued.

  In the above description, the mode in which the step-up / step-down converter 10 is completely stopped when the number of retries exceeds the predetermined number N has been described. However, the current value detected by the reactor current detection unit 18 is an excess as the first threshold value. When the current determination value is exceeded, the driving of the step-up / step-down converter is stopped, and when the current value detected by the reactor current detecting unit 18 decreases to a retry start current value that is a second threshold value lower than the first threshold value, When the elapsed time from when the drive of the converter 10 is restarted and the drive of the buck-boost converter 10 is restarted until the current value detected by the reactor current detection unit 18 again exceeds the first threshold is less than or equal to a predetermined time. Alternatively, it may be determined that an abnormality due to overcurrent has occurred. That is, in the above-described embodiment, at the time when the buck-boost converter 10 is stopped when the first minor abnormality occurs, the controller 20 does not permit the restart of the driving of the buck-boost converter 10 if an abnormality occurs. Also good. In this case, the predetermined time can be set according to the performance and rating of the device to which the buck-boost converter 10 is applied.

  In the above embodiment, the DC drive motor 15 is directly connected to the output terminal 16, but instead, an AC drive motor is connected to the output terminal 16 via an inverter. Also good.

  Note that the control unit of the drive control device of the step-up / down converter according to the present embodiment can be realized by either an electronic circuit or an arithmetic processing unit.

  The drive control device and drive control method for the buck-boost converter according to the exemplary embodiment of the present invention have been described above. However, the present invention is not limited to the specifically disclosed embodiment, and is a patent. Various modifications and changes can be made without departing from the scope of the claims.

It is a figure which shows roughly the circuit structure of the buck-boost converter of this Embodiment. It is a figure which shows the operation example which shows the drive control process performed by the drive control apparatus of the buck-boost converter of this Embodiment with the operation | movement of a buck-boost converter, (a) is the electric current value detected by the reactor current detection part 18. (B) is a figure which shows the starting state of the buck-boost converter 10, (c) is the frequency | count of retry, (d) is a figure which shows an alarm state. These are all shown as time change characteristics on the same time axis. It is a figure which shows the other operation example which shows the drive control process performed with the drive control apparatus of the buck-boost converter of this Embodiment with the operation | movement of a buck-boost converter, (a) is detected by the reactor current detection part 18 (B) is a starting state of the buck-boost converter 10, (c) is the number of retries, and (d) is a diagram showing an alarm state. It is a figure which shows the process sequence of the drive control process performed by the drive control apparatus of the buck-boost converter of this Embodiment.

Explanation of symbols

10 Buck-Boost Converter 11 Reactor 12A Boost IGBT
12B IGBT for step-down
DESCRIPTION OF SYMBOLS 13 Battery 14 Power supply connection terminal 14A, 16A Voltage detection part 15 Motor 16 Output terminal 17 Capacitor 18 Reactor current detection part 19 DC bus 20 Controller

Claims (6)

A drive control device for a buck-boost converter connected between a capacitor and a load that performs both power running and regenerative operation,
A main controller that drives the buck-boost converter so that a voltage value of a DC bus between the load and the buck-boost converter follows a target voltage value;
A current detector for detecting a current flowing through the buck-boost converter,
When the current value detected by the current detection unit exceeds a first threshold value, the main control unit stops driving the buck-boost converter, and the current value detected by the current detection unit is greater than the first threshold value. If the current value detected by the current detection unit exceeds the first threshold value more than a predetermined number, an abnormality due to overcurrent occurs. A step-up / down converter drive control device that determines that the operation has been performed. A counter that further accumulates the number of times that the current value detected by the current detector exceeds a first threshold;
2. The drive control device for a step-up / down converter according to claim 1, wherein the main control unit resets an integrated value of the counter when the counter is not incremented for a predetermined time. A drive control device for a buck-boost converter connected between a capacitor and a load that performs both power running and regenerative operation,
A main controller that drives the buck-boost converter so that a voltage value of a DC bus between the load and the buck-boost converter follows a target voltage value;
A current detector for detecting a current flowing through the buck-boost converter,
When the current value detected by the current detection unit exceeds a first threshold value, the main control unit stops driving the buck-boost converter, and the current value detected by the current detection unit is greater than the first threshold value. When the current value detected by the current detection unit exceeds the first threshold again after restarting the driving of the buck-boost converter and restarting the driving of the buck-boost converter. A drive control device for a buck-boost converter that determines that an abnormality due to overcurrent has occurred when an elapsed time is equal to or less than a predetermined time.   4. The buck-boost converter according to claim 1, wherein when the main control unit determines that an abnormality due to the overcurrent has occurred, the main control unit stops the buck-boost converter and does not allow resumption of driving. 5. Drive control device.   The main control unit determines that the buck-boost converter is a light abnormality having a lighter level than the abnormality when a current value detected by the current detection unit exceeds a first threshold value. 4. The drive control device for a buck-boost converter according to any one of 4 above. A drive control method for a buck-boost converter connected between a storage battery and a load that performs both power running operation and regenerative operation,
A first step of stopping driving of the step-up / down converter when a current value detected by the current detection unit exceeds a first threshold;
A second step of resuming driving of the step-up / step-down converter when the current value detected by the current detection unit in the first step decreases to a second threshold value lower than the first threshold value;
A step-up / step-down converter drive control comprising: a third step of determining that an abnormality has occurred in the step-up / down converter when the number of times that the current value detected by the current detection unit exceeds the first threshold exceeds a predetermined number Method.

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