JP4937895B2 - Drive controller for buck-boost converter - Google Patents

Description

  The present invention relates to a drive control device for a step-up / down converter having a step-up switching element and a step-down switching element and performing control of power supply to a load and control of supply of regenerative power obtained from the load to a capacitor. .

Conventionally, in a general buck-boost converter, the duty command for driving the step-up switching element and the step-down switching element by PWM (Pulse Width Modulation) is based on the value of the current flowing through the reactor and the value of the output voltage. It is derived by PI (Proportional Integral) control of the feedback system to be used (for example, see Patent Document 1).
JP 2005-176567 A

  By the way, when the buck-boost converter is feedback-controlled, the current response is delayed with respect to the duty command because the rise of the current is delayed in a region where the current value close to the switching point between the step-up operation and the step-down operation is small. There is.

  Such a delay in the current response appears as a dead zone as shown in FIG. 7 in the current characteristics with respect to the duty command. Since the current value is small in this dead zone region, the voltage step-up operation or the step-down operation is not appropriately performed, and the voltage value of the DC bus between the buck-boost converter and the load tends to fluctuate. For this reason, when the DC bus voltage fluctuates in the dead zone, the voltage supplied from the DC bus to the load such as a motor also fluctuates, which makes it difficult to accurately control the load.

  Further, when performing the step-down operation, if the DC bus voltage rises too much due to a delay in current response, the driver of the load may be damaged by overvoltage. On the other hand, when the boosting operation is performed, if the DC bus voltage decreases too much and becomes equal to the voltage of the capacitor, there is a problem that it is difficult to control the load because current always flows from the capacitor to the load. It was.

  Therefore, an object of the present invention is to provide a drive control device for a buck-boost converter with improved responsiveness in the vicinity of a switching point between a step-up operation and a step-down operation.

  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 control unit that calculates a PWM duty value for driving the step-up / down converter so that a voltage value (hereinafter referred to as a DC bus voltage value) of the DC bus between the step-up and step-down converter follows a target voltage value. A compensation duty value calculation unit for calculating a compensation duty value for compensating the PWM duty value in a predetermined low current region in a current value characteristic with respect to the PWM duty value of the buck-boost converter, and calculation by the main control unit And a summing unit that performs summing processing for summing the compensation duty value with the PWM duty value.

Further, the main control unit is configured to calculate the PWM duty value by PI control based on a deviation between the DC bus voltage value and the target voltage value,
A replacement unit may be further provided that replaces the integral component value included in the PWM duty value with a reciprocal of the proportional component value when starting the summing process.

  In this case, the summing process is performed such that a deviation between the DC bus voltage value and the target voltage value is an absolute value equal to or greater than a predetermined voltage value, and a current value flowing through the buck-boost converter is an absolute value and a predetermined low value. The activation may be started when the current value becomes lower than the current value.

  In addition, the replacement unit, when the start of the summing process, the integral component value included in the PWM duty value, the integral component value included in the PWM duty value immediately before the start of the summing process, and the compensation duty value, It may be replaced with the total value of.

  In this case, the summing process is such that the current value flowing through the buck-boost converter is an absolute value that is equal to or less than a predetermined low current value, and the deviation between the DC bus voltage value and the target voltage value becomes zero. In this case, the activation may be terminated when the sign of the deviation is inverted.

  The compensation duty value calculation unit calculates a duty value corresponding to a PWM duty value at an inflection point on the step-up or step-down side in the current value characteristic with respect to the PWM duty value of the buck-boost converter as the compensation duty value. May be.

  According to the present invention, it is possible to provide a unique effect that it is possible to provide a drive control device for a buck-boost converter with improved responsiveness in the vicinity of the switching point between the step-up operation and the step-down operation.

  Hereinafter, an embodiment to which a drive control device for a buck-boost converter according to the present invention is 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 step-up IGBT (Insulated Gate Bipolar Transistor) 12A, a step-down IGBT 12B, a power supply connection terminal 14 for connecting a battery 13, an output terminal 16 for connecting a motor 15, and a pair of A smoothing capacitor 17 inserted in parallel with the output terminal 16 and a reactor current detector 18 are provided. The output terminal 16 of the converter 10 and the motor 15 are connected by a DC 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, and the 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 step-up / down 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 power 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. The voltage detection unit 14A detects the voltage value (vbat_det) of the battery 13, and the voltage detection unit 16A detects the voltage of the DC bus 19 (hereinafter, DC bus voltage: vdc_det).

  The motor 15 that is a load connected to the output terminal 16 may be an electric motor capable of power running operation and regenerative operation. For example, the motor 15 may be configured by an IPM (Interior Permanent Magnetic) motor in which a magnet is embedded in the rotor. it can. 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 positive terminal and the negative terminal of the output terminal 16 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.

"Buck-boost operation"
In such a step-up / 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. Inductive electromotive force generated in the reactor 11 when the power is turned on / off is supplied to the DC bus 19. Thereby, 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, the power stored in the DC bus 19 is charged in the battery 13 and the DC bus 19 is stepped down.

  By the way, in the power running operation and the regenerative operation of the motor 15, the electric power necessary for the power running operation is supplied from the DC bus 19 to the motor 15, and the electric power obtained by the regenerative operation is supplied from the motor 15 to the DC bus 19. The voltage value of the DC bus 19 varies.

  However, according to the step-up / down converter drive control device of the present embodiment, the current response near the switching point between the step-up operation and the step-down operation is improved by the control method described below, whereby the voltage of the DC bus 19 is increased. Keep the value within a certain range.

  FIG. 2 is a control block diagram showing a circuit configuration of the drive control device for the buck-boost converter according to the present embodiment. As shown in this figure, the drive control unit 20 of the buck-boost converter according to the present embodiment includes a voltage control command generation unit 21, a voltage control unit 22, a PWM command calculation unit 23, a PWM command summation unit 24, and a buck-boost switching control. Part 25, compensation value calculation part 26, and compensation value switching part 27.

  Among these, the voltage control command generation unit 21, the voltage control unit 22, the PWM command calculation unit 23, the PWM command summation unit 24, and the step-up / step-down switching control unit 25 have a DC bus voltage value (vdc_det) and a DC bus target voltage value. A feedback loop for generating a drive command for driving the buck-boost converter 10 by PI control based on a deviation from (vdc_ref) is formed. This feedback loop functions as a main control unit for generating a drive command.

  Further, the PWM command summing unit 24, the compensation value calculating unit 26, and the compensation value switching unit 27 use a DC bus voltage value (vdc_det), a battery voltage value (vbat_det), and a battery current value (ibat_det) to generate a buck-boost converter. A compensation value for compensating the ten drive commands is calculated, and a feedforward loop for adding the compensation value to the drive command is formed.

  The battery current value (ibat_det) is positive in the direction flowing from the battery 13 to the DC bus 19.

"Description of each part"
The voltage control command generator 21 outputs a DC bus target voltage value (vdc_ref) that is a target voltage of the DC bus 19. Since the DC bus voltage before starting the driving of the motor 15 is 0 (V), the DC bus target voltage value (vdc_ref) gradually increases from 0 (V) when the driving of the motor 15 is started. Is set to be held at a constant value when the DC bus voltage exceeds a predetermined value. The DC bus target voltage value (vdc_ref) is input to the voltage control unit 22 and the compensation value switching unit 27.

  The voltage control unit 22 performs PI control so as to approach the DC bus voltage value (vdc_det) and the DC bus target voltage value (vdc_ref) (that is, to reduce this deviation), and a voltage control command ( datl). The generated voltage control command (datl) is input to the PWM command calculation unit 23.

  The PWM command calculation unit 23 performs a calculation process for converting the voltage control command (datl) into a PWM voltage command value (pwm_v) representing a duty value necessary for PWM control. The calculated PWM voltage command value (pwm_v) is input to the PWM command summation unit 24.

  The PWM command summation unit 24 receives the PWM voltage command value (pwm_v) input from the PWM command calculation unit 23 and the compensation duty value (pwm_duty) input from the compensation value calculation unit 26 from the compensation value switching unit 27. Is added according to the value of the flag (duty.flg), and a summing process for outputting the summed duty value (pwm_sum) is performed (function as summing unit). In this summation process, the method of summing the PWM voltage command value (pwm_v) and the compensation duty value (pwm_duty) is changed according to the value of the flag (duty.flg) by the dead band compensation function of the PWM command summation unit 24. The The summing process by the dead band compensation function will be described later.

  The summed duty value (pwm_sum) output from the PWM command summing unit 24 is a control amount (%) before being converted into a PWM duty value.

  The step-up / step-down switching control unit 25 converts the total duty value (pwm_sum) into a duty command value (pwm_ref) that is a PWM duty value. This duty command value (pwm_ref) is a value (%) representing a PWM duty for driving the step-up IGBT 12A and the step-down IGBT 12B of the buck-boost converter 10.

  Here, in the duty command value (pwm_ref), a positive sign is added to the boosting value, and a negative sign is added to the boosting value to distinguish the step-up / step-down values. Therefore, when the duty command value (pwm_ref) is a positive value, the step-up / step-down switching control unit 25 sends the duty command value (pwm_ref) to the boosting IGBT 12A, and the duty command value (pwm_ref) is a negative value. If there is, the duty command value (pwm_ref) is sent to the step-down IGBT 12B.

  The compensation value calculation unit 26 performs a summing process by a dead band compensation function for compensating the PWM voltage command value (pwm_v) based on the DC bus voltage value (vdc_det), the battery voltage value (vbat_det), and the battery current value (ibat_det). Compensation duty value (pwm_duty) required for. This compensation duty value (pwm_duty) is a control amount corresponding to a PWM duty value representing an inflection point on the step-up or step-down side in the current characteristic (see FIG. 7) with respect to the PWM duty of the buck-boost converter 10. The control amount corresponding to the PWM duty value representing the inflection point is given by the ratio of the battery voltage value (vbat_det) to the DC bus voltage value (vdc_det) (vbat_det) / (vdc_det). The value is given by {1- (vbat_det) / (vdc_det)}. The compensation value calculation unit 26 calculates a control amount representing a ratio (vbat_det) / (vdc_det) of the battery voltage value (vbat_det) to the DC bus voltage value (vdc_det) as a compensation duty value (pwm_duty), and a compensation value switching unit 27 To enter.

  The compensation value switching unit 27 derives a flag (duty.flg) based on the DC bus target voltage value (vdc_ref), the DC bus voltage value (vdc_det), and the battery current value (ibat_det), and this flag (duty.flg ) And the compensation duty value (pwm_duty) are input to the PWM command summation unit 24. The flag (duty.flg) takes a value of “−1”, “0”, or “+1”. This flag (duty.flg) is used for summing processing by a dead band compensation function described later.

  FIG. 3 is a diagram illustrating a relationship between a flag (duty.flg) derived by the compensation value switching unit 27 of the drive control device for the buck-boost converter according to the present embodiment and the drive region of the buck-boost converter 10.

  In FIG. 3, the horizontal axis represents the battery current value (ibat_det), and the vertical axis represents the DC bus voltage deviation {DC bus target voltage value (vdc_ref) −DC bus voltage value (vdc_det)}.

  Here, since the battery current value (ibat_det) is positive in the direction of flowing from the battery 13 to the DC bus 19, the region where the horizontal axis is positive boosts the DC bus 19 (power is supplied from the reactor 11 to the DC bus 19). Supply) area. When this operation is continued, the electric power stored in the battery 13 is supplied to the DC bus 19 (discharge from the battery 13 to the DC bus 19 is performed). On the other hand, the region where the horizontal axis is negative is a region where the DC bus 19 is stepped down (the battery 13 is charged).

  Further, since the DC bus voltage deviation on the vertical axis is expressed by {DC bus target voltage value (vdc_ref) −DC bus voltage value (vdc_det)}, the region where the vertical axis is positive indicates the DC bus target voltage value (vdc_ref). ) Is lower than the DC bus voltage value (vdc_det), and the voltage of the DC bus 19 drops. In this region, the DC bus voltage value (vdc_det) decreases due to fluctuations in the load of the motor or the like, so that the buck-boost converter 10 performs control for boosting the DC bus voltage value (vdc_det). As a result, the battery 13 is discharged to the DC bus 19. On the other hand, the region where the vertical axis is negative is a region where the DC bus voltage value (vdc_det) is higher than the DC bus target voltage value (vdc_ref) and the voltage of the DC bus 19 is rising. In this region, the DC bus voltage value (vdc_det) increases due to fluctuations in the load of the motor or the like. Therefore, the buck-boost converter 10 is used to charge the battery 13 in order to decrease the DC bus voltage value (vdc_det). Take control.

  On the horizontal axis, two threshold values of -bat_I and + bat_I are set with the central battery current value (ibat_det) = 0 interposed therebetween. As a result, the drive region of the buck-boost converter 10 is -bat_I ≦ battery current value (ibat_det), -bat_I <battery current value (ibat_det) <+ bat_I, according to the battery current value (ibat_det) in the horizontal axis direction. It is divided into three areas: + bat_I ≦ battery current value (ibat_det). Note that between -bat_I and + bat_I, which are predetermined thresholds, is a minute region of a current value in which a dead zone region (see FIG. 7) is generated in the conventional buck-boost converter.

  In addition, three predetermined threshold values of DC bus voltage deviation {DC bus target voltage value (vdc_ref) −DC bus voltage value (vdc_det)} = − dc_V, 0, + dc_V are set on the vertical axis. . As a result, the drive region of the step-up / down converter 10 corresponds to the DC bus voltage deviation in the vertical axis direction, DC bus voltage deviation ≦ −dc_V, −dc_V <DC bus voltage deviation <0, 0 ≦ DC bus voltage deviation < It is divided into four areas: + dc_V, + dc_V ≦ DC bus voltage deviation.

  Here, the predetermined threshold value on the vertical axis is determined in accordance with the control accuracy based on the characteristics of the DC bus 19. When the threshold value + dc_V is increased, it becomes difficult to switch, and the DC bus 19 becomes overvoltage. On the other hand, if the threshold value + dc_V is reduced, switching is frequently performed, current compensation becomes excessive, and as a result, a loss of current flowing through the DC bus 19 increases. The same applies to the absolute value of the threshold value -dc_V.

  By setting the threshold values on the horizontal axis and the vertical axis in this way, the drive region of the buck-boost converter 10 is divided into 12 regions (1) to (12) arranged in a matrix as shown in FIG. Is done. When the buck-boost converter 10 is driven, the battery current value (ibat_det) and the DC bus voltage deviation {DC bus target voltage value (vdc_ref) −DC bus voltage value (vdc_det)} fluctuate. Transition in 12). Thereby, it is possible not only to easily switch to a different processing form, but also to quickly activate the dead zone compensation function.

  As described above, the flag (duty.flg) is a flag used for summing processing by the dead band compensation function described later, and that the flag (duty.flg) is “+1” means that the dead band compensation is performed during the boost operation. The function is in the activated state, and the flag (duty.flg) being “−1” indicates that the dead band compensation function is in the activated state during the step-down operation. The flag (duty.flg) being “0” indicates that the dead band compensation function is in a released state. The dead zone function is activated when it is activated and is deactivated when it is activated.

“Description of Drive Regions (1) to (12)”
Region (1) is a drive region of “battery current value (ibat_det) ≦ −bat_I and + dc_V ≦ DC bus voltage deviation”. Even if the drive region transitions to the region (1), the flag can be used as it is because it is a region away from the charge / discharge switching, that is, a region away from the current dead zone of the DC bus 19. Specifically, the flag (duty.flg) is set to the same value as the previous flag (duty.flg) before the transition (duty.flg = previous duty.flg).

  Region (2) is a drive region of “−bat_I <battery current value (ibat_det) <+ bat_I and + dc_V ≦ DC bus voltage deviation”. When the drive region transitions to the region (2), the flag (duty.flg) is set to “+1” (duty.flg = + 1). Here, when the transition is made to the region (2), the flag (duty.flg) is set to “+1” because the battery current value (ibat_det) is an absolute value smaller than the threshold value during the boosting operation, and When the DC bus voltage deviation is equal to or greater than the threshold value (+ dc_V), the DC bus voltage value (vdc_det) is relatively low and the DC bus 19 needs to be boosted, but the current does not flow sufficiently. This is to promote the boosting operation by starting the dead zone compensation function and increasing the battery current value (ibat_det) because it is in the state. Here, when the flag (duty.flg) is switched to “+1”, for example, the DC bus voltage deviation increases from the state where the flag (duty.flg) is “0” in the region (5) and exceeds + dc_V. Is executed when the area (2) is reached. As a result, when charge / discharge control based on the DC bus voltage deviation is performed, an operation for compensating a PWM voltage command value (pwm_v), which will be described later, is started in order to force a current to flow in the dead zone of the DC bus 19.

  Region (3) is a drive region of “+ bat_I ≦ battery current value (ibat_det) and + dc_V ≦ DC bus voltage deviation”. When the drive area changes to area (3), set the flag (duty.flg) to the same value as the previous (previous) flag (duty.flg) (duty.flg = previous duty.flg) ).

  Region (4) is a drive region of “battery current value (ibat_det) ≦ −bat_I and 0 ≦ DC bus voltage deviation <+ dc_V”. When the drive area changes to area (4), set the flag (duty.flg) to the same value as the previous (previous) flag (duty.flg) (duty.flg = previous duty.flg) ).

  Region (5) is a drive region of “-bat_I <battery current value (ibat_det) <+ bat_I and 0 ≦ DC bus voltage deviation <+ dc_V”. That is, the DC bus voltage deviation is small, and the battery current value (ibat_det) also corresponds to a transition region in which charging / discharging is switched. When the driving region transitions to the region (5) and the (previous) flag (duty.flg) before the transition is “−1” or “0”, the (current) flag (duty.flg) is set. If it is set to “0” and the (previous) flag (duty.flg) before transition is “+1”, the (current) flag (duty.flg) is changed to the (previous) flag (duty.flg). Set to the same value “+1”.

  Here, in the case of transition to the region (5), when the (previous) flag (duty.flg) before the transition is “−1”, the (current) flag (duty.flg) is set to “0”. The flag (duty.flg) is “−1” and the dead band compensation function is activated during the step-down operation, so that the battery current value (ibat_det) is an absolute value smaller than the threshold, and When the DC bus voltage deviation is less than the threshold (+ dc_V) (region (5)), the DC bus voltage value (vdc_det) is sufficiently stepped down by the dead band compensation function during the step-down operation before the transition. This is because it is considered unnecessary to increase the battery current value (ibat_det) by the dead zone compensation function after the transition to the region (5). Thereby, in the charge / discharge control based on the DC bus voltage deviation, an operation for compensating a PWM voltage command value (pwm_v) described later is released.

  Region (6) is a drive region of “+ bat_I ≦ battery current value (ibat_det) and 0 ≦ DC bus voltage deviation <+ dc_V”. When the drive region transitions to region (6), set the flag (duty.flg) to the same value as the previous (previous) flag (duty.flg) (duty.flg = previous duty.flg) ).

  Region (7) is a drive region where “battery current value (ibat_det) ≦ −bat_I and −dc_V <DC bus voltage deviation <0”. When the drive area changes to area (7), set the flag (duty.flg) to the same value as the previous (previous) flag (duty.flg) (duty.flg = previous duty.flg) ).

  Region (8) is a drive region where “−bat_I <battery current value (ibat_det) <+ bat_I and −dc_V <DC bus voltage deviation <0”. When the driving region transitions to the region (8) and the (previous) flag (duty.flg) before the transition is “−1”, the (current) flag (duty.flg) is set to (previous). Set to the same value “−1” as the flag (duty.flg), and the (previous) flag (duty.flg) before the transition is “0” or “+1”, the (current) flag (duty .flg) is set to “0”.

  Here, in the case of transition to the region (8), when the (previous) flag (duty.flg) before the transition is “+1”, the (current) flag (duty.flg) is set to “0”. This is because when the flag (duty.flg) is “+1” and the dead band compensation function is activated during boost operation, the battery current value (ibat_det) is an absolute value smaller than the threshold value and the DC bus When the voltage deviation is higher than the threshold (−dc_V) (region (8)), the DC bus voltage value (vdc_det) is sufficiently boosted by the dead band compensation function during the boosting operation before the transition, This is because it is considered that an increase in the battery current value (ibat_det) by the dead zone compensation function is unnecessary after the transition to the region (8). Thereby, in the charge / discharge control based on the DC bus voltage deviation, an operation for compensating a PWM voltage command value (pwm_v) described later is released.

  Region (9) is a drive region where “+ bat_I ≦ battery current value (ibat_det) and −dc_V <DC bus voltage deviation <0”. When the drive region transitions to region (9), set the flag (duty.flg) to the same value as the previous (previous) flag (duty.flg) (duty.flg = previous duty.flg) ).

  Region (10) is a drive region of “battery current value (ibat_det) ≦ −bat_I and DC bus voltage deviation ≦ −dc_V”. When the drive area transitions to the area (10), set the flag (duty.flg) to the same value as the previous (previous) flag (duty.flg) (duty.flg = previous duty.flg) ).

  The region (11) is a drive region of “−bat_I <battery current value (ibat_det) <+ bat_I and DC bus voltage deviation ≦ −dc_V”. When the drive region transitions to the region (11), the flag (duty.flg) is set to “−1” (duty.flg = + 1). Here, when transitioning to the region (11), the flag (duty.flg) is set to “−1” because the battery current value (ibat_det) is an absolute value smaller than the threshold value during the step-down operation, and When the DC bus voltage deviation is equal to or less than the threshold (−dc_V), the DC bus voltage value (vdc_det) is relatively increased and the DC bus 19 needs to be stepped down. Since the current is not sufficiently flowing to the battery 13, the battery current value (ibat_det) represented by a negative value as the current flowing from the DC bus 19 toward the battery 13 is started by starting the dead zone compensation function. This is because the step-down operation is promoted by increasing the absolute value of.

  Region (12) is a drive region of “+ bat_I ≦ battery current value (ibat_det) and DC bus voltage deviation ≦ −dc_V”. When the drive area transitions to the area (12), the flag (duty.flg) is set to the same value as the previous (previous) flag (duty.flg) (duty.flg = previous duty.flg) ).

  Here, when the buck-boost converter 10 is activated, “battery current value (ibat_det) = 0 and DC bus voltage deviation {DC bus target voltage value (vdc_ref) −DC bus voltage value (vdc_det)} = 0”. This driving state is included in the region (5). For this reason, when the buck-boost converter 10 is started, the drive region shown in FIG. 3 starts from the region (5), and the battery current value (ibat_det) and the DC bus voltage deviation {DC bus target voltage value (vdc_ref) −DC bus voltage It changes to another area by changing the value (vdc_det)}.

  Therefore, the dead zone compensation function is started when the flag (duty.flg) is changed from “0” to the drive region (2) and the flag (duty.flg) is changed to “+1”. Or the flag (duty.flg) changes from “0” to the drive region (11) and the flag (duty.flg) changes to “−1”. In other words, the dead band compensation function is started when the DC bus voltage deviation is an absolute value greater than or equal to the predetermined voltage value (dc_V) and the battery current value (ibat_det) is smaller than the predetermined low current value (bat_I). The

In addition, the dead zone compensation function is activated and terminated when the flag (duty.flg) changes from “−1” to the drive region (5) and the flag (duty.flg) changes to “0”. Or the flag (duty.flg) changes from “+1” to the drive region (8) and the flag (duty.flg) changes to “0”. In other words, the dead band compensation function is the case where the battery current value (ibat_det) is absolute and less than a predetermined low current value (bat_I) and the DC bus voltage deviation becomes zero, or the sign of the DC bus voltage deviation is If it is reversed, the startup will be terminated.
In other cases, if the flag (duty.flg) remains “0” even if the drive region transitions, the dead zone compensation function is held in the released state, and the flag (duty.flg. When flg) remains “−1” or “+1”, the dead zone compensation function is maintained in the activated state.

  As described above, the region where the horizontal axis is negative is a region where the DC bus 19 is stepped down (charging the battery 13), and the region where the vertical axis is positive is a region where the voltage of the DC bus 19 is decreasing. Therefore, the region (1) and the region (4) are drive regions that are not normally passed.

  Similarly, the region where the horizontal axis is positive is a region where the DC bus 19 is boosted (power is supplied from the reactor 11 to the DC bus 19), and the region where the vertical axis is negative is where the voltage of the DC bus 19 is rising. Since these are areas, the areas (9) and (12) are drive areas that do not normally pass through.

"Summarization with dead band compensation function"
Next, the processing content of the PWM command summation unit 24 (summation processing by the dead band compensation function) will be described. Here, the dead zone compensation function is activated when the flag (duty.flg) is “−1” or “+1”, and is deactivated when the flag (duty.flg) is “0”.

  The PWM command summation unit 24 switches the summing method as follows according to the value of the flag (duty.flg).

  When the flag (duty.flg) is “0”, the compensation duty value (pwm_duty) is not summed (summing the compensation duty value (pwm_duty) as zero), and the PWM duty command value (pwm_sum) as the summed duty value (pwm_sum) pwm_v) is output. That is, the total duty value (pwm_sum) = PWM voltage command value (pwm_v).

  When the flag (duty.flg) is “1”, the compensation duty value (pwm_duty) is added to the PWM voltage command value (pwm_v). That is, the total duty value (pwm_sum) = PWM voltage command value (pwm_v) + compensation duty value (pwm_duty).

  When the flag (duty.flg) is “−1”, the compensation duty value (pwm_duty) with the sign inverted is added to the PWM voltage command value (pwm_v). That is, the total duty value (pwm_sum) = PWM voltage command value (pwm_v) −compensation duty value (pwm_duty).

  Thus, the compensation duty value (pwm_duty) is added up when the flag (duty.flg) is “1” or “−1”.

  Further, the PWM command summation unit 24 sets the inflection point when the flag (duty.flg) changes from “0” to “1” or “−1” (when the dead band compensation function is started). A control amount corresponding to the represented PWM duty value is added as a compensation duty value (pwm_duty). Then, with respect to the integral component value (I component value) and the proportional component value (P component value) included in the PWM voltage command value (pwm_v) output from the PWM command calculation unit 23, the integral component value (I component value). Is replaced with the inverse of the proportional component value (P component value). As a result, the value of the PWM voltage command value (pwm_v) becomes zero (function as a replacement unit).

  Conversely, the PWM command summing unit 24 changes the flag (duty.flg) from “1” or “−1” to “0” (when the dead zone compensation function is activated). Compensates the value of the integral component value (I component value) included in the PWM voltage command value (pwm_v) output from the PWM command calculation unit 23 with the integral component value (I component value) immediately before the start of the dead band compensation function. Replace with the total value with the duty value (pwm_duty) (function as a replacement unit).

  Next, the summing process by the dead zone compensation function as described above will be described with reference to FIGS.

"Total processing by dead band compensation function during step-down"
FIG. 4 is a principle diagram for explaining the summing process by the dead band compensation function at the time of step-down in the drive control device of the buck-boost converter 10 of the present embodiment, and (a) is the process at the start of the start of the dead band compensation function. , (B) shows processing at the end of activation of the dead zone compensation function, and (c) shows processing during activation of the dead zone compensation function over time. The summing process by the dead band compensation function is executed by the PWM command summing unit 24.

  In the figure, P and I shown in the bar graph of the PWM voltage command value (pwm_v) represent the ratio between the proportional component value (P component value) and the integral component value (I component value).

  Here, the dead zone compensation function is started at the time of step-down when the flag (duty.flg) is changed from “0” to the drive region (11) and the flag (duty.flg) is “−1”. It is a case where it changes to. The dead zone compensation function is activated and terminated when the flag (duty.flg) changes from “−1” to the drive region (5) and the flag (duty.flg) changes to “0”. This is the case.

  As shown in FIG. 4A, before the start of the dead zone compensation function (when flag (duty.flg) = “0”), the compensation duty value (pwm_duty) input from the compensation value switching unit 27 is zero. Therefore, the total duty value (pwm_sum) = PWM voltage command value (pwm_v).

  Next, when the driving region transitions to the region (11), the flag (duty.flg) changes to “−1” and the dead zone compensation function starts to be activated, the compensation duty value (pwm_duty) is set to the PWM voltage command. It is added to the value (pwm_v), and the total duty value (pwm_sum) = PWM voltage command value (pwm_v) + compensation duty value (pwm_duty).

  At this time, as shown in FIG. 4A, the proportional component value (P component value) included in the PWM voltage command value (pwm_v) has the same value before and after starting the dead band compensation function. The integral component value (I component value) immediately after the start of function activation is replaced by the inverse of the proportional component value (P component value). Thus, immediately after the start of the dead zone compensation function, the value of the PWM voltage command value (pwm_v) is set to zero.

  Therefore, in practice, the total duty value (pwm_sum) = compensation duty value (pwm_duty).

  Here, the value of the compensation duty value (pwm_duty) is a control corresponding to the PWM duty value representing the inflection point on the step-down side in the characteristic of the current value with respect to the PWM duty value of the buck-boost converter 10. Amount. Thereafter, based on the sum of the compensation duty value (pwm_duty) and the PWM duty value, a duty command value (pwm_ref) is obtained, and charge / discharge control is performed.

  Therefore, according to the drive control device for the buck-boost converter of the present embodiment, the absolute value of the battery current value (ibat_det) of the buck-boost converter 10 is less than a predetermined value, and the DC bus voltage deviation is an absolute value and a predetermined value. When it is determined that sufficient battery current value (ibat_det) cannot be obtained when the DC bus voltage value (vdc_det) rises and step-down operation is necessary, start up the dead band compensation function. Since the PWM command summing unit 24 sums the compensation duty value (pwm_duty) to the PWM voltage command value (pwm_v), the summed duty value (pwm_sum) is increased by an absolute value as shown in FIG. As a result, the final duty command value (pwm_ref) for driving the buck-boost converter 10 is increased in absolute value. For this reason, the current flowing from the DC bus 19 toward the battery 13 is increased, and the current response does not delay with respect to the PWM duty in the low current region as in the prior art, and the current response is good and the DC bus 19 Thus, it is possible to provide a drive control device for the buck-boost converter 10 that can maintain the voltage value within a certain range.

  Next, the operation when the dead zone compensation function at the time of step-down is completed will be described with reference to FIG. In the start-up state of the dead band compensation function (when flag (duty.flg) = “− 1”), the compensation duty value (pwm_duty) input from the compensation value switching unit 27 is summed, so the summed duty value (pwm_sum) ) = PWM voltage command value (pwm_v) + compensation duty value (pwm_duty).

  Next, when the flag (duty.flg) is changed to “0” and the dead zone compensation function is activated, the compensation duty value (pwm_duty) is set to zero and the total duty value (pwm_sum) = PWM voltage command value (pwm_v ).

  At this time, as shown in FIG. 4B, the proportional component value (P component value) included in the PWM voltage command value (pwm_v) has the same value before and after starting the dead band compensation function. The integral component value (I component value) immediately after the activation of the function is replaced with the total value of the integral component value (I component value) and the compensation duty value (pwm_duty) immediately before the activation of the dead band compensation function.

  Therefore, before and after the start of the dead band compensation function, the sum of duty values (pwm_sum) is the same and the continuity is maintained. Therefore, the controllability of the buck-boost converter 10 is reduced even after the dead band compensation function is finished. Can be suppressed.

  After the dead band compensation function has been activated, the flag (duty.flg) becomes “0” and the compensation duty value (pwm_duty) is not added to the total duty value (pwm_sum), and the total duty value (pwm_sum) = PWM Since the voltage command value (pwm_v) is obtained, the buck-boost converter 10 is driven by the PWM voltage command value (pwm_v) generated by the PI control in the PWM command calculation unit 23.

"Total processing by dead band compensation function during boosting"
FIG. 5 is a principle diagram for explaining the summing process by the dead zone compensation function at the time of boosting in the drive control device of the buck-boost converter 10 of the present embodiment, and (a) is the process at the start of the dead zone compensation function start. , (B) shows processing at the end of activation of the dead zone compensation function, and (c) shows processing during activation of the dead zone compensation function over time. The summing process by the dead zone compensation function at the time of boosting is executed by the PWM command summing unit 24 in the same manner as the process at the time of stepping down. In the figure, P and I shown in the bar graph of the PWM voltage command value (pwm_v) represent the ratio between the proportional component value (P component value) and the integral component value (I component value).

  Here, the dead zone compensation function is started at the time of boosting because the driving region transitions to the region (2) from the state where the flag (duty.flg) is “0” due to the fluctuation of the DC bus voltage deviation. duty.flg) changes to “+1”. In addition, the dead zone compensation function is activated and terminated when the flag (duty.flg) changes from “+1” to the drive region (8) and the flag (duty.flg) changes to “0”. This is the case.

  As shown in FIG. 5A, before the start of the dead zone compensation function (when flag (duty.flg) = “0”), the compensation duty value (pwm_duty) input from the compensation value switching unit 27 is zero. Therefore, the total duty value (pwm_sum) = PWM voltage command value (pwm_v).

  Next, when the driving region transitions to the region (2), the flag (duty.flg) changes to “+1” and the dead zone compensation function starts to be activated, the compensation duty value (pwm_duty) is changed to the PWM voltage command value. (pwm_v) is summed, and the total duty value (pwm_sum) = PWM voltage command value (pwm_v) + compensation duty value (pwm_duty).

  At this time, as shown in FIG. 5A, the proportional component value (P component value) included in the PWM voltage command value (pwm_v) has the same value before and after starting the dead band compensation function. The integral component value (I component value) immediately after the start of function activation is replaced by the inverse of the proportional component value (P component value). As a result, the value of the PWM voltage command value (pwm_v) becomes zero immediately after the start of the dead zone compensation function.

  Therefore, in practice, the total duty value (pwm_sum) = compensation duty value (pwm_duty).

  Here, the value of the compensation duty value (pwm_duty) is the control corresponding to the PWM duty value representing the inflection point on the boost side in the characteristic of the current value with respect to the PWM duty value of the buck-boost converter 10. Amount.

  Therefore, according to the drive control device for the buck-boost converter of the present embodiment, the absolute value of the battery current value (ibat_det) of the buck-boost converter 10 is less than a predetermined value, and the DC bus voltage deviation is an absolute value and a predetermined value. When it is determined that sufficient battery current value (ibat_det) cannot be obtained when the DC bus voltage value (vdc_det) decreases and boosting operation is required, start up the dead band compensation function. Since the PWM command summing unit 24 sums the compensation duty value (pwm_duty) to the PWM voltage command value (pwm_v), the summed duty value (pwm_sum) is increased as an absolute value as shown in FIG. As a result, the final duty command value (pwm_ref) for driving the buck-boost converter 10 is increased in absolute value. For this reason, the current flowing from the battery 13 in the direction of the DC bus 19 is increased, and the current response is not delayed with respect to the PWM duty in the low current region as in the conventional case, and the buck-boost converter has a good current response. Ten drive control devices can be provided.

  Next, the operation when the dead zone compensation function at the time of boosting is started will be described with reference to FIG. In the start-up state of the dead band compensation function (when flag (duty.flg) = “+ 1”), since the compensation duty value (pwm_duty) input from the compensation value switching unit 27 is summed, the summed duty value (pwm_sum) = PWM voltage command value (pwm_v) + compensation duty value (pwm_duty).

  Next, when the flag (duty.flg) changes to “0” and the dead zone compensation function is started and finished, the compensation duty value (pwm_duty) is set to zero and the total duty value (pwm_sum) = PWM voltage command value (pwm_v ).

  At this time, as shown in FIG. 5B, the proportional component value (P component value) included in the PWM voltage command value (pwm_v) has the same value before and after the start of the dead band compensation function. The integral component value (I component value) immediately after the activation of the function is replaced with the total value of the integral component value (I component value) and the compensation duty value (pwm_duty) immediately before the activation of the dead band compensation function.

  Therefore, before and after the start of the dead band compensation function, the sum of duty values (pwm_sum) is the same and the continuity is maintained. Therefore, the controllability of the buck-boost converter 10 is reduced even after the dead band compensation function is finished. Can be suppressed.

  After the dead band compensation function has been activated, the flag (duty.flg) becomes “0” and the compensation duty value (pwm_duty) is not added to the total duty value (pwm_sum), and the total duty value (pwm_sum) = PWM Since the voltage command value (pwm_v) is obtained, the buck-boost converter 10 is driven by the PWM voltage command value (pwm_v) generated by the PI control in the PWM command calculation unit 23.

  FIG. 6 is a characteristic diagram showing an example of operation characteristics of the drive control device for the buck-boost converter according to the present embodiment.

  Immediately after the drive of the buck-boost converter 10 is started, since the drive region is the region (5), the flag (duty.flg) is held at “0”, so the total duty value (pwm_sum) = PWM voltage command value (pwm_v), and the buck-boost converter 10 is PI-controlled by the PWM voltage command value (pwm_v) generated by the PWM command calculation unit 23.

  The DC bus voltage value (vdc_det) changes between −dc_V to + dc_V from the start of driving to the time point A. This state corresponds to a state where the region (5) and the region (8) shown in FIG. 3 are moved back and forth due to slight fluctuations in the DC bus voltage deviation.

  Thus, in the state where the drive region is in the region (5) or the region (8), the flag (duty.flg) is held at “0”, so the total duty value (pwm_sum) = PWM voltage command value (pwm_v) Thus, the buck-boost converter 10 is PI-controlled by the PWM voltage command value (pwm_v) generated by the PWM command calculation unit 23.

  Next, when the time point A is exceeded, the DC bus voltage value (vdc_det) increases, and thereby the DC bus voltage deviation {DC bus target voltage value (vdc_ref) −DC bus voltage value (vdc_det)} becomes smaller than zero. .

  At this time, the drive region transitions to the region (8), but the state where the flag (duty.flg) is held at “0” continues.

  In addition, when an electric load such as a motor performs regenerative operation, a regenerative current is generated, so that the DC bus voltage value (vdc_det) increases and the ratio of the battery voltage value (vbat_det) / DC bus voltage value (vdc_det) is small. Become. This is because the current value flowing from the battery 13 to the DC bus 19 decreases because the DC bus voltage detection value needs to be stepped down (charging of the battery 13).

  Although not shown in FIG. 6, when an electric load such as a motor performs a power running operation, power supply is required from the electric load, and the DC bus voltage value (vdc_det) decreases. In this case, the DC bus 19 needs to be boosted (the battery 13 is discharged) due to a decrease in the DC bus voltage value (vdc_det).

  Next, when the time point B is exceeded and the DC bus voltage value (vdc_det) further increases, the DC bus voltage deviation {DC bus target voltage value (vdc_ref) −DC bus voltage value (vdc_det)} is smaller than the threshold “−dc_v”. Become.

  Conventionally, when the absolute value of the DC bus voltage deviation continues to increase in this way, the low current region near the switching point between the step-up operation and the step-down operation is affected by the dead zone region. As a result, the DC bus voltage value (vdc_det) increases excessively and becomes overvoltage, and there is a problem that equipment such as the driver of the motor 15 is damaged.

  However, according to the drive control device for the buck-boost converter according to the present embodiment, in a state where the DC bus voltage deviation is large in the low current region, the dead zone compensation function is started, and thus the DC bus voltage value (vdc_det) is In order to decrease the current, a current is actively passed. This state changes from the region (8) to the region (11) in the drive region shown in FIG. 3, and the flag (duty.flg) is set to “−1”.

  As a result, the PWM command summation unit 24 adds the compensation duty value (pwm_duty) to the PWM voltage command value (pwm_v), and the summed duty value (pwm_sum) = PWM voltage command value (pwm_v) + compensation duty value (pwm_duty) ) Summed duty value (pwm_sum) is output.

  At this time, the proportional component value (P component value) included in the PWM voltage command value (pwm_v) has the same value before and after the start of the dead band compensation function, but the integral component value immediately after the start of the dead band compensation function ( (I component value) is replaced by the inverse of the proportional component value (P component value). Thus, immediately after the start of the dead zone compensation function, the value of the PWM voltage command value (pwm_v) becomes zero (P + I = 0). Therefore, in practice, the total duty value (pwm_sum) = compensation duty value (pwm_duty ).

  As a result, like the battery current value (ibat_det) shown in FIG. 6, in order to step down the DC bus 9, the current from the DC bus 9 to the battery 13 increases (that is, the battery current value (ibat_det) increases in absolute value. Thus, the DC bus voltage value (vdc_det) can be reduced.

  As a result, the current responsiveness in the low current region near the switching point between the step-up operation and the step-down operation can be improved, and thereby the DC bus voltage value (vdc_det) can be held within a certain range without greatly fluctuating. be able to.

  After that, the PWM command summation unit 24 continues to add the compensation duty value (pwm_duty) to the PWM voltage command value (pwm_v), and the PWM voltage command value (pwm_v) is the PI value in the PWM command calculation unit 23. Since the value is generated by the control, the step-down operation is continued and the DC bus voltage value (vdc_det) is stepped down. Due to the decrease in the DC bus voltage value (vdc_det), the DC bus voltage deviation becomes smaller in absolute value, and when the threshold value “−dc_V” is exceeded, the drive region transitions (returns) to the region (8). This corresponds to time point C.

  Even if the drive region transitions to the region (8) beyond the time point C, the flag (duty.flg) is held at “−1”. After that, the PWM command summation unit 24 continues to add the compensation duty value (pwm_duty) to the PWM voltage command value (pwm_v), and the PWM voltage command value (pwm_v) is the PI value in the PWM command calculation unit 23. Since the value is generated by the control, the step-down operation is continued and the DC bus voltage deviation is stabilized. At this time, when the DC bus voltage deviation becomes 0 (V) or more, the drive region transitions to the region (5). This corresponds to time point D.

  When the driving region transitions from the region (8) to the region (5) at the time point D, the flag (duty.flg) has transitioned to the region (5) in a state of “−1”. flg) is switched to "0", and the dead zone compensation function is activated and terminated.

  In this way, the dead band compensation function is terminated when the DC bus voltage value (vdc_det) is sufficiently stepped down by the dead band compensation function during step-down operation, and there is no need to increase the battery current value (ibat_det) by the dead band compensation function. It is because it is thought that it became.

  When the dead zone compensation function is activated, the compensation duty value (pwm_duty) is made zero and the total duty value (pwm_sum) = PWM voltage command value (pwm_v). At this time, as shown in FIG. 4B, the proportional component value (P component value) included in the PWM voltage command value (pwm_v) has the same value before and after starting the dead band compensation function. The integral component value (I component value) immediately after the activation of the function is replaced with the total value of the integral component value (I component value) and the compensation duty value (pwm_duty) immediately before the activation of the dead band compensation function.

  Therefore, before and after the start of the dead band compensation function, the value of the total duty value (pwm_sum) is the same as shown in FIG. 4C, and the continuity is maintained. As shown in FIG. 6, the DC bus voltage value (vdc_det) of the buck-boost converter 10 can be stabilized at a substantially constant value.

  After the dead band compensation function has been activated, the flag (duty.flg) becomes “0” and the compensation duty value (pwm_duty) is not added to the total duty value (pwm_sum), and the total duty value (pwm_sum) = PWM Since the voltage command value (pwm_v) is obtained, the buck-boost converter 10 is driven by the PWM voltage command value (pwm_v) generated by the PI control in the PWM command calculation unit 23.

  When the dead band compensation function is activated and the flag (duty.flg) is “0” and driven in the region (5), if the DC bus voltage deviation falls below 0 (V) due to a minute change. The drive region transitions to the region (8) again, but when the region (5) transitions to the region (8), the flag (duty.flg) is held at “0”. Is driven by the PWM voltage command value (pwm_v) generated by the PI control in the PWM command calculation unit 23.

  As described above, according to the buck-boost converter drive control device of the present embodiment, the current response in the low current region in the vicinity of the switching point between the step-up operation and the step-down operation is improved, whereby the voltage of the DC bus 19 is improved. The value can be kept within a certain range, damage to the driver of the load due to overvoltage can be suppressed, and the controllability of the load can be kept in a good state.

  Note that the operation example of FIG. 6 shows a case where the dead zone compensation function at the time of step-down is started to start by transitioning the regions (5), (8), and (11), and then the start-up is ended. Since the start / end of activation of the dead zone compensation function at the same time is performed in the same manner by changing the regions (2), (5), and (8), the description thereof is omitted.

  6 shows the case of -bat_I <battery current value (ibat_det) <+ bat_I, but in the case of battery current value (ibat_det) ≦ -bat_I (regions (1), (4), ( 7) and (10)), since the value of the flag (duty.flg) is held at the value before the transition (previous value), even if the battery current value (ibat_det) ≦ -bat_I, The activation state or cancellation state of the dead zone compensation function is only maintained. For this reason, the description of the operation when the battery current value (ibat_det) ≦ −bat_I is omitted. Similarly, this is the same in the case of + bat_I ≦ battery current value (ibat_det) (in the case of regions (3), (6), (9), and (12)).

  In the above description, the DC drive motor 15 is directly connected to the output terminal 16, but instead, an AC drive motor may be connected to the output terminal 16 via an inverter.

  The controller of the drive control device for the buck-boost converter according to the present embodiment can be realized by either an electronic circuit or an arithmetic processing device.

  In the above, the mode using PI control has been described. However, the control method is not limited to the PI control method, and hysteresis control, robust control, adaptive control, proportional control, integral control, gain scheduling control, or sliding Mode control may be used.

  As mentioned above, although the drive control apparatus of the step-up / step-down converter according to the exemplary embodiment of the present invention has been described, the present invention is not limited to the specifically disclosed embodiment, and from the claims. Various modifications and changes can be made without departing.

It is a figure which shows roughly the circuit structure of the buck-boost converter of this Embodiment. It is a control block diagram which shows the circuit structure of the drive control apparatus of the buck-boost converter of this Embodiment. It is a figure which shows the relationship between the flag derived | led-out by the compensation value switching part of the drive control apparatus of the buck-boost converter of this Embodiment, and the drive area | region of a buck-boost converter. It is a principle figure for demonstrating the summation process by the dead zone compensation function at the time of pressure | voltage fall in the drive control apparatus of the buck-boost converter of this Embodiment, (a) is a process at the time of starting activation of a dead zone compensation function, (b) is. FIG. 10C is a diagram illustrating the processing at the end of activation of the dead zone compensation function, and (c) is a diagram illustrating the processing during activation of the dead zone compensation function over time. It is a principle figure for demonstrating the summation process by the dead zone compensation function at the time of pressure | voltage rise in the drive control apparatus of the buck-boost converter of this Embodiment, (a) is a process at the time of starting activation of a dead zone compensation function, (b) is. FIG. 10C is a diagram illustrating the processing at the end of activation of the dead zone compensation function, and (c) is a diagram illustrating the processing during activation of the dead zone compensation function over time. It is a characteristic view which shows an example of the operation characteristic by the drive control apparatus of the buck-boost converter of this Embodiment. It is a figure showing the variation | change_quantity of the electric current with respect to the PWM duty in the drive control apparatus of the conventional step-up / step-down converter.

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 terminal 15 Motor 16 Output terminal 17 Capacitor 18 Reactor current detection part 19 DC bus 20 Drive control part 21 Voltage control command generation part 22 Voltage control part 23 PWM command calculation part 24 PWM command summing part 25 Buck-boost switching control Unit 26 compensation value calculation unit 27 compensation value switching unit

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 PWM duty value for driving the buck-boost converter is calculated so that a DC bus voltage value between the load and the buck-boost converter (hereinafter referred to as a DC bus voltage value) follows a target voltage value. A main control unit,
A compensation duty value computing unit for computing a compensation duty value for compensating the PWM duty value in a predetermined low current region in a current value characteristic with respect to the PWM duty value of the buck-boost converter;
A step-up / down converter drive control device, comprising: a summing unit that performs summing processing for summing the compensation duty value to the PWM duty value computed by the main control unit. The main control unit is configured to calculate the PWM duty value by PI control based on a deviation between the DC bus voltage value and the target voltage value,
The step-up / down converter drive control device according to claim 1, further comprising a replacement unit that replaces an integral component value included in the PWM duty value with a reciprocal of a proportional component value at the start of the summing process.   In the summing process, a deviation between the DC bus voltage value and the target voltage value is an absolute value that is equal to or greater than a predetermined voltage value, and a current value that flows through the buck-boost converter is an absolute value that is equal to or less than a predetermined low current value. The drive control device for a step-up / down converter according to claim 2, which starts to be started.   The replacement unit, at the end of the start of the summing process, calculates the integral component value included in the PWM duty value as the sum of the integral component value included in the PWM duty value immediately before the end of the summing process and the compensation duty value. The drive control device for a step-up / down converter according to claim 2 or 3, wherein the drive control device is replaced with a value.   The summing process is performed when the current value flowing through the buck-boost converter is an absolute value that is equal to or less than a predetermined low current value, and the deviation between the DC bus voltage value and the target voltage value becomes zero, or The drive control device for a step-up / step-down converter according to claim 4, wherein activation is terminated when the sign of the deviation is inverted.   The compensation duty value calculation unit calculates, as the compensation duty value, a duty value corresponding to a PWM duty value at a step-up or step-down inflection point in a current value characteristic with respect to a PWM duty value of the buck-boost converter. 6. The drive control device for a buck-boost converter according to any one of claims 1 to 5.

Images