JP5225761B2 - 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.

  As shown in FIG. 5, such a delay in the current response appears as a dead zone near the switching point between the step-up operation and the step-down operation of the current characteristic 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.

  Therefore, the present invention provides a drive control device for a step-up / down converter that achieves both improvement in responsiveness in the vicinity of a switching point between step-up operation and step-down operation and ensuring good controllability in a charge region and a discharge region. For the purpose.

  A drive control device for a step-up / down converter according to one aspect of the present invention is connected between a power storage device and a load that performs both a power running operation and a regenerative operation, and performs drive charge / discharge control of the power storage device. A PWM duty for calculating a PWM duty value for driving the buck-boost converter by PI control based on a deviation between a voltage value of a DC bus between the load and the buck-boost converter and a target voltage value A calculation unit and a gain setting unit that switches and sets the first and second gains corresponding to the calculated PWM duty value are included.

  The first gain may be set in a charge region or a discharge region, and the second gain may be set in the vicinity of a charge / discharge switching region.

The region between the inflection point on the boost side and the inflection point on the step-down side in the current value characteristic with respect to the PWM duty value of the buck-boost converter is a dead zone region of the current value with respect to the PWM duty value, The gain setting unit may set a proportional gain or an integral gain as the second gain in the step-up or step-down region of the dead zone region.

Further, the gain setting unit is configured with PWM duty value is set the proportional gain or integral gain in the case of more than the 1PWM duty value in absolute value to the first gain, the PWM duty value is first 2PWM duty in absolute value the proportional gain or integral gain if the value below is configured to set the second gain, wherein in the region between the first 1PWM duty value and the second 2PWM duty value, the proportional gain or integral gain a it may be set to an intermediate value between the first gain and the second gain.

  The intermediate value may be set to a stepwise value according to the PWM duty value.

  Further, the intermediate value may be set so as to continuously change between the first gain and the second gain in accordance with the PWM duty value.

Further, the setting of the proportional gain or the integral gain by the gain setting unit may be performed on both the step-up side and the step-down side.

  ADVANTAGE OF THE INVENTION According to this invention, the drive control apparatus of the buck-boost converter which aimed at coexistence with the improvement of the responsiveness near the switching point of step-up operation and step-down operation, and ensuring favorable controllability in a charge area | region and a discharge area | region can be provided. A unique effect is obtained.

  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 a voltage value (vbat_det) between terminals of the battery 13, and the voltage detection unit 16A detects a 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 drive control device for the buck-boost converter according to the present embodiment, the responsiveness is improved near the switching point between the step-up operation and the step-down operation by the control method described below, and good control in the charge region and the discharge region is achieved. The voltage value of the DC bus 19 is kept 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, and a buck-boost switching control unit 24.

  The voltage control command generation unit 21, the voltage control unit 22, the PWM command calculation unit 23, and the step-up / step-down switching control unit 24 perform PI control based on a deviation between the DC bus voltage value (vdc_det) and the DC bus target voltage value (vdc_ref). Thus, a feedback loop for generating a drive command for driving the buck-boost converter 10 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.

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

  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 step-up / step-down switching control unit 24.

  The step-up / step-down switching control unit 24 converts the PWM voltage command value (pwm_v) 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 24 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.

  FIG. 3 is a block diagram illustrating a configuration of the voltage control unit 22 included in the drive control device for the buck-boost converter according to the present embodiment.

  The voltage control unit 22 includes an adder 101, a limiter 102, a proportional gain operation amount calculation unit 103, a limiter 104, an adder 105, a limiter 106, a gain setting unit 107, an integration time operation amount calculation unit 108, an adder 109, and a limiter. 110 is included.

  The adder 101 calculates a deviation (dev) between the DC bus target voltage value (vdc_ref) and the DC bus voltage value (vdc_det). The DC bus target voltage value (vdc_ref) is input from the voltage control command generator 21 shown in FIG. 2, and the DC bus voltage value (vdc_det) is input from the voltage detector 16A with the sign inverted.

  The limiter 102 has a limiting characteristic that limits the deviation (dev) input from the adder 101, and outputs the deviation (dev) by limiting it to a predetermined limit value or less. This deviation (dev) is input to the proportional gain manipulated variable calculation unit 103.

  The proportional gain operation amount calculation unit 103 calculates the operation amount (vdc_p) by multiplying the deviation (dev) input from the limiter 102 and the proportional gain (P) input from the gain setting unit 107. This manipulated variable (vdc_p) is input to the limiter 104.

  The limiter 104 has a limiting characteristic that limits the operation amount (vdc_p) input from the proportional gain operation amount calculation unit 103, and outputs an operation amount (vdc_p) with a limit equal to or less than a predetermined limit value. The operation amount (vdc_p) that has passed through the limiter 104 is input to the adder 105.

  The adder 105 adds the operation amount (vdc_p) input from the limiter 104 and the operation amount (vdc_i) input from the limiter 110, and outputs a voltage control command (datl). This voltage control command (datl) is input to the limiter 106.

  The limiter 106 has a limiting characteristic that limits the voltage control command (datl) input from the adder 105, and outputs a voltage control command (datl) with a limit equal to or less than a predetermined limit value. The voltage control command (datl) output from the limiter 106 is input to the PWM command calculation unit 23 shown in FIG.

  The gain setting unit 107 determines the values of the proportional gain (P) and the integral gain (I) based on the DC bus voltage value (vdc_det), the voltage value between terminals of the battery 13 (vbat_det), and the PWM voltage command value (pwm_v). Set. The DC bus voltage value (vdc_det) is input from the voltage detection unit 16A, and the inter-terminal voltage value (vbat_det) is input from the voltage detection unit 14A. Further, the PWM voltage command value (pwm_v) is inputted by feeding back the output of the PWM command calculation unit 23. A method for setting the proportional gain (P) and the integral gain (I) will be described later with reference to FIG.

  The integration time manipulated variable calculator 108 multiplies the deviation (dev) input from the limiter 102 and the integral gain (I) input from the gain setting unit 107 to calculate a minute manipulated variable (Δvdc_i). The minute manipulated variable (Δvdc_i) is input to the adder 109 as a minute value of the integral calculation.

  The adder 109 adds the minute operation amount (Δvdc_i) input from the integration time operation amount calculation unit 108 and the operation amount (vdc_i) input from the limiter 110 to calculate the operation amount (vdc_i). Since this calculation process is repeatedly executed, the operation amount (vdc_i) input from the limiter 110 to the adder 109 is the previous calculation result, and the operation amount (vdc_i) output from the adder 109 is the current calculation. Result. By repeating this addition processing, integration calculation in PI control is realized. The operation amount (vdc_i) output from the adder 109 is input to the limiter 110.

  The limiter 110 has a limiting characteristic that limits the operation amount (vdc_i) input from the adder 109, and outputs the operation amount (vdc_i) by limiting it to a predetermined limit value or less. The manipulated variable (vdc_i) output from the limiter 110 is input to the adder 105 and also input to the adder 109 as a previous value for the next integration calculation.

  FIG. 4 is a diagram illustrating characteristics used for setting a proportional gain and an integral gain in the drive control device for the buck-boost converter according to the first embodiment. The setting of the proportional gain and the integral gain is executed by the gain setting unit 107 in the voltage control unit 22.

  FIG. 4 shows the characteristics used for setting the proportional gain and integral gain together with the current characteristics of the buck-boost converter. The horizontal axis of the current characteristic represents the PWM duty value, and the horizontal axis of the setting characteristic of the proportional gain and the integral gain represents the PWM voltage command value (pwm_v). The PWM voltage command value (pwm_v) is Since it is converted to a duty command value (pwm_ref) which is a PWM duty value, the horizontal axis of the current characteristic and the characteristic used for setting the proportional gain and integral gain are substantially the same.

  On the horizontal axis, the right side from the origin is the boost side, and the left side is the step-down side. Between the inflection point on the step-up side and the inflection point on the step-down side is a dead zone region of the current of the buck-boost converter. As shown in this current characteristic, a weak current actually flows even in the dead zone, but the region on the right side of the dead zone is discharged in the discharge zone (the battery 13 discharges and boosts the voltage value of the DC bus 19). Area on the left side of the dead zone area is referred to as a charging area (an operating area in which the voltage value of the DC bus 19 is stepped down to charge the battery 13).

  The gain setting unit 107 switches the proportional gain (P) and the integral gain (I) between the first gain and the second gain according to the PWM voltage command value (pwm_v).

Specifically, on the boost side, when the PWM voltage command value (pwm_v) is A1 or more, the proportional gain (P) is set to P _up1 and the integral gain (I) is set to I _up1 as the first gain. When the PWM voltage command value (pwm_v) is A2 or less, the proportional gain (P) is set to _Pup2 and the integral gain (I) is set to _Iup2 . P _up2 takes a value several tens of times greater than P _up1 , and I _up2 takes a value several tens of times greater than I _up1 .

Further, when the PWM voltage command value (pwm_v) is between A2 and A1, the values of the proportional gain (P) and the integral gain (I) are set according to the PWM voltage command value (pwm_v). As shown in FIG. 4, between PWM voltage instruction value (PWM_V) from the A2 to A1, the value of the proportional gain (P), depending on the PWM voltage instruction value (PWM_V), between the P _up2 and P _up1 The value is proportionally distributed. Similarly, the integral gain (I) is a value that is proportionally distributed between I _up2 and I _up1 .

Note that P _up1 and I _up1 are the same normal values as the proportional gain and the integral gain when the gain is not changed as in the conventional buck-boost converter. In contrast, in the drive control device for the buck-boost converter according to the present embodiment, the proportional gain (P) and the integral gain (integral gain (Pwm_v) are used as the second gain in the low load region where the PWM voltage command value (pwm_v) is small in absolute value. Set the value of I) to large values P _up2 and I _up2 .

Here, the value of the PWM voltage instruction value representing the inflection point of the step-up side (PWM_V) is determined by the ratio of the inter-terminal voltage value of the DC bus voltage value and the battery 13, duty _{Stay up-in} Figure 4, the following It is given by the formula.

duty _up = 1− (vbat_det) / (vdc_det)
Using this duty _up , the values of A1 and A2 are given by the following equations.

A1 = duty _up1 = duty _up × PWM _up1 = {1− (vbat_det) / (vdc_det)} × PWM _{up1
A2 = duty up2 = duty up ×} PWM up2 = {1- (vbat_det) / (vdc_det)} × PWM up2
Here, PWM _up1 and PWM _up2 is a value that indicates the percentage to be determined as the value of A1 and A2 falls dead band region, respectively, is set to 95-70% and 5-30%. That is, the values of A1 and A2 are 95 to 70% and 5 to 30% of the duty _up value representing the inflection point on the boost side, respectively.

Note that the duty _up value representing the inflection point on the boosting side changes depending on fluctuations in the value of the DC bus voltage value (vdc_det) and the voltage value between terminals of the battery 13 (vbat_det). The values of A1 and A2 vary according to the value of duty _up. However, as shown in FIG. 4, the proportional gain (P) and the integral gain are obtained by preset values A1 and A2 so as to be within the dead zone. The region where (I) increases is always within the dead zone region. For this reason, in the discharge region located outside the dead zone region, the proportional gain (P) and the integral gain (I) are always set to the normal values P _up1 and I _up1 , so the proportional gain ( P) and integral gain (I) are not increased.

Similarly, on the step-down side, when the PWM voltage command value (pwm_v) is B1 or less, the proportional gain (P) is set to P _dw1 and the integral gain (I) is set to I _dw1 as the first gain. When the PWM voltage command value (pwm_v) is B2 or more, the proportional gain (P) is set to P _dw2 and the integral gain (I) is set to I _dw2 . P _dw2 takes a value several tens of times greater than P _dw1 , and I _dw2 takes a value several tens of times greater than I _dw1 .

Further, when the PWM voltage command value (pwm_v) is between B2 and B1, the values of the proportional gain (P) and the integral gain (I) are set according to the PWM voltage command value (pwm_v). As shown in FIG. 4, when the PWM voltage command value (pwm_v) is between B2 and B1, the value of the proportional gain (P) is between P _dw2 and P _dw1 according to the PWM voltage command value (pwm_v). The value is proportionally distributed. Similarly, the integral gain (I) is a value proportionally distributed between I _dw2 and I _dw1 .

P _dw1 and I _dw1 are the same normal values as the proportional gain and the integral gain when the gain is not changed as in the conventional buck-boost converter. In contrast, in the drive control device for the buck-boost converter according to the present embodiment, the proportional gain (P) and the integral gain (integral gain (Pwm_v) are used as the second gain in the low load region where the PWM voltage command value (pwm_v) is small in absolute value. The value of I) is set to large values such as P _dw2 and I _dw2 .

Further, in the present _{embodiment, P dw1, I dw1, P} dw2, I dw2 in buck side are identical to the values of _{P up1, I up1, P up2} , I up2 in boost.

Here, the value duty _dw of the PWM voltage command value (pwm_v) representing the inflection point on the step-down side is given by the following equation.

duty _dw = − (vbat_det) / (vdc_det)
For this reason, when duty _dw is used, the values of B1 and B2 are given by the following equations.

B1 = duty _dw1 = duty _dw × PWM _dw1 = − (vbat_det) / (vdc_det) × PWM _dw1
B2 = duty _dw2 = duty _dw x PWM _dw2 =-(vbat_det) / (vdc_det)} x PWM _dw2
Here, PWM _dw1 and PWM _dw2 are values indicating percentages for determining the values of B1 and B2 to be within the dead zone region, and are set to 95 to 70% and 5 to 30%, respectively. That is, the values of B1 and B2 are 95 to 70% and 5 to 30% of the value of duty _dw representing the inflection point on the step-down side, respectively.

Note that the value of the duty _dw representing the inflection point on the step-down side varies depending on the fluctuation of the DC bus voltage value (vdc_det) and the voltage value between the terminals of the battery 13 (vbat_det), but the values of B1 and B2 _Since it fluctuates according to the value of _dw , the region where the proportional gain (P) and integral gain (I) increase as shown in FIG. 4 is always within the dead zone region. For this reason, in the charging region located outside the dead zone region, the proportional gain (P) and the integral gain (I) are always set to the normal values P _dw1 and I _dw1. P) and integral gain (I) are not increased.

  Thus, according to the drive control device for the buck-boost converter of the present embodiment, in the vicinity of the charge / discharge switching region in the dead zone where the current response to the PWM duty value decreases, the proportional gain (P) Since the integral gain (I) is increased, the responsiveness in the dead zone can be improved.

  Further, in the discharge region and the charge region outside the dead zone region, the proportional gain (P) and the integral gain (I) are set to normal values, so that it is possible to ensure good controllability in the discharge region and the charge region. it can.

  Conventionally, when the DC bus voltage fluctuates in the dead zone region, the voltage supplied from the DC bus to a load such as a motor also fluctuates, which makes it difficult to accurately control the load.

  In addition, if the gain of PI control is increased in order to improve the response in such a dead zone, the DC bus voltage value oscillates because the gain is too high in the charge zone and the discharge zone other than the dead zone. There was a problem that the controllability was lowered.

  However, according to the drive control device for the buck-boost converter of the present embodiment, the proportional gain (P) and the integral gain (I) are increased only in the dead zone where the current responsiveness decreases with respect to the PWM duty value. Therefore, the responsiveness in the dead zone region can be improved.

  Further, as shown in FIG. 4, the values of the proportional gain (P) and the integral gain (I) are set to be large especially in the low load region (the region where the PWM voltage command value (pwm_v) is small in absolute value). The responsiveness in the low load region can be greatly improved.

  At the same time, good controllability in the discharge region and the charge region can be ensured.

  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.

  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.

  In the above, as shown in FIG. 4, the proportional gain (P) and the integral gain (I) are linearly proportionally distributed when the PWM voltage command value (pwm_v) is between A2 and A1 and between B2 and B1. However, the present invention is not limited to the linearly proportional characteristic, but may be a characteristic that changes in a curved line or a characteristic that changes in a step shape.

In the _{above, P up1, I up1, P} up2, I up2 in boost has been described _{P dw1, I dw1, P dw2} , form is the same as the value of I _dw2 in buck side, boost Different values may be used on the step-down side.

  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 block diagram which shows the structure of the voltage control part 22 contained in the drive control apparatus of the buck-boost converter of this Embodiment. It is a figure which shows the characteristic used for the setting of the proportional gain and integral gain in the drive control apparatus of the buck-boost converter of Embodiment 1. FIG. 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 Buck-boost switching control part 101 Adder 102 Limiter 103 Proportional gain operation amount calculation unit 104 Limiter 105 Adder 106 Limiter 107 Gain setting unit 108 Integration time operation amount calculation unit 109 Adder 110 Limiter

Claims (7)

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, and performs charge / discharge control of the capacitor,
A PWM duty calculator for calculating a PWM duty value for driving the buck-boost converter by PI control based on a deviation between a voltage value of a DC bus between the load and the buck-boost converter and a target voltage value;
A drive controller for a step-up / down converter, comprising: a gain setting unit that switches and sets the first and second gains corresponding to the calculated PWM duty value.   The step-up / down converter drive control device according to claim 1, wherein the first gain is set in a charge region or a discharge region, and the second gain is set in the vicinity of a charge / discharge switching region. A region between the inflection point on the boost side and the inflection point on the step-down side in the current value characteristic with respect to the PWM duty value of the buck-boost converter is a dead zone region of the current value with respect to the PWM duty value,
3. The drive control device for a step-up / down converter according to claim 1, wherein the gain setting unit sets a proportional gain or an integral gain to the second gain in a step-up or step-down region in the dead zone region. . The gain setting unit is configured with PWM duty value is set the proportional gain or integral gain in the case of more than the 1PWM duty value in absolute value to the first gain, the PWM duty value is less the 2PWM duty value with an absolute value is configured to set the second gain proportional gain or integral gain in the case of,
Wherein in the region between the first 1PWM duty value and the second 2PWM duty value, setting the proportional gain or integral gain to an intermediate value between the first gain and the second gain, any one of claims 1 to 3 The drive control device of the step-up / step-down converter described in 1.   The step-up / down converter drive control device according to claim 4, wherein the intermediate value is set to a stepwise value in accordance with the PWM duty value.   5. The drive control device for a step-up / down converter according to claim 4, wherein the intermediate value is set so as to continuously change between the first gain and the second gain in accordance with the PWM duty value. . The step-up / down converter drive control apparatus according to any one of claims 1 to 6, wherein the setting of the proportional gain or the integral gain by the gain setting unit is performed on both the boost side and the step-down side.

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