JP2013115926A - Dc-dc converter and method of controlling dc-dc converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily change from power running to regeneration or from regeneration to power running in a DC-DC converter.SOLUTION: A DC-DC converter is configured that includes a voltage-type power converter at the primary side of a transformer and a current-type power converter at the secondary side of the transformer. A controller generates a first operation amount on the basis of a voltage value at an input/output end of the voltage-type power converter, generates a second operation amount on the basis of a voltage value at an input/output end of the current-type power converter, and generates a command value for PWM control or PFM control on the basis of the first operation amount, the second operation amount, and an input/output current at the input/output end of the current-type power converter or the voltage-type power converter. Moreover, the controller controls the operation of the voltage-type power converter and the current-type power converter on the basis of the command value.

Description

  The present invention relates to a DCDC converter.

  A bi-directional DCDC converter is sometimes used when powering and regenerating an electric motor or the like, or when charging or discharging a storage battery (Patent Document 1).

JP 2008-35675 A

  However, the conventional bidirectional DC-DC converter cannot easily switch from power running to regeneration or from regeneration to power running. Further, since it is necessary to perform both power running control and regenerative control, there is a problem that the control system becomes complicated.

  Then, an object of this invention is to provide the DCDC converter which can perform switching from power running to regeneration, or switching from regeneration to power running easily.

  In order to solve the above-described problem, according to the first DCDC converter according to the present invention, the DCDC converter is connected between an inverter that drives an electric motor and a storage battery, and the DCDC converter includes a transformer, A voltage source power converter configured on the primary side of the transformer, a first voltage detection circuit for detecting a voltage at an input / output terminal of the voltage source power converter, and a secondary side of the transformer Current source power converter, second voltage detection circuit for detecting voltage at input / output terminal of current source power converter, and current detection circuit for detecting input / output current at input / output terminal of current source power converter And a controller for controlling the operation of the voltage source power converter and the current source power converter in power conversion from the primary side to the secondary side of the transformer and power conversion from the secondary side to the primary side, and The voltage type The input / output terminal of the power converter is connected to the inverter, the input / output terminal of the current source power converter is connected to the storage battery, and the controller sets the voltage value at the input / output terminal of the voltage source power converter. A first control system for generating a first manipulated variable related to the input / output current based on the first control system, and a second manipulated variable related to the input / output current generated based on a voltage value at the input / output terminal of the current source power converter And a third control system that generates a command value for PWM control based on the first manipulated variable, the second manipulated variable, and the input / output current. The range of controlling the operation of the voltage source power converter and the current source power converter based on the value and limiting the manipulated variable Q1 generated by the first control system is the maximum charging current to the storage battery. The value is I1, and the maximum discharge current from the storage battery is I2. Is set to satisfy −I2 ≦ Q1 ≦ I1, and the range for limiting the operation amount Q2 generated in the second control system is set to satisfy Q2 = 0. To do.

  According to the second DCDC converter according to the present invention, the DCDC converter is connected between an inverter that drives an electric motor and a storage battery, and the DCDC converter is configured on a transformer and a primary side of the transformer. Voltage-type power converter, a first voltage detection circuit for detecting the voltage at the input / output terminal of the voltage-type power converter, a current-type power converter configured on the secondary side of the transformer, and the current A second voltage detection circuit for detecting a voltage at the input / output terminal of the power converter, a current detection circuit for detecting an input / output current at the input / output terminal of the current-type power converter, and a primary side of the transformer The voltage source power converter comprising: the voltage source power converter in the power conversion to the secondary side and the power conversion from the secondary side to the primary side; and a controller for controlling the operation of the current source power converter. The input / output terminals of Connected to a barter, the input / output terminal of the current source power converter is connected to the storage battery, and the controller is configured to control the first input / output current based on the voltage value of the input / output terminal of the voltage source power converter. A first control system that generates a manipulated variable of the current source, a second control system that generates a second manipulated variable related to the input / output current based on the voltage value of the input / output terminal of the current source power converter, And a third control system for generating a command value for PFM control based on the first manipulated variable, the second manipulated variable, and the input / output current, and the voltage-type power conversion based on the command value The range in which the operation amount Q1 generated by the first control system is controlled is I1, the maximum charging current to the storage battery is I1, and the discharge from the storage battery When the maximum value of the current is I2, -I2 ≦ Q1 ≦ I1 Is set to satisfy a range for limiting the operation amount Q2 generated by the second control system, characterized in that it is set to satisfy Q2 = 0.

  As described above, according to the present invention, switching from power running to regeneration or switching from regeneration to power running can be easily performed.

FIG. 1 is a block diagram showing a schematic configuration of the DCDC converter according to the first embodiment of the present invention. FIG. 2 is a circuit diagram showing a schematic configuration of the current source power converter 2 and the voltage source power converter 4 of FIG. FIG. 3 is a block diagram showing a schematic configuration of the controller 5 of FIG. FIG. 4 is a timing chart showing waveforms of the gate drive signals S1, S2 and Sa to Sd in FIG. FIG. 5 is a block diagram showing a schematic configuration of a controller applied to the DCDC converter according to the second embodiment of the present invention. FIG. 6 is a block diagram showing a schematic configuration of a controller applied to the DCDC converter according to the third embodiment of the present invention. FIG. 7 is a block diagram showing a schematic configuration of a controller applied to the DCDC converter according to the fourth embodiment of the present invention. FIG. 8 is a block diagram showing a schematic configuration of a power supply system to which the DCDC converter of FIG. 1 is applied. FIG. 9 is a circuit diagram showing a schematic configuration of the current source power converter 62 and the voltage source power converter 4 applied to the DCDC converter according to the fifth embodiment of the present invention. FIG. 10 is a block diagram showing a schematic configuration when the DCDC converter of FIG. 1 is applied to a motor drive device. FIG. 11 is a block diagram showing a schematic configuration when the dead zone 12 is deleted from the controller applied to the DCDC converter according to the third embodiment of the present invention.

  Hereinafter, a DCDC converter according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a schematic configuration of the DCDC converter according to the first embodiment of the present invention.

  In FIG. 1, the DCDC converter includes a transformer 3, a voltage-type power converter 4 that performs power conversion by controlling a voltage applied to the primary side of the transformer 3, and a secondary side of the transformer 3. A current source power converter 2 that performs power conversion by controlling current, and a voltage source power converter 4 and a controller 5 that controls the current source power converter 2 are provided.

  When power conversion is performed from the secondary side to the primary side of the transformer 3, the current input to the input / output terminal of the current source power converter 2 is converted into alternating current by the current source power converter 2. This alternating current is given to the voltage source power converter 4 via the transformer 3. The alternating current applied to the voltage source power converter 4 via the transformer 3 is converted into direct current by the voltage source power converter 4. This direct current is output from the input / output terminal of the voltage source power converter 4.

  When power conversion is performed from the primary side to the secondary side of the transformer 3, the direct current input from the input / output terminal of the voltage source power converter 4 is converted into alternating current by the voltage source power converter 4. This alternating current is given to the current source power converter 2 via the transformer 3. The alternating current given to the voltage source power converter 4 via the transformer 3 is converted into direct current by the current source power converter 2. This direct current is output from the input / output terminal of the current source power converter 2.

  Here, the voltage at the input / output terminal of the current source power converter 2 is set to the voltage V2, the voltage at the input / output terminal of the voltage source power converter 4 is set to the voltage V1, and is output from the input / output terminal of the current source power converter 2. Current I is defined as current I. The value of the current I is a positive value when a current is output from the input / output terminal of the current source power converter 2, and is a negative value when a current flows into the input / output terminal of the current source power converter 2. . The controller 5 controls increase / decrease of the current I with reference to the voltage V1, the voltage V2, and the current I.

  In the case of power conversion from the primary side to the secondary side of the transformer 3, referring to the voltage V1, the voltage V2, and the current I, increase / decrease of the current (I) output from the input / output terminal of the current source power converter 2 To control. For example, when the voltage V2 is to be increased or the voltage V1 is to be decreased, the current source power converter 2 and the voltage are increased so as to increase the current (I) output from the input / output terminal of the current source power converter 2. When the voltage-type power converter 4 is controlled and the voltage V2 is to be lowered or the voltage V1 is to be raised, the current (I) output from the input / output terminal of the current-type power converter 2 is reduced. The type power converter 2 and the voltage type power converter 4 are controlled. On the other hand, in the case of power conversion from the secondary side to the primary side of the transformer 3, the current (−I) flowing into the input / output terminal of the current source power converter 2 is referred to with reference to the voltage V1, the voltage V2, and the current I. Control the increase and decrease. For example, when it is desired to increase the voltage V1, the current (−I) flowing into the input / output terminal of the current source power converter 2 is increased (so that the absolute value of the negative current I increases). When the current source power converter 2 and the voltage source power converter 4 are controlled to reduce the voltage V1, the current (−I) flowing into the input / output terminal of the current source power converter 2 is reduced (negative). The current-type power converter 2 and the voltage-type power converter 4 are controlled so that the absolute value of the current I, which is the value of, becomes smaller.

  FIG. 2 is a circuit diagram showing a schematic configuration of the current source power converter 2 and the voltage source power converter 4 of FIG. In the embodiment of FIG. 2, a push-pull configuration is used as the current source power converter 2 and a full bridge configuration is used as the voltage source power converter 4.

  The current source power converter 2 includes switching elements Q1 and Q2 and an inductor L as main components. The switching element Q1 is connected between one end of the secondary winding of the transformer 3 and the negative terminal side, and the switching element Q2 is connected between the other end of the secondary winding of the transformer 3 and the negative terminal side. Has been. An inductor L is connected between the intermediate tap of the secondary winding of the transformer 3 and the positive terminal side.

  Here, the input / output terminal of the current source power converter 2 includes a positive terminal and a negative terminal, and the voltage between the positive terminal and the negative terminal corresponds to the voltage V2.

  The voltage source power converter 4 includes switching elements Qa to Qd and a smoothing capacitor C as main components. The switching elements Qa and Qb are connected in series with each other, and the switching elements Qc and Qd are connected in series with each other. The series circuit of the switching elements Qa and Qb and the series circuit of the switching elements Qc and Qd are connected in parallel to each other, and between the connection point of the switching elements Qa and Qb and the connection point of the switching elements Qc and Qd, A primary winding is connected. The series circuit of the switching elements Qa and Qb, the series circuit of the switching elements Qc and Qd, and the smoothing capacitor C are connected between the positive terminal side and the negative terminal side. Here, the input / output terminal of the voltage source power converter 4 is composed of a positive terminal and a negative terminal, and a voltage between the positive terminal and the negative terminal corresponds to the voltage V1.

  As switching elements Q1, Q2, and Qa to Qd, field effect transistors may be used, bipolar transistors may be used, or IGBTs may be used. In addition, body diodes may be formed in the switching elements Q1, Q2, and Qa to Qd.

  FIG. 3 is a block diagram showing a schematic configuration of the controller 5 of FIG.

  In FIG. 3, the controller 5 includes a first voltage control system 101, a second voltage control system 102, and a current control system 103. The current control system 103 is arranged at the subsequent stage of the first voltage control system 101 and the second voltage control system 102. Therefore, the output value output from the first voltage control system 101 and the output value output from the second voltage control system 102 are input to the current control system 103.

  In the first voltage control system 101, a dead zone 12 is provided after the subtractor 11, a CV controller 13 is provided after the dead zone 12, and a limiter 14 is provided after the CV controller 13. The CV controller 13 compares the voltage V1 with its target value V1_ref, generates an operation amount of the current I based on the comparison result, and outputs the operation amount. The dead zone 12 is provided to prevent the CV controller 13 from operating if the fluctuation of the voltage V1 is within an allowable range. The limiter 14 is provided to limit the range of the operation amount output from the CV controller 13. When the operation amount output from the CV controller 13 is within the range set in the limiter 14, the operation amount output from the CV controller 13 is output as it is from the first voltage control system 101. On the other hand, when the operation amount output from the CV controller 13 is out of the range set in the limiter 14, the lower limit value or the upper limit value set in the limiter 14 is output from the first voltage control system 101. Is done.

  In the second voltage control system 102, a CV controller 23 is provided after the subtractor 21, and a limiter 24 is provided after the CV controller 23. The CV controller 23 compares the voltage V2 with its target value V2_ref, generates an operation amount of the current I based on the comparison result, and outputs the operation amount. The limiter 24 is provided to limit the range of the operation amount output from the CV controller 23. When the operation amount output from the CV controller 23 is within the range set in the limiter 24, the operation amount output from the CV controller 23 is output as it is from the second voltage control system 102. On the other hand, when the operation amount output from the CV controller 23 is out of the range set in the limiter 24, the lower limit value or the upper limit value set in the limiter 24 is output from the second voltage control system 102. Is done.

  In the current control system 103, an adder / subtracter 32 is provided after the adder 31, a CC controller 33 is provided after the adder / subtractor 32, and a limiter 34 is provided after the CC controller 33. The CC controller 33 compares the current I with a value obtained by adding the operation amount output from the first voltage control system 101 and the operation amount output from the second voltage control system 102. Based on the comparison result, a duty ratio command value in PWM (Pulse Width Modulation) control is generated, and the command value is output. The limiter 34 is provided to limit the range of command values output from the CC controller 33. When the command value output from the CC controller 33 is within the range set in the limiter 24, the command value output from the CC controller 33 is output from the current control system 103 as it is. On the other hand, when the command value output from the CC controller 33 is out of the range set in the limiter 34, the lower limit value or the upper limit value set in the limiter 34 is output from the current control system 103. In the case of PFM (Pulse Frequency Modulation) control, the CC controller 33 generates a frequency command value in PFM (Pulse Frequency Modulation) control. Further, the control parameter of the CC controller 33 is a value common to the case of power conversion from the primary side to the secondary side of the transformer 3 and the case of power conversion from the secondary side to the primary side of the transformer 3. Can be set to

In the case of power conversion from the primary side to the secondary side of the transformer 3, the limiters 14, 24, and 34 can be set as follows.
Limiter 14: lower limit value = −ΔI, upper limit value = ΔI
Limiter 24: lower limit = 0, upper limit = I_ref
Limiter 34: lower limit value = 0, upper limit value = maximum duty Here, I_ref is a target value of the current I output from the input / output terminal of the current source power converter 2, and ΔI is set to a predetermined value. Can do. When the ranges of the limiters 14, 24, and 34 are thus set, the outputs from the first voltage control system 101, the second voltage control system 102, and the current control system 103 are limited as follows. When the operation amount output from the CV controller 13 is larger than ΔI, the operation amount output from the first voltage control system 101 is ΔI, and the operation amount output from the CV controller 13 is Δ−I. If the value is smaller, the operation amount output from the first voltage control system 101 is Δ−I. When the operation amount output from the CV controller 23 is larger than I_ref, the operation amount output from the second voltage control system 102 is I_ref, and the operation amount output from the CV controller 23 is more than zero. When it is small, the operation amount output from the first voltage control system 101 is zero. When the command value output from the CC controller 33 is larger than the value of the maximum duty ratio, the command value output from the current control system 103 becomes the value of the maximum duty ratio, and the command value output from the CC controller 33 Is less than 0, the command value output from the current control system 103 is 0. Therefore, the maximum value of the sum of the operation amount output from the first voltage control system 101 and the operation amount output from the second voltage control system 102 is I_ref + ΔI, and the minimum value is −ΔI. As a result, the current I changes between I_ref + ΔI and −ΔI.

In the case of power conversion from the secondary side to the primary side of the transformer 3, the limiters 14, 24, and 34 can be set as follows.
Limiter 14: Lower limit = −I_ref, Upper limit = 0
Limiter 24: lower limit = 0, upper limit = 0
Limiter 34: Lower limit value = 0, upper limit value = maximum duty ratio In the case of power conversion from the secondary side to the primary side of the transformer 3, control is performed to increase or decrease the current flowing into the input / output terminal of the current source power converter 2. Is called. The target value of the current I becomes a negative value.

  In this example, the operation amount output from the first voltage control system 101 is limited to a range from -I_ref to 0. That is, the first voltage control system 101 outputs an operation amount such that the current flowing into the input / output terminal of the current source power converter 2 varies in the range of 0 to I_ref. Further, since the lower limit value and the upper limit value of the limiter 24 are set to 0, the operation amount output from the second voltage control system 102 is always 0. Thus, the function of the second voltage control system 102 can be substantially stopped by the set value of the limiter 24. The current control system 103 also compares the operation amount output from the first voltage control system 101 with the current I, and generates a duty ratio command value based on the comparison result.

  The operation when the limiters 14, 24, and 34 are set as described above will be described. First, the case of power conversion from the secondary side of the transformer 3 to the primary side will be described. In the case of power conversion from the secondary side to the primary side of the transformer 3, the width of the dead zone 12 is set to zero. The subtractor 11 outputs a value obtained by subtracting the voltage V1, which is a detected voltage at the input / output terminal of the voltage source power converter 4, from the target value V1_ref. This subtraction value is input to the CV controller 13 via the dead zone 12. The CV controller 13 generates an operation amount such that the subtraction value approaches 0 (an operation amount such that the voltage V1 approaches the target value V1_ref). The manipulated variable is output from the first voltage control system 101 after being limited to a range of -I_ref to 0 by the limiter 14. The data is output to the adder / subtractor 32 via the adder 31.

  The operation amount output from the first voltage control system 101 is input to the adder / subtractor 32 via the adder 31. The adder / subtracter 32 adds the output value of the adder 31 and the target value I_ref of the charging current, and subtracts the detected value of the current I from the added value. This calculated value is input to the CC controller 33. The CC controller 33 generates a command value such that the calculated value approaches zero. The limiter 34 limits the command value within the range of 0 to the maximum duty ratio, and then outputs it as a duty command Duty.

  Next, the case of power conversion from the primary side to the secondary side of the transformer 3 will be described. In the case of power conversion from the primary side to the secondary side of the transformer 3, an operation amount is output from both the first voltage control system 101 and the second voltage control system 102 according to the settings of the limiters 14 and 24. The operation amount output from the first voltage control system 101 is set so that it can take a positive or negative value.

  The width of the dead zone 12 of the first voltage control system 101 is set to an arbitrary value of 0 or more. The subtractor 11 subtracts the voltage V1 from the target value V1_ref. This subtraction value is input to the CV controller 13 via the dead zone 12.

  The CV controller 13 generates an operation amount such that the input subtraction value approaches 0 (an operation amount such that the detected value of the voltage V1 approaches the target value V1_ref of the rail voltage). The limiter 14 limits the manipulated variable within the range of -ΔI to ΔI. The operation amount output from the limiter 14 is input to the adder 31.

  The subtracter 21 subtracts a voltage V2 that is a detection voltage at the input / output terminal of the current source power converter 2 from the target value V2_ref. This subtraction value is input to the CV controller 23.

  The CV controller 23 generates an operation amount such that the input subtraction value approaches 0 (an operation amount such that the voltage V2 approaches the target value V2_ref). The limiter 24 limits the operation amount within the range of 0 to I_ref. The operation amount output from the limiter 14 is input to the adder 31.

  The adder 31 adds the output values from the limiters 14 and 24. This added value is input to the adder / subtractor 32. The adder / subtracter 32 adds the output value of the adder 31 and the target value I_ref, and subtracts the current I, which is the detected value of the current output from the input / output terminal of the current source power converter 2, from the added value. . This calculated value is input to the CC controller 33. The CC controller 33 generates a command value so that the output value of the adder / subtractor 32 approaches zero. The limiter 34 limits the command value within the range of 0 to the maximum duty ratio, and then outputs it as a duty command Duty.

  Next, the gate drive signals S1, S2, Sa to Sd generated based on the duty command Duty will be described. The switching elements Q1 and Q2 in FIG. 2 are driven by gate drive signals S1 and S2, and the switching elements Qa to Qd in FIG. 2 are driven by gate drive signals Sa to Sd.

  FIG. 4 is a timing chart showing waveforms of the gate drive signals S1, S2 and Sa to Sd in FIG. The duty ratio of the gate drive signals Sa to Sd is set based on the duty command Duty. The duty ratios of the gate drive signals Sa to Sd are set to be the same. Here, the gate drive signals Sa and Sd and the gate drive signals Sb and Sc are out of phase by a half period.

  The gate drive signal S1 is generated by inverting the gate drive signals Sb and Sc, and the gate drive signal S2 is generated by inverting the gate drive signals Sa and Sd. Thus, all the drive signals of the gate drive signals S1, S2, Sa to Sd can be generated based on the duty command Duty.

  In the case of power conversion from the primary side to the secondary side of the transformer 3, the second voltage control system 102 in FIG. 3 operates to increase the voltage V2 when the voltage V2 decreases. The first voltage control system 101 operates to increase the voltage V1 when the voltage V1 decreases. The operations of the first voltage control system 101 and the second voltage control system 102 are executed in parallel.

  In this way, the operation of the first voltage control system 101 and the operation of the second voltage control system 102 are executed in parallel, so that power conversion from the primary side to the secondary side of the transformer 3 can be performed. The fluctuation of the voltage V1 when performing can be suppressed. For example, when the voltage V1 decreases because the voltage V1 has decreased, it is possible to suppress the increase in the voltage V2 and increase the voltage V1.

  FIG. 5 is a block diagram showing a schematic configuration of a control system applied to the DCDC converter according to the second embodiment of the present invention.

  In FIG. 5, a current control system 104 is provided instead of the current control system 103 of FIG. In the current control system 104, a limiter 41 is provided before the adder / subtractor 32.

In the case of power conversion from the primary side to the secondary side of the transformer 3, the limiter 41 can be set as follows.
Limiter 41: lower limit value = 0, upper limit value = I_ref
However, the positive value indicates the current value of the current output from the input / output terminal of the current source power converter 2, and the negative value indicates the current value of the current flowing into the input / output terminal of the current source power converter 2. Show.

In the case of power conversion from the secondary side to the primary side of the transformer 3, the limiter 41 can be set as follows.
Limiter 41: lower limit value = −I_ref, upper limit value = 0
By providing the limiter 41 before the adder / subtractor 32, the output value of the adder 31 can be limited to a range of 0 to I_ref. That is, the sum of the operation amount given from the operation of the first voltage control system 101 and the operation amount given from the second voltage control system 102 is limited to a range from 0 to I_ref.

  FIG. 6 is a block diagram showing a schematic configuration of a control system applied to the DCDC converter according to the third embodiment of the present invention.

  In FIG. 6, a current control system 105 is provided instead of the current control system 103 of FIG. In the current control system 105, a subtracter 32 ′ is provided instead of the adder / subtractor 32. In the subtractor 32 ′, the input of the target value I_ref is omitted, and the detected value of the current I is subtracted from the output value of the adder 31.

In this control system, in the case of power conversion from the primary side to the secondary side of the transformer 3, the limiters 14, 24, and 34 can be set as follows.
Limiter 14: lower limit value = −ΔI, upper limit value = ΔI
Limiter 24: lower limit = 0, upper limit = I_ref
Limiter 34: Lower limit value = 0, upper limit value = maximum duty ratio However, a positive value indicates the current value of the current output from the input / output terminal of the current source power converter 2, and a negative value indicates the current source power. The current value of the current flowing into the input / output terminal of the converter 2 is shown. In this case, the current I ranges from −ΔI to I_ref + ΔI. The current I is a current output from the input / output terminal of the current source power converter 2 in the range of 0 to I_ref + ΔI, and the current flowing into the input / output terminal of the current source power converter 2 in the range of −ΔI to 0. become.

Further, in the case of power conversion from the secondary side to the primary side of the transformer 3, the output of the limiters 14, 24, and 34 can be limited as follows.
Limiter 14: Lower limit = −I_ref, Upper limit = 0
Limiter 24: lower limit = 0, upper limit = 0
Limiter 34: lower limit value = 0, upper limit value = maximum duty ratio In this case, the range of the current I is in the range of −I_ref + ΔI to 0. The current I is a current that flows into the input / output terminal of the current source power converter 2.

  FIG. 7 is a block diagram showing a schematic configuration of a control system applied to the DCDC converter according to the fourth embodiment of the present invention.

  In FIG. 7, a current control system 106 is provided instead of the current control system 105 of FIG. In this current control system 106, a limiter 41 is provided before the subtractor 32 ′ of the current control system 105.

In the case of power conversion from the primary side to the secondary side of the transformer 3, the limiters 14, 24, 34, and 41 can be set as follows.
Limiter 14: lower limit value = −ΔI, upper limit value = ΔI
Limiter 24: lower limit = 0, upper limit = I_ref
Limiter 34: lower limit value = 0, upper limit value = maximum duty ratio limiter 41: lower limit value = 0, upper limit value = I_ref
In this case, the sum of the operation amount given from the operation of the first voltage control system 101 and the operation amount given from the second voltage control system 102 is limited to a range from 0 to I_ref.

In the case of power conversion from the secondary side to the primary side of the transformer 3, the limiters 14, 24, 34, and 41 can limit the output as follows.
Limiter 14: Minimum value = −I_ref, Maximum value = 0
Limiter 24: Minimum value = 0, maximum value = 0
Limiter 34: Minimum value = 0, Maximum value = Maximum duty limiter 41: Minimum value = −I_ref, Maximum value = 0
In this case, the current I ranges from −I_ref + ΔI to zero. The current I is a current that flows into the input / output terminal of the current source power converter 2.

  FIG. 8 is a block diagram showing an example of a power supply system to which the DCDC converter of FIG. 1 is applied.

  In FIG. 8, a load 53 is connected to an AC power source 51 via an ACDC converter 52. The load 53 may be, for example, an electronic device that operates with a direct current, or a direct current motor. Or a solar cell may be sufficient and a generator may be sufficient.

  The capacitor 1 is connected to the load 53 via a DCDC converter 54.

  The alternating current output from the alternating current power supply 51 is converted into direct current by the ACDC converter 52 and supplied to the load 53.

  When energy generated by the load 53 is stored in the battery 1, the DC / DC converter 54 converts the voltage V1 into the voltage V2, and the battery 1 is charged with the voltage V2. On the other hand, when the AC power supply 51 is cut off, the DC / DC converter 54 converts the voltage V2 into the voltage V1 and the converted power is supplied to the load 53.

  Here, by using the configuration of FIG. 1 as the DCDC converter 54, the fluctuation of the voltage V1 can be suppressed during charging. For example, when the voltage V2 decreases because the voltage V1 has decreased, it is possible to suppress the increase in the voltage V2 and increase the rail voltage V1.

  FIG. 9 is a circuit diagram showing a schematic configuration of the current source power converter 62 and the voltage source power converter 4 applied to the DCDC converter according to the fifth embodiment of the present invention. In the embodiment of FIG. 9, a full bridge configuration is taken as an example of the current source power converter 6.

  In FIG. 9, a current source power converter 62 and a transformer 63 are provided instead of the current source power converter 2 and the transformer 3 of FIG. 1. Other configurations are the same as those in FIG.

  The current source power converter 62 includes switching elements Q11 to Q14 and an inductor L2. Switching elements Q11 and Q12 are connected in series with each other, and switching elements Q13 and Q14 are connected in series with each other. The series circuit of the switching elements Q11 and Q12 and the series circuit of the switching elements Q13 and Q14 are connected in parallel to each other, and the transformer 63 is connected between the connection point of the switching elements Q11 and Q12 and the connection point of the switching elements Q13 and Q14. A secondary winding is connected. An inductor L2 is connected to a connection point between the switching elements Q11 and Q13.

  As switching elements Q11 to Q14, field effect transistors may be used, bipolar transistors may be used, or IGBTs may be used. Further, body diodes may be formed in switching elements Q11 to Q14.

  In the DCDC converter, the gates of the switching elements Q12 and Q13 are driven by the gate drive signal S1 in FIG. 4, and the gates of the switching elements Q11 and Q14 are driven by the gate drive signal S2 in FIG. Other operations are the same as those of the DCDC converter of FIG.

  2 is effective when the voltage V2 is low or the variation range of the voltage V1 is narrow. In this current source power converter 2, the circuit configuration can be simplified as compared with the current source power converter 62 having the full bridge configuration of FIG.

  On the other hand, when the voltage V2 is high or when the fluctuation range of the voltage V1 is wide, the voltage stress of the switching elements Q1 and Q2 increases, so the current-type power converter 62 having the full bridge configuration of FIG. 9 is suitable.

  Further, in this embodiment, the input / output current at the input / output terminal of the current source power converter 2 is detected, and the control is generated by generating the control amount for this current. Control may be performed by detecting an input / output current at the end and generating a control amount for this current. Further, when current is output from the input / output terminal of the current source power converter 2, the input / output current at the input / output terminal of the current source power converter 2 is detected, and a control amount for this current is generated and controlled. When current is output from the input / output terminal of the voltage source power converter 4, the input / output current at the input / output terminal of the voltage source power converter 4 is detected, and a control amount is generated for this current to perform control. Also good.

  Moreover, the DCDC converter of FIG. 1 can be connected and used between the inverter 73 which drives the electric motor 74, and the storage battery 71, as shown in FIG. In this configuration, a power running operation for driving the electric motor 74 with electric power from the storage battery 71 and a regeneration operation for regenerating energy from the electric motor 74 to the storage battery 71 are performed.

  The DCDC converter 72 has an input / output terminal on the current source power converter side connected to the storage battery 71, and an input / output terminal on the voltage source power converter side connected to the inverter 73. In the control in the power running operation, the voltage at the input / output terminal connected to the inverter 73 of the DCDC converter 72 is maintained at a predetermined voltage value, and the voltage flowing out from the storage battery 71 does not exceed the predetermined current value. The operations of the type power converter and the current type power converter are controlled. In the control in the regenerative operation, the voltage at the input / output terminal on the side connected to the inverter 73 of the DCDC converter 72 is maintained at a predetermined voltage value so that the current flowing into the storage battery 71 does not exceed the predetermined current value. The operations of the type power converter and the current type power converter are controlled.

Such control can be realized by setting the control system of FIG. 6 as follows.
Limiter 14: Lower limit = −I2, upper limit = I1
Limiter 24: lower limit = 0, upper limit = 0
Limiter 34: lower limit value = 0, upper limit value = maximum duty ratio However, the width of the dead zone 12 is set to zero.

  When set in this way, the current value of the current flowing into the storage battery 71 during the regenerative operation is allowed up to I1. On the other hand, the current value of the current flowing out from the storage battery 71 during the power running operation is allowed up to I2. Therefore, the charging current (current flowing into the storage battery 71) varies between 0 and I1, and the discharging current (current flowing out from the storage battery 71) varies between 0 and I2. Here, I1 and I2 are set based on the rating of the storage battery 71. That is, I1 is set within a range not exceeding the maximum charging current of the storage battery 71, and I2 is set within a range not exceeding the maximum output current of the storage battery 71.

  When the width of the dead zone 12 is set to 0, it is substantially the same as deleting the dead zone 12 from the first voltage control system 101 of FIG. That is, as shown in FIG. 11, the voltage control system 101 is equivalent to being replaced with the first voltage control system 106 having no dead band 12.

  The DCDC converter of the present invention can be used as a bidirectional DCDC converter.

DESCRIPTION OF SYMBOLS 1 Capacitor 2, 62 Current type power converter 3, 63 Transformer 4 Voltage type power converter 5 Controller L, L2 Inductor C Smoothing capacitor Q1, Q2, Qa-Qd, Q11-Q14 Switching element 11, 21, 32 'Subtraction Device 12 Dead band 13, 23 CV controller 14, 24, 34, 41 Limiter 31 Adder 32 Adder / Subtractor 33 CC controller 51 AC power supply 52 ACDC converter 53 Load 54 DCDC converter 101 First side voltage control system 102 Second Voltage control system 103-106 Current control system

Claims (2)

A DCDC converter connected between an inverter that drives an electric motor and a storage battery,
The DCDC converter
With a transformer,
A voltage source power converter configured on the primary side of the transformer;
A first voltage detection circuit for detecting a voltage at an input / output terminal of the voltage source power converter;
A current source power converter configured on the secondary side of the transformer;
A second voltage detection circuit for detecting a voltage at an input / output terminal of the current source power converter;
A current detection circuit for detecting an input / output current at an input / output terminal of the current source power converter;
The voltage-type power converter in the power conversion from the primary side to the secondary side of the transformer and the power conversion from the secondary side to the primary side, and a controller that controls the operation of the current-type power converter. ,
The input / output terminal of the voltage source power converter is connected to the inverter,
The input / output terminal of the current source power converter is connected to the storage battery,
The controller includes: a first control system that generates a first manipulated variable related to the input / output current based on a voltage value at an input / output terminal of the voltage source power converter; and an input / output of the current source power converter. A second control system for generating a second manipulated variable related to the input / output current based on a voltage value at the end, and a PWM control based on the first manipulated variable, the second manipulated variable, and the input / output current. And a third control system for generating a command value for controlling the operations of the voltage source power converter and the current source power converter based on the command value,
The range for limiting the manipulated variable Q1 generated in the first control system is such that -I2≤ when the maximum value of the charging current to the storage battery is I1 and the maximum value of the discharge current from the storage battery is I2. Set to satisfy Q1 ≦ I1,
The DCDC converter is characterized in that a range for limiting the operation amount Q2 generated by the second control system is set so as to satisfy Q2 = 0. A DCDC converter connected between an inverter that drives an electric motor and a storage battery,
The DCDC converter
With a transformer,
A voltage source power converter configured on the primary side of the transformer;
A first voltage detection circuit for detecting a voltage at an input / output terminal of the voltage source power converter;
A current source power converter configured on the secondary side of the transformer;
A second voltage detection circuit for detecting a voltage at an input / output terminal of the current source power converter;
A current detection circuit for detecting an input / output current at an input / output terminal of the current source power converter;
The voltage-type power converter in the power conversion from the primary side to the secondary side of the transformer and the power conversion from the secondary side to the primary side, and a controller that controls the operation of the current-type power converter. ,
The input / output terminal of the voltage source power converter is connected to the inverter,
The input / output terminal of the current source power converter is connected to the storage battery,
The controller includes: a first control system that generates a first manipulated variable related to the input / output current based on a voltage value at an input / output terminal of the voltage source power converter; and an input / output of the current source power converter. A second control system for generating a second manipulated variable related to the input / output current based on a voltage value at the end; and a PFM control based on the first manipulated variable, the second manipulated variable, and the input / output current. And a third control system for generating a command value for controlling the operations of the voltage source power converter and the current source power converter based on the command value,
The range for limiting the manipulated variable Q1 generated in the first control system is such that -I2≤ when the maximum value of the charging current to the storage battery is I1 and the maximum value of the discharge current from the storage battery is I2. Set to satisfy Q1 ≦ I1,
The DCDC converter is characterized in that a range for limiting the operation amount Q2 generated by the second control system is set so as to satisfy Q2 = 0.

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