JP5262732B2 - Resonant buck-boost converter controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resonance type step-up and step-down converter control device that reliably protects each switching element. <P>SOLUTION: The resonance type step-up and step-down converter control device 1 includes a resonance type step-up and step-down converter 10 and a controlling means 20, wherein the resonance type step-up and step-down converter 10 includes a first switching element pair Q1 and Q2, a resonant circuit including capacitors C1 and C2 and reactors L1 and L2 which are connected to the first switching element pair Q1 and Q2, and a second switching element pair Q3 and Q4 for discharging electric charges accumulated in the capacitors C1 and C2 and the controlling means 20 controls the first switching element pair Q1 and Q2 and the second switching element pair Q3 and Q4 of the resonance type step-up and step-down converter 10. When the controlling means 20 determines that the second switching element pair Q3 and Q4 are operating, it does not generate a control signal to stop all the operations of the first switching element pair Q1 and Q2 and the second switching element pair Q3 and Q4. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a resonance type buck-boost converter control device having a resonance type buck-boost converter and control means for controlling switching elements constituting the resonance type buck-boost converter.

  Conventionally, a first switching element pair including a first high-side switching element and a first low-side switching element, a resonance circuit including a capacitor and a reactor connected to the first switching element pair, and a capacitor A resonant buck-boost converter having a second switching element pair including a second high-side switching element and a second low-side switching element that discharges accumulated charges is known.

  In such a resonant buck-boost converter, the operation of all the switching elements may be stopped without determining whether or not each switching element is operating.

JP 2000-37081 A JP 07-222444 A JP 2008-113473 A JP 2008-199736 A

  However, if the operation of all the switching elements is stopped without determining whether or not each switching element is in operation, a high voltage exceeding the withstand voltage may be applied to the switching elements depending on the timing of stopping, There was a problem that the switching element was destroyed.

  In view of the above points, an object of the present invention is to provide a resonant buck-boost converter control device capable of reliably protecting each switching element.

  The resonance type buck-boost converter control device includes a first switching element pair, a resonance circuit including a capacitor and a reactor connected to the first switching element pair, and a second discharging electric charge accumulated in the capacitor. And a control means for controlling the first switching element pair and the second switching element pair of the resonant buck-boost converter, and the control A means for determining whether or not the second switching element pair is in operation, and a control signal for generating a control signal to be supplied to the first switching element pair and the second switching element pair And the control signal generator is configured such that the determination unit determines that the second switching element pair is in operation. The, the first switching element pairs and the second requirement not to generate a control signal for stopping all operation of the switching element pairs.

  ADVANTAGE OF THE INVENTION According to this invention, the resonance type | mold buck-boost converter control apparatus which can protect each switching element reliably can be provided.

It is a circuit diagram which illustrates the resonance type buck-boost converter control device concerning this embodiment. It is a block diagram which illustrates the inside of a gate signal control part. It is a figure which illustrates the relationship between the gate signal which a gate signal control part produces | generates, and status.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is a circuit diagram illustrating a resonant buck-boost converter control device according to this embodiment. Referring to FIG. 1, a resonant buck-boost converter control device 1 includes a resonant buck-boost converter 10 and control means 20.

  The resonant buck-boost converter 10 includes a switching element Q1, a switching element Q2, a switching element Q3, a switching element Q4, a diode D1, a diode D2, a diode D3, a diode D4, a reactor L1, and a reactor L2. And a reactor Lr, a capacitor C1, a capacitor C2, a capacitor C3, and a capacitor C4.

  The switching element Q1, the switching element Q2, the switching element Q3, and the switching element Q4 are, for example, insulated gate bipolar transistors (IGBT). An insulated gate bipolar transistor (IGBT) is a bipolar transistor in which a MOSFET is incorporated in a gate, and has three terminals of an emitter, a collector, and a gate.

  The switching element Q1 and the switching element Q2 constitute a typical example of the first switching element pair in the present invention. Further, the reactor L1, the reactor L2, the reactor Lr, the capacitor C1, and the capacitor C2 constitute a typical example of the resonance circuit in the present invention. The switching element Q3 and the switching element Q4 constitute a typical example of the second switching element pair in the present invention.

  In the resonant buck-boost converter 10, the emitter of the switching element Q1 is the collector of the switching element Q2, the anode of the diode D1, the cathode of the diode D2, one end of the capacitor C1, one end of the capacitor C2, one end of the reactor L1, and the reactor L2. Connected to one end. The collector of the switching element Q1 is connected to the cathode of the diode D1, the other end of the capacitor C1, the collector of the switching element Q3, and one end of the capacitor C4.

  Reactor L2 is electromagnetically coupled to reactor L1. Reactor Lr is a leakage inductance of reactor L2. An electromotive force is induced with the same polarity at the connection point between the reactor L1 and the capacitor C3 and the connection point between the reactor L1 and the reactor L2. The electromagnetic coupling is a case where a transformer is constituted by the reactor L1 and the reactor L2.

  The emitter of the switching element Q2, the anode of the diode D2, the other end of the capacitor C2, the cathode of the diode D4, and the other end of the capacitor C4 are connected to the reference potential G. The other end of the reactor L1 is connected to one end of a capacitor C3, and the other end of the capacitor C3 is connected to a reference potential G.

  The other end of reactor L2 is connected to one end of reactor Lr, and the other end of reactor Lr is connected to the cathode of diode D3 and the collector of switching element Q4. The emitter of the switching element Q3 is connected to the anode of the diode D3. The emitter of the switching element Q4 is connected to the anode of the diode D4. VL represents the voltage across the capacitor C3, and VH represents the voltage across the capacitor C4. IL indicates a current flowing through the reactor L1.

  The gate of the switching element Q1, the gate of the switching element Q2, the gate of the switching element Q3, and the gate of the switching element Q4 are connected to a control means described later, and a control signal (switched at a predetermined timing from the control means described later) Gate signal).

  The switching elements Q1 and Q3 may be referred to as a high side switching element, and the switching elements Q2 and Q4 may be referred to as a low side switching element. The high-side switching element is a switching element connected to a high potential side (for example, a power supply), and the low-side switching element is a switching element connected to a low potential side (for example, GND).

  The resonant step-up / step-down converter 10 turns the switching elements Q1 to Q4 on / off at a predetermined timing according to a command from the control means 20 described later, thereby changing the DC voltage applied to both ends of the capacitor C3 to a predetermined DC voltage. It has a function of converting (boosting) and outputting from both ends of the capacitor C4.

  More specifically, when the switching element Q1 is turned off and the switching element Q2 is turned on, a current IL flows from the capacitor C3 side to the reactor L1, and the reactor L1 temporarily stores electric energy. Next, when the switching element Q1 is turned on and the switching element Q2 is turned off, the electrical energy temporarily stored in the reactor L1 flows to the capacitor C4 side via the return diode D1 (flywheel diode). That is, the voltage VL at both ends of the capacitor C3 is boosted to the voltage VH and output from both ends of the capacitor C4.

  By the way, if the switching element Q2 is turned on while the electric charge is accumulated in the capacitor C2, a switching loss occurs. Therefore, the switching element Q4 is turned on several μs before the switching element Q2 is turned on, and the charge accumulated in the capacitor C2 is discharged through the reactor L2, the reactor Lr, the switching element Q4, and the diode D4. At this time, a resonance current flows through the switching element Q4. If the switching element Q2 is turned on when all the electric charge stored in the capacitor C2 is discharged and the voltage across the switching element Q2 becomes zero, the switching loss is greatly reduced (theoretically zero). Can do. The diode D4 is provided to prevent a reverse current flow.

  In addition, the resonant buck-boost converter 10 turns on / off the switching elements Q1 to Q4 at a predetermined timing according to a command from the control means 20 described later, whereby a DC voltage applied to both ends of the capacitor C4 is changed to a predetermined DC voltage. It has a function of converting (stepping down) the voltage to output from both ends of the capacitor C3.

  More specifically, when the switching element Q1 is turned on and the switching element Q2 is turned off, a current flows from the capacitor C4 side to the reactor L1, and the reactor L1 temporarily stores electric energy. Next, when the switching element Q1 is turned off and the switching element Q2 is turned on, the electrical energy temporarily stored in the reactor L1 is refluxed via the reflux diode D2 (flywheel diode). That is, the voltage VH across the capacitor C4 is stepped down to the voltage VL and output from both ends of the capacitor C3.

  By the way, when the switching element Q1 is turned on while the electric charge is accumulated in the capacitor C1, a switching loss occurs. Therefore, the switching element Q3 is turned on several μs before the switching element Q1 is turned on, and the electric charge accumulated in the capacitor C1 is discharged via the switching element Q3, the diode D3, the reactor L2, and the reactor Lr. At this time, a resonance current flows through the switching element Q3. If the charge stored in the capacitor C1 is completely discharged and the switching element Q1 is turned on when the voltage across the switching element Q1 becomes zero, the switching loss is greatly reduced (theoretically zero). Can do. The diode D3 is provided in order to prevent a reverse current flow.

  As described above, the resonant buck-boost converter 10 can significantly reduce (in theory, zero) the switching loss at the time of step-up and step-down. Furthermore, the carrier frequency can be increased due to a significant reduction in switching loss. In the resonant buck-boost converter 10, if the carrier frequency can be increased, the reactor L1 can be reduced. Therefore, the resonant buck-boost converter 10 can be reduced in size and cost.

  Further, by raising the carrier frequency to outside the audible band (for example, 20 KHz), it is possible to prevent high frequency noise (for example, 10 KHz) from occurring during switching. Furthermore, since no high frequency noise is generated, a soundproof material is not required, and the resonant buck-boost converter 10 can be reduced in size and cost.

  Moreover, heat generation of the switching element can be prevented due to a significant reduction in switching loss. As a result, the area of the switching element can be reduced, and the resonant buck-boost converter 10 can be reduced in size and cost.

  Moreover, since the efficiency at the time of voltage step-up and step-down is increased due to the significant reduction of the switching loss, the fuel consumption when the resonance type buck-boost converter 10 is mounted on the vehicle can be improved.

  In the resonant buck-boost converter 10, for example, a voltage source is connected to both ends of the capacitor C3, and a motor is connected to both ends of the capacitor C4, for example, as a load. In this case, the voltage VL applied across the capacitor C3 from the voltage source is boosted to generate a voltage VH that is a motor driving voltage, and the motor is driven. In addition, the voltage source can be charged by reducing the regenerative energy of the motor.

  The control means 20 includes a step-up / down control unit 21, a gate signal control unit 22, and an abnormality detection unit 23. The torque command 25 indicates a signal received from an external ECU (hybrid ECU) or the like as a required torque for a motor mounted on a hybrid vehicle, for example. The SDWN command 26 indicates a signal received from an external ECU (hybrid ECU) or the like when the resonant buck-boost converter 10 needs to be shut down, for example, depending on the vehicle state.

  The current sensor signal SIL is a signal input from a predetermined current sensor and indicates a current flowing through the reactor L1. The voltage sensor signal SVL is a signal input from a predetermined voltage sensor and indicates the voltage across the capacitor C3. The voltage sensor signal SVH is a signal input from a predetermined voltage sensor and indicates the voltage across the capacitor C4. The temperature sensor signal ST is a signal input from a predetermined temperature sensor and indicates the temperature of the resonant buck-boost converter 10.

  The step-up / down control unit 21 calculates a duty command value of a control signal (gate signals G1 to G4) supplied to the gates of the switching elements Q1 to Q4 based on the torque command 25, the voltage sensor signal SVL, and the voltage sensor signal SVH. The calculated duty command value is output to the gate signal control unit 22.

  The gate signal control unit 22 has a function of generating control signals (gate signals G1 to G4) to be supplied to the gates of the switching elements Q1 to Q4. The gate signal control unit 22 will be described in detail separately.

  The abnormality detection unit 23 detects overcurrent, overvoltage, and temperature abnormality in the resonant buck-boost converter 10 based on the current sensor signal SIL, the voltage sensor signal SVL, the voltage sensor signal SVH, and the temperature sensor signal ST. A function of outputting an overcurrent detection flag, an overvoltage detection flag, and a temperature abnormality detection flag to the gate signal control unit 22 is provided. The abnormality detection unit 23 is not necessarily provided in the control unit 20 and may be realized by an external analog circuit, a custom IC, or the like.

  As described above, the control unit 20 has a function of controlling the resonant buck-boost converter 10. The control means 20 includes, for example, a CPU, ROM, main memory, etc. (not shown), and various functions of the control means 20 are realized by a control program recorded in the ROM etc. being read into the main memory and executed by the CPU. Is done. However, part or all of the control means 20 may be realized only by hardware. Further, the control means 20 may be physically constituted by a plurality of devices. However, since the statuses of the gate signals G1 to G4 are switched on the order of several μs, the gate signal control unit 22 needs to support high-speed processing. The control means 20 can be provided in, for example, an ECU (Electronic Control Unit).

  FIG. 2 is a block diagram illustrating the inside of the gate signal control unit. FIG. 3 is a diagram illustrating the relationship between the gate signal generated by the gate signal control unit and the status. The gate signal control unit 22 will be described in detail with reference to FIGS. Referring to FIG. 2, the gate signal control unit 22 includes a gate signal generation unit 22a, a status determination unit 22b, a circuit abnormality determination unit 22c, an external SDWN permission determination unit 22d, and a status abnormality determination unit 22e. . Referring to FIG. 3, statuses S1 to S7 are defined for the gate signals G1 to G4.

  The gate signal generation unit 22a has a function of generating gate signals G1 to G4 which are control signals supplied to the gates of the switching elements Q1 to Q4 from the duty command value 31 calculated by the step-up / step-down control unit 21 and the carrier counter 32. Have. The gate signals G1 to G4 generated by the gate signal generation unit 22a are input to the status determination unit 22b. The status determination unit 22b determines which of the statuses S1 to S7 shown in FIG. 3 is the current status, and sends the status determination result to the circuit abnormality determination unit 22c, the external SDWN permission determination unit 22d, and the status abnormality determination unit 22e. Has a function to output.

  The circuit abnormality determination unit 22c is input from the status determination unit 22b when any of the overcurrent detection flag 33, the overvoltage detection flag 34, and the temperature abnormality detection flag 35 input from the abnormality detection unit 23 indicates an abnormality. If the status determination result is other than statuses S3, S4, S6, and S7, the output A is set to zero. If the status determination result input from the status determination unit 22b is any of the statuses S3, S4, S6, and S7, the output A is set to zero after waiting for other statuses (S1, S2, and S5).

  When the SDWN command 26 is input, the external SDWN permission determination unit 22d sets the output B to zero if the status determination result input from the status determination unit 22b is other than the statuses S3, S4, S6, and S7. If the status determination result input from the status determination unit 22b is any of the statuses S3, S4, S6, and S7, the output B is set to zero after waiting for other statuses (S1, S2, and S5).

  The status abnormality determination unit 22e sets the output C to zero when the status determination result input from the status determination unit 22b is other than the statuses S1 to S7. Further, the status abnormality determination unit 22e, if the status transitions out of the order shown in FIG. 3, if the status determination result input from the status determination unit 22b is any of the statuses S3, S4, S6, S7, otherwise The output C is set to zero after waiting until the status (S1, S2, S5) is reached.

  The gate signal generation unit 22a outputs the gate signals G1 to G4 when any one of the output A of the circuit abnormality determination unit 22c, the output B of the external SDWN permission determination unit 22d, and the output C of the status abnormality determination unit 22e is zero. All are turned off (all switching elements Q1 to Q4 are turned off). That is, when all of the switching elements Q1 to Q4 of the resonant buck-boost converter 10 have to be forcibly turned off, the gate signal generation unit 22a has the status determination results of status S3, S4, S6, and S7. All the gate signals G1 to G4 are turned off after waiting for transition to other statuses (S1, S2, S5).

  The status determination result of status S3, S4, S6, S7 means that the switching element Q3 or Q4 is operating. When it is determined that the switching element Q3 or Q4 is operating, the gate signal generation unit 22a does not generate the gate signals G1 to G4 for turning off all the switching elements Q1 to Q4, and the statuses S3 and S4 The gate signals G1 to G4 for turning off all the switching elements Q1 to Q4 are generated after waiting for transition to a status (S1, S2, S5) other than S6, S7.

  In the statuses S3 and S4, since the resonance current flows through the switching element Q4, when the switching element Q4 is turned off in this state, the destination of the resonance current disappears, and the collector of the switching element Q4 (the emitter of the switching element Q3) This is because a high voltage exceeding the withstand voltage may be applied to the switching elements Q3 and Q4. Similarly, in the statuses S6 and S7, since the resonance current flows through the switching element Q3, if the switching element Q3 is turned off in this state, the resonance current does not flow, and the emitter of the switching element Q3 (the collector of the switching element Q4) This is because a high voltage exceeding the withstand voltage may be applied to the switching elements Q3 and Q4.

  According to the resonant buck-boost converter control device according to the present embodiment, when all the switching elements of resonant buck-boost converter 10 must be forcibly turned off (when a shutdown command is received from an external ECU or the like) If the status determination result is status S3, S4, S6, or S7 when a temperature abnormality is detected and the shutdown is necessary, etc., wait until transition to other statuses (S1, S2, S5). To turn off all the gate signals G1 to G4. As a result, a high voltage exceeding the withstand voltage is not applied to each switching element, so that each switching element can be prevented from being destroyed. That is, it is possible to provide a resonance type buck-boost converter control device capable of reliably protecting each switching element.

  Further, since a high voltage exceeding the withstand voltage is not applied to each switching element, it is not necessary to select an expensive switching element with a high withstand voltage. As a result, an inexpensive switching element can be selected, and the cost of the resonant buck-boost converter control device can be reduced.

  Further, according to the resonant buck-boost converter control device according to the present embodiment, since each switching element can be reliably protected, it can be mounted on a vehicle such as a hybrid vehicle.

  The preferred embodiment has been described in detail above. However, the present invention is not limited to the above-described embodiment, and various modifications and replacements are made to the above-described embodiment without departing from the scope described in the claims. Can be added.

  For example, in the present embodiment, an example in which an insulated gate bipolar transistor (IGBT) is used as the switching element Q1, the switching element Q2, the switching element Q3, and the switching element Q4 has been described, but the switching element Q1, the switching element Q2, and the switching element Switching elements other than insulated gate bipolar transistors (IGBTs) may be used for the elements Q3 and Q4. As the switching element Q1, the switching element Q2, the switching element Q3, and the switching element Q4, for example, a field effect transistor (FET), a bipolar transistor, or the like may be used.

  The diode D1 and the diode D2 may be built in the switching element Q1 and the switching element Q2, or may be externally attached.

DESCRIPTION OF SYMBOLS 1 Resonant type buck-boost converter control device 10 Resonant type buck-boost converter 20 Control means 21 Buck-boost control part 22 Gate signal control part 22a Gate signal generation part 22b Status determination part 22c Circuit abnormality determination part 22d External SDWN permission determination part 22e Status abnormality Determination unit 23 Abnormality detection unit 25 Torque command 26 SDWN command 31 Duty command value 32 Carrier counter 33 Overcurrent detection flag 34 Overvoltage detection flag 35 Temperature abnormality detection flag C1, C2, C3, C4 Capacitor D1, D2, D3, D4 Diode G1 , G2, G3, G4 Gate signal L1, L2, Lr Reactor Q1, Q2, Q3, Q4 Switching element S1, S2, S3, S4, S5, S6, S7 Status SIL Current sensor signal ST Temperature sensor signal SVL, SVH Voltage sensor signal

Claims (1)

A resonance type comprising: a first switching element pair; a resonance circuit including a capacitor and a reactor connected to the first switching element pair; and a second switching element pair for discharging the charge accumulated in the capacitor. A buck-boost converter;
Control means for controlling the first switching element pair and the second switching element pair of the resonant buck-boost converter,
The control means generates a determination unit that determines whether or not the second switching element pair is in operation, and a control signal to be supplied to the first switching element pair and the second switching element pair. A control signal generator, and
When the determination unit determines that “the second switching element pair is in operation”, the control signal generation unit determines all of the first switching element pair and the second switching element pair. A resonant buck-boost converter control device that does not generate a control signal for stopping operation.

Images