WO2020012895A1 - Dc-dc converter - Google Patents

Dc-dc converter Download PDF

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Publication number
WO2020012895A1
WO2020012895A1 PCT/JP2019/024207 JP2019024207W WO2020012895A1 WO 2020012895 A1 WO2020012895 A1 WO 2020012895A1 JP 2019024207 W JP2019024207 W JP 2019024207W WO 2020012895 A1 WO2020012895 A1 WO 2020012895A1
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WO
WIPO (PCT)
Prior art keywords
current
voltage side
circuit
converter
low
Prior art date
Application number
PCT/JP2019/024207
Other languages
French (fr)
Japanese (ja)
Inventor
勇輝 山辺
謹 永渕
Original Assignee
日立オートモティブシステムズ株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Application filed by 日立オートモティブシステムズ株式会社 filed Critical 日立オートモティブシステムズ株式会社
Priority to JP2020530066A priority Critical patent/JP7018505B2/en
Publication of WO2020012895A1 publication Critical patent/WO2020012895A1/en

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac

Definitions

  • the present invention relates to a DC-DC converter.
  • the DC-DC converter that performs power conversion from the high voltage side to the low voltage side is provided with a synchronous rectifier circuit and a circuit cutoff switch on the low voltage side, and turns off the circuit cutoff switch according to the value of the current sensor of the low voltage side circuit. ing.
  • the synchronous rectifier circuit and the circuit cutoff switch are unintentionally set to ON, the current flows backward from the low voltage side to the high voltage side, and the components are damaged by the boosting operation. ⁇ May deteriorate.
  • Patent Literature 1 discloses a technique of detecting a reverse current of a current by a current sensor of a low voltage side circuit and performing control to turn off a circuit cutoff switch.
  • a DC-DC converter is a DC-DC converter that steps down an input DC voltage and outputs the reduced DC voltage.
  • the DC-DC converter includes a high-side circuit connected to a primary side of a transformer, and a secondary side of the transformer.
  • a low-voltage side circuit connected and provided with a synchronous rectification circuit and a circuit cutoff switch, a current sensor for detecting currents of the high-voltage side circuit and the low-voltage side circuit, and control for controlling switching of the synchronous rectification circuit and the circuit cutoff switch
  • a control unit wherein at least one of the high-side circuit and the low-side circuit current detected by the current sensor is lower than a predetermined value, the synchronous rectifier circuit or the circuit cutoff. Turn off the switch.
  • FIG. 3 is a circuit configuration diagram of a DC-DC converter. It is a block diagram of a DC-DC converter control device. It is a flowchart which shows the processing operation
  • 5 is a flowchart illustrating a first processing operation of a synchronous rectification switch on / off determination unit.
  • 9 is a flowchart illustrating a second processing operation of a synchronous rectification switch on / off determination unit.
  • 9 is a timing chart showing an example in which the low-voltage side current sensor has failed when the low-voltage side current is low.
  • 9 is a timing chart showing an example in which a low-voltage side current sensor has failed when the low-voltage side current is high.
  • 9 is a timing chart showing another example in which the low voltage side current sensor has failed when the low voltage side current is high.
  • the DC-DC converter according to the present embodiment performs the following control. Before describing the specific configuration, the DC-DC converter will be described.
  • the DC-DC converter in this embodiment performs power conversion from a high voltage side to a low voltage side for a vehicle.
  • voltage control and current control can be switched.
  • the voltage control is a method of controlling the output voltage to be equal to the output voltage command based on the output voltage command received from the external control device.
  • the current control is a method of controlling the low voltage side current so as not to exceed the current limit value based on the current limit value calculated by the DC-DC converter.
  • Switching between voltage control and current control is performed based on the low voltage side current and the current limit value. Voltage control is performed when the low voltage side current is smaller than the current limit value, and current control is performed when the low voltage side current is larger than the current limit value. The control method is switched so that control is performed.
  • the DC-DC converter in the present embodiment can switch between the synchronous switching operation and the asynchronous switching operation.
  • the synchronous switching operation is for performing a switching operation of the MOSFET on the low voltage side, and the switching timing is controlled so as to be synchronized with the MOSFET on the high voltage side.
  • the feature of the synchronous switching operation is that the current responsiveness and the power conversion efficiency are improved, but there is a risk that the current flows backward from the low voltage side to the high voltage side.
  • the asynchronous switching operation is a control for stopping the switching of the MOSFET on the low voltage side and performing power conversion while limiting the flow direction by the parasitic diode. As a feature of the asynchronous switching operation, although the backflow of the current can be prevented, the current responsiveness and the power conversion efficiency are reduced.
  • the switching between the synchronous switching operation and the asynchronous switching operation is performed based on the low voltage side current.
  • the control method is such that the asynchronous switching operation is performed when the low voltage side current is lower than a predetermined value, and the synchronous switching operation is performed when the low voltage side current is higher than the predetermined value. Switch.
  • the reason why the non-synchronous switching operation is performed when the low-voltage side current is lower than the predetermined value is that if the low-voltage side current is small and the synchronous switching operation is performed near 0 A (ampere), the current may flow backward due to the ripple of the low-voltage side current. Because there is.
  • the low voltage side current sensor when the low voltage side current sensor is small, the asynchronous switching operation is performed, and the circuit cutoff switch is turned off, the low voltage side current sensor fails and the sensor value becomes higher than a predetermined value. And the circuit cutoff switch is turned on. At that time, a step-up operation (current reverse flow) occurs due to the current ripple. When the low-voltage side current sensor fails and the sensor value becomes higher than the current limit value, a step-up operation (current reverse flow) occurs due to unintended current control.
  • the current limit value is a value higher than a predetermined value at which the asynchronous switching operation and the circuit cutoff switch are turned off. In the present embodiment, as described below, the occurrence of these step-up operations (current reverse flow) is prevented.
  • FIG. 1 is a circuit configuration diagram of a DC-DC converter 100 according to the present embodiment.
  • the high-voltage side circuit of the DC-DC converter 100 is connected to the high-voltage side battery 300, and the low-voltage side circuit of the DC-DC converter 100 includes the low-voltage side battery 400 and an auxiliary system load 500 (hereinafter, load 500) in parallel. Connected to.
  • the high voltage side circuit and the low voltage side circuit of the DC-DC converter 100 are magnetically coupled via a transformer 140.
  • the DC-DC converter 100 is controlled by a DC-DC converter control device 200.
  • the high-voltage side circuit of the DC-DC converter 100 includes a filter capacitor 120, a current sensor 150, a voltage sensor 160, MOSFETs 110, 111, 112, 113, and a resonance inductor 130.
  • the low voltage side circuit of the DC-DC converter 100 includes smoothing capacitors 121 and 122, smoothing inductors 131 and 132, a current sensor 151, a voltage sensor 161, and MOSFETs 114, 115, 116 and 117.
  • the high-potential side of the high-voltage battery 300 is connected to one end of the filter capacitor 120, one end of the voltage sensor 160, and the drains of the MOSFETs 110 and 112, and the low-potential side of the high-voltage battery 300 is connected to the other end of the filter capacitor 120.
  • the other end of the voltage sensor 160 and the sources of the MOSFETs 111 and 113 are connected.
  • the high-voltage battery 300 is a nickel-metal hydride battery, a lithium-ion battery, or the like.
  • the filter capacitor 120 has one end connected to the high potential side of the high voltage side battery 300, one end of the voltage sensor 160, and the drains of the MOSFETs 110 and 112, and the other end of the filter capacitor 120 connected to the low potential side of the high voltage side battery 300. And the other end of the voltage sensor 160 and the sources of the MOSFETs 111 and 113.
  • the current sensor 150 is connected to the other end of the filter capacitor 120, the other end of the voltage sensor 160, the sources of the MOSFETs 111 and 113, and the low potential side of the high voltage side battery 300.
  • the detection value of the current sensor 150 is input to the DC-DC converter control device 200 as the high-voltage side current I10.
  • the current sensor 150 includes a shunt resistor, a Hall element, and the like.
  • the voltage sensor 160 has one end connected to the high potential side of the high voltage side battery 300, one end of the filter capacitor 120, and the drains of the MOSFETs 110 and 112, and the other end of the voltage sensor 160 connected to the low potential side of the high voltage side battery 300. And the other end of the filter capacitor 120 and the sources of the MOSFETs 111 and 113.
  • the input voltage V10 detected by the voltage sensor 160 is input to the DC-DC converter control device 200.
  • the voltage sensor 160 includes a non-inverting amplifier and a differential amplifier using a voltage dividing resistor and an operational amplifier.
  • the drain of the MOSFET 110 is connected to the high potential side of the high-voltage battery 300, one end of the filter capacitor 120, one end of the voltage sensor 160, and the drain of the MOSFET 112.
  • the source of the MOSFET 110 is the drain of the MOSFET 111, and one end of the resonance inductor 130. Connected to.
  • the drain of the MOSFET 111 is connected to the source of the MOSFET 110 and one end of the resonance inductor 130, and the source of the MOSFET 111 is connected to the low potential side of the high-voltage battery 300, the other end of the filter capacitor 120, and the other end of the voltage sensor 160. , MOSFET 113.
  • the drain of the MOSFET 112 is connected to the high potential side of the high-voltage battery 300, one end of the filter capacitor 120, one end of the voltage sensor 160, and the drain of the MOSFET 110.
  • the source of the MOSFET 112 is the drain of the MOSFET 113 and one end of the transformer 140. Connected to.
  • the drain of the MOSFET 113 is connected to the source of the MOSFET 112 and one end of the transformer 140, and the source of the MOSFET 113 is connected to the low potential side of the high-voltage battery 300, the other end of the filter capacitor 120, the other end of the voltage sensor 160, and the source of the MOSFET 111. Connected to.
  • the resonance inductor 130 one end of the resonance inductor 130 is connected to the source of the MOSFET 110 and the drain of the MOSFET 111, and the other end of the resonance inductor 130 is connected to one end of the high-voltage side winding 141 of the transformer 140.
  • the resonance inductor 130 may be replaced with a leakage inductance of the transformer 140 or a wiring inductance.
  • the transformer 140 includes the high-voltage side winding 141 and the low-voltage side windings 142 and 143.
  • the high voltage side winding 141 of the transformer 140 has one end of the high voltage side winding 141 connected to the resonance inductor 130, and the other end connected to the source of the MOSFET 112 and the drain of the MOSFET 113.
  • the low-voltage winding 142 of the transformer 140 has one end of the low-voltage winding 142 connected to the drain of the MOSFET 114, and the other end of the low-voltage winding 142 connected to the low-voltage winding 143 on the secondary side of the transformer 140. And one end of the smoothing inductor 131.
  • the low voltage side winding 143 of the transformer 140 has one end of the low voltage side winding 143 connected to the other end of the secondary side low voltage side winding 142 of the transformer 140 and one end of the smoothing inductor 131.
  • the other end of the line 143 is connected to the drain of the MOSFET 115.
  • the smoothing capacitor 121 has one end connected to the other end of the smoothing inductor 131 and the drain of the MOSFET 116, and the other end of the smoothing capacitor 121 connected to the current sensor 151, the smoothing capacitor 122, and the voltage sensor. 161, the low potential side of the low voltage side battery 400, and the load 500.
  • the smoothing capacitor 122 has one end connected to the smoothing inductor 132, one end of the voltage sensor 161, the high potential side of the low-voltage battery 400, and one end of the load 500. The ends are connected to the current sensor 151, the other end of the smoothing capacitor 121, the other end of the voltage sensor 161, the low potential side of the low-voltage battery 400, and the other end of the load 500.
  • the smoothing inductor 131 has one end connected to the other end of the low-voltage side winding 142 and one end of the low-voltage side winding 143 of the transformer 140, the other end of the smoothing inductor 131 connected to the drain of the MOSFET 116, Connected to one end of smoothing capacitor 121.
  • One end of the smoothing inductor 132 is connected to the drain of the MOSFET 117, and the other end of the smoothing inductor 132 is connected to one end of the smoothing capacitor 122, one end of the voltage sensor 161, and the high potential of the low voltage side battery 400. Side and one end of the load 500.
  • the current sensor 151 is connected to the sources of the MOSFETs 114 and 115, the other ends of the smoothing capacitors 121 and 122, the other end of the voltage sensor 161, the low potential side of the low-voltage battery 400, and the other end of the load 500. . Then, the detection value of the current sensor 151 is input to the DC-DC converter control device 200 as the low-voltage side current I11.
  • the current sensor 151 includes a shunt resistor, a Hall element, and the like.
  • the voltage sensor 161 has one end connected to the other end of the smoothing inductor 132, one end of the smoothing capacitor 122, the high potential side of the low-voltage battery 400, and one end of the load 500. The other end is connected to the current sensor 151, the other ends of the smoothing capacitors 121 and 122, the low potential side of the low-voltage battery 400, and the other end of the load 500.
  • the output voltage V11 of the voltage sensor 161 is input to the DC-DC converter control device 200.
  • the voltage sensor 161 includes a non-inverting amplifier and a differential amplifier using a voltage dividing resistor and an operational amplifier.
  • the drain of the MOSFET 114 is connected to one end of the low-voltage winding 142 of the transformer 140, and the source of the MOSFET 114 is connected to the source of the MOSFET 115 and the current sensor 151.
  • the drain of the MOSFET 115 is connected to the other end of the low voltage side winding 143 of the transformer 140, and the source of the MOSFET 115 is connected to the source of the MOSFET 114 and the current sensor 151.
  • the MOSFETs 114 and 115 constitute a synchronous rectification circuit (synchronous rectification switch).
  • the drain of the MOSFET 116 is connected to the other end of the smoothing inductor 131 and one end of the smoothing capacitor 121, and the source of the MOSFET 116 is connected to the source of the MOSFET 117.
  • the drain of the MOSFET 117 is connected to one end of the smoothing inductor 132, and the source of the MOSFET 117 is connected to the source of the MOSFET 116.
  • the MOSFET 117 forms a circuit cutoff switch.
  • one end of the low-voltage battery 400 is connected to the other end of the smoothing inductor 132, one end of the voltage sensor 161, one end of the smoothing capacitor 122, and one end of the load 500.
  • the other end of the smoothing capacitor 122, the other end of the voltage sensor 161, the current sensor 151, and the other end of the load 500 are connected.
  • the low-voltage side battery 400 is configured by a lead storage battery or the like.
  • the load 500 has one end connected to the other end of the smoothing inductor 132, one end of the voltage sensor 161, one end of the smoothing capacitor 122, and the high potential side of the low-voltage battery 400.
  • the other end of the capacitor 122, the other end of the voltage sensor 161, the current sensor 151, and the low potential side of the low voltage side battery 400 are connected.
  • the temperature sensor 170 is installed in the DC-DC converter 100, and the temperature T10 of the temperature sensor 170 is input to the DC-DC converter control device 200.
  • the DC-DC converter control device 200 turns on the MOSFET 110, which is a switching element of the DC-DC converter 100, based on the input voltage V10, the output voltage V11, the high-side current I10, the low-side current I11, and the temperature T10.
  • a gate voltage V20 for controlling / OFF is generated, and the generated gate voltage V20 is input to the gate of the MOSFET 110.
  • the DC-DC converter control device 200 similarly inputs the gate voltage V21 to the gate of the MOSFET 111, the gate voltage V22 to the gate of the MOSFET 112, the gate voltage V23 to the gate of the MOSFET 113, and the gate voltage V24.
  • the gate voltage of the MOSFET 114 is input, the gate voltage V25 is input to the gate of the MOSFET 115, the gate voltage V26 is input to the gate of the MOSFET 116, and the gate voltage V27 is input to the gate of the MOSFET 117.
  • FIG. 2 is a configuration diagram of the DC-DC converter control device 200 according to the embodiment of the present invention.
  • the DC-DC converter control device 200 includes a first control device 210 and a second control device 220.
  • the first control device 210 includes an A / D converter 211 that converts an analog value into a digital value, a communication device 212 that communicates with an external control device and the second control device 220, a circuit cutoff switch on / off determination unit 213, It includes a limit value calculation unit 214, a communication device 215 that communicates with the second control device 220, a switching signal generation unit 216, and a gate drive circuit 217.
  • the second control device 220 includes an A / D converter 221 that converts an analog value into a digital value, a communication device 222 that communicates with the first control device 210, a control method switching unit 223 that switches between voltage control and current control, It includes a duty calculation section 224, a synchronous rectification switch on / off determination section 225, a switching signal generation section 226, and a gate drive circuit 227.
  • the A / D converter 211 converts the analog value of the input voltage V10 of the DC-DC converter 100 detected by the voltage sensor 160 into a digital value VD10.
  • the A / D converter 211 converts the analog value of the output voltage V11 of the DC-DC converter 100 detected by the voltage sensor 161 into a digital value VD11.
  • the A / D converter 211 converts an analog value of the high-side current I10 of the DC-DC converter 100 detected by the current sensor 150 into a digital value ID10.
  • the A / D converter 211 converts an analog value of the low-voltage side current I11 of the DC-DC converter 100 detected by the current sensor 151 into a digital value ID11.
  • the A / D converter 211 converts an analog value of the temperature T10 of the DC-DC converter 100 detected by the temperature sensor 170 into a digital value TD10.
  • the circuit cutoff switch on / off determination unit 213 generates a circuit cutoff switch on / off switching flag fSwitch1 based on the digital value ID10 of the high voltage side current I10 and the digital value ID11 of the low voltage side current I11.
  • the current limit value calculation unit 214 calculates the current limit value Ilim based on the digital value VD10 of the input voltage V10, the digital value VD11 of the output voltage V11, and the digital value TD10 of the temperature T10.
  • the current limit value calculation unit 214 includes an input voltage limit value calculation unit (not shown) therein.
  • the input voltage limit value calculation unit calculates an input voltage / current limit value Ilim_VD10 based on the digital value VD10 of the input voltage V10.
  • the calculation method uses a map calculation or the like.
  • the input voltage limit value calculator calculates an output voltage / current limit value Ilim_VD11 based on the digital value VD11 of the output voltage V11.
  • the calculation method uses a map calculation or the like.
  • the input voltage limit value calculation unit calculates a temperature current limit value Ilim_TD10 based on the digital value TD10 of the temperature T10.
  • the calculation method uses a map calculation or the like. Then, the minimum value is calculated as the current limit value Ilim based on the input voltage / current limit value Ilim_VD10, the output voltage / current limit value Ilim_VD11, and the temperature / current limit value Ilim_TD10.
  • the communication unit 212 transmits the output voltage command Vref received from the external control device and the current limit value Ilim calculated by the current limit value calculation unit 214 to the second control device 220.
  • the switching signal generation section 216 generates ON / OFF signals S26 and S27 for the MOSFETs 116 and 117 of the DC-DC converter 100 based on the circuit cutoff switch on / off switching flag fSwitch1 generated by the circuit cutoff switch on / off determination section 213.
  • the gate drive circuit 217 turns ON / OFF the MOSFETs 116 and 117 of the DC-DC converter 100 based on the ON / OFF signals S26 and S27 of the MOSFETs 116 and 117 of the DC-DC converter 100 generated by the switching signal generation unit 216. Gate voltages V26 and V27 are generated.
  • the A / D converter 221 converts the analog value of the input voltage V10 of the DC-DC converter 100 detected by the voltage sensor 160 into a digital value VD10.
  • the A / D converter 221 converts the analog value of the output voltage V11 of the DC-DC converter 100 detected by the voltage sensor 161 into a digital value VD11.
  • the A / D converter 221 converts the analog value of the high-side current I10 of the DC-DC converter 100 detected by the current sensor 150 into a digital value ID10. Further, the A / D converter 221 converts the analog value of the low voltage side current I11 of the DC-DC converter 100 detected by the current sensor 151 into a digital value ID11.
  • the communication device 222 receives the output voltage command Vref and the current limit value Ilim from the communication device 212.
  • the duty calculation unit 224 is based on the output voltage command Vref, the current limit value Ilim, the digital value VD10 of the input voltage V10, the digital value VD11 of the output voltage V11, the digital value ID11 of the low-voltage side current I11, and the control method switching flag fSwitch3. , MOSFETs 110, 111, 112, and 113 are calculated.
  • the synchronous rectification switch on / off determination unit 225 generates a synchronous rectification switch on / off switching flag fSwitch2 based on the digital value ID10 of the high voltage side current I10, the digital value ID11 of the low voltage side current I11, and the control method switching flag fSwitch3.
  • the switching signal generation unit 226 determines the MOSFETs 110, 111 of the DC-DC converter 100 based on the Duty of the MOSFETs 110, 111, 112, 113 of the DC-DC converter 100 calculated by the duty calculation unit 224 and the synchronous rectification switch on / off switching flag fSwitch2. , 112, 113, 114, and 115 are generated as ON / OFF signals S 20, S 21, S 22, S 23, S 24, and S 25.
  • the gate drive circuit 227 is based on the ON / OFF signals S20, S21, S22, S23, S24, and S25 of the MOSFETs 110, 111, 112, 113, 114, and 115 of the DC-DC converter 100 generated by the switching signal generator 226. , A gate voltage V20, V21, V22, V23, V24, V25 for turning on / off the MOSFET 110, 111, 112, 113, 114, 115 of the DC-DC converter 100.
  • FIG. 3 is a flowchart showing the processing operation of the circuit cutoff switch on / off determination unit 213. This flowchart shows a processing operation per one processing cycle, and the circuit cutoff switch on / off determination unit 213 repeatedly performs this processing operation.
  • step A10 the processing operation is started, and the process proceeds to step A20.
  • step A20 it is determined whether the digital value ID11 of the low voltage side current I11 is lower than a predetermined value LvIlim, and if it is lower, the process proceeds to step A50. If it is higher than the predetermined value LvIlim, the process transits to Step A30.
  • step A30 it is determined whether the digital value ID10 of the high-side current is lower than a predetermined value HvIlim. If it is higher than the predetermined value HvIlim, the process transits to Step A40.
  • step A40 0 is set to the circuit cutoff switch on / off switching flag fSwitch1 and output.
  • 0 is set to the circuit cutoff switch on / off switching flag fSwitch1
  • a request is made to the switching signal generator 216 to turn on the MOSFET 117, which is one of the circuit cutoff switches.
  • the process transits to Step A60.
  • step A50 1 is set to a circuit cutoff switch on / off switching flag fSwitch1 and output.
  • the circuit cutoff switch on / off switching flag fSwitch1 is set to 1
  • a request is made to the switching signal generator 216 to turn off the MOSFET 117, which is one of the circuit cutoff switches.
  • the process transits to Step A60.
  • step A60 the processing of one processing cycle performed by the circuit cutoff switch on / off determination unit 213 ends.
  • FIG. 4 is a flowchart showing a first processing operation of the synchronous rectification switch on / off determination unit 225. This flowchart shows a processing operation per one processing cycle, and the synchronous rectification switch on / off determination unit 225 repeatedly performs this processing operation.
  • step B10 the process is started, and the process proceeds to step B20.
  • step B20 it is determined whether the digital value ID11 of the low voltage side current I11 is lower than a predetermined value LvIlim, and if it is lower, the process proceeds to step B50.
  • the digital value ID11 of the low voltage side current I11 is higher than the predetermined value LvIlim, the process proceeds to Step B30.
  • step B30 it is determined whether the digital value ID10 of the high-voltage side current I10 is lower than a predetermined value HvIlim. If the digital value ID10 is lower, the process proceeds to step B50. When the digital value ID10 of the high-voltage side current I10 is higher than the predetermined value HvIlim, the process proceeds to Step B40.
  • step B40 the synchronous rectification switch ON / OFF switching flag fSwitch2 is set to 0 and output.
  • the switching signal generation unit 226 is instructed so that the MOSFETs 114 and 115, which are synchronous rectification switches, perform a switching operation based on the duty ratio calculated by the duty calculation unit 224. Request.
  • the process transits to Step B60.
  • step B50 the synchronous rectification switch on / off switching flag fSwitch2 is set to 1 and output.
  • the synchronous rectification switch on / off switching flag fSwitch2 is set to 1 and output.
  • a request is made to the switching signal generation unit 226 to turn off the MOSFETs 114 and 115, which are synchronous rectification switches.
  • the process transits to Step B60.
  • step B60 the processing of one processing cycle performed by the synchronous rectification switch on / off determination unit 225 is completed.
  • FIG. 5 is a flowchart illustrating a second processing operation of the synchronous rectification switch on / off determination unit 225. This flowchart shows a processing operation per one processing cycle, and the synchronous rectification switch on / off determination unit 225 repeatedly performs this processing operation.
  • the synchronous rectification switch on / off determining unit 225 may be the first processing operation shown in FIG. 4 or the second processing operation shown in this example.
  • step C10 the process is started, and the process proceeds to step C20.
  • step C20 it is determined whether the digital value ID11 of the low voltage side current I11 is lower than a predetermined value LvIlim, and if it is lower, the process proceeds to step C50.
  • the digital value ID11 of the low voltage side current I11 is higher than the predetermined value LvIlim, the process proceeds to Step C30.
  • step C40 the synchronous rectification switch on / off switching flag fSwitch2 is set to 0 and output.
  • the switching signal generation unit 226 is instructed so that the MOSFETs 114 and 115, which are synchronous rectification switches, perform a switching operation based on the duty ratio calculated by the duty calculation unit 224. Request.
  • the process transits to Step C60.
  • step C50 the synchronous rectification switch on / off switching flag fSwitch2 is set to 1 and output.
  • the synchronous rectification switch on / off switching flag fSwitch2 is set to 1 and output.
  • a request is made to the switching signal generation unit 226 to turn off the MOSFETs 114 and 115, which are synchronous rectification switches.
  • the process transits to Step C60.
  • step C60 the processing of one processing cycle performed by the synchronous rectification switch on / off determination unit 225 is ended.
  • FIG. 6 is a timing chart showing an example in which the low voltage side current sensor 151 has failed when the low voltage side current I11 is low.
  • the digital value ID11 of the low voltage side current is lower than the predetermined value LvIlim (when the asynchronous switching operation and the circuit cutoff switch are off)
  • the low voltage side current sensor 151 fails at time t1.
  • the digital value ID11 of the low voltage side current I11 is higher than a predetermined value LvIlim.
  • the ON / OFF signal S27 of the MOSFET 117 of the DC-DC converter 100 is turned off by the switching signal generation unit 216, and the circuit cutoff switch (the low-voltage side of the DC-DC converter 100) is turned off.
  • MOSFET 117) in the circuit is turned off.
  • the synchronous rectification switch on / off determination unit 225 keeps the synchronous rectification switch on / off switching flag fSwitch2 set to 1 as shown in FIG. Then, as shown in FIG. 6F, the ON / OFF signals S24 and S25 of the MOSFETs 114 and 115 of the DC-DC converter 100 are turned off by the switching signal generation unit 226, and the circuit cutoff switch (DC-DC converter The MOSFETs 114 and 115 in the low-voltage side circuit 100 are turned off.
  • the predetermined value LvIlim and the predetermined value HvIlim used in the circuit cutoff switch on / off judgment unit 213 and the synchronous rectification switch on / off judgment unit 225 are the currents caused by the current ripple of the low voltage side circuit when the synchronous switching operation and the circuit cutoff switch are on. Is set to a value that does not cause the boosting operation due to the backflow of.
  • the predetermined value LvIlim and the predetermined value HvIlim are appropriately set from the outside to the circuit cutoff switch on / off determination unit 213 and the synchronous rectification switch on / off determination unit 225, and the circuit cutoff switch on / off determination unit 213 and the synchronous rectification switch on / off.
  • the determination unit 225 may execute the processing shown in FIGS. 3 to 5 using the set value.
  • FIG. 7 is a timing chart showing an example in which the low voltage side current sensor 151 has failed when the low voltage side current I11 is high.
  • This timing chart shows a case where the first processing operation of the synchronous rectification switch on / off determination unit 225 shown in FIG. 4 is applied.
  • FIG. 7A when the digital value ID11 of the low-voltage side current I11 is higher than the predetermined value LvIlim and lower than the current limit value Ilim (when the voltage control and the synchronous switching operation are performed and the circuit cutoff switch is turned on).
  • An example is shown in which the low voltage side current sensor 151 fails at time t1 and the digital value ID11 of the low voltage side current I11 becomes higher than the current limit value Ilim.
  • the control method switching unit 223 performs current control.
  • Set fSwitch3 1.
  • the digital value ID10 of the high-voltage side current I10 decreases as shown in FIG. 7C.
  • the digital value ID10 of the high-voltage side current I10 becomes lower than the predetermined value HvIlim, as shown in FIG. Set. Then, as shown in FIG.
  • the ON / OFF signal S27 of the MOSFET 117 of the DC-DC converter 100 is set to OFF by the switching signal generation unit 216, and the circuit cutoff switch (the low-voltage side of the DC-DC converter 100) MOSFET 117) in the circuit is turned off.
  • the synchronous rectification switch on / off switching flag fSwitch2 is set to 1 by the synchronous rectification switch on / off determination unit 225. Then, as shown in FIG. 7 (f), the switching signal generation unit 226 sets the ON / OFF signals S24 and S25 of the MOSFETs 114 and 115 of the DC-DC converter 100 to OFF, and the synchronous rectification switch (DC-DC converter The MOSFETs 114 and 115 in the low-voltage side circuit 100 are turned off.
  • the predetermined value LvIlim and the predetermined value HvIlim used in the circuit cutoff switch on / off determination unit 213 and the synchronous rectification switch on / off determination unit 225 are designed based on the response of the current control and the switching cycle of the circuit cutoff switch or the synchronous rectification switch. It is necessary to set a value that can prevent a step-up operation (current reverse flow) due to current control.
  • FIG. 8 is a timing chart showing another example in which the low voltage side current sensor 151 has failed when the low voltage side current I11 is high.
  • This timing chart shows a case where the second processing operation of the synchronous rectification switch on / off determination unit 225 shown in FIG. 5 is applied.
  • FIG. 8A when the digital value ID11 of the low-voltage side current I11 is higher than the predetermined value LvIlim and lower than the current limit value Ilim (when the voltage control and the synchronous switching operation are performed and the circuit cutoff switch is turned on).
  • An example is shown in which the low voltage side current sensor 151 fails at time t1 and the digital value ID11 of the low voltage side current becomes higher than the current limit value Ilim.
  • the control method switching unit 223 performs the current control.
  • Set fSwitch3 1.
  • the synchronous rectification switch on / off determination unit 225 sets 1 to the synchronous rectification switch on / off switching flag fSwitch2 as shown in FIG. Then, as shown in FIG.
  • the switching signal generation unit 226 sets the ON / OFF signals S24 and S25 of the MOSFETs 114 and 115 of the DC-DC converter 100 to OFF, and the synchronous rectification switch (DC-DC converter The MOSFETs 114 and 115 in the low-voltage side circuit 100 are turned off.
  • the digital value ID10 of the high-side current decreases due to the current control, and at time t2, the digital value ID10 of the high-side current becomes lower than the predetermined value HvIlim.
  • the circuit cutoff switch on / off determination unit 213 sets 1 to the circuit cutoff switch on / off switching flag fSwitch1.
  • the ON / OFF signal S27 of the MOSFET 117 of the DC-DC converter 100 is turned off by the switching signal generation unit 216, and the circuit cutoff switch (the low-voltage side of the DC-DC converter 100) is turned off.
  • MOSFET 117) in the circuit is turned off.
  • the DC-DC converter 100 is a DC-DC converter 100 that steps down and outputs an input DC voltage, and includes a high-voltage side circuit connected to the primary side of a transformer 140 and a transformer 140.
  • a low voltage side circuit connected to the next side and including synchronous rectification circuit MOSFETs 114 and 115 and a circuit cutoff switch MOSFET 117; current sensors 150 and 151 for detecting currents of the high voltage side circuit and the low voltage side circuit; A control unit 200 for controlling switching of the circuit cutoff switch MOSFET 117, wherein the control unit 200 detects that at least one of the currents of the high voltage side circuit and the low voltage side circuit detected by the current sensors 150 and 151 is lower than a predetermined value. In this case, the synchronous rectification circuit MOSFETs 114 and 115 or To turn off the switch MOSFET117.
  • the predetermined value of the current is preferably a value that does not cause a boosting operation due to a reverse current of the current caused by the current ripple of the low-voltage side circuit.
  • the low voltage side current and the high voltage side current have a positive correlation. Therefore, when the low-voltage side current is small, the asynchronous switching operation is performed, and the circuit cutoff switch is turned off, the low-voltage side current sensor fails and even if the low-voltage side current sensor value becomes higher than the predetermined value, the high-voltage side current sensor fails. The sensor value of the current remains below the predetermined value. As a result, an unintended synchronous switching operation and circuit break switch-on do not occur, and a boosting operation due to a reverse current is prevented.
  • the control unit 200 controls the synchronous rectification circuit MOSFETs 114 and 115 and the circuit cutoff switch MOSFET 117. Turn off both. As a result, even if one of the high-voltage side current sensor and the low-voltage side current sensor fails, it is possible to prevent the boosting operation due to the current reverse flow.
  • the control unit 200 controls the synchronous rectification circuit MOSFET 114 while the DC-DC converter 100 is executing the current control based on the output current when the current of the low-voltage side circuit exceeds a predetermined current limit value Ilim. , 115 are turned off.
  • the current limit value Ilim is a value higher than a predetermined value at which the asynchronous switching operation and the circuit cutoff switch are turned off.
  • the present invention is not limited to the above embodiments, and other forms that can be considered within the scope of the technical idea of the present invention are also included in the scope of the present invention unless the characteristics of the present invention are impaired. . Further, a configuration in which the above embodiments are combined may be adopted.
  • DC-DC converter 110 111, 112, 113 MOSFET 114, 115, 116, 117 MOSFET Reference Signs List
  • filter capacitor 121 122 smoothing capacitor 130 resonance inductor 140 transformer 141 high-voltage side winding 142, 143 low-voltage side winding 150, 151 current sensor 160, 161 voltage sensor 170 temperature sensor 200
  • DC-DC converter controller 300 high voltage Side battery 400 low voltage side battery 500 load

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Abstract

The purpose of the present invention is to prevent, in advance, a boosting action in which the current flows back from the low-voltage side to the high-voltage side when a current sensor experiences a malfunction. In step A20, a determination is made as to whether or not the digital value ID11 of a low-voltage-side current I11 is lower than a prescribed value LvIlim, and if so, the process flow proceeds to step A50. In step A30, a determination is made as to whether or not the digital value ID10 of a high-voltage-side current is lower than a prescribed value HvIlim, and if so, the process flow proceeds to step A50. In step A50, a circuit cutoff switch on/off switching flag fSwitch1 is set to 1 and outputed. If the circuit cutoff switch on/off switching flag fSwitch1 is set to 1, a request is made to a switching signal generator 216 so that a MOSFET 117, which is one of circuit cutoff switches, is switched off.

Description

ＤＣ－ＤＣコンバータDC-DC converter
　本発明は、ＤＣ－ＤＣコンバータに関する。 The present invention relates to a DC-DC converter.
　高圧側から低圧側へ電力変換を実施するＤＣ－ＤＣコンバータは、低圧側に同期整流回路および回路遮断スイッチを備え、低圧側回路の電流センサの値に応じて回路遮断スイッチをオフする構成になっている。このようなＤＣ－ＤＣコンバータにおいて、電流センサが故障した場合に、意図せず同期整流回路および回路遮断スイッチをオンに設定し、低圧側から高圧側へ電流が逆流して昇圧動作により部品が破損・劣化する場合がある。
　特許文献１には、低圧側回路の電流センサによって電流の逆流を検知して回路遮断スイッチをオフする制御を行う技術が記載されている。 The DC-DC converter that performs power conversion from the high voltage side to the low voltage side is provided with a synchronous rectifier circuit and a circuit cutoff switch on the low voltage side, and turns off the circuit cutoff switch according to the value of the current sensor of the low voltage side circuit. ing. In such a DC-DC converter, when the current sensor fails, the synchronous rectifier circuit and the circuit cutoff switch are unintentionally set to ON, the current flows backward from the low voltage side to the high voltage side, and the components are damaged by the boosting operation.・ May deteriorate.
Patent Literature 1 discloses a technique of detecting a reverse current of a current by a current sensor of a low voltage side circuit and performing control to turn off a circuit cutoff switch.
特開２００９-１４８１３１号公報JP 2009-148131 A
　特許文献１に記載の技術では、電流センサが故障した場合に、低圧側から高圧側へ電流が逆流する昇圧動作を未然に防止することができない。 According to the technique described in Patent Document 1, when a current sensor fails, a boosting operation in which a current flows backward from a low voltage side to a high voltage side cannot be prevented beforehand.
　本発明によるＤＣ－ＤＣコンバータは、入力された直流電圧を降圧して出力するＤＣ－ＤＣコンバータであって、変圧器の一次側に接続された高圧側回路と、前記変圧器の二次側に接続され、同期整流回路および回路遮断スイッチを備える低圧側回路と、前記高圧側回路および前記低圧側回路の電流を検出する電流センサと、前記同期整流回路および前記回路遮断スイッチのスイッチングを制御する制御部と、を備え、前記制御部は、前記電流センサで検出された前記高圧側回路および前記低圧側回路の電流の少なくとも一方が所定の値よりも低い場合に、前記同期整流回路または前記回路遮断スイッチをオフにする。 A DC-DC converter according to the present invention is a DC-DC converter that steps down an input DC voltage and outputs the reduced DC voltage. The DC-DC converter includes a high-side circuit connected to a primary side of a transformer, and a secondary side of the transformer. A low-voltage side circuit connected and provided with a synchronous rectification circuit and a circuit cutoff switch, a current sensor for detecting currents of the high-voltage side circuit and the low-voltage side circuit, and control for controlling switching of the synchronous rectification circuit and the circuit cutoff switch A control unit, wherein at least one of the high-side circuit and the low-side circuit current detected by the current sensor is lower than a predetermined value, the synchronous rectifier circuit or the circuit cutoff. Turn off the switch.
　本発明によれば、電流センサが故障した場合であっても、低圧側から高圧側へ電流が逆流する昇圧動作を未然に防止することができる。 According to the present invention, even when the current sensor fails, a boosting operation in which a current flows backward from a low voltage side to a high voltage side can be prevented beforehand.
ＤＣ－ＤＣコンバータの回路構成図である。FIG. 3 is a circuit configuration diagram of a DC-DC converter. ＤＣ－ＤＣコンバータ制御装置の構成図である。It is a block diagram of a DC-DC converter control device. 回路遮断スイッチオンオフ判定部の処理動作を示すフローチャートである。It is a flowchart which shows the processing operation | movement of a circuit interruption switch ON / OFF determination part. 同期整流スイッチオンオフ判定部の第１の処理動作を示すフローチャートである。5 is a flowchart illustrating a first processing operation of a synchronous rectification switch on / off determination unit. 同期整流スイッチオンオフ判定部の第２の処理動作を示すフローチャートである。9 is a flowchart illustrating a second processing operation of a synchronous rectification switch on / off determination unit. 低圧側電流が低い場合に低圧側の電流センサが故障した例を示すタイミングチャートである。9 is a timing chart showing an example in which the low-voltage side current sensor has failed when the low-voltage side current is low. 低圧側電流が高い場合に低圧側の電流センサが故障した例を示すタイミングチャートである。9 is a timing chart showing an example in which a low-voltage side current sensor has failed when the low-voltage side current is high. 低圧側電流が高い場合に低圧側の電流センサが故障した他の例を示すタイミングチャートである。9 is a timing chart showing another example in which the low voltage side current sensor has failed when the low voltage side current is high.
　本実施形態におけるＤＣ－ＤＣコンバータは、以下に述べる制御を行うものであり、具体的な構成を説明する前にＤＣ－ＤＣコンバータについて述べる。 ＤＣ The DC-DC converter according to the present embodiment performs the following control. Before describing the specific configuration, the DC-DC converter will be described.
　本実施形態におけるＤＣ－ＤＣコンバータは、車載用に高圧側から低圧側へ電力変換を実施する。そして、制御方式として電圧制御と電流制御を切り替えることができる。電圧制御とは、外部制御装置から受信した出力電圧指令に基づいて、出力電圧が出力電圧指令に等しくなるよう制御する方式である。電流制御とは、ＤＣ－ＤＣコンバータが算出した電流制限値に基づいて、低圧側電流が電流制限値を超えないように制御する方式である。 ＤＣ The DC-DC converter in this embodiment performs power conversion from a high voltage side to a low voltage side for a vehicle. As a control method, voltage control and current control can be switched. The voltage control is a method of controlling the output voltage to be equal to the output voltage command based on the output voltage command received from the external control device. The current control is a method of controlling the low voltage side current so as not to exceed the current limit value based on the current limit value calculated by the DC-DC converter.
　また、電圧制御と電流制御の切り替えは低圧側電流と電流制限値に基づいて実施し、低圧側電流が電流制限値より少ない場合は電圧制御に、低圧側電流が電流制限値より多い場合は電流制御となるように制御方式を切り替える。 Switching between voltage control and current control is performed based on the low voltage side current and the current limit value. Voltage control is performed when the low voltage side current is smaller than the current limit value, and current control is performed when the low voltage side current is larger than the current limit value. The control method is switched so that control is performed.
　さらに、本実施形態におけるＤＣ－ＤＣコンバータは同期スイッチング動作と非同期スイッチング動作を切り替えることができる。同期スイッチング動作は、低圧側のＭＯＳＦＥＴのスイッチング動作を行うものであり、そのスイッチングタイミングは高圧側のＭＯＳＦＥＴと同期させるように制御するものである。同期スイッチング動作の特徴は、電流応答性及び電力変換効率は向上するが、電流が低圧側から高圧側へ逆流が発生するリスクが存在する。一方、非同期スイッチング動作は、低圧側のＭＯＳＦＥＴのスイッチングを停止し、寄生ダイオードにより通流方向を制限しながら電力変換を実施する制御である。非同期スイッチング動作の特徴は、電流の逆流を防止できるものの、電流応答性及び電力変換効率は低下する。 Furthermore, the DC-DC converter in the present embodiment can switch between the synchronous switching operation and the asynchronous switching operation. The synchronous switching operation is for performing a switching operation of the MOSFET on the low voltage side, and the switching timing is controlled so as to be synchronized with the MOSFET on the high voltage side. The feature of the synchronous switching operation is that the current responsiveness and the power conversion efficiency are improved, but there is a risk that the current flows backward from the low voltage side to the high voltage side. On the other hand, the asynchronous switching operation is a control for stopping the switching of the MOSFET on the low voltage side and performing power conversion while limiting the flow direction by the parasitic diode. As a feature of the asynchronous switching operation, although the backflow of the current can be prevented, the current responsiveness and the power conversion efficiency are reduced.
　同期スイッチング動作と非同期スイッチング動作の切り替えは低圧側電流に基づいて実施し、低圧側電流が所定値より低い場合は非同期スイッチング動作、所定値よりも高い場合は同期スイッチング動作となるように制御方式を切り替える。低圧側電流が所定値より低い場合に非同期スイッチング動作とする理由は、低圧側の電流が小さく0Ａ（アンペア）近傍で同期スイッチング動作を実施すると低圧側の電流のリプルにより電流の逆流が発生するリスクがあるためである。 The switching between the synchronous switching operation and the asynchronous switching operation is performed based on the low voltage side current.The control method is such that the asynchronous switching operation is performed when the low voltage side current is lower than a predetermined value, and the synchronous switching operation is performed when the low voltage side current is higher than the predetermined value. Switch. The reason why the non-synchronous switching operation is performed when the low-voltage side current is lower than the predetermined value is that if the low-voltage side current is small and the synchronous switching operation is performed near 0 A (ampere), the current may flow backward due to the ripple of the low-voltage side current. Because there is.
　一般に、低圧側電流が小さく、非同期スイッチング動作で、かつ回路遮断スイッチオフとなるような条件の時に、低圧側の電流センサが故障し、センサ値が所定値より高くなると、意図せず同期スイッチング動作で、かつ回路遮断スイッチオンとなる。その際、電流リプルにより昇圧動作（電流逆流）が発生する。
　また、低圧側の電流センサが故障し、センサ値が電流制限値より高くなると、意図せぬ電流制御により昇圧動作（電流逆流）が発生する。なお、電流制限値は、非同期スイッチング動作かつ回路遮断スイッチオフとなる所定値より高い値である。
　本実施形態では、以下に述べるように、これらの昇圧動作（電流逆流）の発生を防止する。 Generally, when the low voltage side current sensor is small, the asynchronous switching operation is performed, and the circuit cutoff switch is turned off, the low voltage side current sensor fails and the sensor value becomes higher than a predetermined value. And the circuit cutoff switch is turned on. At that time, a step-up operation (current reverse flow) occurs due to the current ripple.
When the low-voltage side current sensor fails and the sensor value becomes higher than the current limit value, a step-up operation (current reverse flow) occurs due to unintended current control. Note that the current limit value is a value higher than a predetermined value at which the asynchronous switching operation and the circuit cutoff switch are turned off.
In the present embodiment, as described below, the occurrence of these step-up operations (current reverse flow) is prevented.
　次に、本実施形態に係るＤＣ－ＤＣコンバータの具体的な構成について、図面を参照して説明する。図１は、本実施形態に係るＤＣ－ＤＣコンバータ１００の回路構成図である。
　ＤＣ－ＤＣコンバータ１００の高圧側回路は、高圧側バッテリ３００に接続され、ＤＣ－ＤＣコンバータ１００の低圧側回路は、低圧側バッテリ４００と、補機系負荷５００（以下、負荷５００）とが並列に接続される。ＤＣ－ＤＣコンバータ１００の高圧側回路と低圧側回路は変圧器１４０を介して磁気的に結合されている。また、ＤＣ－ＤＣコンバータ１００はＤＣ－ＤＣコンバータ制御装置２００により制御される。 Next, a specific configuration of the DC-DC converter according to the present embodiment will be described with reference to the drawings. FIG. 1 is a circuit configuration diagram of a DC-DC converter 100 according to the present embodiment.
The high-voltage side circuit of the DC-DC converter 100 is connected to the high-voltage side battery 300, and the low-voltage side circuit of the DC-DC converter 100 includes the low-voltage side battery 400 and an auxiliary system load 500 (hereinafter, load 500) in parallel. Connected to. The high voltage side circuit and the low voltage side circuit of the DC-DC converter 100 are magnetically coupled via a transformer 140. The DC-DC converter 100 is controlled by a DC-DC converter control device 200.
　ＤＣ－ＤＣコンバータ１００の高圧側回路は、フィルタキャパシタ１２０と、電流センサ１５０と、電圧センサ１６０と、ＭＯＳＦＥＴ１１０、１１１、１１２、１１３と、共振用インダクタ１３０より構成される。 The high-voltage side circuit of the DC-DC converter 100 includes a filter capacitor 120, a current sensor 150, a voltage sensor 160, MOSFETs 110, 111, 112, 113, and a resonance inductor 130.
　ＤＣ－ＤＣコンバータ１００の低圧側回路は、平滑用キャパシタ１２１、１２２と、平滑用インダクタ１３１、１３２と、電流センサ１５１と、電圧センサ１６１と、ＭＯＳＦＥＴ１１４、１１５、１１６、１１７より構成される。 The low voltage side circuit of the DC-DC converter 100 includes smoothing capacitors 121 and 122, smoothing inductors 131 and 132, a current sensor 151, a voltage sensor 161, and MOSFETs 114, 115, 116 and 117.
　高圧側バッテリ３００は、高圧側バッテリ３００の高電位側がフィルタキャパシタ１２０の一端と電圧センサ１６０の一端とＭＯＳＦＥＴ１１０、１１２のドレインに接続され、高圧側バッテリ３００の低電位側がフィルタキャパシタ１２０の他端と電圧センサ１６０の他端とＭＯＳＦＥＴ１１１、１１３のソースに接続される。高圧側バッテリ３００は、ニッケル水素蓄電池やリチウムイオン電池などである。 In the high-voltage battery 300, the high-potential side of the high-voltage battery 300 is connected to one end of the filter capacitor 120, one end of the voltage sensor 160, and the drains of the MOSFETs 110 and 112, and the low-potential side of the high-voltage battery 300 is connected to the other end of the filter capacitor 120. The other end of the voltage sensor 160 and the sources of the MOSFETs 111 and 113 are connected. The high-voltage battery 300 is a nickel-metal hydride battery, a lithium-ion battery, or the like.
　フィルタキャパシタ１２０は、フィルタキャパシタ１２０の一端が高圧側バッテリ３００の高電位側と電圧センサ１６０の一端とＭＯＳＦＥＴ１１０、１１２のドレインに接続され、フィルタキャパシタ１２０の他端が高圧側バッテリ３００の低電位側と電圧センサ１６０の他端とＭＯＳＦＥＴ１１１、１１３のソースに接続される。 The filter capacitor 120 has one end connected to the high potential side of the high voltage side battery 300, one end of the voltage sensor 160, and the drains of the MOSFETs 110 and 112, and the other end of the filter capacitor 120 connected to the low potential side of the high voltage side battery 300. And the other end of the voltage sensor 160 and the sources of the MOSFETs 111 and 113.
　電流センサ１５０は、フィルタキャパシタ１２０の他端と、電圧センサ１６０の他端と、ＭＯＳＦＥＴ１１１、１１３のソースと、高圧側バッテリ３００の低電位側に接続される。電流センサ１５０の検出値は高圧側電流Ｉ１０としてＤＣ－ＤＣコンバータ制御装置２００へ入力される。電流センサ１５０はシャント抵抗やホール素子などにより構成される。 The current sensor 150 is connected to the other end of the filter capacitor 120, the other end of the voltage sensor 160, the sources of the MOSFETs 111 and 113, and the low potential side of the high voltage side battery 300. The detection value of the current sensor 150 is input to the DC-DC converter control device 200 as the high-voltage side current I10. The current sensor 150 includes a shunt resistor, a Hall element, and the like.
　電圧センサ１６０は、電圧センサ１６０の一端が高圧側バッテリ３００の高電位側とフィルタキャパシタ１２０の一端とＭＯＳＦＥＴ１１０、１１２のドレインに接続され、電圧センサ１６０の他端が高圧側バッテリ３００の低電位側とフィルタキャパシタ１２０の他端とＭＯＳＦＥＴ１１１、１１３のソースに接続される。電圧センサ１６０の検出値である入力電圧Ｖ１０は、ＤＣ－ＤＣコンバータ制御装置２００へ入力される。電圧センサ１６０は分圧抵抗とオペアンプを用いた非反転増幅器や差動増幅器などにより構成される。 The voltage sensor 160 has one end connected to the high potential side of the high voltage side battery 300, one end of the filter capacitor 120, and the drains of the MOSFETs 110 and 112, and the other end of the voltage sensor 160 connected to the low potential side of the high voltage side battery 300. And the other end of the filter capacitor 120 and the sources of the MOSFETs 111 and 113. The input voltage V10 detected by the voltage sensor 160 is input to the DC-DC converter control device 200. The voltage sensor 160 includes a non-inverting amplifier and a differential amplifier using a voltage dividing resistor and an operational amplifier.
　ＭＯＳＦＥＴ１１０は、ＭＯＳＦＥＴ１１０のドレインが高圧側バッテリ３００の高電位側とフィルタキャパシタ１２０の一端と電圧センサ１６０の一端とＭＯＳＦＥＴ１１２のドレインに接続され、ＭＯＳＦＥＴ１１０のソースはＭＯＳＦＥＴ１１１のドレインと、共振用インダクタ１３０の一端に接続される。 In the MOSFET 110, the drain of the MOSFET 110 is connected to the high potential side of the high-voltage battery 300, one end of the filter capacitor 120, one end of the voltage sensor 160, and the drain of the MOSFET 112. The source of the MOSFET 110 is the drain of the MOSFET 111, and one end of the resonance inductor 130. Connected to.
　ＭＯＳＦＥＴ１１１は、ＭＯＳＦＥＴ１１１のドレインがＭＯＳＦＥＴ１１０のソースと共振用インダクタ１３０の一端に接続され、ＭＯＳＦＥＴ１１１のソースは高圧側バッテリ３００の低電位側と、フィルタキャパシタ１２０の他端と、電圧センサ１６０の他端と、ＭＯＳＦＥＴ１１３のソースに接続される。 In the MOSFET 111, the drain of the MOSFET 111 is connected to the source of the MOSFET 110 and one end of the resonance inductor 130, and the source of the MOSFET 111 is connected to the low potential side of the high-voltage battery 300, the other end of the filter capacitor 120, and the other end of the voltage sensor 160. , MOSFET 113.
　ＭＯＳＦＥＴ１１２は、ＭＯＳＦＥＴ１１２のドレインはが高圧側バッテリ３００の高電位側とフィルタキャパシタ１２０の一端と電圧センサ１６０の一端とＭＯＳＦＥＴ１１０のドレインに接続され、ＭＯＳＦＥＴ１１２のソースはＭＯＳＦＥＴ１１３のドレインと、変圧器１４０の一端に接続される。 In the MOSFET 112, the drain of the MOSFET 112 is connected to the high potential side of the high-voltage battery 300, one end of the filter capacitor 120, one end of the voltage sensor 160, and the drain of the MOSFET 110. The source of the MOSFET 112 is the drain of the MOSFET 113 and one end of the transformer 140. Connected to.
　ＭＯＳＦＥＴ１１３は、ＭＯＳＦＥＴ１１３のドレインがＭＯＳＦＥＴ１１２のソースと変圧器１４０の一端に接続され、ＭＯＳＦＥＴ１１３のソースは高圧側バッテリ３００の低電位側とフィルタキャパシタ１２０の他端と電圧センサ１６０の他端とＭＯＳＦＥＴ１１１のソースに接続される。 The drain of the MOSFET 113 is connected to the source of the MOSFET 112 and one end of the transformer 140, and the source of the MOSFET 113 is connected to the low potential side of the high-voltage battery 300, the other end of the filter capacitor 120, the other end of the voltage sensor 160, and the source of the MOSFET 111. Connected to.
　共振用インダクタ１３０は、共振用インダクタ１３０の一端がＭＯＳＦＥＴ１１０のソース及びＭＯＳＦＥＴ１１１のドレインに接続され、共振用インダクタ１３０の他端が変圧器１４０の高圧側巻線１４１の一端に接続される。共振用インダクタ１３０は、変圧器１４０の漏れインダクタンス、あるいは配線インダクタンスで代替してもよい。 In the resonance inductor 130, one end of the resonance inductor 130 is connected to the source of the MOSFET 110 and the drain of the MOSFET 111, and the other end of the resonance inductor 130 is connected to one end of the high-voltage side winding 141 of the transformer 140. The resonance inductor 130 may be replaced with a leakage inductance of the transformer 140 or a wiring inductance.
　変圧器１４０は、高圧側巻線１４１と、低圧側巻線１４２、１４３を備える。変圧器１４０の高圧側巻線１４１は、高圧側巻線１４１の一端が共振用インダクタ１３０に接続され、高圧側巻線１４１の他端はＭＯＳＦＥＴ１１２のソースと、ＭＯＳＦＥＴ１１３のドレインに接続される。 The transformer 140 includes the high-voltage side winding 141 and the low- voltage side windings 142 and 143. The high voltage side winding 141 of the transformer 140 has one end of the high voltage side winding 141 connected to the resonance inductor 130, and the other end connected to the source of the MOSFET 112 and the drain of the MOSFET 113.
　変圧器１４０の低圧側巻線１４２は、低圧側巻線１４２の一端が、ＭＯＳＦＥＴ１１４のドレインに接続され、低圧側巻線１４２の他端は、変圧器１４０の２次側の低圧側巻線１４３の一端及び平滑用インダクタ１３１の一端に接続される。変圧器１４０の低圧側巻線１４３は、低圧側巻線１４３の一端が、変圧器１４０の２次側の低圧側巻線１４２の他端及び平滑用インダクタ１３１の一端に接続され、低圧側巻線１４３の他端は、ＭＯＳＦＥＴ１１５のドレインに接続される。 The low-voltage winding 142 of the transformer 140 has one end of the low-voltage winding 142 connected to the drain of the MOSFET 114, and the other end of the low-voltage winding 142 connected to the low-voltage winding 143 on the secondary side of the transformer 140. And one end of the smoothing inductor 131. The low voltage side winding 143 of the transformer 140 has one end of the low voltage side winding 143 connected to the other end of the secondary side low voltage side winding 142 of the transformer 140 and one end of the smoothing inductor 131. The other end of the line 143 is connected to the drain of the MOSFET 115.
　平滑用キャパシタ１２１は、平滑用キャパシタ１２１の一端が平滑用インダクタ１３１の他端と、ＭＯＳＦＥＴ１１６のドレインに接続され、平滑用キャパシタ１２１の他端が電流センサ１５１と、平滑用キャパシタ１２２と、電圧センサ１６１と、低圧側バッテリ４００の低電位側と、負荷５００に接続される。
　平滑用キャパシタ１２２は、平滑用キャパシタ１２２の一端が平滑用インダクタ１３２と、電圧センサ１６１の一端と、低圧側バッテリ４００の高電位側と、負荷５００の一端に接続され、平滑用キャパシタ１２２の他端が電流センサ１５１と、平滑用キャパシタ１２１の他端と、電圧センサ１６１の他端と、低圧側バッテリ４００の低電位側と、負荷５００の他端に接続される。 The smoothing capacitor 121 has one end connected to the other end of the smoothing inductor 131 and the drain of the MOSFET 116, and the other end of the smoothing capacitor 121 connected to the current sensor 151, the smoothing capacitor 122, and the voltage sensor. 161, the low potential side of the low voltage side battery 400, and the load 500.
The smoothing capacitor 122 has one end connected to the smoothing inductor 132, one end of the voltage sensor 161, the high potential side of the low-voltage battery 400, and one end of the load 500. The ends are connected to the current sensor 151, the other end of the smoothing capacitor 121, the other end of the voltage sensor 161, the low potential side of the low-voltage battery 400, and the other end of the load 500.
　平滑用インダクタ１３１は、平滑用インダクタ１３１の一端が変圧器１４０の低圧側巻線１４２の他端及び低圧側巻線１４３の一端に接続され、平滑用インダクタ１３１の他端がＭＯＳＦＥＴ１１６のドレインと、平滑用キャパシタ１２１の一端に接続される。
　平滑用インダクタ１３２は、平滑用インダクタ１３２の一端がＭＯＳＦＥＴ１１７のドレインに接続され、平滑用インダクタ１３２の他端が平滑用キャパシタ１２２の一端と、電圧センサ１６１の一端と、低圧側バッテリ４００の高電位側と、負荷５００の一端に接続される。 The smoothing inductor 131 has one end connected to the other end of the low-voltage side winding 142 and one end of the low-voltage side winding 143 of the transformer 140, the other end of the smoothing inductor 131 connected to the drain of the MOSFET 116, Connected to one end of smoothing capacitor 121.
One end of the smoothing inductor 132 is connected to the drain of the MOSFET 117, and the other end of the smoothing inductor 132 is connected to one end of the smoothing capacitor 122, one end of the voltage sensor 161, and the high potential of the low voltage side battery 400. Side and one end of the load 500.
　電流センサ１５１は、ＭＯＳＦＥＴ１１４、１１５のソースと、平滑用キャパシタ１２１、１２２の他端と、電圧センサ１６１の他端と、低圧側バッテリ４００の低電位側と、負荷５００の他端に接続される。そして、電流センサ１５１の検出値はＤＣ－ＤＣコンバータ制御装置２００へ低圧側電流Ｉ１１として入力される。電流センサ１５１はシャント抵抗やホール素子などにより構成される。 The current sensor 151 is connected to the sources of the MOSFETs 114 and 115, the other ends of the smoothing capacitors 121 and 122, the other end of the voltage sensor 161, the low potential side of the low-voltage battery 400, and the other end of the load 500. . Then, the detection value of the current sensor 151 is input to the DC-DC converter control device 200 as the low-voltage side current I11. The current sensor 151 includes a shunt resistor, a Hall element, and the like.
　電圧センサ１６１は、電圧センサ１６１の一端が平滑用インダクタ１３２の他端と、平滑用キャパシタ１２２の一端と、低圧側バッテリ４００の高電位側と、負荷５００の一端に接続され、電圧センサ１６１の他端が電流センサ１５１と、平滑用キャパシタ１２１、１２２の他端と、低圧側バッテリ４００の低電位側と、負荷５００の他端に接続される。電圧センサ１６１の出力電圧Ｖ１１はＤＣ－ＤＣコンバータ制御装置２００へ入力される。電圧センサ１６１は分圧抵抗とオペアンプを用いた非反転増幅器や差動増幅器などにより構成される。 The voltage sensor 161 has one end connected to the other end of the smoothing inductor 132, one end of the smoothing capacitor 122, the high potential side of the low-voltage battery 400, and one end of the load 500. The other end is connected to the current sensor 151, the other ends of the smoothing capacitors 121 and 122, the low potential side of the low-voltage battery 400, and the other end of the load 500. The output voltage V11 of the voltage sensor 161 is input to the DC-DC converter control device 200. The voltage sensor 161 includes a non-inverting amplifier and a differential amplifier using a voltage dividing resistor and an operational amplifier.
　ＭＯＳＦＥＴ１１４は、ＭＯＳＦＥＴ１１４のドレインが変圧器１４０の低圧側巻線１４２の一端に接続され、ＭＯＳＦＥＴ１１４のソースはＭＯＳＦＥＴ１１５のソースと電流センサ１５１に接続される。
　ＭＯＳＦＥＴ１１５は、ＭＯＳＦＥＴ１１５のドレインが変圧器１４０の低圧側巻線１４３の他端に接続され、ＭＯＳＦＥＴ１１５のソースはＭＯＳＦＥＴ１１４のソースと電流センサ１５１に接続される。ＭＯＳＦＥＴ１１４、１１５は同期整流回路（同期整流スイッチ）を構成する。 The drain of the MOSFET 114 is connected to one end of the low-voltage winding 142 of the transformer 140, and the source of the MOSFET 114 is connected to the source of the MOSFET 115 and the current sensor 151.
The drain of the MOSFET 115 is connected to the other end of the low voltage side winding 143 of the transformer 140, and the source of the MOSFET 115 is connected to the source of the MOSFET 114 and the current sensor 151. The MOSFETs 114 and 115 constitute a synchronous rectification circuit (synchronous rectification switch).
　ＭＯＳＦＥＴ１１６は、ＭＯＳＦＥＴ１１６のドレインが平滑用インダクタ１３１の他端と、平滑用キャパシタ１２１の一端に接続され、ＭＯＳＦＥＴ１１６のソースはＭＯＳＦＥＴ１１７のソースに接続される。
　ＭＯＳＦＥＴ１１７は、ＭＯＳＦＥＴ１１７のドレインが平滑用インダクタ１３２の一端に接続され、ＭＯＳＦＥＴ１１７のソースはＭＯＳＦＥＴ１１６のソースに接続される。ＭＯＳＦＥＴ１１７は、回路遮断スイッチを構成する。 In the MOSFET 116, the drain of the MOSFET 116 is connected to the other end of the smoothing inductor 131 and one end of the smoothing capacitor 121, and the source of the MOSFET 116 is connected to the source of the MOSFET 117.
The drain of the MOSFET 117 is connected to one end of the smoothing inductor 132, and the source of the MOSFET 117 is connected to the source of the MOSFET 116. The MOSFET 117 forms a circuit cutoff switch.
　低圧側バッテリ４００は、低圧側バッテリ４００の一端が平滑用インダクタ１３２の他端と電圧センサ１６１の一端と平滑用キャパシタ１２２の一端と負荷５００の一端に接続され、低圧側バッテリ４００の他端が平滑用キャパシタ１２２の他端と電圧センサ１６１の他端と電流センサ１５１と負荷５００の他端に接続される。低圧側バッテリ４００は鉛蓄電池などで構成される。 In the low-voltage battery 400, one end of the low-voltage battery 400 is connected to the other end of the smoothing inductor 132, one end of the voltage sensor 161, one end of the smoothing capacitor 122, and one end of the load 500. The other end of the smoothing capacitor 122, the other end of the voltage sensor 161, the current sensor 151, and the other end of the load 500 are connected. The low-voltage side battery 400 is configured by a lead storage battery or the like.
　負荷５００は、負荷５００の一端が平滑用インダクタ１３２の他端と電圧センサ１６１の一端と平滑用キャパシタ１２２の一端と低圧側バッテリ４００の高電位側に接続され、負荷５００の他端が平滑用キャパシタ１２２の他端と電圧センサ１６１の他端と電流センサ１５１と低圧側バッテリ４００の低電位側に接続される。
　温度センサ１７０は、ＤＣ－ＤＣコンバータ１００に設置され、温度センサ１７０の温度Ｔ１０はＤＣ－ＤＣコンバータ制御装置２００へ入力される。 The load 500 has one end connected to the other end of the smoothing inductor 132, one end of the voltage sensor 161, one end of the smoothing capacitor 122, and the high potential side of the low-voltage battery 400. The other end of the capacitor 122, the other end of the voltage sensor 161, the current sensor 151, and the low potential side of the low voltage side battery 400 are connected.
The temperature sensor 170 is installed in the DC-DC converter 100, and the temperature T10 of the temperature sensor 170 is input to the DC-DC converter control device 200.
　ＤＣ－ＤＣコンバータ制御装置２００は、入力電圧Ｖ１０と、出力電圧Ｖ１１と、高圧側電流Ｉ１０と、低圧側電流Ｉ１１と、温度Ｔ１０に基づいて、ＤＣ－ＤＣコンバータ１００のスイッチング素子であるＭＯＳＦＥＴ１１０のＯＮ／ＯＦＦを制御するためのゲート電圧Ｖ２０を生成し、生成したゲート電圧Ｖ２０をＭＯＳＦＥＴ１１０のゲートに入力する。ＤＣ－ＤＣコンバータ制御装置２００は、以下同様に、ゲート電圧Ｖ２１をＭＯＳＦＥＴ１１１のゲートに入力し、ゲート電圧Ｖ２２をＭＯＳＦＥＴ１１２のゲートに入力し、ゲート電圧Ｖ２３をＭＯＳＦＥＴ１１３のゲートに入力し、ゲート電圧Ｖ２４をＭＯＳＦＥＴ１１４のゲートに入力し、ゲート電圧Ｖ２５をＭＯＳＦＥＴ１１５のゲートに入力し、ゲート電圧Ｖ２６をＭＯＳＦＥＴ１１６のゲートに入力し、ゲート電圧Ｖ２７をＭＯＳＦＥＴ１１７のゲートに入力する。 The DC-DC converter control device 200 turns on the MOSFET 110, which is a switching element of the DC-DC converter 100, based on the input voltage V10, the output voltage V11, the high-side current I10, the low-side current I11, and the temperature T10. A gate voltage V20 for controlling / OFF is generated, and the generated gate voltage V20 is input to the gate of the MOSFET 110. The DC-DC converter control device 200 similarly inputs the gate voltage V21 to the gate of the MOSFET 111, the gate voltage V22 to the gate of the MOSFET 112, the gate voltage V23 to the gate of the MOSFET 113, and the gate voltage V24. The gate voltage of the MOSFET 114 is input, the gate voltage V25 is input to the gate of the MOSFET 115, the gate voltage V26 is input to the gate of the MOSFET 116, and the gate voltage V27 is input to the gate of the MOSFET 117.
　図２は、本発明の実施形態に係るＤＣ－ＤＣコンバータ制御装置２００の構成図である。ＤＣ－ＤＣコンバータ制御装置２００は、第１制御装置２１０と第２制御装置２２０を備える。 FIG. 2 is a configuration diagram of the DC-DC converter control device 200 according to the embodiment of the present invention. The DC-DC converter control device 200 includes a first control device 210 and a second control device 220.
　第１制御装置２１０は、アナログ値をデジタル値に変換するＡ／Ｄ変換器２１１と、外部制御装置及び第２制御装置２２０と通信する通信器２１２と、回路遮断スイッチオンオフ判定部２１３と、電流制限値算出部２１４と、第２制御装置２２０と通信する通信器２１５と、スイッチング信号生成部２１６と、ゲートドライブ回路２１７を備える。 The first control device 210 includes an A / D converter 211 that converts an analog value into a digital value, a communication device 212 that communicates with an external control device and the second control device 220, a circuit cutoff switch on / off determination unit 213, It includes a limit value calculation unit 214, a communication device 215 that communicates with the second control device 220, a switching signal generation unit 216, and a gate drive circuit 217.
　第２制御装置２２０は、アナログ値をデジタル値に変換するＡ／Ｄ変換器２２１と、第１制御装置２１０と通信する通信器２２２と、電圧制御と電流制御を切り替える制御方式切替部２２３と、Ｄｕｔｙ算出部２２４と、同期整流スイッチオンオフ判定部２２５と、スイッチング信号生成部２２６と、ゲートドライブ回路２２７を備える。 The second control device 220 includes an A / D converter 221 that converts an analog value into a digital value, a communication device 222 that communicates with the first control device 210, a control method switching unit 223 that switches between voltage control and current control, It includes a duty calculation section 224, a synchronous rectification switch on / off determination section 225, a switching signal generation section 226, and a gate drive circuit 227.
　Ａ／Ｄ変換器２１１は、電圧センサ１６０で検出したＤＣ－ＤＣコンバータ１００の入力電圧Ｖ１０のアナログ値をデジタル値ＶＤ１０に変換する。また、Ａ／Ｄ変換器２１１は、電圧センサ１６１で検出したＤＣ－ＤＣコンバータ１００の出力電圧Ｖ１１のアナログ値をデジタル値ＶＤ１１に変換する。また、Ａ／Ｄ変換器２１１は、電流センサ１５０で検出したＤＣ－ＤＣコンバータ１００の高圧側電流Ｉ１０のアナログ値をデジタル値ＩＤ１０に変換する。また、Ａ／Ｄ変換器２１１は、電流センサ１５１で検出したＤＣ－ＤＣコンバータ１００の低圧側電流Ｉ１１のアナログ値をデジタル値ＩＤ１１に変換する。また、Ａ／Ｄ変換器２１１は、温度センサ１７０で検出したＤＣ－ＤＣコンバータ１００の温度Ｔ１０のアナログ値をデジタル値ＴＤ１０に変換する。 The A / D converter 211 converts the analog value of the input voltage V10 of the DC-DC converter 100 detected by the voltage sensor 160 into a digital value VD10. The A / D converter 211 converts the analog value of the output voltage V11 of the DC-DC converter 100 detected by the voltage sensor 161 into a digital value VD11. Further, the A / D converter 211 converts an analog value of the high-side current I10 of the DC-DC converter 100 detected by the current sensor 150 into a digital value ID10. Further, the A / D converter 211 converts an analog value of the low-voltage side current I11 of the DC-DC converter 100 detected by the current sensor 151 into a digital value ID11. The A / D converter 211 converts an analog value of the temperature T10 of the DC-DC converter 100 detected by the temperature sensor 170 into a digital value TD10.
　回路遮断スイッチオンオフ判定部２１３は、高圧側電流Ｉ１０のデジタル値ＩＤ１０と低圧側電流Ｉ１１のデジタル値ＩＤ１１に基づいて、回路遮断スイッチオンオフ切替フラグfSwitch1を生成する。 The circuit cutoff switch on / off determination unit 213 generates a circuit cutoff switch on / off switching flag fSwitch1 based on the digital value ID10 of the high voltage side current I10 and the digital value ID11 of the low voltage side current I11.
　電流制限値算出部２１４は、入力電圧Ｖ１０のデジタル値ＶＤ１０と出力電圧Ｖ１１のデジタル値ＶＤ１１と温度Ｔ１０のデジタル値ＴＤ１０に基づいて、電流制限値Ilimを算出する。具体的には、電流制限値算出部２１４は、その内部に図示省略した入力電圧制限値算出部を備える。この入力電圧制限値算出部は、入力電圧Ｖ１０のデジタル値ＶＤ１０に基づいて、入力電圧電流制限値Ilim_VD10を算出する。算出方法はマップ計算などを用いる。さらに、入力電圧制限値算出部は、出力電圧Ｖ１1のデジタル値ＶＤ１1に基づいて、出力電圧電流制限値Ilim_VD11を算出する。算出方法はマップ計算などを用いる。さらに、入力電圧制限値算出部は、温度Ｔ１０のデジタル値ＴＤ１０に基づいて、温度電流制限値Ilim_TD10を算出する。算出方法はマップ計算などを用いる。そして、入力電圧電流制限値Ilim_VD10、出力電圧電流制限値Ilim_VD11、温度電流制限値Ilim_TD10に基づいて、最小値を電流制限値Ilimとして算出する。 The current limit value calculation unit 214 calculates the current limit value Ilim based on the digital value VD10 of the input voltage V10, the digital value VD11 of the output voltage V11, and the digital value TD10 of the temperature T10. Specifically, the current limit value calculation unit 214 includes an input voltage limit value calculation unit (not shown) therein. The input voltage limit value calculation unit calculates an input voltage / current limit value Ilim_VD10 based on the digital value VD10 of the input voltage V10. The calculation method uses a map calculation or the like. Further, the input voltage limit value calculator calculates an output voltage / current limit value Ilim_VD11 based on the digital value VD11 of the output voltage V11. The calculation method uses a map calculation or the like. Further, the input voltage limit value calculation unit calculates a temperature current limit value Ilim_TD10 based on the digital value TD10 of the temperature T10. The calculation method uses a map calculation or the like. Then, the minimum value is calculated as the current limit value Ilim based on the input voltage / current limit value Ilim_VD10, the output voltage / current limit value Ilim_VD11, and the temperature / current limit value Ilim_TD10.
　通信器２１２は、外部制御装置から受信した出力電圧指令Vrefと電流制限値算出部２１４により算出された電流制限値Ilimを第２制御装置２２０に送信する。
　スイッチング信号生成部２１６は、回路遮断スイッチオンオフ判定部２１３で生成した回路遮断スイッチオンオフ切替フラグfSwitch1に基づいて、ＤＣ－ＤＣコンバータ１００のＭＯＳＦＥＴ１１６、１１７のＯＮ／ＯＦＦ信号Ｓ２６、Ｓ２７を生成する。 The communication unit 212 transmits the output voltage command Vref received from the external control device and the current limit value Ilim calculated by the current limit value calculation unit 214 to the second control device 220.
The switching signal generation section 216 generates ON / OFF signals S26 and S27 for the MOSFETs 116 and 117 of the DC-DC converter 100 based on the circuit cutoff switch on / off switching flag fSwitch1 generated by the circuit cutoff switch on / off determination section 213.
　ゲートドライブ回路２１７は、スイッチング信号生成部２１６で生成したＤＣ－ＤＣコンバータ１００のＭＯＳＦＥＴ１１６、１１７のＯＮ／ＯＦＦ信号Ｓ２６、Ｓ２７に基づいて、ＤＣ－ＤＣコンバータ１００のＭＯＳＦＥＴ１１６、１１７をＯＮ／ＯＦＦさせるためのゲート電圧Ｖ２６、Ｖ２７を生成する。 The gate drive circuit 217 turns ON / OFF the MOSFETs 116 and 117 of the DC-DC converter 100 based on the ON / OFF signals S26 and S27 of the MOSFETs 116 and 117 of the DC-DC converter 100 generated by the switching signal generation unit 216. Gate voltages V26 and V27 are generated.
　Ａ／Ｄ変換器２２１は、電圧センサ１６０で検出したＤＣ－ＤＣコンバータ１００の入力電圧Ｖ１０のアナログ値をデジタル値ＶＤ１０に変換する。また、Ａ／Ｄ変換器２２１は、電圧センサ１６１で検出したＤＣ－ＤＣコンバータ１００の出力電圧Ｖ１１のアナログ値をデジタル値ＶＤ１１に変換する。また、Ａ／Ｄ変換器２２１は、電流センサ１５０で検出したＤＣ－ＤＣコンバータ１００の高圧側電流Ｉ１０のアナログ値をデジタル値ＩＤ１０に変換する。また、Ａ／Ｄ変換器２２１は、電流センサ１５１で検出したＤＣ－ＤＣコンバータ１００の低圧側電流Ｉ１１のアナログ値をデジタル値ＩＤ１１に変換する。 The A / D converter 221 converts the analog value of the input voltage V10 of the DC-DC converter 100 detected by the voltage sensor 160 into a digital value VD10. The A / D converter 221 converts the analog value of the output voltage V11 of the DC-DC converter 100 detected by the voltage sensor 161 into a digital value VD11. The A / D converter 221 converts the analog value of the high-side current I10 of the DC-DC converter 100 detected by the current sensor 150 into a digital value ID10. Further, the A / D converter 221 converts the analog value of the low voltage side current I11 of the DC-DC converter 100 detected by the current sensor 151 into a digital value ID11.
　通信器２２２は、通信器２１２から出力電圧指令Vrefと電流制限値Ilimを受信する。
　制御方式切替部２２３は、電流制限値Ilimと低圧側電流のデジタル値ＩＤ１１に基づいて、電圧制御と電流制御を切り替えるための制御方式切替フラグfSwitch3を生成する。ただし、Ilim<ＩＤ１１の条件が成立する場合は電流制御としてfSwitch3=1を設定し、条件が成立しない場合はfSwitch3=0を設定する。 The communication device 222 receives the output voltage command Vref and the current limit value Ilim from the communication device 212.
The control method switching unit 223 generates a control method switch flag fSwitch3 for switching between voltage control and current control based on the current limit value Ilim and the digital value ID11 of the low voltage side current. However, if the condition of Ilim <ID11 is satisfied, fSwitch3 = 1 is set as the current control, and if the condition is not satisfied, fSwitch3 = 0 is set.
　Ｄｕｔｙ算出部２２４は、出力電圧指令Ｖｒｅｆ、電流制限値Ilim、入力電圧Ｖ１０のデジタル値ＶＤ１０、出力電圧Ｖ１１のデジタル値ＶＤ１１、低圧側電流Ｉ１１のデジタル値ＩＤ１１、及び制御方式切替フラグfSwitch3に基づいて、ＭＯＳＦＥＴ１１０、１１１、１１２、１１３のＤｕｔｙを算出する。 The duty calculation unit 224 is based on the output voltage command Vref, the current limit value Ilim, the digital value VD10 of the input voltage V10, the digital value VD11 of the output voltage V11, the digital value ID11 of the low-voltage side current I11, and the control method switching flag fSwitch3. , MOSFETs 110, 111, 112, and 113 are calculated.
　同期整流スイッチオンオフ判定部２２５は、高圧側電流Ｉ１０のデジタル値ＩＤ１０と低圧側電流Ｉ１１のデジタル値ＩＤ１１と制御方式切替フラグfSwitch3とに基づいて、同期整流スイッチオンオフ切替フラグfSwitch2を生成する。 The synchronous rectification switch on / off determination unit 225 generates a synchronous rectification switch on / off switching flag fSwitch2 based on the digital value ID10 of the high voltage side current I10, the digital value ID11 of the low voltage side current I11, and the control method switching flag fSwitch3.
　スイッチング信号生成部２２６は、Ｄｕｔｙ算出部２２４で算出したＤＣ－ＤＣコンバータ１００のＭＯＳＦＥＴ１１０、１１１、１１２、１１３のＤｕｔｙと同期整流スイッチオンオフ切替フラグfSwitch2に基づいて、ＤＣ－ＤＣコンバータ１００のＭＯＳＦＥＴ１１０、１１１、１１２、１１３、１１４、１１５のＯＮ／ＯＦＦ信号Ｓ２０、Ｓ２１、Ｓ２２、Ｓ２３、Ｓ２４、Ｓ２５を生成する。 The switching signal generation unit 226 determines the MOSFETs 110, 111 of the DC-DC converter 100 based on the Duty of the MOSFETs 110, 111, 112, 113 of the DC-DC converter 100 calculated by the duty calculation unit 224 and the synchronous rectification switch on / off switching flag fSwitch2. , 112, 113, 114, and 115 are generated as ON / OFF signals S 20, S 21, S 22, S 23, S 24, and S 25.
　ゲートドライブ回路２２７は、スイッチング信号生成部２２６で生成したＤＣ－ＤＣコンバータ１００のＭＯＳＦＥＴ１１０、１１１、１１２，１１３，１１４，１１５のＯＮ／ＯＦＦ信号Ｓ２０、Ｓ２１、Ｓ２２、Ｓ２３、Ｓ２４、Ｓ２５に基づいて、ＤＣ－ＤＣコンバータ１００のＭＯＳＦＥＴ１１０、１１１、１１２，１１３，１１４，１１５をＯＮ／ＯＦＦさせるためのゲート電圧Ｖ２０、Ｖ２１、Ｖ２２、Ｖ２３、Ｖ２４、Ｖ２５を生成する。 The gate drive circuit 227 is based on the ON / OFF signals S20, S21, S22, S23, S24, and S25 of the MOSFETs 110, 111, 112, 113, 114, and 115 of the DC-DC converter 100 generated by the switching signal generator 226. , A gate voltage V20, V21, V22, V23, V24, V25 for turning on / off the MOSFET 110, 111, 112, 113, 114, 115 of the DC-DC converter 100.
　図３は回路遮断スイッチオンオフ判定部２１３の処理動作を示すフローチャートである。このフローチャートは、１処理周期あたりの処理動作を示すもので、回路遮断スイッチオンオフ判定部２１３は、この処理動作を繰り返し実施する。 FIG. 3 is a flowchart showing the processing operation of the circuit cutoff switch on / off determination unit 213. This flowchart shows a processing operation per one processing cycle, and the circuit cutoff switch on / off determination unit 213 repeatedly performs this processing operation.
　ステップＡ１０において、処理動作を開始し、ステップＡ２０に遷移する。ステップＡ２０において、低圧側電流Ｉ１１のデジタル値ＩＤ１１が所定値LvIlimより低いかを判断し、低い場合はステップＡ５０に遷移する。所定値LvIlimより高い場合はステップＡ３０に遷移する。 に お い て In step A10, the processing operation is started, and the process proceeds to step A20. In step A20, it is determined whether the digital value ID11 of the low voltage side current I11 is lower than a predetermined value LvIlim, and if it is lower, the process proceeds to step A50. If it is higher than the predetermined value LvIlim, the process transits to Step A30.
　ステップＡ３０において、高圧側電流のデジタル値ＩＤ１０が所定値HvIlimより低いかを判断し、低い場合はステップＡ５０に遷移する。所定値HvIlimより高い場合はステップＡ４０に遷移する。 In step A30, it is determined whether the digital value ID10 of the high-side current is lower than a predetermined value HvIlim. If it is higher than the predetermined value HvIlim, the process transits to Step A40.
　ステップＡ４０において、回路遮断スイッチオンオフ切替フラグfSwitch1に０をセットして出力する。回路遮断スイッチオンオフ切替フラグfSwitch1に０がセットされた場合、回路遮断スイッチの１つであるＭＯＳＦＥＴ１１７がオンとなるようスイッチング信号生成部２１６に対して要求する。出力完了後、ステップＡ６０へ遷移する。 (4) In step A40, 0 is set to the circuit cutoff switch on / off switching flag fSwitch1 and output. When 0 is set to the circuit cutoff switch on / off switching flag fSwitch1, a request is made to the switching signal generator 216 to turn on the MOSFET 117, which is one of the circuit cutoff switches. After the output is completed, the process transits to Step A60.
　ステップＡ５０において、回路遮断スイッチオンオフ切替フラグfSwitch1に１をセットして出力する。回路遮断スイッチオンオフ切替フラグfSwitch1に１がセットされた場合、回路遮断スイッチの１つであるＭＯＳＦＥＴ１１７がオフとなるようスイッチング信号生成部２１６に対して要求する。出力完了後、ステップＡ６０へ遷移する。
　ステップＡ６０において、回路遮断スイッチオンオフ判定部２１３で実施される１処理周期の処理を終了する。 In step A50, 1 is set to a circuit cutoff switch on / off switching flag fSwitch1 and output. When the circuit cutoff switch on / off switching flag fSwitch1 is set to 1, a request is made to the switching signal generator 216 to turn off the MOSFET 117, which is one of the circuit cutoff switches. After the output is completed, the process transits to Step A60.
In step A60, the processing of one processing cycle performed by the circuit cutoff switch on / off determination unit 213 ends.
　図４は同期整流スイッチオンオフ判定部２２５の第１の処理動作を示すフローチャートである。このフローチャートは、１処理周期あたりの処理動作を示すもので、同期整流スイッチオンオフ判定部２２５は、この処理動作を繰り返し実施する。 FIG. 4 is a flowchart showing a first processing operation of the synchronous rectification switch on / off determination unit 225. This flowchart shows a processing operation per one processing cycle, and the synchronous rectification switch on / off determination unit 225 repeatedly performs this processing operation.
　ステップＢ１０において、処理を開始し、ステップＢ２０に遷移する。ステップＢ２０において、低圧側電流Ｉ１１のデジタル値ＩＤ１１が所定値LvIlimより低いかを判断し、低い場合はステップＢ５０に遷移する。低圧側電流Ｉ１１のデジタル値ＩＤ１１が所定値LvIlimより高い場合はステップＢ３０に遷移する。 処理 In step B10, the process is started, and the process proceeds to step B20. In step B20, it is determined whether the digital value ID11 of the low voltage side current I11 is lower than a predetermined value LvIlim, and if it is lower, the process proceeds to step B50. When the digital value ID11 of the low voltage side current I11 is higher than the predetermined value LvIlim, the process proceeds to Step B30.
　ステップＢ３０において、高圧側電流Ｉ１０のデジタル値ＩＤ１０が所定値HvIlimより低いかを判断し、低い場合はステップＢ５０に遷移する。高圧側電流Ｉ１０のデジタル値ＩＤ１０が所定値HvIlimより高い場合はステップＢ４０に遷移する。 In step B30, it is determined whether the digital value ID10 of the high-voltage side current I10 is lower than a predetermined value HvIlim. If the digital value ID10 is lower, the process proceeds to step B50. When the digital value ID10 of the high-voltage side current I10 is higher than the predetermined value HvIlim, the process proceeds to Step B40.
　ステップＢ４０において、同期整流スイッチオンオフ切替フラグfSwitch2に０をセットして出力する。同期整流スイッチオンオフ切替フラグfSwitch2に０がセットされた場合、同期整流スイッチであるＭＯＳＦＥＴ１１４、１１５がＤｕｔｙ算出部２２４で算出したデューティ比に基づいてスイッチング動作が実施されるようスイッチング信号生成部２２６に対して要求する。出力完了後、ステップＢ６０へ遷移する。 In step B40, the synchronous rectification switch ON / OFF switching flag fSwitch2 is set to 0 and output. When the synchronous rectification switch on / off switching flag fSwitch2 is set to 0, the switching signal generation unit 226 is instructed so that the MOSFETs 114 and 115, which are synchronous rectification switches, perform a switching operation based on the duty ratio calculated by the duty calculation unit 224. Request. After the output is completed, the process transits to Step B60.
　ステップＢ５０では、同期整流スイッチオンオフ切替フラグfSwitch2に１をセットして出力する。同期整流スイッチオンオフ切替フラグfSwitch2に１がセットされた場合、同期整流スイッチであるＭＯＳＦＥＴ１１４、１１５がオフとなるようスイッチング信号生成部２２６に対して要求する。出力完了後、ステップＢ６０へ遷移する。
　ステップＢ６０において、同期整流スイッチオンオフ判定部２２５で実施される１処理周期の処理を終了する。 In step B50, the synchronous rectification switch on / off switching flag fSwitch2 is set to 1 and output. When the synchronous rectification switch on / off switching flag fSwitch2 is set to 1, a request is made to the switching signal generation unit 226 to turn off the MOSFETs 114 and 115, which are synchronous rectification switches. After the output is completed, the process transits to Step B60.
In step B60, the processing of one processing cycle performed by the synchronous rectification switch on / off determination unit 225 is completed.
　図５は同期整流スイッチオンオフ判定部２２５の第２の処理動作を示すフローチャートである。このフローチャートは、１処理周期あたりの処理動作を示すもので、同期整流スイッチオンオフ判定部２２５は、この処理動作を繰り返し実施する。
　同期整流スイッチオンオフ判定部２２５は、図４に示した第１の処理動作であってもよく、本例で示す第２の処理動作であってもよい。 FIG. 5 is a flowchart illustrating a second processing operation of the synchronous rectification switch on / off determination unit 225. This flowchart shows a processing operation per one processing cycle, and the synchronous rectification switch on / off determination unit 225 repeatedly performs this processing operation.
The synchronous rectification switch on / off determining unit 225 may be the first processing operation shown in FIG. 4 or the second processing operation shown in this example.
　ステップＣ１０において、処理を開始し、ステップＣ２０に遷移する。ステップＣ２０において、低圧側電流Ｉ１１のデジタル値ＩＤ１１が所定値LvIlimより低いかを判断し、低い場合はステップＣ５０に遷移する。低圧側電流Ｉ１１のデジタル値ＩＤ１１が所定値LvIlimより高い場合はステップＣ３０に遷移する。 に お い て In step C10, the process is started, and the process proceeds to step C20. In step C20, it is determined whether the digital value ID11 of the low voltage side current I11 is lower than a predetermined value LvIlim, and if it is lower, the process proceeds to step C50. When the digital value ID11 of the low voltage side current I11 is higher than the predetermined value LvIlim, the process proceeds to Step C30.
　ステップＣ３０において、制御方式切替部２２３で算出された制御方式切替フラグfSwitch3に基づいて電流制御が実施されているかを判断し、電流制御が実施されている場合はステップＣ５０に遷移する。電圧制御が実施されている場合はステップＣ４０に遷移する。前述したように、制御方式切替部２２３は、電流制限値Ilimと低圧側電流のデジタル値ＩＤ１１に基づいて、電圧制御と電流制御を切り替える制御方式切替フラグfSwitch3を生成し、Ilim<ＩＤ１１の条件が成立する場合は電流制御としてfSwitch3=1を設定している。 In step C30, it is determined whether or not current control is being performed based on the control method switching flag fSwitch3 calculated by the control method switching unit 223. If current control is being performed, the process proceeds to step C50. When the voltage control is performed, the process proceeds to Step C40. As described above, the control method switching unit 223 generates the control method switching flag fSwitch3 for switching between voltage control and current control based on the current limit value Ilim and the digital value ID11 of the low voltage side current, and the condition of Ilim <ID11 is satisfied. If the condition is satisfied, fSwitch3 = 1 is set as the current control.
　ステップＣ４０において、同期整流スイッチオンオフ切替フラグfSwitch2に０をセットして出力する。同期整流スイッチオンオフ切替フラグfSwitch2に０がセットされた場合、同期整流スイッチであるＭＯＳＦＥＴ１１４、１１５がＤｕｔｙ算出部２２４で算出したデューティ比に基づいてスイッチング動作が実施されるようスイッチング信号生成部２２６に対して要求する。出力完了後、ステップＣ６０へ遷移する。 In step C40, the synchronous rectification switch on / off switching flag fSwitch2 is set to 0 and output. When the synchronous rectification switch on / off switching flag fSwitch2 is set to 0, the switching signal generation unit 226 is instructed so that the MOSFETs 114 and 115, which are synchronous rectification switches, perform a switching operation based on the duty ratio calculated by the duty calculation unit 224. Request. After the output is completed, the process transits to Step C60.
　ステップＣ５０では、同期整流スイッチオンオフ切替フラグfSwitch2に１をセットして出力する。同期整流スイッチオンオフ切替フラグfSwitch2に１がセットされた場合、同期整流スイッチであるＭＯＳＦＥＴ１１４、１１５がオフとなるようスイッチング信号生成部２２６に対して要求する。出力完了後、ステップＣ６０へ遷移する。
　ステップＣ６０において、同期整流スイッチオンオフ判定部２２５で実施される１処理周期の処理を終了する。 In step C50, the synchronous rectification switch on / off switching flag fSwitch2 is set to 1 and output. When the synchronous rectification switch on / off switching flag fSwitch2 is set to 1, a request is made to the switching signal generation unit 226 to turn off the MOSFETs 114 and 115, which are synchronous rectification switches. After the output is completed, the process transits to Step C60.
In step C60, the processing of one processing cycle performed by the synchronous rectification switch on / off determination unit 225 is ended.
　図６は、低圧側電流Ｉ１１が低い場合に低圧側の電流センサ１５１が故障した例を示すタイミングチャートである。図６（ａ）に示すように、低圧側電流のデジタル値ＩＤ１１が所定値LvIlimより低い時（非同期スイッチング動作かつ回路遮断スイッチオフの時）に、低圧側の電流センサ１５１が時刻ｔ１で故障し、低圧側電流Ｉ１１のデジタル値ＩＤ１１が所定値LvIlimより高くなる場合の例である。 FIG. 6 is a timing chart showing an example in which the low voltage side current sensor 151 has failed when the low voltage side current I11 is low. As shown in FIG. 6A, when the digital value ID11 of the low voltage side current is lower than the predetermined value LvIlim (when the asynchronous switching operation and the circuit cutoff switch are off), the low voltage side current sensor 151 fails at time t1. This is an example in which the digital value ID11 of the low voltage side current I11 is higher than a predetermined value LvIlim.
　低圧側の電流センサ１５１が時刻ｔ１で故障し、低圧側電流Ｉ１１のデジタル値ＩＤ１１が所定値LvIlimより高くなる場合であっても、図６（ｂ）に示すように、制御方式切替部２２３は、電流制御としてfSwitch3=０を設定したままである。そして、低圧側電流Ｉ１１と正の相関関係にある高圧側電流Ｉ１０のデジタル値ＩＤ１０は、図６（ｃ）に示すように、所定値HvIlimより低いままである。このため、回路遮断スイッチオンオフ判定部２１３により、図６（ｄ）に示すように、回路遮断スイッチオンオフ切替フラグfSwitch1に１がセットされたままである。そして、スイッチング信号生成部２１６により、図６（ｇ）に示すように、ＤＣ－ＤＣコンバータ１００のＭＯＳＦＥＴ１１７のＯＮ／ＯＦＦ信号Ｓ２７にオフがセットされ、回路遮断スイッチ（ＤＣ－ＤＣコンバータ１００の低圧側回路におけるＭＯＳＦＥＴ１１７）がオフとなる。 Even if the low voltage side current sensor 151 fails at time t1 and the digital value ID11 of the low voltage side current I11 becomes higher than the predetermined value LvIlim, as shown in FIG. , FSwitch3 = 0 remains set as the current control. Then, the digital value ID10 of the high voltage side current I10 having a positive correlation with the low voltage side current I11 remains lower than the predetermined value HvIlim as shown in FIG. For this reason, as shown in FIG. 6D, the circuit cutoff switch on / off switching flag fSwitch1 remains set to 1 by the circuit cutoff switch on / off determination unit 213. Then, as shown in FIG. 6 (g), the ON / OFF signal S27 of the MOSFET 117 of the DC-DC converter 100 is turned off by the switching signal generation unit 216, and the circuit cutoff switch (the low-voltage side of the DC-DC converter 100) is turned off. MOSFET 117) in the circuit is turned off.
　また、同期整流スイッチオンオフ判定部２２５により、図６（ｅ）に示すように、同期整流スイッチオンオフ切替フラグfSwitch2に１がセットされたままとなる。そして、スイッチング信号生成部２２６により、図６（ｆ）に示すように、ＤＣ－ＤＣコンバータ１００のＭＯＳＦＥＴ１１４、１１５のＯＮ／ＯＦＦ信号Ｓ２４、Ｓ２５にオフがセットされ、回路遮断スイッチ（ＤＣ－ＤＣコンバータ１００の低圧側回路におけるＭＯＳＦＥＴ１１４、１１５）がオフとなる。 (6) The synchronous rectification switch on / off determination unit 225 keeps the synchronous rectification switch on / off switching flag fSwitch2 set to 1 as shown in FIG. Then, as shown in FIG. 6F, the ON / OFF signals S24 and S25 of the MOSFETs 114 and 115 of the DC-DC converter 100 are turned off by the switching signal generation unit 226, and the circuit cutoff switch (DC-DC converter The MOSFETs 114 and 115 in the low-voltage side circuit 100 are turned off.
　以上の動作により、低圧側の電流センサ１５１が故障した場合であっても、意図せぬ同期スイッチング動作かつ回路遮断スイッチオンは発生せず、昇圧動作（電流逆流）を防止することができる。 By the above operation, even if the low-voltage side current sensor 151 breaks down, an unintended synchronous switching operation and a circuit cutoff switch-on do not occur, and a boosting operation (current reverse flow) can be prevented.
　なお、回路遮断スイッチオンオフ判定部２１３、同期整流スイッチオンオフ判定部２２５で使用する所定値LvIlim、所定値HvIlimは、同期スイッチング動作かつ回路遮断スイッチオンの時の低圧側回路の電流リプルに起因する電流の逆流による昇圧動作が発生しない値に設定する。また、所定値LvIlim、所定値HvIlimは、回路遮断スイッチオンオフ判定部２１３、同期整流スイッチオンオフ判定部２２５に対して外部よりその値を適宜設定し、回路遮断スイッチオンオフ判定部２１３、同期整流スイッチオンオフ判定部２２５は設定された値を用いて、図３～図５で示した処理を実行してもよい。 The predetermined value LvIlim and the predetermined value HvIlim used in the circuit cutoff switch on / off judgment unit 213 and the synchronous rectification switch on / off judgment unit 225 are the currents caused by the current ripple of the low voltage side circuit when the synchronous switching operation and the circuit cutoff switch are on. Is set to a value that does not cause the boosting operation due to the backflow of. The predetermined value LvIlim and the predetermined value HvIlim are appropriately set from the outside to the circuit cutoff switch on / off determination unit 213 and the synchronous rectification switch on / off determination unit 225, and the circuit cutoff switch on / off determination unit 213 and the synchronous rectification switch on / off. The determination unit 225 may execute the processing shown in FIGS. 3 to 5 using the set value.
　図７は、低圧側電流Ｉ１１が高い場合に低圧側の電流センサ１５１が故障した例を示すタイミングチャートである。このタイミングチャートは、図４で示した同期整流スイッチオンオフ判定部２２５の第１の処理動作を適用した場合を示す。図７（ａ）に示すように、低圧側電流Ｉ１１のデジタル値ＩＤ１１が所定値LvIlimより高く、かつ電流制限値Ilimよりも低い時（電圧制御かつ同期スイッチング動作、回路遮断スイッチオンの時）に、低圧側の電流センサ１５１が時刻ｔ１で故障し、低圧側電流Ｉ１１のデジタル値ＩＤ１１が電流制限値Ilimより高くなる場合の例を示す。 FIG. 7 is a timing chart showing an example in which the low voltage side current sensor 151 has failed when the low voltage side current I11 is high. This timing chart shows a case where the first processing operation of the synchronous rectification switch on / off determination unit 225 shown in FIG. 4 is applied. As shown in FIG. 7A, when the digital value ID11 of the low-voltage side current I11 is higher than the predetermined value LvIlim and lower than the current limit value Ilim (when the voltage control and the synchronous switching operation are performed and the circuit cutoff switch is turned on). An example is shown in which the low voltage side current sensor 151 fails at time t1 and the digital value ID11 of the low voltage side current I11 becomes higher than the current limit value Ilim.
　低圧側の電流センサ１５１が時刻ｔ１で故障し、低圧側電流Ｉ１１のデジタル値ＩＤ１１が電流制限値Ilimより高くなると、図７（ｂ）に示すように、制御方式切替部２２３は、電流制御としてfSwitch3=1を設定する。この電流制御により高圧側電流Ｉ１０のデジタル値ＩＤ１０が、図７（ｃ）に示すように、低下する。やがて時刻ｔ２で、高圧側電流Ｉ１０のデジタル値ＩＤ１０は所定値HvIlimより低くなると、図７（ｄ）に示すように、回路遮断スイッチオンオフ判定部２１３により、回路遮断スイッチオンオフ切替フラグfSwitch1に１がセットされる。そして、スイッチング信号生成部２１６により、図７（ｇ）に示すように、ＤＣ－ＤＣコンバータ１００のＭＯＳＦＥＴ１１７のＯＮ／ＯＦＦ信号Ｓ２７にオフがセットされ、回路遮断スイッチ（ＤＣ－ＤＣコンバータ１００の低圧側回路におけるＭＯＳＦＥＴ１１７）がオフとなる。 When the low voltage side current sensor 151 fails at time t1 and the digital value ID11 of the low voltage side current I11 becomes higher than the current limit value Ilim, as shown in FIG. 7 (b), the control method switching unit 223 performs current control. Set fSwitch3 = 1. By this current control, the digital value ID10 of the high-voltage side current I10 decreases as shown in FIG. 7C. Eventually, at time t2, when the digital value ID10 of the high-voltage side current I10 becomes lower than the predetermined value HvIlim, as shown in FIG. Set. Then, as shown in FIG. 7 (g), the ON / OFF signal S27 of the MOSFET 117 of the DC-DC converter 100 is set to OFF by the switching signal generation unit 216, and the circuit cutoff switch (the low-voltage side of the DC-DC converter 100) MOSFET 117) in the circuit is turned off.
　また、同期整流スイッチオンオフ判定部２２５により、図７（ｅ）に示すように、同期整流スイッチオンオフ切替フラグfSwitch2に１がセットされる。そして、スイッチング信号生成部２２６により、図７（ｆ）に示すように、ＤＣ－ＤＣコンバータ１００のＭＯＳＦＥＴ１１４、１１５のＯＮ／ＯＦＦ信号Ｓ２４、Ｓ２５にオフがセットされ、同期整流スイッチ（ＤＣ－ＤＣコンバータ１００の低圧側回路におけるＭＯＳＦＥＴ１１４、１１５）がオフとなる。 {Circle around (1)} As shown in FIG. 7E, the synchronous rectification switch on / off switching flag fSwitch2 is set to 1 by the synchronous rectification switch on / off determination unit 225. Then, as shown in FIG. 7 (f), the switching signal generation unit 226 sets the ON / OFF signals S24 and S25 of the MOSFETs 114 and 115 of the DC-DC converter 100 to OFF, and the synchronous rectification switch (DC-DC converter The MOSFETs 114 and 115 in the low-voltage side circuit 100 are turned off.
　以上の動作により、低圧側の電流センサ１５１が故障した場合であっても、非同期スイッチング動作かつ回路遮断スイッチオフとなるため、昇圧動作（電流逆流）を防止することができる。 By the above operation, even if the low voltage side current sensor 151 fails, the asynchronous switching operation and the circuit cutoff switch are turned off, so that the boosting operation (current reverse flow) can be prevented.
　なお、回路遮断スイッチオンオフ判定部２１３、同期整流スイッチオンオフ判定部２２５で使用する所定値LvIlim、所定値HvIlimは、電流制御の応答性および、回路遮断スイッチあるいは同期整流スイッチのスイッチング周期から、意図せぬ電流制御による昇圧動作（電流逆流）を未然に防止できるような値に設定する必要がある。 The predetermined value LvIlim and the predetermined value HvIlim used in the circuit cutoff switch on / off determination unit 213 and the synchronous rectification switch on / off determination unit 225 are designed based on the response of the current control and the switching cycle of the circuit cutoff switch or the synchronous rectification switch. It is necessary to set a value that can prevent a step-up operation (current reverse flow) due to current control.
　図８は、低圧側電流Ｉ１１が高い場合に低圧側の電流センサ１５１が故障した他の例を示すタイミングチャートである。このタイミングチャートは、図５で示した同期整流スイッチオンオフ判定部２２５の第２の処理動作を適用した場合を示す。図８（ａ）に示すように、低圧側電流Ｉ１１のデジタル値ＩＤ１１が所定値LvIlimより高く、かつ電流制限値Ilimよりも低い時（電圧制御かつ同期スイッチング動作、回路遮断スイッチオンの時）に、低圧側の電流センサ１５１が時刻ｔ１で故障し、低圧側電流のデジタル値ＩＤ１１が電流制限値Ilimより高くなる場合の例を示す。 FIG. 8 is a timing chart showing another example in which the low voltage side current sensor 151 has failed when the low voltage side current I11 is high. This timing chart shows a case where the second processing operation of the synchronous rectification switch on / off determination unit 225 shown in FIG. 5 is applied. As shown in FIG. 8A, when the digital value ID11 of the low-voltage side current I11 is higher than the predetermined value LvIlim and lower than the current limit value Ilim (when the voltage control and the synchronous switching operation are performed and the circuit cutoff switch is turned on). An example is shown in which the low voltage side current sensor 151 fails at time t1 and the digital value ID11 of the low voltage side current becomes higher than the current limit value Ilim.
　低圧側の電流センサ１５１が時刻ｔ１で故障し、低圧側電流Ｉ１１のデジタル値ＩＤ１１が電流制限値Ilimより高くなると、図８（ｂ）に示すように、制御方式切替部２２３は、電流制御としてfSwitch3=1を設定する。この時、同期整流スイッチオンオフ判定部２２５により、図８（ｅ）に示すように、同期整流スイッチオンオフ切替フラグfSwitch2に１がセットされる。そして、スイッチング信号生成部２２６により、図８（ｆ）に示すように、ＤＣ－ＤＣコンバータ１００のＭＯＳＦＥＴ１１４、１１５のＯＮ／ＯＦＦ信号Ｓ２４、Ｓ２５にオフがセットされ、同期整流スイッチ（ＤＣ－ＤＣコンバータ１００の低圧側回路におけるＭＯＳＦＥＴ１１４、１１５）がオフとなる。 When the low voltage side current sensor 151 fails at time t1 and the digital value ID11 of the low voltage side current I11 becomes higher than the current limit value Ilim, as shown in FIG. 8B, the control method switching unit 223 performs the current control. Set fSwitch3 = 1. At this time, the synchronous rectification switch on / off determination unit 225 sets 1 to the synchronous rectification switch on / off switching flag fSwitch2 as shown in FIG. Then, as shown in FIG. 8F, the switching signal generation unit 226 sets the ON / OFF signals S24 and S25 of the MOSFETs 114 and 115 of the DC-DC converter 100 to OFF, and the synchronous rectification switch (DC-DC converter The MOSFETs 114 and 115 in the low-voltage side circuit 100 are turned off.
　また、図８（ｃ）に示すように、電流制御により高圧側電流のデジタル値ＩＤ１０が低下し、時刻ｔ２で高圧側電流のデジタル値ＩＤ１０は所定値HvIlimより低くなる。この時、図８（ｄ）に示すように、回路遮断スイッチオンオフ判定部２１３により、回路遮断スイッチオンオフ切替フラグfSwitch1に１がセットされる。そして、スイッチング信号生成部２１６により、図８（ｇ）に示すように、ＤＣ－ＤＣコンバータ１００のＭＯＳＦＥＴ１１７のＯＮ／ＯＦＦ信号Ｓ２７にオフがセットされ、回路遮断スイッチ（ＤＣ－ＤＣコンバータ１００の低圧側回路におけるＭＯＳＦＥＴ１１７）がオフとなる。 As shown in FIG. 8C, the digital value ID10 of the high-side current decreases due to the current control, and at time t2, the digital value ID10 of the high-side current becomes lower than the predetermined value HvIlim. At this time, as shown in FIG. 8D, the circuit cutoff switch on / off determination unit 213 sets 1 to the circuit cutoff switch on / off switching flag fSwitch1. Then, as shown in FIG. 8 (g), the ON / OFF signal S27 of the MOSFET 117 of the DC-DC converter 100 is turned off by the switching signal generation unit 216, and the circuit cutoff switch (the low-voltage side of the DC-DC converter 100) is turned off. MOSFET 117) in the circuit is turned off.
　以上の動作により、低圧側の電流センサ１５１が故障した場合であっても、非同期スイッチング動作かつ回路遮断スイッチオフとなるため、昇圧動作（電流逆流）を防止することができる。 By the above operation, even if the low voltage side current sensor 151 fails, the asynchronous switching operation and the circuit cutoff switch are turned off, so that the boosting operation (current reverse flow) can be prevented.
　以上説明した実施形態によれば、次の作用効果が得られる。
（１）ＤＣ－ＤＣコンバータ１００は、入力された直流電圧を降圧して出力するＤＣ－ＤＣコンバータ１００であって、変圧器１４０の一次側に接続された高圧側回路と、変圧器１４０の二次側に接続され、同期整流回路ＭＯＳＦＥＴ１１４、１１５および回路遮断スイッチＭＯＳＦＥＴ１１７を備える低圧側回路と、高圧側回路および低圧側回路の電流を検出する電流センサ１５０、１５１と、同期整流回路ＭＯＳＦＥＴ１１４、１１５および回路遮断スイッチＭＯＳＦＥＴ１１７のスイッチングを制御する制御部２００と、を備え、制御部２００は、電流センサ１５０、１５１で検出された高圧側回路および低圧側回路の電流の少なくとも一方が所定の値よりも低い場合に、同期整流回路ＭＯＳＦＥＴ１１４、１１５または回路遮断スイッチＭＯＳＦＥＴ１１７をオフにする。なお、電流の所定の値は、低圧側回路の電流リプルに起因する電流の逆流による昇圧動作が発生しない値が望ましい。これにより、電流センサが故障した場合であっても、低圧側から高圧側へ電流が逆流する昇圧動作を未然に防止することができる。
　より具体的に述べると、低圧側電流と高圧側電流は正の相関関係にある。そのため、低圧側電流が小さく、非同期スイッチング動作かつ回路遮断スイッチオフとなるような条件の時に、低圧側の電流センサが故障し、低圧側電流のセンサ値が所定値より高くなっても、高圧側電流のセンサ値は所定値より低いままである。その結果、意図せぬ同期スイッチング動作かつ回路遮断スイッチオンは発生せず、電流逆流による昇圧動作は防止される。 According to the embodiment described above, the following operation and effect can be obtained.
(1) The DC-DC converter 100 is a DC-DC converter 100 that steps down and outputs an input DC voltage, and includes a high-voltage side circuit connected to the primary side of a transformer 140 and a transformer 140. A low voltage side circuit connected to the next side and including synchronous rectification circuit MOSFETs 114 and 115 and a circuit cutoff switch MOSFET 117; current sensors 150 and 151 for detecting currents of the high voltage side circuit and the low voltage side circuit; A control unit 200 for controlling switching of the circuit cutoff switch MOSFET 117, wherein the control unit 200 detects that at least one of the currents of the high voltage side circuit and the low voltage side circuit detected by the current sensors 150 and 151 is lower than a predetermined value. In this case, the synchronous rectification circuit MOSFETs 114 and 115 or To turn off the switch MOSFET117. Note that the predetermined value of the current is preferably a value that does not cause a boosting operation due to a reverse current of the current caused by the current ripple of the low-voltage side circuit. Thus, even when the current sensor has failed, it is possible to prevent a boosting operation in which a current flows backward from the low voltage side to the high voltage side.
More specifically, the low voltage side current and the high voltage side current have a positive correlation. Therefore, when the low-voltage side current is small, the asynchronous switching operation is performed, and the circuit cutoff switch is turned off, the low-voltage side current sensor fails and even if the low-voltage side current sensor value becomes higher than the predetermined value, the high-voltage side current sensor fails. The sensor value of the current remains below the predetermined value. As a result, an unintended synchronous switching operation and circuit break switch-on do not occur, and a boosting operation due to a reverse current is prevented.
（２）制御部２００は、電流センサ１５０、１５１で検出された高圧側回路および低圧側回路の電流の少なくとも一方が所定の値よりも低い場合に、同期整流回路ＭＯＳＦＥＴ１１４、１１５および回路遮断スイッチＭＯＳＦＥＴ１１７の両方をオフにする。これにより、高圧側の電流センサあるいは低圧側の電流センサのどちらか一方が故障しても電流逆流による昇圧動作を防止できる。 (2) When at least one of the currents of the high-voltage side circuit and the low-voltage side circuit detected by the current sensors 150 and 151 is lower than a predetermined value, the control unit 200 controls the synchronous rectification circuit MOSFETs 114 and 115 and the circuit cutoff switch MOSFET 117. Turn off both. As a result, even if one of the high-voltage side current sensor and the low-voltage side current sensor fails, it is possible to prevent the boosting operation due to the current reverse flow.
（３）制御部は２００、ＤＣ－ＤＣコンバータ１００が出力電流に基づく電流制御を実行中には、低圧側回路の電流が予め定められた電流制限値Ilimを超えた場合に、同期整流回路ＭＯＳＦＥＴ１１４、１１５のスイッチをオフにする。電流制限値Ilimは、非同期スイッチング動作かつ回路遮断スイッチオフとなる所定値より高い値である。これにより、低圧側の電流センサが故障してセンサ値が電流制限値Ilimより高くなり、意図せぬ電流制御が実施されても、電流逆流による昇圧動作を防止できる。 (3) The control unit 200 controls the synchronous rectification circuit MOSFET 114 while the DC-DC converter 100 is executing the current control based on the output current when the current of the low-voltage side circuit exceeds a predetermined current limit value Ilim. , 115 are turned off. The current limit value Ilim is a value higher than a predetermined value at which the asynchronous switching operation and the circuit cutoff switch are turned off. As a result, even if the current sensor on the low voltage side fails and the sensor value becomes higher than the current limit value Ilim, and unintended current control is performed, it is possible to prevent the boosting operation due to the current reverse flow.
　本発明は、上記の実施形態に限定されるものではなく、本発明の特徴を損なわない限り、本発明の技術思想の範囲内で考えられるその他の形態についても、本発明の範囲内に含まれる。また、上述の実施形態を組み合わせた構成としてもよい。 The present invention is not limited to the above embodiments, and other forms that can be considered within the scope of the technical idea of the present invention are also included in the scope of the present invention unless the characteristics of the present invention are impaired. . Further, a configuration in which the above embodiments are combined may be adopted.
１００　ＤＣ－ＤＣコンバータ
１１０、１１１、１１２、１１３　ＭＯＳＦＥＴ
１１４、１１５、１１６、１１７　ＭＯＳＦＥＴ
１２０　フィルタキャパシタ
１２１、１２２　平滑用キャパシタ
１３０　共振用インダクタ
１４０　変圧器
１４１　高圧側巻線
１４２、１４３　低圧側巻線
１５０、１５１　電流センサ
１６０、１６１　電圧センサ
１７０　温度センサ
２００　ＤＣ－ＤＣコンバータ制御装置
３００　高圧側バッテリ
４００　低圧側バッテリ
５００　負荷 100 DC- DC converter 110, 111, 112, 113 MOSFET
114, 115, 116, 117 MOSFET
Reference Signs List 120 filter capacitor 121, 122 smoothing capacitor 130 resonance inductor 140 transformer 141 high-voltage side winding 142, 143 low-voltage side winding 150, 151 current sensor 160, 161 voltage sensor 170 temperature sensor 200 DC-DC converter controller 300 high voltage Side battery 400 low voltage side battery 500 load

Claims (4)

  1. 　入力された直流電圧を降圧して出力するＤＣ－ＤＣコンバータであって、
    　変圧器の一次側に接続された高圧側回路と、
    　前記変圧器の二次側に接続され、同期整流回路および回路遮断スイッチを備える低圧側回路と、
    　前記高圧側回路および前記低圧側回路の電流を検出する電流センサと、
    　前記同期整流回路および前記回路遮断スイッチのスイッチングを制御する制御部と、
    を備え、
    　前記制御部は、前記電流センサで検出された前記高圧側回路および前記低圧側回路の電流の少なくとも一方が所定の値よりも低い場合に、前記同期整流回路または前記回路遮断スイッチをオフにするＤＣ－ＤＣコンバータ。     A DC-DC converter that steps down and outputs an input DC voltage,
    A high-side circuit connected to the primary side of the transformer,
    A low voltage side circuit connected to the secondary side of the transformer and including a synchronous rectification circuit and a circuit cutoff switch;
    A current sensor for detecting a current of the high voltage side circuit and the low voltage side circuit,
    A control unit that controls switching of the synchronous rectifier circuit and the circuit cutoff switch,
    With
    The control unit is configured to turn off the synchronous rectifier circuit or the circuit cutoff switch when at least one of the currents of the high voltage side circuit and the low voltage side circuit detected by the current sensor is lower than a predetermined value. -DC converter.
  2. 　請求項１に記載のＤＣ－ＤＣコンバータにおいて、
    　前記所定の値は、前記低圧側回路の電流リプルに起因する電流の逆流による昇圧動作が発生しない値であるＤＣ－ＤＣコンバータ。     The DC-DC converter according to claim 1,
    The DC-DC converter, wherein the predetermined value is a value that does not cause a boosting operation due to a reverse current of the current caused by the current ripple of the low-voltage side circuit.
  3. 　請求項１または請求項２に記載のＤＣ－ＤＣコンバータにおいて、
    　前記制御部は、前記電流センサで検出された前記高圧側回路および前記低圧側回路の電流の少なくとも一方が前記所定の値よりも低い場合に、前記同期整流回路および前記回路遮断スイッチの両方をオフにするＤＣ－ＤＣコンバータ。     In the DC-DC converter according to claim 1 or 2,
    The control unit turns off both the synchronous rectifier circuit and the circuit cutoff switch when at least one of the high-side circuit and the low-side circuit current detected by the current sensor is lower than the predetermined value. DC-DC converter.
  4. 　請求項１または請求項２に記載のＤＣ－ＤＣコンバータにおいて、
    　前記制御部は、前記ＤＣ－ＤＣコンバータが出力電流に基づく電流制御を実行中には、前記低圧側回路の電流が予め定められた電流制限値を超えた場合に、前記同期整流回路のスイッチをオフにするＤＣ－ＤＣコンバータ。     In the DC-DC converter according to claim 1 or 2,
    While the DC-DC converter is performing the current control based on the output current, the control unit switches the synchronous rectifier circuit switch when the current of the low voltage side circuit exceeds a predetermined current limit value. DC-DC converter to turn off.
PCT/JP2019/024207 2018-07-09 2019-06-19 Dc-dc converter WO2020012895A1 (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001292572A (en) * 2000-04-07 2001-10-19 Yokogawa Electric Corp Switching power supply
JP2007202349A (en) * 2006-01-27 2007-08-09 Denso Corp Controller for voltage converting circuit
JP2009148131A (en) * 2007-12-18 2009-07-02 Shindengen Electric Mfg Co Ltd Synchronously rectifying converter

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001292572A (en) * 2000-04-07 2001-10-19 Yokogawa Electric Corp Switching power supply
JP2007202349A (en) * 2006-01-27 2007-08-09 Denso Corp Controller for voltage converting circuit
JP2009148131A (en) * 2007-12-18 2009-07-02 Shindengen Electric Mfg Co Ltd Synchronously rectifying converter

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