WO2020189656A1 - Vehicle-mounted dc/dc converter - Google Patents

Vehicle-mounted dc/dc converter Download PDF

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Publication number
WO2020189656A1
WO2020189656A1 PCT/JP2020/011619 JP2020011619W WO2020189656A1 WO 2020189656 A1 WO2020189656 A1 WO 2020189656A1 JP 2020011619 W JP2020011619 W JP 2020011619W WO 2020189656 A1 WO2020189656 A1 WO 2020189656A1
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Prior art keywords
voltage
duty
conductive path
correction value
control unit
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PCT/JP2020/011619
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French (fr)
Japanese (ja)
Inventor
貴史 川上
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株式会社オートネットワーク技術研究所
住友電装株式会社
住友電気工業株式会社
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Application filed by 株式会社オートネットワーク技術研究所, 住友電装株式会社, 住友電気工業株式会社 filed Critical 株式会社オートネットワーク技術研究所
Publication of WO2020189656A1 publication Critical patent/WO2020189656A1/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
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only

Definitions

  • the present disclosure relates to an in-vehicle DCDC converter.
  • the in-vehicle DCDC converter shown in Patent Document 1 implements voltage feedback control by a feedback circuit in order to stabilize the output voltage.
  • measures are taken to suppress the influence when, for example, an in-vehicle DCDC converter is short-circuited, by mounting a protective element in addition to the voltage conversion unit.
  • the voltage is compared with the target voltage.
  • the control unit that controls the voltage conversion unit stops the PWM output, and at the same time, the protection circuit is opened to prevent current from flowing into the voltage conversion unit side.
  • the control unit restarts the PWM output.
  • the time until the voltage of the lead-acid battery is transmitted to the control unit, the time required for the calculation to start the PWM output in the control unit, the time required for the protection circuit to switch from the open state to the closed state, and the like are involved. Therefore, there is a problem that it takes time to supply the output voltage from the voltage conversion unit to the lead storage battery.
  • the protection circuit is installed on the output terminal side of the feedback circuit, the voltage on the voltage conversion unit side can be output with the target magnitude, but the output in the conductive path between the voltage conversion unit and the output terminal. There is a problem that the magnitude of the voltage on the output terminal side becomes smaller due to the increase in the resistance value due to the current value and the temperature rise.
  • the present invention has been made based on the above circumstances, and an object of the present invention is to provide an in-vehicle DCDC converter capable of achieving both output responsiveness and accuracy of an output voltage even when a protection circuit is mounted. Is.
  • the vehicle-mounted DCDC converter of the present disclosure has a voltage conversion unit having a switch element that receives a PWM signal, a control unit that controls the voltage conversion unit, and a protection circuit.
  • the control unit gives the PWM signal to the switch element
  • the voltage conversion unit is an in-vehicle DCDC converter that steps down or boosts the input voltage applied to the first conductive path by the switching operation of the switch element in response to the PWM signal and applies the voltage to the second conductive path.
  • a first voltage detection unit that detects the first output voltage applied to the second conductive path
  • a second voltage detection unit that detects a second output voltage applied to a third conductive path provided on the downstream side of the second conductive path among the current paths through which the output current from the voltage conversion unit flows.
  • the protection circuit includes at least a protection switch interposed between the second conductive path and the third conductive path.
  • the control unit performs a first feedback calculation for determining a first duty for bringing the magnitude of the first output voltage closer to the first target voltage based on the first output voltage, and the second output voltage.
  • a second feedback calculation is performed to determine the second duty for approaching the magnitude of the second target voltage based on the second output voltage, and a correction value based on the second duty is applied to the first duty.
  • the voltage is controlled so as to output the PWM signal of the reflected use duty to the switch element.
  • FIG. 1 is a circuit diagram schematically showing an in-vehicle DCDC converter according to the first embodiment.
  • FIG. 2 is a flowchart showing a procedure of the first feedback calculation in the control unit of the vehicle-mounted DCDC converter of the first embodiment.
  • FIG. 3 is a flowchart showing a procedure of the second feedback calculation in the control unit of the vehicle-mounted DCDC converter of the first embodiment.
  • FIG. 4 is a flowchart showing the procedure of the second feedback calculation in the control unit of the vehicle-mounted DCDC converter of the first embodiment, the step of determining whether the current control is being executed, and the timing of switching from the voltage control to the current control.
  • a state in which a step of determining the above and a step of determining the timing of switching from the current control to the voltage control are provided.
  • the vehicle-mounted DCDC converter of the present disclosure is (1) It has a voltage conversion unit having a switch element that receives a PWM signal, a control unit that controls the voltage conversion unit, and a protection circuit.
  • the control unit gives a PWM signal to the switch element, and the voltage conversion unit .
  • An in-vehicle DCDC converter that lowers or boosts the input voltage applied to the first conductive path by the switching operation of the switch element in response to the PWM signal and applies the voltage to the second conductive path.
  • the first voltage detection unit that detects the first output voltage to be applied and the third conductive path provided on the downstream side of the second conductive path among the current paths through which the output current from the voltage conversion unit flows. It has a second voltage detection unit for detecting a second output voltage, the protection circuit includes at least a protection switch interposed between the second conductive path and the third conductive path, and the control unit is the first.
  • the first feedback calculation for determining the first duty for bringing the magnitude of the output voltage closer to the first target voltage based on the first output voltage, and the magnitude of the second output voltage closer to the second target voltage.
  • the control unit calculates the first duty for each first cycle and updates it as the used duty, calculates the second duty for each second cycle larger than the first cycle, and calculates the second duty.
  • the correction value may be updated every time.
  • the control unit may calculate the difference between the second duty and the first duty as a correction value.
  • the control unit executes voltage control when the magnitude of the load current flowing through the load connected to the third conductive path is less than the threshold value, and when the magnitude of the load current is greater than or equal to the threshold value, the first conductive path.
  • current control is executed based on the input current flowing through the current and the output current flowing through the second conductive path or the third conductive path, and when switching from voltage control to current control, the correction value immediately before switching to current control is retained.
  • the retained correction value may be added to the first duty.
  • the control unit calculates the correction value based on the second duty in the voltage control
  • the correction value is adopted when the correction value is within a predetermined range, and the correction value is corrected based on the second duty in the voltage control.
  • the value is calculated, it is not necessary to adopt the correction value when the magnitude of the correction value is out of the predetermined range. With such a configuration, it is not necessary to adopt a correction value outside the predetermined range, so that it is possible to prevent the PWM signal output to the switch element from showing an unexpected value.
  • the in-vehicle DCDC converter 1 (hereinafter, also referred to as “DCDC converter 1”) according to the first embodiment is configured as an in-vehicle buck-boost DCDC converter.
  • the DCDC converter 1 is configured to boost or step down the DC voltage applied to either the first conductive path 91 or the second conductive path 92 and output it to the other conductive path.
  • the DCDC converter 1 includes an input conductive path 90 as a power line, a first conductive path 91, a second conductive path 92, and a third conductive path 93.
  • the input conductive path 90 is connected to the first terminal Pin.
  • a terminal on the high potential side of the first power supply unit (not shown) can be electrically connected to the first terminal Pin, and a predetermined input voltage can be applied to the input conductive path 90 from the first power supply unit. it can.
  • the input voltage applied to the input conductive path 90 is stepped down or boosted by the voltage conversion unit 10 via the first protection circuit 11 and the first conductive path 91, and is output to the second conductive path 92.
  • the output voltage is output from the voltage conversion unit 10 to the second conductive path 92.
  • the output voltage output to the second conductive path 92 is the third conductive path provided on the downstream side of the second conductive path 92 in the current path through which the output current from the second protection circuit 14 and the voltage conversion unit 10 flows. It is output to the second terminal Pout via the road 93.
  • the third conductive path 93 is provided on the opposite side of the voltage conversion unit 10 with the second conductive path 92 interposed therebetween.
  • the third conductive path 93 is provided on the opposite side of the second conductive path 92 with the second protection circuit 14 interposed therebetween.
  • the first power supply unit is composed of known means such as a lead storage battery, a lithium ion battery, an electric double layer capacitor, a lithium ion capacitor, another power storage unit, and a generator.
  • the DCDC converter 1 includes a voltage conversion unit 10, a first protection circuit 11, an input voltage detection unit 12, a second protection circuit 14, a first voltage detection unit 13, a second voltage detection unit 15, and a control unit. It has 16.
  • the voltage conversion unit 10 lowers or boosts the input voltage applied to the first conductive path 91 by the switching operation of the switch elements T1, T2, T3, and T4 in response to the PWM signal from the control unit 16, and the second conductive. It has a function of applying an output voltage to the road 92.
  • the voltage conversion unit 10 is provided between the first conductive path 91 and the second conductive path 92.
  • the voltage conversion unit 10 has a step-down function for performing a step-down operation and a step-up function for performing a step-up operation. In the following description, an example will be described in which the voltage conversion unit 10 executes a step-down function of stepping down the voltage applied to the first conductive path 91 and outputting it to the second conductive path 92.
  • the voltage conversion unit 10 includes switch elements T1, T2, T3, T4, a coil L1, a capacitor C1, and a capacitor C2 arranged in an H-bridge structure.
  • the voltage conversion unit 10 functions as a so-called bidirectional DCDC converter.
  • the switch elements T1, T2, T3, and T4 are configured as, for example, MOSFETs.
  • the coil L1 is configured as a known coil.
  • the first conductive path 91 is electrically connected to the drain of the switch element T1, and the drain of the switch element T2 and one end of the coil L1 are electrically connected to the source of the switch element T1.
  • the second conductive path 92 is electrically connected to the drain of the switch element T3, and the drain of the switch element T4 and the other end of the coil L1 are electrically connected to the source of the switch element T3.
  • Each source of the switch elements T2 and T4 is electrically connected to the ground.
  • a PWM signal from the control unit 16 is input to each gate of the switch elements T1, T2, T3, and T4.
  • One electrode of the capacitor C1 is electrically connected to a connection point where the drain of the switch element T1 and the first conductive path 91 are electrically connected.
  • One electrode of the capacitor C1 has the same potential as the drain of the switch element T1 and the first conductive path 91.
  • the other electrode of the capacitor C1 is electrically connected to the ground.
  • One electrode of the capacitor C2 is electrically connected to a connection point where the drain of the switch element T3 and the second conductive path 92 are electrically connected.
  • One electrode of the capacitor C2 has the same potential as the drain of the switch element T3 and the second conductive path 92.
  • the other electrode of the capacitor C2 is electrically connected to the ground.
  • the first protection circuit 11 is interposed between the input conductive path 90 and the first conductive path 91.
  • the first protection circuit 11 includes a resistor R1, a coil L3, and a switch T5.
  • the resistor R1 is interposed between the first conductive path 91 and the input conductive path 90.
  • the resistor R1 is used when detecting the current flowing through the input conductive path 90 and the first conductive path 91.
  • the voltage across the resistor R1 is amplified by the differential amplifier and output to the control unit 16.
  • the control unit 16 specifies the magnitude of the current flowing through the input conductive path 90 and the first conductive path 91 based on the value input from the differential amplifier.
  • the coil L3 is interposed between the resistor R1 and the input conductive path 90.
  • the switch T5 is interposed between the coil L3 and the input conductive path 90.
  • the switch T5 is configured as, for example, a MOSFET.
  • the drain is arranged on the input conductive path 90 side, and the source is arranged on the coil L3 side.
  • the switch T5 is configured such that the control unit 16 controls switching of on / off operation.
  • the input voltage detection unit 12 is configured as a known voltage detection circuit.
  • the input voltage detection unit 12 divides the voltage of the input conductive path 90 by a voltage dividing circuit, detects it, and inputs it to the control unit 16 as a detection value.
  • the second protection circuit 14 is interposed between the second conductive path 92 and the third conductive path 93.
  • the second protection circuit 14 includes a capacitor C3, a resistor R2, a coil L2, and a switch T6 which is a protection switch.
  • One end of the capacitor C3 is electrically connected between the second conductive path 92 and the third conductive path 93, and the other electrode is electrically connected to the ground.
  • the electrode on one end side of the capacitor C3 has the same potential as the second conductive path 92.
  • the resistor R2 is interposed between one electrode of the capacitor C3 electrically connected to the second conductive path 92 and the third conductive path 93.
  • the resistor R2 is used when detecting the current flowing through the second conductive path 92 and the third conductive path 93.
  • the voltage across the resistor R2 is amplified by the differential amplifier and output to the control unit 16.
  • the control unit 16 specifies the magnitude of the current flowing through the second conductive path 92 and the third conductive path 93 based on the value input from the differential amplifier.
  • the coil L2 is interposed between the resistor R2 and the third conductive path 93.
  • the switch T6 is interposed between the coil L2 and the third conductive path 93.
  • the switch T6 is configured as, for example, a MOSFET. In the switch T6, the drain is arranged on the third conductive path 93 side, and the source is arranged on the coil L2 side.
  • the switch T6 is configured such that the control unit 16 controls the switching of the on / off operation.
  • the resistor R2, the coil L2, and the switch T6 are interposed between the second conductive path 92 and the third conductive path 93.
  • the first voltage detection unit 13 detects the voltage applied to the second conductive path 92 by dividing it by a voltage dividing circuit, and inputs it to the control unit 16 as a detection value.
  • the second voltage detection unit 15 detects the voltage applied to the third conductive path 93 by dividing it by a voltage dividing circuit, and inputs it to the control unit 16 as a detection value.
  • the control unit 16 is configured as, for example, a microcomputer.
  • the control unit 16 can specify the voltage value of the input conductive path 90 based on the value V1 (hereinafter, also referred to as the value V1) input from the input voltage detection unit 12.
  • the control unit 16 can specify the voltage value of the second conductive path 92 based on the value V2 (hereinafter, also referred to as the value V2) input from the first voltage detection unit 13.
  • the control unit 16 can specify the voltage value of the third conductive path 93 based on the value V3 (hereinafter, also referred to as the value V3) input from the second voltage detection unit 15.
  • the control unit 16 is configured to input a target value G (hereinafter, also referred to as a target value G) from an external ECU (Engine Control Unit) or the like.
  • the control unit 16 performs feedback control by a known method based on the values input from the input voltage detection unit 12, the first voltage detection unit 13, and the second voltage detection unit 15 and the target value G, and each switch element.
  • the duty of the PWM signal given to T1, T2, T3, and T4 is set.
  • the magnitude of the target value G is set by the first voltage detection unit 13 and the second voltage detection when the magnitude of the output voltage of the second conductive path 92 and the third conductive path 93 reaches a desired magnitude. It is set to the size of the value input from the unit 15.
  • the control unit 16 outputs a PWM signal of the set duty to the switch elements T1, T2, T3, and T4.
  • the control unit 16 can execute the first feedback calculation and the second feedback calculation.
  • the first feedback calculation uses the values input from the input voltage detection unit 12 and the first voltage detection unit 13 and the target value G, and uses the output voltage from the voltage conversion unit 10 in the second conductive path 92 (hereinafter, The first duty for bringing the magnitude of (also referred to as the first output voltage) closer to a predetermined first target voltage is determined based on the value input from the first voltage detection unit 13 based on the first output voltage.
  • the second feedback calculation uses the values input from the input voltage detection unit 12 and the second voltage detection unit 15 and the target value G, and uses the voltage in the third conductive path 93 (hereinafter, also referred to as the second output voltage).
  • the control unit 16 switches between the PWM signal whose use duty is the first duty determined in this way and the PWM signal whose use duty is the second duty instead of the first duty, and outputs the PWM signal to the switch elements T1, T2, T3, and T4. To do.
  • the control unit 16 is configured to be able to monitor the magnitude of the load current flowing through the load (not shown) connected to the third conductive path 93 via the second terminal Pout. When the load current is less than a predetermined threshold value, the control unit 16 is configured to be able to execute voltage control based on the values input from the input voltage detection unit 12, the first voltage detection unit 13, and the second voltage detection unit 15. ing. Specifically, the voltage control is a control aimed at bringing the voltage in the second conductive path 92 and the third conductive path 93 closer to a predetermined target voltage.
  • the control unit 16 determines the current flowing through the input conductive path 90 and the first conductive path 91 obtained based on the voltage across the resistor R1.
  • the configuration is such that current control based on the current flowing through the second conductive path 92 and the third conductive path 93 obtained based on the voltage across the resistor R2 can be executed.
  • the current control is a control aimed at bringing the current flowing through the second conductive path 92 and the third conductive path 93 closer to a predetermined target current.
  • the control unit 16 is configured to be able to execute voltage control when the magnitude of the load current becomes less than a predetermined threshold value while executing current control.
  • the operation of the control unit 16 complementarily outputs a PWM signal in a form in which a dead time is set for each gate of the switch elements T1 and T2.
  • Synchronous rectification control is performed. Specifically, during the output of the on signal (for example, H level signal) to the switch element T1, the off signal (for example, L level signal) is output to the switch element T2, and the on signal (for example, H level) to the switch element T2 is output.
  • the off signal for example, L level signal
  • an operation of stepping down the input voltage input to the first terminal Pin is performed, and an output voltage lower than the input voltage applied to the first terminal Pin is output to the second terminal Pout.
  • the output voltage output to the second terminal Pout is determined according to the duty of the PWM signal given to the gate of the switch element T1.
  • an ON signal is continuously input to the gate of the switch element T3, and the switch element T3 is maintained in the ON state.
  • an off signal is continuously input to the gate of the switch element T4, and the switch element T4 is maintained in the off state.
  • the control unit 16 performs known PID-type feedback control.
  • the control unit 16 is configured to be able to start operation when a predetermined start condition is satisfied. Further, as a state in which the control unit 16 operates, an initialization state in which a predetermined initialization process is performed, a standby state in which the step-up operation or the step-down operation is stopped and standby, a step-up operation state in which the step-up operation is executed, and a step-down operation There is a step-down operation state to execute.
  • the predetermined start condition is, for example, that the start switch for starting the vehicle (for example, the ignition switch) is switched from the off state to the on state.
  • the first feedback calculation and the second feedback calculation are repeatedly executed by the control unit 16 that starts the operation when a predetermined start condition is satisfied.
  • the control unit 16 sets the first duty in step S1.
  • An initial value of the first duty is set when step S1 is executed for the first time when a predetermined start condition is satisfied and the control unit 16 starts operation.
  • the initial value is set based on the input voltage of the input conductive path 90 acquired in step S2 and the first output voltage of the second conductive path 92.
  • the value calculated in the previous first feedback calculation is set as the first duty when the second and subsequent steps S1 are executed.
  • step S2 the input voltage of the input conductive path 90, the first output voltage of the second conductive path 92, and the target value G are acquired.
  • the control unit 16 specifies the input voltage of the input conductive path 90 based on the value V1 and specifies the first output voltage based on the value V2. Further, the control unit 16 acquires the target value G input from an external ECU or the like.
  • step S3 it is determined whether or not the condition for updating the first duty is satisfied.
  • the control unit 16 is configured to be able to count the number of PWM signals output to the voltage conversion unit 10. When the number of PWM signals reaches the predetermined number of times M and the difference in magnitude between the value V2 and the target value G is equal to or greater than the predetermined magnitude, the condition for updating the first duty is satisfied. To determine. When it is determined that the number of PWM signals reaches a predetermined number of times M and the difference between the value V2 and the target value G is equal to or greater than a predetermined magnitude (Yes in step S3), the process proceeds to step S5 and the value V1 , V2 is used to calculate a new first duty and update it as the used duty.
  • Step S5 is executed in a cycle (first cycle) in which the number of PWM signals is a predetermined number of times M when the difference in magnitude between the value V2 and the target value G is equal to or greater than a predetermined magnitude.
  • the control unit 16 repeats the calculation of the first duty every first cycle by the first feedback calculation, and updates the first duty as the used duty every time the calculation of the first duty is performed.
  • the new first duty is calculated by a feedback calculation of the PID method based on the mathematical formula shown in Equation 1, for example.
  • the operation amount u for bringing the voltage value of the conductive path 92 closer to the first target voltage is determined.
  • the operation amount u is, for example, a value indicating an increase / decrease amount of duty (an increase / decrease amount of on-time).
  • the control unit 16 determines the duty based on the operation amount u.
  • step S3 If it is determined that the number of PWM signals has not reached the predetermined number of times M, or the difference between the value V2 and the target value G is less than the predetermined magnitude (No in step S3), the process proceeds to step S4.
  • the value calculated in the previous first feedback calculation is set as the first duty.
  • step S6 the process proceeds to step S6 to acquire the correction value ⁇ .
  • the correction value ⁇ determined in step S17 of the second feedback calculation and the correction value ⁇ adopted in step S25, which will be described later, are acquired (see FIG. 4).
  • the correction value ⁇ is set to 0 as an initial value when a predetermined start condition is satisfied and the control unit 16 starts operation. Therefore, the value of the correction value ⁇ acquired when step S6 is executed for the first time is 0.
  • step S7 the correction value ⁇ is added to the first duty, and the PWM signal is output to the switch elements T1, T2, T3, and T4 with the value reflecting the correction value ⁇ for the first duty as the used duty.
  • the voltage is controlled so as to be performed.
  • control unit 16 determines the first duty for bringing the magnitude of the first output voltage closer to the predetermined first target voltage based on the value V2 based on the first output voltage.
  • the control unit 16 does not add the correction value ⁇ to the first duty. In this way, the procedure for executing the first feedback calculation is completed.
  • the control unit 16 sets the correction value ⁇ in step S11.
  • the correction value ⁇ is set to 0 as an initial value when a predetermined start condition is satisfied and the control unit 16 starts operation.
  • step S12 the input voltage of the input conductive path 90, the second output voltage of the third conductive path 93, and the target value G are acquired.
  • the control unit 16 specifies the voltage value of the input conductive path 90 based on the value V1 and specifies the second output voltage based on the value V3. Further, the control unit 16 acquires the target value G input from an external ECU or the like.
  • step S13 it is determined whether or not the condition for updating the correction value ⁇ is satisfied.
  • the control unit 16 is configured to execute either current control or voltage control based on the magnitude of the load current.
  • the control unit 16 is currently under voltage control, the number of PWM signals output to the voltage conversion unit 10 reaches a predetermined number of times W, and the difference between the value V3 and the target value G is equal to or greater than a predetermined size (step).
  • step S13 the process proceeds to step S15, and a new correction value ⁇ is calculated. Specifically, the control unit 16 calculates the second duty based on the values V1 and V3.
  • the second duty is calculated by a feedback calculation of the PID method based on, for example, the mathematical formula shown in Equation 1. Then, the control unit 16 calculates and determines the difference between the first duty calculated by the first feedback calculation and the second duty as the correction value ⁇ . The first duty used when calculating the correction value ⁇ is calculated immediately before the time when the second duty is calculated.
  • Step S13 may be executed only when the number of PWM signals reaches a predetermined number of times W.
  • the predetermined number of times W is a value larger than the predetermined number of times M.
  • step S15 is executed in a cycle (second cycle) in which the number of PWM signals is a predetermined number of times W. Since the predetermined number of times W is a value larger than the predetermined number of times M, step S15 is executed every cycle (second cycle) longer than the cycle (first cycle) in which step S5 is executed.
  • step S7 the correction value ⁇ is added to the first duty, and the PWM signal is output based on the value obtained by adding the correction value ⁇ to the first duty.
  • the value obtained by adding the correction value ⁇ to the first duty is substantially the second duty. That is, the PWM signal based on the second duty is substantially updated as the used duty, and the switch elements T1, T2, T3, and T4 are output. That is, the control unit 16 can determine whether to use the first duty as the working duty as it is or to substantially use the second duty as the working duty by adding the correction value ⁇ .
  • the control unit 16 repeats the calculation of the second duty by the second feedback calculation every second cycle larger than the first cycle, and each time the second duty is calculated, the difference from the first duty is set as the correction value ⁇ . Update. Further, the control unit 16 determines the second duty for bringing the magnitude of the second output voltage closer to a predetermined second target voltage based on the value V3 based on the second output voltage, and determines the first duty and the first duty. The difference from the 2 duty is calculated as the correction value ⁇ .
  • the first target voltage and the second target voltage may be the same voltage or different voltages.
  • the control unit 16 is not currently executing voltage control, or the number of PWM signals output to the voltage conversion unit 10 has not reached a predetermined number of times W, or the difference between the value V3 and the target value G is large. If it is determined that the size is less than the predetermined size (No in step S13), the process proceeds to step S14, and the same correction value ⁇ as the previous time is adopted.
  • step S16 it is determined whether or not the failure condition is satisfied.
  • a range in which the correction value ⁇ can be taken is set in advance, and the control unit 16 is configured to be able to store a constant that determines this range.
  • This constant is determined in consideration of, for example, variations in the performance of the components constituting the DCDC converter 1, variations in the characteristics of the components due to changes in temperature, variations in deterioration of the components, and the like.
  • step S16 when the control unit 16 is currently executing voltage control, it is determined whether or not the absolute value of the correction value ⁇ is less than the constant stored in the control unit 16.
  • the control unit 16 determines that the DCDC converter 1 has not failed (No in step S16). The process proceeds to step S17, and the correction value ⁇ is determined and adopted. Further, when the magnitude of the absolute value of the correction value ⁇ is 0.2 or more (that is, outside the predetermined range), the control unit 16 determines that the DCDC converter 1 is out of order (Yes in step S16), and steps. Moving to S18, it is determined that any part of the DCDC converter 1 is out of order, and the value of the correction value ⁇ is not fixed.
  • the failure state signal indicating the failure state is changed from the L level to the H level.
  • the failure state signal is changed from the L level indicating the non-failed state to the H level indicating the failed state.
  • the failure status signal is set to L level in step S17.
  • step S21 for determining whether voltage control is being executed, and the timing of switching from voltage control to current control are determined.
  • Step S22 and step S23 for determining the timing of switching from current control to voltage control may be provided.
  • step S21 it is determined in step S21 whether voltage control is being executed.
  • step S21 for example, a general arbitration method between voltage control and current control may be used, or a method for determining whether or not the load current is equal to or higher than a predetermined threshold value may be used.
  • step S22 the timing of switching from the voltage control to the current control is determined in step S22.
  • the correction value ⁇ immediately before switching from voltage control to current control is obtained.
  • step S24 The obtained value is held in the control unit 16 (step S24).
  • step S21 the timing of switching from the voltage control to the current control
  • step S23 the timing of switching from the current control to the voltage control
  • step S25 the correction value ⁇ held by the control unit 16 is adopted as the correction value for processing.
  • step S16 the control unit 16 may set the correction value ⁇ to 0 as an initial value.
  • the reason for switching from voltage control (for example, a predetermined voltage such as 12V) to current control is to prevent the resistance from becoming smaller and the current value from becoming infinitely large as the load increases.
  • the voltage control for example, a predetermined voltage such as 12V
  • the voltage is controlled so as to be the same as the initial voltage (for example, 12V), so that the correction value ⁇ immediately before is used for control.
  • the voltage control can be executed earlier than the case where the voltage control is executed by recalculation.
  • the vehicle-mounted DCDC converter 1 of the present disclosure is (1) A voltage conversion unit 10 having switch elements T1, T2, T3, and T4 that receive PWM signals, a control unit 16 that controls the voltage conversion unit 10, and a second protection circuit 14, and the control unit 16 Gives a PWM signal to the switch elements T1, T2, T3, and T4, and the voltage conversion unit 10 is applied to the first conductive path 91 by the switching operation of the switch elements T1, T2, T3, and T4 in response to the PWM signal.
  • An in-vehicle DCDC converter 1 that lowers the input voltage and applies a voltage to the second conductive path 92, and a first voltage detecting unit 13 that detects a first output voltage applied to the second conductive path 92.
  • the second voltage detection unit 15 that detects the second output voltage applied to the third conductive path 93 provided on the downstream side of the second conductive path 92 in the current path through which the output current from the voltage conversion unit 10 flows.
  • the second protection circuit 14 has a resistor R2 interposed between the second conductive path 92 and the third conductive path 93, and a coil interposed between the second conductive path 92 and the third conductive path 93.
  • the control unit 16 performs a first feedback calculation for determining a first duty for bringing the magnitude of the first output voltage closer to a predetermined first target voltage based on the first output voltage, and a second output voltage.
  • the second feedback calculation for determining the second duty for bringing the magnitude of the voltage closer to the predetermined second target voltage is performed based on the second output voltage, and the correction value ⁇ based on the second duty is set for the first duty.
  • the output responsiveness and accuracy of the second output voltage can be compatible with each other.
  • the control unit 16 calculates the first duty for each first cycle and updates it as the used duty, and updates the correction value ⁇ every time the second duty is calculated every second cycle larger than the first cycle. To do. With this configuration, it is possible to prevent the PWM signals of the first duty and the second duty from being frequently switched and output to the switch elements T1, T2, T3, and T4, and to suppress the output to the first output voltage and the first output voltage. It is possible to suppress hunting of the output voltage of 2.
  • the control unit 16 calculates the difference between the second duty and the first duty as the correction value ⁇ . With this configuration, the control unit 16 can handle the value of the first duty based on the first output voltage as a reference, so that it is easy to distinguish between the first duty and the second duty. ..
  • the control unit 16 executes voltage control when the magnitude of the load current flowing through the load connected to the third conductive path 93 is less than the threshold value, and when the magnitude of the load current is greater than or equal to the threshold value, the first When current control is executed based on the input current flowing through the conductive path 91 and the output current flowing through the second conductive path 92 or the third conductive path 93, and the voltage control is switched to the current control, the correction immediately before switching to the current control is performed. When the value ⁇ is held and the current control is switched to the voltage control, the held correction value ⁇ is added to the first duty. With this configuration, it is possible to prevent the first output voltage and the second output voltage from suddenly fluctuating when the current control is switched to the voltage control.
  • the control unit 16 determines the correction value ⁇ within a predetermined range during voltage control, the correction value ⁇ is within a predetermined range during voltage control. If it is outside, the correction value ⁇ is not fixed. With this configuration, it is not necessary to determine the correction value ⁇ outside the predetermined range, so that it is possible to prevent the PWM signals output to the switch elements T1, T2, T3, and T4 from showing unexpected values. be able to.
  • the bidirectional buck-boost DCDC converter has been illustrated, but it may be a step-down DCDC converter or a step-up DCDC converter. Further, it may be a bidirectional DCDC converter in which the input side and the output side can be changed as in the first embodiment, or a unidirectional DCDC converter in which the input side and the output side are fixed. ..
  • the synchronous rectification type DCDC converter is exemplified in the first embodiment, it may be a diode type DCDC converter in which some switch elements are replaced with diodes.
  • the switch elements T1, T2, T3, and T4 configured as MOSFETs are exemplified as the switch elements, but other switches such as bipolar transistors may be used.
  • control unit 16 is mainly composed of a microcomputer, but it may be realized by a plurality of hardware circuits other than the microcomputer.
  • the second protection circuit 14 includes the capacitor C3, the resistor R2, the coil L2, and the switch T6, but may be configured to include at least one of the capacitor, the resistor, the coil, and the switch.

Abstract

A vehicle mounted DC/DC converter is provided which, even in the case of being equipped with a protection circuit, enables achieving both output responsiveness and precision of the output voltage.　In this vehicle-mounted DC/DC converter (1), a second protection circuit (14) contains at least a switch (T6) which is interposed between a second conduction path (92) and a third conduction path (93), the control unit (16) performs first feedback calculations for determining, on the basis of a first output voltage, a first duty for causing the magnitude of the first output voltage in the second conductive path (92) to approach a prescribed first target voltage, and second feedback calculations for determining, on the basis of a second output voltage, a second duty for causing the magnitude of the second output voltage in the third conduction path (93) to approach a prescribed second target voltage, and a PWM signal of the use duty, in which a correction value (α) based on the second duty is reflected in the first duty, is outputted to switch elements (T1, T2, T3, T4).

Description

車載用ＤＣＤＣコンバータIn-vehicle DCDC converter
　本開示は、車載用ＤＣＤＣコンバータに関するものである。 The present disclosure relates to an in-vehicle DCDC converter.
　特許文献１に示す車載用ＤＣＤＣコンバータは、出力電圧を安定化させるためにフィードバック回路による電圧フィードバック制御を実施している。こうした構成を採用する場合、電圧変換部に加えて、保護素子を搭載することによって、例えば車載用ＤＣＤＣコンバータが短絡故障した際の影響を抑える対策をとることが行われている。 The in-vehicle DCDC converter shown in Patent Document 1 implements voltage feedback control by a feedback circuit in order to stabilize the output voltage. When such a configuration is adopted, measures are taken to suppress the influence when, for example, an in-vehicle DCDC converter is short-circuited, by mounting a protective element in addition to the voltage conversion unit.
特開２００８－１８２８３９号公報Japanese Unexamined Patent Publication No. 2008-182839 特開２００９－２９１００６号公報JP-A-2009-291006
　例えば、保護素子に代えて、スイッチ等を含む構成の保護回路をフィードバック回路よりも電圧変換部側に設置し、出力端子に鉛蓄電池等の外部機器が接続された状況において、目標電圧に比べて出力端子側の電圧（鉛蓄電池の電圧）が大きい場合、電圧変換部を制御する制御部はＰＷＭの出力を停止し、これと同時に電圧変換部側に電流が流れ込むことを防ぐために保護回路がオープン状態になる。その後、鉛蓄電池の電圧が目標電圧より小さくなり、電圧変換部が出力可能な状態になったとき、制御部はＰＷＭの出力を再開することになる。このとき、制御部に鉛蓄電池の電圧が伝達するまでの時間、制御部内でＰＷＭの出力を開始するための演算に係る時間、及び保護回路がオープン状態からクローズ状態に切り替わるまでの時間等が係るため、鉛蓄電池に電圧変換部からの出力電圧を供給するまでに時間がかかるという課題がある。
　一方で、保護回路をフィードバック回路より出力端子側に設置すると、電圧変換部側の電圧は目標通りの大きさで出力することができるが、電圧変換部と出力端子との間の導電路における出力電流値や温度上昇による抵抗値の増加によって、出力端子側の電圧の大きさが小さくなるという課題がある。 For example, in the situation where a protection circuit including a switch or the like is installed on the voltage conversion unit side of the feedback circuit instead of the protection element and an external device such as a lead storage battery is connected to the output terminal, the voltage is compared with the target voltage. When the voltage on the output terminal side (lead-acid battery voltage) is large, the control unit that controls the voltage conversion unit stops the PWM output, and at the same time, the protection circuit is opened to prevent current from flowing into the voltage conversion unit side. Become in a state. After that, when the voltage of the lead-acid battery becomes smaller than the target voltage and the voltage conversion unit can output, the control unit restarts the PWM output. At this time, the time until the voltage of the lead-acid battery is transmitted to the control unit, the time required for the calculation to start the PWM output in the control unit, the time required for the protection circuit to switch from the open state to the closed state, and the like are involved. Therefore, there is a problem that it takes time to supply the output voltage from the voltage conversion unit to the lead storage battery.
On the other hand, if the protection circuit is installed on the output terminal side of the feedback circuit, the voltage on the voltage conversion unit side can be output with the target magnitude, but the output in the conductive path between the voltage conversion unit and the output terminal. There is a problem that the magnitude of the voltage on the output terminal side becomes smaller due to the increase in the resistance value due to the current value and the temperature rise.
　本発明は上述した事情に基づいてなされたものであり、保護回路を搭載した場合であっても、出力電圧の出力応答性及び精度を両立することができる車載用ＤＣＤＣコンバータを提供することが目的である。 The present invention has been made based on the above circumstances, and an object of the present invention is to provide an in-vehicle DCDC converter capable of achieving both output responsiveness and accuracy of an output voltage even when a protection circuit is mounted. Is.
　本開示の車載用ＤＣＤＣコンバータは、
　ＰＷＭ信号を受けるスイッチ素子を有する電圧変換部と、前記電圧変換部を制御する制御部と、保護回路と、を有し、
　前記制御部は、前記スイッチ素子に前記ＰＷＭ信号を与え、
　前記電圧変換部は、前記ＰＷＭ信号に応じた前記スイッチ素子のスイッチング動作によって第１導電路に印加される入力電圧を降圧又は昇圧して第２導電路に電圧を印加する車載用ＤＣＤＣコンバータであって、
　前記第２導電路に印加される第１の出力電圧を検出する第１電圧検出部と、
　前記電圧変換部からの出力電流が流れる電流経路のうち前記第２導電路よりも下流側に設けられた第３導電路に印加される第２の出力電圧を検出する第２電圧検出部と、
　を有し、
　前記保護回路は、少なくとも前記第２導電路と前記第３導電路との間に介在する保護スイッチを含み、
　前記制御部は、前記第１の出力電圧の大きさを第１目標電圧に近づけるための第１デューティを前記第１の出力電圧に基づいて決定する第１フィードバック演算と、前記第２の出力電圧の大きさを第２目標電圧に近づけるための第２デューティを前記第２の出力電圧に基づいて決定する第２フィードバック演算とを行い、前記第１デューティに対し前記第２デューティに基づく補正値を反映した使用デューティの前記ＰＷＭ信号を前記スイッチ素子に出力するように電圧制御を行う。 The vehicle-mounted DCDC converter of the present disclosure is
It has a voltage conversion unit having a switch element that receives a PWM signal, a control unit that controls the voltage conversion unit, and a protection circuit.
The control unit gives the PWM signal to the switch element,
The voltage conversion unit is an in-vehicle DCDC converter that steps down or boosts the input voltage applied to the first conductive path by the switching operation of the switch element in response to the PWM signal and applies the voltage to the second conductive path. hand,
A first voltage detection unit that detects the first output voltage applied to the second conductive path, and
A second voltage detection unit that detects a second output voltage applied to a third conductive path provided on the downstream side of the second conductive path among the current paths through which the output current from the voltage conversion unit flows.
Have,
The protection circuit includes at least a protection switch interposed between the second conductive path and the third conductive path.
The control unit performs a first feedback calculation for determining a first duty for bringing the magnitude of the first output voltage closer to the first target voltage based on the first output voltage, and the second output voltage. A second feedback calculation is performed to determine the second duty for approaching the magnitude of the second target voltage based on the second output voltage, and a correction value based on the second duty is applied to the first duty. The voltage is controlled so as to output the PWM signal of the reflected use duty to the switch element.
　本開示によれば、第２の出力電圧の出力応答性と精度とを両立させることができる。 According to the present disclosure, it is possible to achieve both the output responsiveness and accuracy of the second output voltage.
図１は、実施形態１の車載用ＤＣＤＣコンバータを概略的に示す回路図である。FIG. 1 is a circuit diagram schematically showing an in-vehicle DCDC converter according to the first embodiment. 図２は、実施形態１の車載用ＤＣＤＣコンバータの制御部における第１フィードバック演算の手順を示すフローチャートである。FIG. 2 is a flowchart showing a procedure of the first feedback calculation in the control unit of the vehicle-mounted DCDC converter of the first embodiment. 図３は、実施形態１の車載用ＤＣＤＣコンバータの制御部における第２フィードバック演算の手順を示すフローチャートである。FIG. 3 is a flowchart showing a procedure of the second feedback calculation in the control unit of the vehicle-mounted DCDC converter of the first embodiment. 図４は、実施形態１の車載用ＤＣＤＣコンバータの制御部における第２フィードバック演算の手順を示すフローチャートであり、電流制御の実行中であるか判別するステップ、電圧制御から電流制御への切り替わりのタイミングを判別するステップ、及び電流制御から電圧制御への切り替わりのタイミングを判別するステップ等を設けた状態を示す。FIG. 4 is a flowchart showing the procedure of the second feedback calculation in the control unit of the vehicle-mounted DCDC converter of the first embodiment, the step of determining whether the current control is being executed, and the timing of switching from the voltage control to the current control. A state in which a step of determining the above and a step of determining the timing of switching from the current control to the voltage control are provided.
［本開示の実施形態の説明］
　最初に本開示の実施態様を列記して説明する。
　本開示の車載用ＤＣＤＣコンバータは、
（１）ＰＷＭ信号を受けるスイッチ素子を有する電圧変換部と、電圧変換部を制御する制御部と、保護回路と、を有し、制御部は、スイッチ素子にＰＷＭ信号を与え、電圧変換部は、ＰＷＭ信号に応じたスイッチ素子のスイッチング動作によって第１導電路に印加される入力電圧を降圧又は昇圧して第２導電路に電圧を印加する車載用ＤＣＤＣコンバータであって、第２導電路に印加される第１の出力電圧を検出する第１電圧検出部と、電圧変換部からの出力電流が流れる電流経路のうち第２導電路よりも下流側に設けられた第３導電路に印加される第２の出力電圧を検出する第２電圧検出部とを有し、保護回路は、少なくとも第２導電路と第３導電路との間に介在する保護スイッチを含み、制御部は、第１の出力電圧の大きさを第１目標電圧に近づけるための第１デューティを第１の出力電圧に基づいて決定する第１フィードバック演算と、第２の出力電圧の大きさを第２目標電圧に近づけるための第２デューティを第２の出力電圧に基づいて決定する第２フィードバック演算とを行い、第１デューティに対し第２デューティに基づく補正値を反映した使用デューティのＰＷＭ信号をスイッチ素子に出力するように電圧制御を行うことによって、第２導電路の第１の出力電圧と、保護回路を経由した後の第２の出力電圧を参照し、第２の出力電圧の出力応答性と精度とを両立させることができる。 [Explanation of Embodiments of the present disclosure]
First, embodiments of the present disclosure will be listed and described.
The vehicle-mounted DCDC converter of the present disclosure is
(1) It has a voltage conversion unit having a switch element that receives a PWM signal, a control unit that controls the voltage conversion unit, and a protection circuit. The control unit gives a PWM signal to the switch element, and the voltage conversion unit , An in-vehicle DCDC converter that lowers or boosts the input voltage applied to the first conductive path by the switching operation of the switch element in response to the PWM signal and applies the voltage to the second conductive path. It is applied to the first voltage detection unit that detects the first output voltage to be applied and the third conductive path provided on the downstream side of the second conductive path among the current paths through which the output current from the voltage conversion unit flows. It has a second voltage detection unit for detecting a second output voltage, the protection circuit includes at least a protection switch interposed between the second conductive path and the third conductive path, and the control unit is the first. The first feedback calculation for determining the first duty for bringing the magnitude of the output voltage closer to the first target voltage based on the first output voltage, and the magnitude of the second output voltage closer to the second target voltage. Performs a second feedback calculation that determines the second duty for the purpose based on the second output voltage, and outputs a PWM signal of the usage duty that reflects the correction value based on the second duty to the switch element for the first duty. By controlling the voltage in this way, the first output voltage of the second conductive path and the second output voltage after passing through the protection circuit are referred to, and the output responsiveness and accuracy of the second output voltage can be determined. It can be compatible.
（２）制御部が、第１周期毎に第１デューティを算出して使用デューティとして更新し、第１周期よりも大きい第２周期毎に第２デューティを算出して、第２デューティを算出する毎に補正値を更新してもよい。
　このように構成されていれば、第１デューティ、及び第２デューティのそれぞれのＰＷＭ信号が頻繁に切り替わりスイッチ素子に出力されることを抑え、第１の出力電圧及び第２の出力電圧がハンチングすることを抑えることができる。 (2) The control unit calculates the first duty for each first cycle and updates it as the used duty, calculates the second duty for each second cycle larger than the first cycle, and calculates the second duty. The correction value may be updated every time.
With this configuration, it is possible to prevent the PWM signals of the first duty and the second duty from being frequently switched and output to the switch element, and the first output voltage and the second output voltage are hunted. It can be suppressed.
（３）制御部が、第２デューティと第１デューティとの差を補正値として算出してもよい。
　このように構成されていれば、制御部内において、第１の出力電圧に基づいた第１デューティの値を基準として扱うことができるため、第１デューティと第２デューティとを区別して扱い易い。 (3) The control unit may calculate the difference between the second duty and the first duty as a correction value.
With such a configuration, since the value of the first duty based on the first output voltage can be handled as a reference in the control unit, it is easy to distinguish between the first duty and the second duty.
（４）制御部が、第３導電路に接続された負荷に流れる負荷電流の大きさが閾値未満の場合、電圧制御を実行し、負荷電流の大きさが閾値以上の場合、第１導電路に流れる入力電流と、第２導電路又は第３導電路に流れる出力電流とに基づく電流制御を実行し、電圧制御から電流制御に切り替える場合に、電流制御に切り替える直前の補正値を保持し、電流制御から電圧制御に切り替えた際に、保持した補正値を第１デューティに加える構成としてもよい。
　このように構成されていれば、電流制御から電圧制御に切り替わった際に、第１の出力電圧や第２の出力電圧が不意に変動することを抑えることができる。 (4) The control unit executes voltage control when the magnitude of the load current flowing through the load connected to the third conductive path is less than the threshold value, and when the magnitude of the load current is greater than or equal to the threshold value, the first conductive path. When current control is executed based on the input current flowing through the current and the output current flowing through the second conductive path or the third conductive path, and when switching from voltage control to current control, the correction value immediately before switching to current control is retained. When switching from the current control to the voltage control, the retained correction value may be added to the first duty.
With this configuration, it is possible to prevent the first output voltage and the second output voltage from suddenly fluctuating when the current control is switched to the voltage control.
（５）制御部が、電圧制御において第２デューティに基づいて補正値を算出した場合、補正値が所定の範囲内である場合に補正値を採用し、電圧制御において第２デューティに基づいて補正値を算出した場合、補正値の大きさが所定の範囲外である場合に補正値を採用しなくてもよい。
　このように構成されていれば、所定の範囲外の補正値を採用しないで済むため、スイッチ素子に対して出力するＰＷＭ信号が想定外の値を示すことを抑えることができる。
［本開示の実施形態の詳細］ (5) When the control unit calculates the correction value based on the second duty in the voltage control, the correction value is adopted when the correction value is within a predetermined range, and the correction value is corrected based on the second duty in the voltage control. When the value is calculated, it is not necessary to adopt the correction value when the magnitude of the correction value is out of the predetermined range.
With such a configuration, it is not necessary to adopt a correction value outside the predetermined range, so that it is possible to prevent the PWM signal output to the switch element from showing an unexpected value.
[Details of Embodiments of the present disclosure]
　＜実施形態１＞
　実施形態１に係る車載用ＤＣＤＣコンバータ１（以下、「ＤＣＤＣコンバータ１」ともいう）は、車載用の昇降圧型ＤＣＤＣコンバータとして構成されている。ＤＣＤＣコンバータ１は第１導電路９１又は第２導電路９２のいずれか一方の導電路に印加された直流電圧を昇圧又は降圧して他方の導電路に出力する構成をなすものである。 <Embodiment 1>
The in-vehicle DCDC converter 1 (hereinafter, also referred to as “DCDC converter 1”) according to the first embodiment is configured as an in-vehicle buck-boost DCDC converter. The DCDC converter 1 is configured to boost or step down the DC voltage applied to either the first conductive path 91 or the second conductive path 92 and output it to the other conductive path.
〔ＤＣＤＣコンバータ１の全体構成〕
　ＤＣＤＣコンバータ１は、図１に示すように、電力線としての入力導電路９０、第１導電路９１、第２導電路９２、及び第３導電路９３を備える。入力導電路９０は、第１端子Ｐinに接続されている。第１端子Ｐinには第１電源部（図示せず）の高電位側の端子を電気的に接続することができ、入力導電路９０に第１電源部から所定の入力電圧を印加することができる。入力導電路９０に印加された入力電圧は、第１保護回路１１及び第１導電路９１を経由して電圧変換部１０によって降圧又は昇圧され第２導電路９２に出力される。第２導電路９２には電圧変換部１０から出力電圧が出力される。第２導電路９２に出力された出力電圧は、第２保護回路１４、及び電圧変換部１０からの出力電流が流れる電流経路のうち第２導電路９２よりも下流側に設けられた第３導電路９３を経由して第２端子Ｐoutに出力される。また、第３導電路９３は第２導電路９２を挟んで電圧変換部１０の反対側に設けられている。また、第３導電路９３は、第２保護回路１４を挟んで、第２導電路９２の反対側に設けられている。
　第１電源部は、例えば、鉛蓄電池、リチウムイオン電池、電気二重層キャパシタ、リチウムイオンキャパシタ、その他の蓄電部、発電機など、公知の手段によって構成される。 [Overall configuration of DCDC converter 1]
As shown in FIG. 1, the DCDC converter 1 includes an input conductive path 90 as a power line, a first conductive path 91, a second conductive path 92, and a third conductive path 93. The input conductive path 90 is connected to the first terminal Pin. A terminal on the high potential side of the first power supply unit (not shown) can be electrically connected to the first terminal Pin, and a predetermined input voltage can be applied to the input conductive path 90 from the first power supply unit. it can. The input voltage applied to the input conductive path 90 is stepped down or boosted by the voltage conversion unit 10 via the first protection circuit 11 and the first conductive path 91, and is output to the second conductive path 92. The output voltage is output from the voltage conversion unit 10 to the second conductive path 92. The output voltage output to the second conductive path 92 is the third conductive path provided on the downstream side of the second conductive path 92 in the current path through which the output current from the second protection circuit 14 and the voltage conversion unit 10 flows. It is output to the second terminal Pout via the road 93. Further, the third conductive path 93 is provided on the opposite side of the voltage conversion unit 10 with the second conductive path 92 interposed therebetween. Further, the third conductive path 93 is provided on the opposite side of the second conductive path 92 with the second protection circuit 14 interposed therebetween.
The first power supply unit is composed of known means such as a lead storage battery, a lithium ion battery, an electric double layer capacitor, a lithium ion capacitor, another power storage unit, and a generator.
　ＤＣＤＣコンバータ１は、電圧変換部１０と、第１保護回路１１と、入力電圧検出部１２と、第２保護回路１４と、第１電圧検出部１３と、第２電圧検出部１５と、制御部１６とを有している。
　電圧変換部１０は、制御部１６からのＰＷＭ信号に応じたスイッチ素子Ｔ１，Ｔ２，Ｔ３，Ｔ４のスイッチング動作によって、第１導電路９１に印加される入力電圧を降圧又は昇圧して第２導電路９２に出力電圧を印加する機能を有する。電圧変換部１０は第１導電路９１と第２導電路９２との間に設けられている。電圧変換部１０は降圧動作を行う降圧機能と、昇圧動作を行う昇圧機能とを有している。以下の説明では、電圧変換部１０において、第１導電路９１に印加された電圧を降圧して第２導電路９２に出力する降圧機能が実行される例について説明する。 The DCDC converter 1 includes a voltage conversion unit 10, a first protection circuit 11, an input voltage detection unit 12, a second protection circuit 14, a first voltage detection unit 13, a second voltage detection unit 15, and a control unit. It has 16.
The voltage conversion unit 10 lowers or boosts the input voltage applied to the first conductive path 91 by the switching operation of the switch elements T1, T2, T3, and T4 in response to the PWM signal from the control unit 16, and the second conductive. It has a function of applying an output voltage to the road 92. The voltage conversion unit 10 is provided between the first conductive path 91 and the second conductive path 92. The voltage conversion unit 10 has a step-down function for performing a step-down operation and a step-up function for performing a step-up operation. In the following description, an example will be described in which the voltage conversion unit 10 executes a step-down function of stepping down the voltage applied to the first conductive path 91 and outputting it to the second conductive path 92.
　電圧変換部１０は、Ｈブリッジ構造で配置されたスイッチ素子Ｔ１，Ｔ２，Ｔ３，Ｔ４、コイルＬ１、コンデンサＣ１、及びコンデンサＣ２を備えている。電圧変換部１０はいわゆる双方向型のＤＣＤＣコンバータとして機能する。スイッチ素子Ｔ１，Ｔ２，Ｔ３，Ｔ４は、例えば、ＭＯＳＦＥＴとして構成されている。コイルＬ１は公知のコイルとして構成されている。 The voltage conversion unit 10 includes switch elements T1, T2, T3, T4, a coil L1, a capacitor C1, and a capacitor C2 arranged in an H-bridge structure. The voltage conversion unit 10 functions as a so-called bidirectional DCDC converter. The switch elements T1, T2, T3, and T4 are configured as, for example, MOSFETs. The coil L1 is configured as a known coil.
　電圧変換部１０において、スイッチ素子Ｔ１のドレインには、第１導電路９１が電気的に接続され、スイッチ素子Ｔ１のソースには、スイッチ素子Ｔ２のドレイン及びコイルＬ１の一端が電気的に接続されている。スイッチ素子Ｔ３のドレインには、第２導電路９２が電気的に接続され、スイッチ素子Ｔ３のソースには、スイッチ素子Ｔ４のドレイン及びコイルＬ１の他端が電気的に接続されている。スイッチ素子Ｔ２，Ｔ４のそれぞれのソースはグラウンドに電気的に接続されている。スイッチ素子Ｔ１，Ｔ２，Ｔ３，Ｔ４のそれぞれのゲートには、制御部１６からのＰＷＭ信号がそれぞれ入力される。 In the voltage conversion unit 10, the first conductive path 91 is electrically connected to the drain of the switch element T1, and the drain of the switch element T2 and one end of the coil L1 are electrically connected to the source of the switch element T1. ing. The second conductive path 92 is electrically connected to the drain of the switch element T3, and the drain of the switch element T4 and the other end of the coil L1 are electrically connected to the source of the switch element T3. Each source of the switch elements T2 and T4 is electrically connected to the ground. A PWM signal from the control unit 16 is input to each gate of the switch elements T1, T2, T3, and T4.
　コンデンサＣ１はスイッチ素子Ｔ１のドレインと第１導電路９１とが電気的に接続された接続点に一方の電極が電気的に接続されている。コンデンサＣ１の一方の電極はスイッチ素子Ｔ１のドレイン及び第１導電路９１と同電位である。コンデンサＣ１は他方の電極がグラウンドに電気的に接続されている。コンデンサＣ２はスイッチ素子Ｔ３のドレインと第２導電路９２とが電気的に接続された接続点に一方の電極が電気的に接続されている。コンデンサＣ２の一方の電極はスイッチ素子Ｔ３のドレイン及び第２導電路９２と同電位である。コンデンサＣ２は他方の電極がグラウンドに電気的に接続されている。 One electrode of the capacitor C1 is electrically connected to a connection point where the drain of the switch element T1 and the first conductive path 91 are electrically connected. One electrode of the capacitor C1 has the same potential as the drain of the switch element T1 and the first conductive path 91. The other electrode of the capacitor C1 is electrically connected to the ground. One electrode of the capacitor C2 is electrically connected to a connection point where the drain of the switch element T3 and the second conductive path 92 are electrically connected. One electrode of the capacitor C2 has the same potential as the drain of the switch element T3 and the second conductive path 92. The other electrode of the capacitor C2 is electrically connected to the ground.
　第１保護回路１１は、入力導電路９０と第１導電路９１との間に介在している。第１保護回路１１は、抵抗Ｒ１、コイルＬ３、及びスイッチＴ５を備えている。
　抵抗Ｒ１は第１導電路９１と入力導電路９０との間に介在している。抵抗Ｒ１は入力導電路９０及び第１導電路９１に流れる電流を検出する際に用いられる。入力導電路９０及び第１導電路９１に流れる電流を検出する場合、差動増幅器によって抵抗Ｒ１の両端電圧を増幅して制御部１６に出力する。制御部１６は差動増幅器から入力された値に基づいて入力導電路９０及び第１導電路９１に流れる電流の大きさを特定する。 The first protection circuit 11 is interposed between the input conductive path 90 and the first conductive path 91. The first protection circuit 11 includes a resistor R1, a coil L3, and a switch T5.
The resistor R1 is interposed between the first conductive path 91 and the input conductive path 90. The resistor R1 is used when detecting the current flowing through the input conductive path 90 and the first conductive path 91. When detecting the current flowing through the input conductive path 90 and the first conductive path 91, the voltage across the resistor R1 is amplified by the differential amplifier and output to the control unit 16. The control unit 16 specifies the magnitude of the current flowing through the input conductive path 90 and the first conductive path 91 based on the value input from the differential amplifier.
　コイルＬ３は抵抗Ｒ１と入力導電路９０との間に介在している。スイッチＴ５はコイルＬ３と入力導電路９０との間に介在している。スイッチＴ５は、例えば、ＭＯＳＦＥＴとして構成されている。スイッチＴ５は、ドレインが入力導電路９０側に配置され、ソースがコイルＬ３側に配置されている。スイッチＴ５は制御部１６によってオン／オフ動作の切り替えの制御がなされる構成とされている。 The coil L3 is interposed between the resistor R1 and the input conductive path 90. The switch T5 is interposed between the coil L3 and the input conductive path 90. The switch T5 is configured as, for example, a MOSFET. In the switch T5, the drain is arranged on the input conductive path 90 side, and the source is arranged on the coil L3 side. The switch T5 is configured such that the control unit 16 controls switching of on / off operation.
　入力電圧検出部１２は、公知の電圧検出回路として構成されている。入力電圧検出部１２は、入力導電路９０の電圧を分圧回路によって分圧して検出し、検出値として制御部１６に入力する。 The input voltage detection unit 12 is configured as a known voltage detection circuit. The input voltage detection unit 12 divides the voltage of the input conductive path 90 by a voltage dividing circuit, detects it, and inputs it to the control unit 16 as a detection value.
　第２保護回路１４は、第２導電路９２と第３導電路９３との間に介在している。第２保護回路１４は、コンデンサＣ３、抵抗Ｒ２、コイルＬ２、及び保護スイッチであるスイッチＴ６を備えている。コンデンサＣ３は、一端が第２導電路９２と第３導電路９３との間に電気的に接続され、他方の電極がグラウンドに電気的に接続されている。コンデンサＣ３の一端側の電極は第２導電路９２と同電位である。 The second protection circuit 14 is interposed between the second conductive path 92 and the third conductive path 93. The second protection circuit 14 includes a capacitor C3, a resistor R2, a coil L2, and a switch T6 which is a protection switch. One end of the capacitor C3 is electrically connected between the second conductive path 92 and the third conductive path 93, and the other electrode is electrically connected to the ground. The electrode on one end side of the capacitor C3 has the same potential as the second conductive path 92.
　抵抗Ｒ２は第２導電路９２に電気的に接続されたコンデンサＣ３の一方の電極と第３導電路９３との間に介在している。抵抗Ｒ２は第２導電路９２及び第３導電路９３を流れる電流を検出する際に用いられるものである。第２導電路９２及び第３導電路９３を流れる電流を検出する際には、差動増幅器によって抵抗Ｒ２の両端電圧を増幅して制御部１６に出力する。制御部１６は差動増幅器から入力された値に基づいて第２導電路９２及び第３導電路９３を流れる電流の大きさを特定する。 The resistor R2 is interposed between one electrode of the capacitor C3 electrically connected to the second conductive path 92 and the third conductive path 93. The resistor R2 is used when detecting the current flowing through the second conductive path 92 and the third conductive path 93. When detecting the current flowing through the second conductive path 92 and the third conductive path 93, the voltage across the resistor R2 is amplified by the differential amplifier and output to the control unit 16. The control unit 16 specifies the magnitude of the current flowing through the second conductive path 92 and the third conductive path 93 based on the value input from the differential amplifier.
　コイルＬ２は抵抗Ｒ２と第３導電路９３との間に介在している。スイッチＴ６はコイルＬ２と第３導電路９３との間に介在している。スイッチＴ６は、例えば、ＭＯＳＦＥＴとして構成されている。スイッチＴ６は、ドレインが第３導電路９３側に配置され、ソースがコイルＬ２側に配置されている。スイッチＴ６は制御部１６によってオン／オフ動作の切り替えの制御がなされる構成とされている。抵抗Ｒ２、コイルＬ２、及びスイッチＴ６は第２導電路９２と第３導電路９３との間に介在している。 The coil L2 is interposed between the resistor R2 and the third conductive path 93. The switch T6 is interposed between the coil L2 and the third conductive path 93. The switch T6 is configured as, for example, a MOSFET. In the switch T6, the drain is arranged on the third conductive path 93 side, and the source is arranged on the coil L2 side. The switch T6 is configured such that the control unit 16 controls the switching of the on / off operation. The resistor R2, the coil L2, and the switch T6 are interposed between the second conductive path 92 and the third conductive path 93.
　第１電圧検出部１３は、第２導電路９２に印加される電圧を分圧回路によって分圧して検出し、検出値として制御部１６に入力する。 The first voltage detection unit 13 detects the voltage applied to the second conductive path 92 by dividing it by a voltage dividing circuit, and inputs it to the control unit 16 as a detection value.
　第２電圧検出部１５は、第３導電路９３に印加される電圧を分圧回路によって分圧して検出し、検出値として制御部１６に入力する。 The second voltage detection unit 15 detects the voltage applied to the third conductive path 93 by dividing it by a voltage dividing circuit, and inputs it to the control unit 16 as a detection value.
　制御部１６は、例えば、マイクロコンピュータとして構成されている。制御部１６は入力電圧検出部１２から入力された値Ｖ１（以下、値Ｖ１ともいう）に基づいて入力導電路９０の電圧値を特定することができる。制御部１６は第１電圧検出部１３から入力された値Ｖ２（以下、値Ｖ２ともいう）に基づいて第２導電路９２の電圧値を特定することができる。制御部１６は第２電圧検出部１５から入力された値Ｖ３（以下、値Ｖ３ともいう）に基づいて第３導電路９３の電圧値を特定することができる。制御部１６は外部のＥＣＵ（Ｅｎｇｉｎｅ　Ｃｏｎｔｒｏｌ　Ｕｎｉｔ）等から目標値Ｇ（以下、目標値Ｇともいう）が入力される構成とされている。 The control unit 16 is configured as, for example, a microcomputer. The control unit 16 can specify the voltage value of the input conductive path 90 based on the value V1 (hereinafter, also referred to as the value V1) input from the input voltage detection unit 12. The control unit 16 can specify the voltage value of the second conductive path 92 based on the value V2 (hereinafter, also referred to as the value V2) input from the first voltage detection unit 13. The control unit 16 can specify the voltage value of the third conductive path 93 based on the value V3 (hereinafter, also referred to as the value V3) input from the second voltage detection unit 15. The control unit 16 is configured to input a target value G (hereinafter, also referred to as a target value G) from an external ECU (Engine Control Unit) or the like.
　制御部１６は入力電圧検出部１２、第１電圧検出部１３、及び第２電圧検出部１５から入力される値や、目標値Ｇに基づいて、公知の方法でフィードバック制御を行い、各スイッチ素子Ｔ１，Ｔ２，Ｔ３，Ｔ４に与えるＰＷＭ信号のデューティを設定する。ここで、目標値Ｇの大きさは、第２導電路９２及び第３導電路９３の出力電圧の大きさが所望の大きさになった際に第１電圧検出部１３、及び第２電圧検出部１５から入力される値の大きさに設定されている。制御部１６は設定されたデューティのＰＷＭ信号をスイッチ素子Ｔ１，Ｔ２，Ｔ３，Ｔ４に出力する。 The control unit 16 performs feedback control by a known method based on the values input from the input voltage detection unit 12, the first voltage detection unit 13, and the second voltage detection unit 15 and the target value G, and each switch element. The duty of the PWM signal given to T1, T2, T3, and T4 is set. Here, the magnitude of the target value G is set by the first voltage detection unit 13 and the second voltage detection when the magnitude of the output voltage of the second conductive path 92 and the third conductive path 93 reaches a desired magnitude. It is set to the size of the value input from the unit 15. The control unit 16 outputs a PWM signal of the set duty to the switch elements T1, T2, T3, and T4.
　具体的には、制御部１６は第１フィードバック演算及び第２フィードバック演算を実行することができる。
　第１フィードバック演算は、入力電圧検出部１２及び第１電圧検出部１３から入力された値と、目標値Ｇとを用いて、第２導電路９２における電圧変換部１０からの出力電圧（以下、第１の出力電圧ともいう）の大きさを所定の第１目標電圧に近づけるための第１デューティを第１の出力電圧に基づく第１電圧検出部１３から入力された値に基づいて決定する。
　第２フィードバック演算は、入力電圧検出部１２及び第２電圧検出部１５から入力された値と、目標値Ｇとを用いて、第３導電路９３における電圧（以下、第２の出力電圧ともいう）の大きさを第２目標電圧に近づけるための第２デューティを第２の出力電圧に基づく第２電圧検出部１５から入力された値に基づいて決定する。
　制御部１６は、こうして決定した第１デューティを使用デューティとするＰＷＭ信号と第１デューティに替えて第２デューティを使用デューティとするＰＷＭ信号とを切り替えてスイッチ素子Ｔ１，Ｔ２，Ｔ３，Ｔ４に出力する。 Specifically, the control unit 16 can execute the first feedback calculation and the second feedback calculation.
The first feedback calculation uses the values input from the input voltage detection unit 12 and the first voltage detection unit 13 and the target value G, and uses the output voltage from the voltage conversion unit 10 in the second conductive path 92 (hereinafter, The first duty for bringing the magnitude of (also referred to as the first output voltage) closer to a predetermined first target voltage is determined based on the value input from the first voltage detection unit 13 based on the first output voltage.
The second feedback calculation uses the values input from the input voltage detection unit 12 and the second voltage detection unit 15 and the target value G, and uses the voltage in the third conductive path 93 (hereinafter, also referred to as the second output voltage). ) Is determined based on the value input from the second voltage detection unit 15 based on the second output voltage, to determine the second duty for bringing the magnitude of) closer to the second target voltage.
The control unit 16 switches between the PWM signal whose use duty is the first duty determined in this way and the PWM signal whose use duty is the second duty instead of the first duty, and outputs the PWM signal to the switch elements T1, T2, T3, and T4. To do.
　制御部１６は第２端子Ｐoutを介して第３導電路９３に接続された負荷（図示せず）に流れる負荷電流の大きさを監視し得る構成とされている。制御部１６は負荷電流が所定の閾値未満の場合、入力電圧検出部１２、第１電圧検出部１３、及び第２電圧検出部１５から入力される値に基づく電圧制御を実行し得る構成とされている。具体的には、電圧制御は第２導電路９２及び第３導電路９３における電圧を所定の目標電圧に近づけることを目的とした制御である。
　そして、制御部１６は電圧制御を実行中に、負荷電流の大きさが所定の閾値以上の場合、抵抗Ｒ１の両端電圧に基づいて得られる入力導電路９０及び第１導電路９１に流れる電流や、抵抗Ｒ２の両端電圧に基づいて得られる第２導電路９２及び第３導電路９３に流れる電流等に基づく電流制御を実行し得る構成とされている。具体的には、電流制御は第２導電路９２及び第３導電路９３に流れる電流を所定の目標電流に近づけることを目的とした制御である。
　そして、制御部１６は、電流制御を実行中に負荷電流の大きさが所定の閾値未満になると電圧制御を実行し得る構成とされている。 The control unit 16 is configured to be able to monitor the magnitude of the load current flowing through the load (not shown) connected to the third conductive path 93 via the second terminal Pout. When the load current is less than a predetermined threshold value, the control unit 16 is configured to be able to execute voltage control based on the values input from the input voltage detection unit 12, the first voltage detection unit 13, and the second voltage detection unit 15. ing. Specifically, the voltage control is a control aimed at bringing the voltage in the second conductive path 92 and the third conductive path 93 closer to a predetermined target voltage.
Then, during voltage control, when the magnitude of the load current is equal to or greater than a predetermined threshold value, the control unit 16 determines the current flowing through the input conductive path 90 and the first conductive path 91 obtained based on the voltage across the resistor R1. The configuration is such that current control based on the current flowing through the second conductive path 92 and the third conductive path 93 obtained based on the voltage across the resistor R2 can be executed. Specifically, the current control is a control aimed at bringing the current flowing through the second conductive path 92 and the third conductive path 93 closer to a predetermined target current.
The control unit 16 is configured to be able to execute voltage control when the magnitude of the load current becomes less than a predetermined threshold value while executing current control.
　こうして構成されたＤＣＤＣコンバータ１は、降圧モードで動作する場合、制御部１６の動作によって、スイッチ素子Ｔ１，Ｔ２の各ゲートに対してデッドタイムを設定した形でＰＷＭ信号を相補的に出力するように同期整流制御を行う。具体的には、スイッチ素子Ｔ１へのオン信号（例えばＨレベル信号）の出力中は、スイッチ素子Ｔ２へオフ信号（例えばＬレベル信号）が出力され、スイッチ素子Ｔ２へのオン信号（例えばＨレベル信号）の出力中は、スイッチ素子Ｔ１へオフ信号（例えばＬレベル信号）が出力されるように同期整流制御が行われる。この制御により、第１端子Ｐinに入力された入力電圧を降圧する動作がなされ、第２端子Ｐoutには、第１端子Ｐinに印加された入力電圧よりも低い出力電圧が出力される。第２端子Ｐoutに出力される出力電圧は、スイッチ素子Ｔ１のゲートに与えるＰＷＭ信号のデューティに応じて定まる。なお、降圧モードでは、スイッチ素子Ｔ３のゲートにオン信号が継続的に入力され、スイッチ素子Ｔ３はオン状態で維持される。また、スイッチ素子Ｔ４のゲートにオフ信号が継続的に入力され、スイッチ素子Ｔ４はオフ状態で維持される。 When the DCDC converter 1 configured in this way operates in the step-down mode, the operation of the control unit 16 complementarily outputs a PWM signal in a form in which a dead time is set for each gate of the switch elements T1 and T2. Synchronous rectification control is performed. Specifically, during the output of the on signal (for example, H level signal) to the switch element T1, the off signal (for example, L level signal) is output to the switch element T2, and the on signal (for example, H level) to the switch element T2 is output. During the output of the signal), synchronous rectification control is performed so that the off signal (for example, L level signal) is output to the switch element T1. By this control, an operation of stepping down the input voltage input to the first terminal Pin is performed, and an output voltage lower than the input voltage applied to the first terminal Pin is output to the second terminal Pout. The output voltage output to the second terminal Pout is determined according to the duty of the PWM signal given to the gate of the switch element T1. In the step-down mode, an ON signal is continuously input to the gate of the switch element T3, and the switch element T3 is maintained in the ON state. Further, an off signal is continuously input to the gate of the switch element T4, and the switch element T4 is maintained in the off state.
　次に、制御部１６における、第１電圧検出部１３、及び第２電圧検出部１５のそれぞれを用いて第１フィードバック演算、及び第２フィードバック演算の手順を図２、３、４等を参照しつつ説明する。ＤＣＤＣコンバータ１は降圧モードで動作する際、制御部１６により公知のＰＩＤ方式のフィードバック制御がなされる。制御部１６は所定の開始条件が成立した場合に動作を開始し得る構成とされている。また、制御部１６が動作する状態として、所定の初期化処理を行う初期化状態、昇圧動作や降圧動作を停止して待機した状態であるスタンバイ状態、昇圧動作を実行する昇圧動作状態、降圧動作を実行する降圧動作状態等がある。所定の開始条件は、例えば、車両を始動するための始動スイッチ（例えばイグニッションスイッチ）がオフ状態からオン状態に切り替わること等である。第１フィードバック演算、及び第２フィードバック演算は、所定の開始条件が成立した場合に動作を開始した制御部１６において繰り返し実行される。 Next, refer to FIGS. 2, 3, 4, etc. for the procedure of the first feedback calculation and the second feedback calculation using each of the first voltage detection unit 13 and the second voltage detection unit 15 in the control unit 16. I will explain while. When the DCDC converter 1 operates in the step-down mode, the control unit 16 performs known PID-type feedback control. The control unit 16 is configured to be able to start operation when a predetermined start condition is satisfied. Further, as a state in which the control unit 16 operates, an initialization state in which a predetermined initialization process is performed, a standby state in which the step-up operation or the step-down operation is stopped and standby, a step-up operation state in which the step-up operation is executed, and a step-down operation There is a step-down operation state to execute. The predetermined start condition is, for example, that the start switch for starting the vehicle (for example, the ignition switch) is switched from the off state to the on state. The first feedback calculation and the second feedback calculation are repeatedly executed by the control unit 16 that starts the operation when a predetermined start condition is satisfied.
〔第１フィードバック演算の処理フロー〕
　第１電圧検出部１３から入力された値Ｖ２に基づいて第１フィードバック演算を実行する手順について、図２等を参照しつつ説明する。
　先ず、制御部１６はステップＳ１において、第１デューティを設定する。第１デューティは、所定の開始条件が成立して制御部１６が動作を開始して初めてステップＳ１を実行するとき初期値が設定される。初期値はステップＳ２において取得する入力導電路９０の入力電圧、第２導電路９２の第１の出力電圧に基づいて設定される。所定の開始条件が成立して制御部１６が動作を開始した後、２回目以降のステップＳ１の実行の際には、前回の第１フィードバック演算で算出した値を第１デューティとして設定する。 [Processing flow of the first feedback calculation]
A procedure for executing the first feedback calculation based on the value V2 input from the first voltage detection unit 13 will be described with reference to FIG. 2 and the like.
First, the control unit 16 sets the first duty in step S1. An initial value of the first duty is set when step S1 is executed for the first time when a predetermined start condition is satisfied and the control unit 16 starts operation. The initial value is set based on the input voltage of the input conductive path 90 acquired in step S2 and the first output voltage of the second conductive path 92. After the predetermined start condition is satisfied and the control unit 16 starts the operation, the value calculated in the previous first feedback calculation is set as the first duty when the second and subsequent steps S1 are executed.
　次に、ステップＳ２に移行して、入力導電路９０の入力電圧、第２導電路９２の第１の出力電圧、及び目標値Ｇを取得する。具体的には、制御部１６は値Ｖ１に基づいて入力導電路９０の入力電圧を特定し、値Ｖ２に基づいて第１の出力電圧を特定する。さらに、制御部１６は外部のＥＣＵ等から入力される目標値Ｇを取得する。 Next, the process proceeds to step S2, and the input voltage of the input conductive path 90, the first output voltage of the second conductive path 92, and the target value G are acquired. Specifically, the control unit 16 specifies the input voltage of the input conductive path 90 based on the value V1 and specifies the first output voltage based on the value V2. Further, the control unit 16 acquires the target value G input from an external ECU or the like.
　次に、ステップＳ３に移行して、第１デューティを更新する条件が成立するか否かを判別する。制御部１６は電圧変換部１０に対して出力したＰＷＭ信号の回数を計数し得る構成とされている。制御部１６はＰＷＭ信号の回数が所定の回数Ｍに到達し、且つ値Ｖ２と目標値Ｇとの大きさの差が所定の大きさ以上である場合、第１デューティを更新する条件が成立したと判別する。
　ＰＷＭ信号の回数が所定の回数Ｍに到達し、且つ値Ｖ２と目標値Ｇとの差が所定の大きさ以上である（ステップＳ３においてＹｅｓ）と判別すると、ステップＳ５に移行して、値Ｖ１，Ｖ２に基づいて新しい第１デューティを算出して使用デューティとして更新する。ステップＳ５は、値Ｖ２と目標値Ｇとの大きさの差が所定の大きさ以上である場合、ＰＷＭ信号の回数が所定の回数Ｍ毎の周期（第１周期）で実行される。こうして制御部１６は、第１フィードバック演算により、第１周期毎に第１デューティの算出を繰り返し、第１デューティの算出毎に、第１デューティを使用デューティとして更新する。
　ここで、新しい第１デューティは、例えば数１に示す数式に基づいてＰＩＤ方式のフィードバック演算によって算出される。具体的には、Ｖ２と目標値Ｇとの偏差eを求め、この偏差と、予め設定された比例（Ｐ）ゲインＫp、微分（Ｉ）ゲインＫi、積分（Ｄ）ゲインＫdとに基づき、第２導電路９２の電圧値を第１目標電圧に近づけるための操作量ｕを決定する。操作量ｕは、例えばデューティの増減量（オン時間の増減量）を示す値である。制御部１６は、操作量ｕに基づいてデューティを決定する。 Next, the process proceeds to step S3, and it is determined whether or not the condition for updating the first duty is satisfied. The control unit 16 is configured to be able to count the number of PWM signals output to the voltage conversion unit 10. When the number of PWM signals reaches the predetermined number of times M and the difference in magnitude between the value V2 and the target value G is equal to or greater than the predetermined magnitude, the condition for updating the first duty is satisfied. To determine.
When it is determined that the number of PWM signals reaches a predetermined number of times M and the difference between the value V2 and the target value G is equal to or greater than a predetermined magnitude (Yes in step S3), the process proceeds to step S5 and the value V1 , V2 is used to calculate a new first duty and update it as the used duty. Step S5 is executed in a cycle (first cycle) in which the number of PWM signals is a predetermined number of times M when the difference in magnitude between the value V2 and the target value G is equal to or greater than a predetermined magnitude. In this way, the control unit 16 repeats the calculation of the first duty every first cycle by the first feedback calculation, and updates the first duty as the used duty every time the calculation of the first duty is performed.
Here, the new first duty is calculated by a feedback calculation of the PID method based on the mathematical formula shown in Equation 1, for example. Specifically, the deviation e between V2 and the target value G is obtained, and based on this deviation and the preset proportional (P) gain Kp, differential (I) gain Ki, and integral (D) gain Kd, the first 2 The operation amount u for bringing the voltage value of the conductive path 92 closer to the first target voltage is determined. The operation amount u is, for example, a value indicating an increase / decrease amount of duty (an increase / decrease amount of on-time). The control unit 16 determines the duty based on the operation amount u.
Figure JPOXMLDOC01-appb-M000001
Figure JPOXMLDOC01-appb-M000001
　ＰＷＭ信号の回数が所定の回数Ｍに到達していない、又は値Ｖ２と目標値Ｇとの差が所定の大きさ未満である（ステップＳ３においてＮｏ）と判別すると、ステップＳ４に移行して、前回の第１フィードバック演算で算出した値を第１デューティとして設定する。 If it is determined that the number of PWM signals has not reached the predetermined number of times M, or the difference between the value V2 and the target value G is less than the predetermined magnitude (No in step S3), the process proceeds to step S4. The value calculated in the previous first feedback calculation is set as the first duty.
　次に、ステップＳ６に移行して、補正値αを取得する。具体的には、後述する、第２フィードバック演算のステップＳ１７において確定した補正値αや、ステップＳ２５において採用した補正値αを取得する（図４参照。）。補正値αは所定の開始条件が成立して制御部１６が動作を開始する際には初期値として０が設定される。このため、初めてステップＳ６を実行するときに取得される補正値αの値は０である。
　そして、ステップＳ７に移行して、第１デューティに補正値αを加え、第１デューティに対して補正値αを反映した値を使用デューティとしてＰＷＭ信号をスイッチ素子Ｔ１，Ｔ２，Ｔ３，Ｔ４に出力するように電圧制御を行う。
　こうして、制御部１６は、第１の出力電圧の大きさを所定の第１目標電圧に近づけるための第１デューティを第１の出力電圧に基づく値Ｖ２に基づいて決定する。
　なお、電流制御が実行されている場合、制御部１６は第１デューティに補正値αを加えない。こうして第１フィードバック演算を実行する手順を終了する。 Next, the process proceeds to step S6 to acquire the correction value α. Specifically, the correction value α determined in step S17 of the second feedback calculation and the correction value α adopted in step S25, which will be described later, are acquired (see FIG. 4). The correction value α is set to 0 as an initial value when a predetermined start condition is satisfied and the control unit 16 starts operation. Therefore, the value of the correction value α acquired when step S6 is executed for the first time is 0.
Then, in step S7, the correction value α is added to the first duty, and the PWM signal is output to the switch elements T1, T2, T3, and T4 with the value reflecting the correction value α for the first duty as the used duty. The voltage is controlled so as to be performed.
In this way, the control unit 16 determines the first duty for bringing the magnitude of the first output voltage closer to the predetermined first target voltage based on the value V2 based on the first output voltage.
When the current control is executed, the control unit 16 does not add the correction value α to the first duty. In this way, the procedure for executing the first feedback calculation is completed.
〔第２フィードバック演算の処理フロー〕
　次に、第２フィードバック演算を実行する手順について、図３等を参照しつつ説明する。
　先ず、制御部１６はステップＳ１１において補正値αを設定する。補正値αは、所定の開始条件が成立して制御部１６が動作を開始するとき、初期値として０が設定される。 [Processing flow of the second feedback calculation]
Next, the procedure for executing the second feedback calculation will be described with reference to FIG. 3 and the like.
First, the control unit 16 sets the correction value α in step S11. The correction value α is set to 0 as an initial value when a predetermined start condition is satisfied and the control unit 16 starts operation.
　次に、ステップＳ１２に移行して、入力導電路９０の入力電圧、第３導電路９３の第２の出力電圧、及び目標値Ｇを取得する。具体的には、制御部１６は値Ｖ１に基づいて入力導電路９０の電圧値を特定し、値Ｖ３に基づいて第２の出力電圧を特定する。さらに、制御部１６は外部のＥＣＵ等から入力される目標値Ｇを取得する。 Next, the process proceeds to step S12, and the input voltage of the input conductive path 90, the second output voltage of the third conductive path 93, and the target value G are acquired. Specifically, the control unit 16 specifies the voltage value of the input conductive path 90 based on the value V1 and specifies the second output voltage based on the value V3. Further, the control unit 16 acquires the target value G input from an external ECU or the like.
　次に、ステップＳ１３に移行して、補正値αを更新する条件が成立したか否かを判別する。所定の開始条件が成立して制御部１６が動作している際、制御部１６は負荷電流の大きさに基づいて電流制御又は電圧制御のいずれかを実行する構成とされている。
　制御部１６は、現在電圧制御であり、電圧変換部１０に対して出力したＰＷＭ信号の回数が所定の回数Ｗに到達し、値Ｖ３と目標値Ｇとの差が所定の大きさ以上（ステップＳ１３においてＹｅｓ）と判別すると、ステップＳ１５に移行し、新しい補正値αを算出する。具体的には、制御部１６は、値Ｖ１，Ｖ３に基づいて第２デューティを算出する。第２デューティは第１デューティと同様に、例えば数１に示す数式に基づいてＰＩＤ方式のフィードバック演算によって算出される。そして、制御部１６は第１フィードバック演算で算出した第１デューティと、第２デューティとの差を補正値αとして算出して決定する。補正値αを算出する際に用いる第１デューティは第２デューティを算出した時点の直前に算出されたものである。 Next, the process proceeds to step S13, and it is determined whether or not the condition for updating the correction value α is satisfied. When a predetermined start condition is satisfied and the control unit 16 is operating, the control unit 16 is configured to execute either current control or voltage control based on the magnitude of the load current.
The control unit 16 is currently under voltage control, the number of PWM signals output to the voltage conversion unit 10 reaches a predetermined number of times W, and the difference between the value V3 and the target value G is equal to or greater than a predetermined size (step). If it is determined to be Yes) in S13, the process proceeds to step S15, and a new correction value α is calculated. Specifically, the control unit 16 calculates the second duty based on the values V1 and V3. Like the first duty, the second duty is calculated by a feedback calculation of the PID method based on, for example, the mathematical formula shown in Equation 1. Then, the control unit 16 calculates and determines the difference between the first duty calculated by the first feedback calculation and the second duty as the correction value α. The first duty used when calculating the correction value α is calculated immediately before the time when the second duty is calculated.
　ステップＳ１３はＰＷＭ信号の回数が所定の回数Ｗに到達したことのみをきっかけとして実行してもよい。所定の回数Ｗは所定の回数Ｍよりも大きい値である。この場合、ステップＳ１５は、ＰＷＭ信号の回数が所定の回数Ｗ毎の周期（第２周期）で実行される。所定の回数Ｗは所定の回数Ｍよりも大きい値であるため、ステップＳ１５はステップＳ５が実行される周期（第１周期）よりも長い周期（第２周期）毎に実行されることになる。 Step S13 may be executed only when the number of PWM signals reaches a predetermined number of times W. The predetermined number of times W is a value larger than the predetermined number of times M. In this case, step S15 is executed in a cycle (second cycle) in which the number of PWM signals is a predetermined number of times W. Since the predetermined number of times W is a value larger than the predetermined number of times M, step S15 is executed every cycle (second cycle) longer than the cycle (first cycle) in which step S5 is executed.
　なお、ステップＳ７において、第１デューティに補正値αを加え、第１デューティに補正値αを加えた値に基づいてＰＷＭ信号を出力している。第１デューティに補正値αを加えた値は実質的に第２デューティである。つまり、実質的に第２デューティに基づいたＰＷＭ信号を使用デューティとして更新し、スイッチ素子Ｔ１，Ｔ２，Ｔ３，Ｔ４出力していることになる。つまり、制御部１６は、第１デューティをそのまま使用デューティとして用いるか、補正値αを加えることによって、実質的に第２デューティを使用デューティとして用いるかを決定することができる。 In step S7, the correction value α is added to the first duty, and the PWM signal is output based on the value obtained by adding the correction value α to the first duty. The value obtained by adding the correction value α to the first duty is substantially the second duty. That is, the PWM signal based on the second duty is substantially updated as the used duty, and the switch elements T1, T2, T3, and T4 are output. That is, the control unit 16 can determine whether to use the first duty as the working duty as it is or to substantially use the second duty as the working duty by adding the correction value α.
　制御部１６は、第１周期よりも大きい第２周期毎に、第２フィードバック演算により、第２デューティの算出を繰り返し、第２デューティを算出する毎に第１デューティとの差を補正値αとして更新する。また、制御部１６は、第２の出力電圧の大きさを所定の第２目標電圧に近づけるための第２デューティを第２の出力電圧に基づく値Ｖ３に基づいて決定し、第１デューティと第２デューティとの差を補正値αとして算出する。ここで、第１目標電圧と第２目標電圧とは互いに同じ電圧でもよく、異なる電圧でもよい。
　制御部１６は、現在電圧制御が実行されていない、又は電圧変換部１０に対して出力したＰＷＭ信号の回数が所定の回数Ｗに到達していない、又は値Ｖ３と目標値Ｇとの差が所定の大きさ未満である（ステップＳ１３においてＮｏ）と判別すると、ステップＳ１４に移行して、前回と同じ補正値αを採用する。 The control unit 16 repeats the calculation of the second duty by the second feedback calculation every second cycle larger than the first cycle, and each time the second duty is calculated, the difference from the first duty is set as the correction value α. Update. Further, the control unit 16 determines the second duty for bringing the magnitude of the second output voltage closer to a predetermined second target voltage based on the value V3 based on the second output voltage, and determines the first duty and the first duty. The difference from the 2 duty is calculated as the correction value α. Here, the first target voltage and the second target voltage may be the same voltage or different voltages.
The control unit 16 is not currently executing voltage control, or the number of PWM signals output to the voltage conversion unit 10 has not reached a predetermined number of times W, or the difference between the value V3 and the target value G is large. If it is determined that the size is less than the predetermined size (No in step S13), the process proceeds to step S14, and the same correction value α as the previous time is adopted.
　次に、ステップＳ１６に移行して、故障条件が成立しているか否かを判別する。
　例えば、補正値αの取り得る範囲が予め設定されており、制御部１６にこの範囲を決定する定数が記憶され得る構成とされている。この定数は、例えば、ＤＣＤＣコンバータ１を構成する部品の性能のばらつきや、温度の変化に伴う部品の特性の変化のばらつきや、部品の劣化のばらつき等を考慮して決定される。
　ステップＳ１６では、制御部１６において現在電圧制御が実行されている場合、補正値αの絶対値が制御部１６に記憶された定数未満であるか否かを判別する。 Next, the process proceeds to step S16, and it is determined whether or not the failure condition is satisfied.
For example, a range in which the correction value α can be taken is set in advance, and the control unit 16 is configured to be able to store a constant that determines this range. This constant is determined in consideration of, for example, variations in the performance of the components constituting the DCDC converter 1, variations in the characteristics of the components due to changes in temperature, variations in deterioration of the components, and the like.
In step S16, when the control unit 16 is currently executing voltage control, it is determined whether or not the absolute value of the correction value α is less than the constant stored in the control unit 16.
　例えば、補正値αの絶対値の大きさが０．２未満（すなわち、所定の範囲内）の場合、制御部１６は、ＤＣＤＣコンバータ１は故障していない（ステップＳ１６においてＮｏ）と判別し、ステップＳ１７に移行して補正値αを確定して採用する。また、補正値αの絶対値の大きさが０．２以上（すなわち、所定の範囲外）の場合、制御部１６はＤＣＤＣコンバータ１が故障している（ステップＳ１６においてＹｅｓ）と判別し、ステップＳ１８に移行して、ＤＣＤＣコンバータ１のいずれかの部位が故障していると判定し、補正値αの値を確定しない。 For example, when the magnitude of the absolute value of the correction value α is less than 0.2 (that is, within a predetermined range), the control unit 16 determines that the DCDC converter 1 has not failed (No in step S16). The process proceeds to step S17, and the correction value α is determined and adopted. Further, when the magnitude of the absolute value of the correction value α is 0.2 or more (that is, outside the predetermined range), the control unit 16 determines that the DCDC converter 1 is out of order (Yes in step S16), and steps. Moving to S18, it is determined that any part of the DCDC converter 1 is out of order, and the value of the correction value α is not fixed.
　ステップＳ１８で行われる処理の一例として、故障状態であることを示す故障状態信号がＬレベルからＨレベルに変更される構成とすることが考えられる。
　故障状態信号は、補正値αの絶対値の大きさが０．２以上（すなわち、所定の範囲外）の場合、故障していない状態を示すＬレベルから故障した状態を示すＨレベルに変更される。故障状態信号はステップＳ１７ではＬレベルにされる。故障状態信号を制御部１６から外部のＥＣＵ等に出力する構成とすることによって、外部のＥＣＵは故障状態信号によってＤＣＤＣコンバータ１が故障しているか否かを知ることができる。これにより、外部のＥＣＵはＤＣＤＣコンバータ１の状態に対応した動作をすることができる。
　故障状態信号は、Ｌレベルである場合、補正値αが確定していることと同じ意味をなし、Ｈレベルである場合、補正値αが確定していないことと同じ意味をなしている。こうして第２フィードバック演算を実行する手順を終了する。 As an example of the process performed in step S18, it is conceivable that the failure state signal indicating the failure state is changed from the L level to the H level.
When the magnitude of the absolute value of the correction value α is 0.2 or more (that is, outside the predetermined range), the failure state signal is changed from the L level indicating the non-failed state to the H level indicating the failed state. To. The failure status signal is set to L level in step S17. By outputting the failure status signal from the control unit 16 to the external ECU or the like, the external ECU can know whether or not the DCDC converter 1 has failed by the failure status signal. As a result, the external ECU can operate according to the state of the DCDC converter 1.
The failure state signal has the same meaning as that the correction value α is fixed when it is L level, and has the same meaning as that the correction value α is not fixed when it is H level. In this way, the procedure for executing the second feedback calculation is completed.
　なお、図４に示すように、ステップＳ１４、又はステップＳ１５と、ステップＳ１６との間に、電圧制御の実行中であるか判別するステップＳ２１、電圧制御から電流制御への切り替わりのタイミングを判別するステップＳ２２、及び電流制御から電圧制御への切り替わりのタイミングを判別するステップＳ２３等を設けてもよい。 As shown in FIG. 4, between step S14 or step S15 and step S16, step S21 for determining whether voltage control is being executed, and the timing of switching from voltage control to current control are determined. Step S22 and step S23 for determining the timing of switching from current control to voltage control may be provided.
　例えば、ステップＳ１４、又はステップＳ１５が実行された後、ステップＳ２１において電圧制御の実行中であるかを判別する。ステップＳ２１では、例えば、一般的な電圧制御と電流制御との調停方法を用いてもよく、負荷電流が所定の閾値以上であるか否かを判別する方法を用いてもよい。そして、電圧制御の実行中である（ステップＳ２１においてｙｅｓ）と判別すると、ステップＳ２２において電圧制御から電流制御への切り替わりのタイミングを判別する。電圧制御から電流制御への切り替わりのタイミングである（ステップＳ２２においてｙｅｓ）と判別すると、電圧制御から電流制御へ切り替わる直前の補正値α（すなわち、直前に実行されたステップＳ１４、又はステップＳ１５で得られた値）を制御部１６に保持する（ステップＳ２４）。電圧制御から電流制御への切り替わりのタイミングでない（ステップＳ２２においてｎｏ）と判別すると処理を終了する。
　また、ステップＳ２１において電圧制御の実行中でない（ステップＳ２１においてｎｏ）と判別すると、電流制御から電圧制御への切り替わりのタイミングを判別する（ステップＳ２３）。そして、電流制御から電圧制御への切り替わりのタイミングである（ステップＳ２３においてｙｅｓ）と判別すると、ステップＳ２５に移行して、制御部１６が保持していた補正値αを補正値として採用して処理を終了する。そして、電流制御から電圧制御への切り替わりのタイミングでない（ステップＳ２３においてｎｏ）と判別すると、ステップＳ１６に移行する。
　また、電流制御中にスタンバイ状態等に切り替えられた場合、制御部１６は補正値αに初期値として０を設定する構成としてもよい。電圧制御（例えば、１２Ｖ等の所定の電圧）から電流制御に切り替えるのは、負荷が大きくなると抵抗が小さくなり、電流値が際限なく大きくなってしまうことを防止するためである。ところが、電流制御の実行中において、負荷が小さくなると抵抗が大きくなり、電圧が大きくなってしまう。すると、電流値が高くなるため、再び電圧制御（例えば、１２Ｖ等の所定の電圧）に切り替えるのである。ここで、例えば、電流制御から電圧制御に切り替えた際、当初の電圧（例えば、１２Ｖ）と同電圧になるように電圧制御するため、直前の補正値αを用いて制御する。直前の補正値αを用いることによって、再計算して電圧制御を実行する場合に比べ、より早期に電圧制御を実行することができる。 For example, after step S14 or step S15 is executed, it is determined in step S21 whether voltage control is being executed. In step S21, for example, a general arbitration method between voltage control and current control may be used, or a method for determining whether or not the load current is equal to or higher than a predetermined threshold value may be used. Then, when it is determined that the voltage control is being executed (yes in step S21), the timing of switching from the voltage control to the current control is determined in step S22. When it is determined that it is the timing of switching from voltage control to current control (yes in step S22), the correction value α immediately before switching from voltage control to current control (that is, obtained in step S14 or step S15 executed immediately before) is obtained. The obtained value) is held in the control unit 16 (step S24). When it is determined that it is not the timing of switching from the voltage control to the current control (no in step S22), the process ends.
Further, if it is determined in step S21 that the voltage control is not being executed (no in step S21), the timing of switching from the current control to the voltage control is determined (step S23). Then, when it is determined that it is the timing of switching from the current control to the voltage control (yes in step S23), the process proceeds to step S25, and the correction value α held by the control unit 16 is adopted as the correction value for processing. To finish. Then, if it is determined that it is not the timing of switching from the current control to the voltage control (no in step S23), the process proceeds to step S16.
Further, when the state is switched to the standby state or the like during the current control, the control unit 16 may set the correction value α to 0 as an initial value. The reason for switching from voltage control (for example, a predetermined voltage such as 12V) to current control is to prevent the resistance from becoming smaller and the current value from becoming infinitely large as the load increases. However, during the execution of current control, when the load becomes small, the resistance becomes large and the voltage becomes large. Then, since the current value becomes high, the voltage control (for example, a predetermined voltage such as 12V) is switched again. Here, for example, when the current control is switched to the voltage control, the voltage is controlled so as to be the same as the initial voltage (for example, 12V), so that the correction value α immediately before is used for control. By using the immediately preceding correction value α, the voltage control can be executed earlier than the case where the voltage control is executed by recalculation.
　次に、本構成の車載用ＤＣＤＣコンバータ１の効果を例示する。
　本開示の車載用ＤＣＤＣコンバータ１は、
（１）ＰＷＭ信号を受けるスイッチ素子Ｔ１，Ｔ２，Ｔ３，Ｔ４を有する電圧変換部１０と、電圧変換部１０を制御する制御部１６と、第２保護回路１４と、を有し、制御部１６は、スイッチ素子Ｔ１，Ｔ２，Ｔ３，Ｔ４にＰＷＭ信号を与え、電圧変換部１０は、ＰＷＭ信号に応じたスイッチ素子Ｔ１，Ｔ２，Ｔ３，Ｔ４のスイッチング動作によって第１導電路９１に印加される入力電圧を降圧して第２導電路９２に電圧を印加する車載用ＤＣＤＣコンバータ１であって、第２導電路９２に印加される第１の出力電圧を検出する第１電圧検出部１３と、電圧変換部１０からの出力電流が流れる電流経路のうち第２導電路９２よりも下流側に設けられた第３導電路９３に印加される第２の出力電圧を検出する第２電圧検出部１５とを有し、第２保護回路１４は、第２導電路９２と第３導電路９３との間に介在する抵抗Ｒ２、第２導電路９２と第３導電路９３との間に介在するコイルＬ２、第２導電路９２と第３導電路９３との間に介在するスイッチＴ６、及び第２導電路９２と第３導電路９３との間に一端が電気的に接続されるコンデンサＣ３を含み、制御部１６は、第１の出力電圧の大きさを所定の第１目標電圧に近づけるための第１デューティを第１の出力電圧に基づいて決定する第１フィードバック演算と、第２の出力電圧の大きさを所定の第２目標電圧に近づけるための第２デューティを第２の出力電圧に基づいて決定する第２フィードバック演算とを行い、第１デューティに対し第２デューティに基づく補正値αを反映した使用デューティＰＷＭ信号をスイッチ素子Ｔ１，Ｔ２，Ｔ３，Ｔ４に出力するように電圧制御を行うことによって、第２導電路９２の第１の出力電圧と、第２保護回路１４を経由した後の第２の出力電圧を参照し、第２の出力電圧の出力応答性と精度とを両立させることができる。 Next, the effect of the in-vehicle DCDC converter 1 having this configuration will be illustrated.
The vehicle-mounted DCDC converter 1 of the present disclosure is
(1) A voltage conversion unit 10 having switch elements T1, T2, T3, and T4 that receive PWM signals, a control unit 16 that controls the voltage conversion unit 10, and a second protection circuit 14, and the control unit 16 Gives a PWM signal to the switch elements T1, T2, T3, and T4, and the voltage conversion unit 10 is applied to the first conductive path 91 by the switching operation of the switch elements T1, T2, T3, and T4 in response to the PWM signal. An in-vehicle DCDC converter 1 that lowers the input voltage and applies a voltage to the second conductive path 92, and a first voltage detecting unit 13 that detects a first output voltage applied to the second conductive path 92. The second voltage detection unit 15 that detects the second output voltage applied to the third conductive path 93 provided on the downstream side of the second conductive path 92 in the current path through which the output current from the voltage conversion unit 10 flows. The second protection circuit 14 has a resistor R2 interposed between the second conductive path 92 and the third conductive path 93, and a coil interposed between the second conductive path 92 and the third conductive path 93. L2, a switch T6 interposed between the second conductive path 92 and the third conductive path 93, and a capacitor C3 whose one end is electrically connected between the second conductive path 92 and the third conductive path 93. , The control unit 16 performs a first feedback calculation for determining a first duty for bringing the magnitude of the first output voltage closer to a predetermined first target voltage based on the first output voltage, and a second output voltage. The second feedback calculation for determining the second duty for bringing the magnitude of the voltage closer to the predetermined second target voltage is performed based on the second output voltage, and the correction value α based on the second duty is set for the first duty. By performing voltage control so that the reflected use duty PWM signal is output to the switch elements T1, T2, T3, and T4, after passing through the first output voltage of the second conductive path 92 and the second protection circuit 14. With reference to the second output voltage of the above, the output responsiveness and accuracy of the second output voltage can be compatible with each other.
（２）制御部１６が、第１周期毎に第１デューティを算出して使用デューティとして更新し、第１周期よりも大きい第２周期毎に第２デューティを算出する毎に補正値αを更新する。
　このように構成されていれば、第１デューティ、及び第２デューティのそれぞれのＰＷＭ信号が頻繁に切り替わりスイッチ素子Ｔ１，Ｔ２，Ｔ３，Ｔ４に出力されることを抑え、第１の出力電圧や第２の出力電圧がハンチングすることを抑えることができる。 (2) The control unit 16 calculates the first duty for each first cycle and updates it as the used duty, and updates the correction value α every time the second duty is calculated every second cycle larger than the first cycle. To do.
With this configuration, it is possible to prevent the PWM signals of the first duty and the second duty from being frequently switched and output to the switch elements T1, T2, T3, and T4, and to suppress the output to the first output voltage and the first output voltage. It is possible to suppress hunting of the output voltage of 2.
（３）制御部１６が、第２デューティと第１デューティとの差を補正値αとして算出する。
　このように構成されていれば、制御部１６内において、第１の出力電圧に基づいた第１デューティの値を基準として扱うことができるため、第１デューティと第２デューティとを区別して扱い易い。 (3) The control unit 16 calculates the difference between the second duty and the first duty as the correction value α.
With this configuration, the control unit 16 can handle the value of the first duty based on the first output voltage as a reference, so that it is easy to distinguish between the first duty and the second duty. ..
（４）制御部１６が、第３導電路９３に接続された負荷に流れる負荷電流の大きさが閾値未満の場合、電圧制御を実行し、負荷電流の大きさが閾値以上の場合、第１導電路９１に流れる入力電流と、第２導電路９２又は第３導電路９３に流れる出力電流とに基づく電流制御を実行し、電圧制御から電流制御に切り替える場合に、電流制御に切り替える直前の補正値αを保持し、電流制御から電圧制御に切り替えた際に、保持した補正値αを第１デューティに加える。
　このように構成されていれば、電流制御から電圧制御に切り替わった際に、第１の出力電圧や第２の出力電圧が不意に変動することを抑えることができる。 (4) The control unit 16 executes voltage control when the magnitude of the load current flowing through the load connected to the third conductive path 93 is less than the threshold value, and when the magnitude of the load current is greater than or equal to the threshold value, the first When current control is executed based on the input current flowing through the conductive path 91 and the output current flowing through the second conductive path 92 or the third conductive path 93, and the voltage control is switched to the current control, the correction immediately before switching to the current control is performed. When the value α is held and the current control is switched to the voltage control, the held correction value α is added to the first duty.
With this configuration, it is possible to prevent the first output voltage and the second output voltage from suddenly fluctuating when the current control is switched to the voltage control.
（５）制御部１６が、電圧制御のときに補正値αの大きさが所定の範囲内である場合、補正値αを確定し、電圧制御のときに補正値αの大きさが所定の範囲外である場合、補正値αを確定しない。
　このように構成されていれば、所定の範囲外の補正値αを確定しないで済むため、スイッチ素子Ｔ１，Ｔ２，Ｔ３，Ｔ４に対して出力するＰＷＭ信号が想定外の値を示すことを抑えることができる。 (5) When the control unit 16 determines the correction value α within a predetermined range during voltage control, the correction value α is within a predetermined range during voltage control. If it is outside, the correction value α is not fixed.
With this configuration, it is not necessary to determine the correction value α outside the predetermined range, so that it is possible to prevent the PWM signals output to the switch elements T1, T2, T3, and T4 from showing unexpected values. be able to.
　＜他の実施例＞
　本構成は上記記述及び図面によって説明した実施例に限定されるものではなく、例えば次のような実施形態も本発明の技術的範囲に含まれる。 <Other Examples>
The present configuration is not limited to the examples described by the above description and the drawings, and for example, the following embodiments are also included in the technical scope of the present invention.
　実施形態１では、双方向型の昇降圧ＤＣＤＣコンバータを例示したが、降圧ＤＣＤＣコンバータであってもよく、昇圧ＤＣＤＣコンバータであってもよい。また、実施形態１のように入力側と出力側とを変更し得る双方向型のＤＣＤＣコンバータであってもよく、入力側と出力側が固定化された一方向型のＤＣＤＣコンバータであってもよい。 In the first embodiment, the bidirectional buck-boost DCDC converter has been illustrated, but it may be a step-down DCDC converter or a step-up DCDC converter. Further, it may be a bidirectional DCDC converter in which the input side and the output side can be changed as in the first embodiment, or a unidirectional DCDC converter in which the input side and the output side are fixed. ..
　実施形態１では、同期整流式のＤＣＤＣコンバータを例示したが、一部のスイッチ素子をダイオードに置き換えたダイオード方式のＤＣＤＣコンバータとしてもよい。 Although the synchronous rectification type DCDC converter is exemplified in the first embodiment, it may be a diode type DCDC converter in which some switch elements are replaced with diodes.
　実施形態１では、スイッチ素子として、ＭＯＳＦＥＴとして構成されるスイッチ素子Ｔ１，Ｔ２，Ｔ３，Ｔ４を例示したが、バイポーラトランジスタ等の他のスイッチであってもよい。 In the first embodiment, the switch elements T1, T2, T3, and T4 configured as MOSFETs are exemplified as the switch elements, but other switches such as bipolar transistors may be used.
　実施形態１では、制御部１６がマイクロコンピュータを主体として構成されていたが、マイクロコンピュータ以外の複数のハードウェア回路によって実現されてもよい。 In the first embodiment, the control unit 16 is mainly composed of a microcomputer, but it may be realized by a plurality of hardware circuits other than the microcomputer.
　実施形態１では、第２保護回路１４がコンデンサＣ３、抵抗Ｒ２、コイルＬ２、及びスイッチＴ６を備えているが、コンデンサ、抵抗、コイル、及びスイッチの少なくともいずれかを備える構成としてもよい。 In the first embodiment, the second protection circuit 14 includes the capacitor C3, the resistor R2, the coil L2, and the switch T6, but may be configured to include at least one of the capacitor, the resistor, the coil, and the switch.
　今回開示された実施の形態は全ての点で例示であって制限的なものではないと考えられるべきである。本発明の範囲は、今回開示された実施の形態に限定されるものではなく、特許請求の範囲によって示され、特許請求の範囲と均等の意味及び範囲内での全ての変更が含まれることが意図される。 It should be considered that the embodiments disclosed this time are exemplary in all respects and are not restrictive. The scope of the present invention is not limited to the embodiments disclosed this time, but may be indicated by the scope of claims and include all modifications within the meaning and scope equivalent to the scope of claims. Intended.
１…ＤＣＤＣコンバータ
１０…電圧変換部
１１…第１保護回路
１２…入力電圧検出部
１３…第１電圧検出部
１４…第２保護回路
１５…第２電圧検出部
１６…制御部
９０…入力導電路
９１…第１導電路
９２…第２導電路
９３…第３導電路
Ｃ１…コンデンサ
Ｃ２…コンデンサ
Ｃ３…コンデンサ
Ｌ１…コイル
Ｌ２…コイル
Ｌ３…コイル
Ｐin…第１端子
Ｐout…第２端子
Ｒ１…抵抗
Ｒ２…抵抗
Ｔ１…スイッチ素子
Ｔ２…スイッチ素子
Ｔ３…スイッチ素子
Ｔ４…スイッチ素子
Ｔ５…スイッチ
Ｔ６…スイッチ（保護スイッチ） 1 ... DCDC converter 10 ... Voltage conversion unit 11 ... First protection circuit 12 ... Input voltage detection unit 13 ... First voltage detection unit 14 ... Second protection circuit 15 ... Second voltage detection unit 16 ... Control unit 90 ... Input conductive path 91 ... 1st conductive path 92 ... 2nd conductive path 93 ... 3rd conductive path C1 ... Condenser C2 ... Condenser C3 ... Condenser L1 ... Coil L2 ... Coil L3 ... Coil Pin ... 1st terminal Pout ... 2nd terminal R1 ... Resistance R2 ... Resistance T1 ... Switch element T2 ... Switch element T3 ... Switch element T4 ... Switch element T5 ... Switch T6 ... Switch (protection switch)

Claims (5)

  1. 　ＰＷＭ信号を受けるスイッチ素子を有する電圧変換部と、前記電圧変換部を制御する制御部と、保護回路と、を有し、
    　前記制御部は、前記スイッチ素子に前記ＰＷＭ信号を与え、
    　前記電圧変換部は、前記ＰＷＭ信号に応じた前記スイッチ素子のスイッチング動作によって第１導電路に印加される入力電圧を降圧又は昇圧して第２導電路に電圧を印加する車載用ＤＣＤＣコンバータであって、
    　前記第２導電路に印加される第１の出力電圧を検出する第１電圧検出部と、
    　前記電圧変換部からの出力電流が流れる電流経路のうち前記第２導電路よりも下流側に設けられた第３導電路に印加される第２の出力電圧を検出する第２電圧検出部と、
    　を有し、
    　前記保護回路は、少なくとも前記第２導電路と前記第３導電路との間に介在する保護スイッチを含み、
    　前記制御部は、前記第１の出力電圧の大きさを第１目標電圧に近づけるための第１デューティを前記第１の出力電圧に基づいて決定する第１フィードバック演算と、前記第２の出力電圧の大きさを第２目標電圧に近づけるための第２デューティを前記第２の出力電圧に基づいて決定する第２フィードバック演算とを行い、前記第１デューティに対し前記第２デューティに基づく補正値を反映した使用デューティの前記ＰＷＭ信号を前記スイッチ素子に出力するように電圧制御を行う車載用ＤＣＤＣコンバータ。     It has a voltage conversion unit having a switch element that receives a PWM signal, a control unit that controls the voltage conversion unit, and a protection circuit.
    The control unit gives the PWM signal to the switch element,
    The voltage conversion unit is an in-vehicle DCDC converter that steps down or boosts the input voltage applied to the first conductive path by the switching operation of the switch element in response to the PWM signal and applies the voltage to the second conductive path. hand,
    A first voltage detection unit that detects the first output voltage applied to the second conductive path, and
    A second voltage detection unit that detects a second output voltage applied to a third conductive path provided on the downstream side of the second conductive path among the current paths through which the output current from the voltage conversion unit flows.
    Have,
    The protection circuit includes at least a protection switch interposed between the second conductive path and the third conductive path.
    The control unit performs a first feedback calculation for determining a first duty for bringing the magnitude of the first output voltage closer to the first target voltage based on the first output voltage, and the second output voltage. A second feedback calculation is performed to determine the second duty for approaching the magnitude of the second target voltage based on the second output voltage, and a correction value based on the second duty is applied to the first duty. An in-vehicle DCDC converter that controls voltage so as to output the PWM signal of the reflected usage duty to the switch element.
  2. 　前記制御部は、第１周期毎に前記第１デューティを算出して前記使用デューティとして更新し、前記第１周期よりも大きい第２周期毎に前記第２デューティを算出して、前記第２デューティを算出する毎に前記補正値を更新する請求項１に記載の車載用ＤＣＤＣコンバータ。 The control unit calculates the first duty for each first cycle and updates it as the used duty, calculates the second duty for each second cycle larger than the first cycle, and performs the second duty. The vehicle-mounted DCDC converter according to claim 1, wherein the correction value is updated every time the calculation is performed.
  3. 　前記制御部は、前記第２デューティと前記第１デューティとの差を前記補正値として算出する請求項１又は請求項２に記載の車載用ＤＣＤＣコンバータ。 The vehicle-mounted DCDC converter according to claim 1 or 2, wherein the control unit calculates the difference between the second duty and the first duty as the correction value.
  4. 　前記制御部は、
    　前記第３導電路に接続された負荷に流れる負荷電流の大きさが閾値未満の場合、前記電圧制御を実行し、
    　前記負荷電流の大きさが前記閾値以上の場合、前記第１導電路に流れる入力電流と、前記第２導電路又は前記第３導電路に流れる前記出力電流とに基づく電流制御を実行し、
    　前記電圧制御から前記電流制御に切り替える場合に、前記電流制御に切り替える直前の前記補正値を保持し、前記電流制御から前記電圧制御に切り替えた際に、保持した前記補正値を前記第１デューティに加える請求項１から請求項３のいずれか１項に記載の車載用ＤＣＤＣコンバータ。     The control unit
    When the magnitude of the load current flowing through the load connected to the third conductive path is less than the threshold value, the voltage control is executed.
    When the magnitude of the load current is equal to or greater than the threshold value, current control is executed based on the input current flowing through the first conductive path and the output current flowing through the second conductive path or the third conductive path.
    When switching from the voltage control to the current control, the correction value immediately before switching to the current control is held, and when the current control is switched to the voltage control, the held correction value is set to the first duty. The vehicle-mounted DCDC converter according to any one of claims 1 to 3.
  5. 　前記制御部は、前記電圧制御において前記第２デューティに基づいて前記補正値を算出した場合、前記補正値が所定の範囲内である場合に前記補正値を採用し、前記電圧制御において前記第２デューティに基づいて前記補正値を算出した場合、前記補正値の大きさが所定の前記範囲外である場合に前記補正値を採用しない請求項１から請求項４のいずれか１項に記載の車載用ＤＣＤＣコンバータ。 When the correction value is calculated based on the second duty in the voltage control, the control unit adopts the correction value when the correction value is within a predetermined range, and the second control unit adopts the correction value in the voltage control. The vehicle-mounted vehicle according to any one of claims 1 to 4, wherein when the correction value is calculated based on the duty, the correction value is not adopted when the magnitude of the correction value is out of the predetermined range. For DCDC converter.
PCT/JP2020/011619 2019-03-19 2020-03-17 Vehicle-mounted dc/dc converter WO2020189656A1 (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011030390A (en) * 2009-07-29 2011-02-10 Rohm Co Ltd Switching power supply unit
JP2013223286A (en) * 2012-04-13 2013-10-28 Fujitsu Semiconductor Ltd Power supply device and method of controlling power supply
JP2018026949A (en) * 2016-08-10 2018-02-15 ローム株式会社 Switching regulator and integrated circuit package

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011030390A (en) * 2009-07-29 2011-02-10 Rohm Co Ltd Switching power supply unit
JP2013223286A (en) * 2012-04-13 2013-10-28 Fujitsu Semiconductor Ltd Power supply device and method of controlling power supply
JP2018026949A (en) * 2016-08-10 2018-02-15 ローム株式会社 Switching regulator and integrated circuit package

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