WO2018216158A1 - Power conversion device - Google Patents

Power conversion device Download PDF

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Publication number
WO2018216158A1
WO2018216158A1 PCT/JP2017/019476 JP2017019476W WO2018216158A1 WO 2018216158 A1 WO2018216158 A1 WO 2018216158A1 JP 2017019476 W JP2017019476 W JP 2017019476W WO 2018216158 A1 WO2018216158 A1 WO 2018216158A1
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WO
WIPO (PCT)
Prior art keywords
timing
voltage
switching element
power supply
voltage component
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PCT/JP2017/019476
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French (fr)
Japanese (ja)
Inventor
章太 渡辺
義章 石黒
友一 坂下
前田　貴史
陽 山上
達也 平山
Original Assignee
三菱電機株式会社
三菱電機照明株式会社
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Application filed by 三菱電機株式会社, 三菱電機照明株式会社 filed Critical 三菱電機株式会社
Priority to PCT/JP2017/019476 priority Critical patent/WO2018216158A1/en
Priority to JP2019519896A priority patent/JP6659196B2/en
Publication of WO2018216158A1 publication Critical patent/WO2018216158A1/en

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

Definitions

  • the present invention relates to a power conversion device that performs DC / DC power conversion.
  • Zero cross switching control (hereinafter referred to as ZCS control) is known as a highly efficient control method for a power conversion device that includes a switching element and a reactor and converts an input DC voltage into a DC voltage of an arbitrary magnitude.
  • the ZCS control is a control for detecting the timing when the current flowing through the switching element or the current flowing through the reactor becomes zero as a zero current signal and switching the switching element at the timing when the zero current signal is detected.
  • the ZCS control has a problem that the switching frequency is increased at a light load, and the switching loss is increased.
  • Patent Document 1 discloses a method of inserting a delay time between detection of a zero current signal and switching of a switching element.
  • Patent Document 2 discloses a method of counting the number of detected zero current signals and switching the switching element at a timing when the number of zero current signals reaches a certain number.
  • Patent Document 1 and Patent Document 2 the case where an AC voltage component is superimposed on an input DC voltage that is an input voltage of a power converter is not studied. Therefore, when an AC voltage component is superimposed on the input DC voltage, there is a problem that a large ripple occurs in the output voltage.
  • the present invention has been made to solve the above-described problems, and provides a power conversion device capable of reducing ripple of an output voltage even when an AC voltage component is superimposed on an input DC voltage. Objective.
  • a power conversion device includes a power supply main circuit unit that has a switching element and a reactor, converts an input voltage in which an AC voltage component is superimposed on a DC voltage component, and outputs the power to a load.
  • the switching element When the detected value of the input voltage increases due to the AC voltage component superimposed on the DC voltage component, the switching element is turned on more than when the detected value of the input voltage decreases due to the AC voltage component superimposed on the DC voltage component.
  • the power supply control part which determines the ON timing of the said switching element so that timing may be delayed is provided.
  • output voltage ripple can be reduced even when an AC voltage component is superimposed on an input DC voltage.
  • FIG. 1 is a circuit block diagram showing a power conversion apparatus 1 according to Embodiment 1 of the present invention.
  • the power conversion device 1 according to the first embodiment includes a power supply main circuit unit 2 and a power supply control unit 3.
  • the power supply main circuit unit 2 includes a converter 6 having a switching element 11, a diode 13, and a reactor 12, and a capacitor Co that smoothes the output voltage of the converter 6.
  • an input power supply 4 is connected to the input side of the converter 6, and a load 5 is connected to the output side of the capacitor Co.
  • the input power supply 4 is a device that outputs a voltage Vin (hereinafter referred to as an input voltage Vin or a pulsating voltage Vin) including an AC voltage component and a DC voltage component.
  • the input power supply 4 only needs to output a pulsating voltage Vin, and as shown in FIG. 2, the AC voltage Vac output from the AC power supply 41 is full-wave rectified by a diode bridge circuit 42, and then PFC (Power Factor Correction).
  • the circuit 43 may perform power conversion.
  • C1 and C2 indicate capacitors.
  • the input power supply 4 may be configured to output a voltage obtained by full-wave rectifying the AC voltage Vac by the diode bridge circuit 42 without using the PFC circuit 43.
  • the input power supply 4 an AC / DC converter (not shown) that directly converts the AC voltage Vac into a DC voltage without using the diode bridge circuit 42 may be used.
  • the input power supply 4 for generating the pulsating voltage Vin is shown as a circuit diagram in which an AC power supply 4A and a DC power supply 4B are connected in series.
  • the converter 6 is a power converter that inputs an input voltage (pulsation voltage) Vin and converts DC / DC power to a target output voltage Vo.
  • the converter 6 includes a step-down chopper circuit including a switching element 11, a reactor 12, and a diode 13. Composed.
  • the converter 6 may be any circuit that has a switching element and a reactor and performs DC / DC power conversion.
  • the converter 6 may be a step-up chopper circuit, a step-up / step-down chopper circuit, an H-bridge type step-up / step-down circuit, a SEPIC (Single Ended Primary Inductor). Converter), flyback converter, or Cuk converter.
  • SEPIC Single Ended Primary Inductor
  • the switching element 11 includes a FET (Field Effect Transistor) element and an IGBT (Insulated Gate Bipolar Transistor) element driven by a switching element drive signal Ga (hereinafter referred to as a gate signal Ga) generated by a power supply control unit 3 to be described later.
  • a gate signal Ga a switching element drive signal generated by a power supply control unit 3 to be described later.
  • the diode 13 may be changed to a switching element Q1 (not shown) such as an FET element or an IGBT element, and a synchronous rectification method may be employed in which the switching element 11 and the switching element Q1 are turned on / off by reverse logic.
  • the power main circuit unit 2 includes an input voltage detection unit 7, an output voltage detection unit 8, and a zero current detection unit 9.
  • the input voltage detector 7 detects the magnitude of the input voltage (pulsation voltage) Vin as an input voltage detection value Vinsen.
  • Vinsen For example, as shown in FIG. 1, two or more voltage dividing resistors connected in series Is provided.
  • the output voltage detection unit 8 detects the magnitude of the DC output voltage vo as an output voltage detection value Vosen.
  • the zero current detection unit 9 is for detecting the zero point of the current flowing through the reactor 12. For example, as shown in FIG. 1, an auxiliary winding having a reverse polarity with respect to the reactor 12 is provided.
  • the voltage VLsen obtained from the auxiliary winding of the zero current detection unit 9 is output to a zero current signal generation unit 31 of the power supply control unit 3 to be described later, and the zero current signal generation unit 31 detects the zero point of the current of the reactor 12 to zero.
  • the current signal ZCD is output.
  • the zero current detection unit 9 may not be a method using an auxiliary winding as long as it can detect the zero point of the current flowing through the reactor 12, for example, a current detection resistor is installed on the low side of the reactor 12, A method of detecting the zero point of the current of the reactor 12 from the voltage generated at both ends of the current detection resistor may be used.
  • the power supply control unit 3 includes a zero current signal generation unit 31, an on time generation unit 32, an on timing generation unit 33, and a switching drive unit 34.
  • the zero current signal generation unit 31 outputs the zero current signal ZCD representing the timing when the current flowing through the reactor 12 becomes zero based on the voltage VLsen obtained from the zero current detection unit 9.
  • the on-time generation unit 32 derives a time for maintaining the gate signal Ga at High (hereinafter referred to as “H”), that is, an on-time of the switching element 11. .
  • the on-timing generator 33 performs count variable ZCS control based on the zero current signal ZCD, the input voltage detection value Vinsen, and the output voltage detection value Vosen, and the timing when the gate signal Ga is set to “H”, that is, the switching element 11 is turned on. Determine timing.
  • the count variable ZCS control is control for determining the timing at which the gate signal Ga is set to “H” based on the AC voltage component superimposed on the input voltage (pulsation voltage) Vin.
  • the count variable ZCS control will be described in detail later.
  • the switching drive unit 34 receives the on-time from the on-time generation unit 32 and the on-timing from the on-timing generation unit 33, and generates a gate signal Ga that operates the switching element 11.
  • FIG. 3 shows the relationship between the gate signal Ga output from the switching drive unit 34, the reactor current iL flowing through the reactor 12, and the zero current signal ZCD output from the zero current signal generating unit 31 as time on the horizontal axis.
  • the gate signal Ga becomes Low (hereinafter referred to as “L”) and the switching element 11 is turned off, current flows in the order of the reactor 12, the load 5, the diode 13, and the reactor 12, and the reactor current iL decreases to zero. During the period when the reactor current iL decreases to zero, the zero current signal ZCD becomes “L”.
  • the period during which the reactor current iL increases and the period during which the reactor current iL decreases to zero become shorter as the power supplied to the load 5 decreases.
  • variable count ZCS control the rising of the zero current signal ZCD to “H” is counted during the period in which the resonance current flows through the reactor 12, and the gate signal Ga is set to “H” when the count reaches a predetermined number. .
  • the number of counts until the gate signal Ga is set to “H” is varied based on the AC voltage component superimposed on the pulsating voltage Vin. Specifically, when the voltage value of the pulsating voltage Vin increases due to the superimposed AC voltage component, the number of counts until the gate signal Ga is set to “H” is increased. Further, when the voltage value of the pulsation voltage Vin becomes smaller due to the superimposed AC voltage component, the number of counts until the gate signal Ga becomes “H” is decreased.
  • FIG. 4 and 5 are operation explanatory diagrams of the count variable ZCS control.
  • the zero current signal ZCD is counted, and the gate signal Ga is set to “H” at the timing when the count number becomes two.
  • the zero current signal ZCD is counted, and the gate signal Ga is set to “H” at the timing when the count number becomes three. 5 in which the count number of the zero current signal ZCD is increased and the gate signal Ga is set to “H”, the count number of the zero current signal ZCD is decreased and the gate signal Ga is set to “H” in FIG. It can be seen that the period during which the gate signal Ga is set to “L” is increased and the duty ratio of the gate signal Ga is reduced as compared with the one shown.
  • the duty ratio of the gate signal Ga is reduced by increasing the count number of the zero current signal ZCD, thereby suppressing an increase in output voltage.
  • the count number of the zero current signal ZCD is reduced to increase the duty ratio of the gate signal Ga and suppress the decrease in the output voltage.
  • variable count ZCS control varies the count number of the zero current signal ZCD according to the power supplied to the load 5. Specifically, at the time of light load, the count number of the zero current signal ZCD is increased compared with the case of high load. As a result, the power supplied to the load 5 is reduced, and it is possible to prevent the switching frequency from increasing even when the period during which the reactor current iL increases and the period during which the reactor current iL decreases are shortened.
  • the count number of the zero current signal ZCD may be set in any way as long as the switching frequency is set not to increase. For example, the switching frequency is set to be almost the same regardless of the power of the load 5. Alternatively, for example, when the power supplied to the load 5 is small, the switching frequency may be set to be lower than when the power supplied to the load is large.
  • the power supply control unit 3 may be a general digital control circuit (including a circuit using software having the same function as the digital control circuit) that does not use an IC (Interconnected Circuit), and some of the components thereof It may be a digital control circuit. Furthermore, an analog control circuit that does not use a digital control circuit may be used. In this embodiment, a configuration of a digital control circuit using a microcomputer is described.
  • the on-time generator 32 calculates the difference between the output voltage detection value Vosen and the target voltage value Voref, and determines the on-time of the switching element 11 so that the difference becomes zero.
  • the on-time is calculated using the output voltage detection value Vosen and the target voltage, such as PI control (proportional integral control), PID control (proportional derivative integral control), or other modern control, or H ⁇ (H-infinity) control. Any control may be used as long as the control is performed so that the difference between the values Voref is zero.
  • the output voltage Vo can be adjusted to an arbitrary target voltage value Voref by calculating the on-time of the on-time generator 32.
  • the on-timing generator 33 performs count variable ZCS control using the zero current signal ZCD, the input voltage detection value Vinsen, and the output voltage detection value Vosen, and generates the on-timing of the gate signal Ga.
  • the symbol S means a processing step.
  • the on-timing generation unit 33 starts control processing, the input voltage detection value Vinsen obtained by detecting the input voltage (pulsation voltage) Vin by the input voltage detection unit 7 of the power supply main circuit unit 2, and the output voltage detection unit
  • the output voltage detection value Vosen obtained by detecting the output voltage Vo is acquired by 8 (step S1).
  • step S2 the supply power of the load 5 is calculated from the output voltage detection value Vosen and the resistance value of the load 5 known in advance, and the reference count cnt is determined based on the supply power of the load 5 (step S2).
  • the reference count cnt is an integer equal to or greater than 1, and is set so that the numerical value increases as the power supplied to the load 5 decreases.
  • the execution position of step S2 may not be the position shown in FIG. 6, and step S2 may be executed after step S3 or step S4 described later. It is also possible to add a current detection circuit for the current flowing through the load 5 and calculate the power supplied to the load 5 using the detection value of the current flowing through the load 5 and the output voltage detection value Vosen.
  • step S3 the DC voltage component of the input voltage detection value Vinsen is calculated by calculating the average value of the input voltage detection value Vinsen, and the calculated result is set as the comparison threshold value Vcomp (step S3).
  • step S3 need not be performed every control cycle of the on-timing generation unit 33, and step S3 may be omitted after the comparison threshold value Vcomp is set once.
  • the comparison threshold value Vcomp need not be calculated from the input voltage detection value Vinsen. If the magnitude of the DC voltage component of the input power supply 4 is known in advance, the value may be set as the comparison threshold value Vcomp. .
  • the target output voltage of the AC / DC converter may be set in advance as the comparison threshold value Vcomp.
  • step S4 the comparison threshold Vcomp calculated in step S3 is compared with the input voltage detection value Vinsen.
  • FIG. 7 is a diagram for explaining a comparison between the comparison threshold value Vcomp and the input voltage detection value Vinsen.
  • a period T1 in which the input voltage detection value Vinsen is equal to or greater than the comparison threshold Vcomp is indicated by hatching, and is distinguished from a period T2 in which the input voltage detection value Vinsen is smaller than the comparison threshold Vcomp.
  • step S4 As a result of the comparison between the comparison threshold value Vcomp and the input voltage detection value Vinsen in step S4, during the period T2 when the input voltage detection value Vinsen is smaller than the comparison threshold value Vcomp, a value obtained by subtracting the decrease correction value x1 from the reference count cnt is set as the turn-on count ZCDcnt. Set (step S5). During a period T1 where the input voltage detection value Vinsen is equal to or greater than the comparison threshold Vcomp, a value obtained by adding the increase correction value x2 to the reference count cnt is set as the turn-on count ZCDcnt (step S6).
  • the decrease correction value x1 and the increase correction value x2 are both integers of 0 or more, but the decrease correction value x1 and the increase correction value x2 do not become 0 at the same time.
  • the decrease correction value x1 has a value less than the reference count cnt. Therefore, the turn-on count ZCDcnt never becomes zero or negative.
  • the zero current signal generation unit 31 of the power supply control unit 3 outputs a zero current signal ZCD indicating the timing when the reactor current iL becomes zero, and the on timing generation unit 33 detects the zero current signal ZCD (step S7). ). Then, the detection of the zero current signal ZCD is counted, and when the count number reaches the turn-on count ZCDcnt, the timing when the gate signal Ga is set to “H”, that is, the ON timing of the switching element 11 is determined (step S8).
  • the above description is the description of the operation of the on-timing generation unit 33 (the flowchart of FIG. 6). As described above, the count variable ZCS control can be realized by operating.
  • the effect of the count variable ZCS control of the present embodiment was confirmed using circuit simulation of Myway Plus.
  • a DC voltage of 300 V and an AC voltage of 20 V (100 Hz) were connected in series to obtain an input voltage.
  • the comparison threshold Vcomp is set to 300V
  • the reference count cnt is set to 3
  • the decrease correction value x1 is set to 1
  • the increase correction value x2 is set to 1
  • the target voltage value Voref is set to 200V.
  • FIG. 8 and 9 are diagrams showing simulation results when the count variable ZCS control is applied and when it is not applied.
  • the upper diagram shows the waveform of the input voltage detection value Vinsen and the comparison threshold value Vcomp
  • the middle diagram shows the waveform of the output voltage Vo
  • the lower diagram shows the turn-on count ZCDcnt.
  • FIG. 8 compares the input voltage detection value Vinsen and the comparison threshold Vcomp.
  • the turn-on count ZCDcnt is 4
  • the input voltage detection value Vinsen is the comparison threshold Vcomp. It can be confirmed that the turn-on count ZCDcnt is 2 when it is smaller (Vinsen ⁇ Vcomp).
  • FIG. 9 shows simulation results when the turn-on count ZCDcnt is always set to 2 regardless of the magnitude of the input voltage detection value.
  • the simulation result in FIG. 8 confirms that the pulsation of the output voltage Vo is smaller than the simulation result in FIG.
  • the ripple rate of the output voltage Vo calculated by dividing the difference between the maximum value and the minimum value of the output voltage Vo by the average value of the output voltage Vo is 0.068 in the simulation result of FIG. 8, and 0 in the simulation result of FIG. 131. Therefore, the output voltage ripple reduction effect of the variable count ZCS control was confirmed.
  • the turn-on count ZCDcnt is determined by comparing the input voltage detection value Vinsen and the comparison threshold value Vcomp calculated from the input voltage detection value Vinsen.
  • the turn-on count ZCDcnt may be determined in any way as long as it is determined based on the AC voltage component superimposed on the DC voltage component of the input voltage (pulsation voltage).
  • Vcomp1 and Vcomp2 may be provided as comparison threshold values, and the comparison threshold values Vcomp1 and Vcomp2 may be compared with the input voltage detection value Vinsen.
  • the turn-on count ZCDcnt is variable by three during one cycle of the pulsating voltage Vin.
  • a period T30 in which the input voltage detection value Vinsen is smaller than the comparison threshold Vcomp1 a period T20 in which the input voltage detection value Vinsen is smaller than the comparison threshold Vcomp2 and greater than or equal to the comparison threshold Vcomp1
  • the turn-on count ZCDcnt is determined so as to increase in order.
  • the step-down chopper circuit shown in FIG. 1 is used as the converter 6.
  • the converter 6 includes a switching element and a reactor, and any circuit that performs DC / DC conversion can be used.
  • a simple circuit may be used.
  • a booster chopper circuit may be used as the converter 6 as shown in FIG.
  • variable count ZCS control can be performed similarly to the configuration using the step-down chopper circuit for the converter 6 described so far. That is, the ripple of the output voltage Vo can be reduced by varying the turn-on count ZCDcnt according to the AC voltage component superimposed on the input voltage (pulsation voltage) Vin.
  • the effect of the variable count ZCS control of the present embodiment was confirmed using a circuit simulation of Myway Plus Co., in the case of using the boost chopper circuit of FIG.
  • a DC voltage of 100 V and an AC voltage of 20 V (100 Hz) were connected in series to obtain an input voltage.
  • the comparison threshold Vcomp is set to 100V
  • the reference count cnt is set to 3
  • the decrease correction value x1 is set to 1
  • the increase correction value x2 is set to 1
  • the target voltage value Voref is set to 200V.
  • 12 and 13 show simulation results when the variable count ZCS control is applied and when it is not applied when the step-up chopper circuit of FIG. 11 is used as the converter 6.
  • 12 and 13 the upper diagram shows the waveform of the input voltage detection value Vinsen and the comparison threshold Vcomp, the middle diagram shows the waveform of the output voltage Vo, and the lower diagram shows the turn-on count ZCDcnt.
  • FIG. 12 shows a simulation waveform when the variable count ZCS control is applied.
  • Vcomp comparison threshold
  • the turn-on count ZCDcnt 4
  • the input voltage detection value Vinsen is the comparison threshold Vcomp. It can be confirmed that the turn-on count ZCDcnt is 2 when it is smaller (Vinsen ⁇ Vcomp).
  • FIG. 13 is a simulation waveform when the turn-on count ZCDcnt is always set to 2 regardless of the input voltage detection value Vinsen. It can be confirmed that the pulsation of the output voltage Vo is smaller when the count variable ZCS control of FIG. 12 is applied than when the count variable ZCS control is not applied of FIG.
  • the ripple rate of the output voltage Vo calculated by dividing the difference between the maximum value and the minimum value of the output voltage Vo by the average value of the output voltage Vo is 0.043 in the case of FIG. 12, and 0.069 in the case of FIG. Met. Therefore, even when the booster chopper circuit is used as the converter 6, the output voltage ripple reduction effect by the variable count ZCS control can be confirmed.
  • the zero point of the current flowing through the reactor 12 is detected as the zero current signal ZCD using the zero current detecting unit 9 and the zero current signal generating unit 31, and the count variable ZCS control is performed.
  • the timing when the voltage applied to the switching element 11 becomes zero may be detected as the zero voltage signal ZVD, and the zero voltage signal ZVD may be used instead of the zero current signal ZCD.
  • the zero voltage detector 90 and the switching element 11 for detecting the voltage applied to the switching element 11 are applied as shown in FIG.
  • the zero voltage signal generator 310 that outputs the timing when the voltage becomes zero as the zero voltage signal ZVD is used.
  • Other configurations and operations are the same as those described above.
  • the control method for determining the ON timing of the switching element using the count number of the zero current signal ZCD has been described.
  • the ON timing of the switching element is set according to the AC voltage component superimposed on the input voltage.
  • the zero current signal ZCD may not be counted.
  • the ON timing of the switching element may be set to a timing at which a predetermined time has elapsed, and may be realized by a control method in which the predetermined time is made variable by an AC voltage component superimposed on the input voltage.
  • control for varying the predetermined time by the AC voltage component superimposed on the input voltage will be described based on the circuit diagram of the power conversion device in FIG. 15 and the circuit operation diagram in FIG.
  • the configurations of the power supply main circuit unit 2 and the power supply control unit 3 of the power conversion device 1 are basically the same as those of FIG. The operation is different.
  • the power supply control unit 3 includes a zero current signal generation unit 31 that outputs a zero current signal ZCD indicating a timing at which the current flowing through the reactor 12 becomes zero based on the voltage VLsen obtained from the zero current detection unit 9;
  • An on-time generator 32 for deriving an on-time of the switching element 11 based on the output voltage detection value Vosen and the target voltage value Voref, and a timing at which a predetermined time has elapsed based on the zero current signal ZCD is determined as the on-timing of the switching element 11.
  • An on-timing generation unit 33A that receives the on-time from the on-time generation unit 32 and the on-timing from the on-timing generation unit 33A, and generates a gate signal Ga that operates the switching element 11. Yes.
  • the on-timing generator 33A starts time measurement from the first rising timing t1 of the zero current signal ZCD after the switching element 11 is turned off, and switching is performed at the timing when the measured time reaches the predetermined time Td.
  • the on-timing for turning on the element 11 is determined.
  • the predetermined time Td for determining the ON timing of the switching element 11 is determined by an AC voltage component superimposed on the input voltage. That is, when the detected value Vinsen of the input voltage becomes larger due to the AC voltage component superimposed on the DC voltage component, the predetermined time Td than when the detected value of the input voltage Vinsen becomes smaller due to the AC voltage component superimposed on the DC voltage component. Delay control to increase
  • the timing for starting the time measurement is not based on the zero current signal ZCD, but may be based on the zero voltage signal ZVD described in FIG. 14, for example. Alternatively, the timing when the switching element 11 is turned on or the timing when the switching element 11 is turned off may be used.
  • FIG. 17 shows an example of a power converter that starts time measurement from the timing when the switching element 11 is turned on or off.
  • the switching detection unit 35 detects the on / off timing of the switching element 11 based on the gate signal Ga from the switching drive unit 34.
  • the on-timing generation unit 33B starts time measurement from the timing when the switching element 11 is turned on or off, and determines the on-timing for turning on the switching element 11 when the measured time reaches a predetermined time.
  • Other operations are the same as those described in FIGS. 15 and 16.
  • the power supply main circuit unit that has the switching element and the reactor, converts the input voltage in which the AC voltage component is superimposed on the DC voltage component, and outputs the power to the load,
  • the on-timing of the switching element is delayed compared to when the detected value of the input voltage decreases due to the AC voltage component superimposed on the DC voltage component.
  • the power supply control unit that determines the ON timing of the switching element is provided, the ripple generated in the output voltage can be reduced.
  • the power supply control unit compares the detected value of the input voltage with the comparison threshold value, and delays the on-timing of the switching element when the detected value of the input voltage is equal to or greater than the comparison threshold value compared to when it is smaller than the comparison threshold value. Since the ON timing of the switching element is determined, ripple generated in the output voltage can be reduced by simple control.
  • the comparison threshold value is a DC voltage component of the input voltage, ripple generated in the output voltage can be reduced by simple control.
  • the power supply control unit outputs a zero current signal that outputs a zero current signal indicating the timing when the current flowing through the reactor becomes zero, and a zero voltage that outputs a zero voltage signal indicating the timing when the voltage applied to the switching element becomes zero
  • An on-timing generator that counts the number of times either one of the signal generators and one of the zero-current signal and the zero-voltage signal and determines the timing when the count reaches a predetermined number as the on-timing of the switching element
  • a switching drive unit that turns on the switching element at the on-timing determined by the on-timing generation unit, and when the detected value of the input voltage becomes larger due to the AC voltage component superimposed on the DC voltage component, the detected value of the input voltage Compared to when the voltage becomes smaller due to the AC voltage component superimposed on the DC voltage component, Since variable count zero-crossing switching control is performed to increase the predetermined number of times, the ripple generated in the output voltage can be reduced, and the timing at which the current flowing through the reactor becomes zero or the voltage applied to
  • the power supply control unit outputs a zero current signal that indicates a timing when the current flowing through the reactor becomes zero, and a zero voltage that outputs a zero voltage signal that indicates the timing when the voltage applied to the switching element becomes zero From any one of the signal generation unit and the switching detection unit that detects the timing at which the switching element is turned on or off, and the zero current signal, the zero voltage signal, and the timing at which the switching element is turned on or off
  • An on-timing generator that determines when a predetermined time has elapsed as an on-timing of the switching element, and a switching drive unit that turns on the switching element at the on-timing determined by the on-timing generator, and the detected value of the input voltage is a DC voltage component Larger due to AC voltage component superimposed on When the detected value of the input voltage becomes smaller due to the AC voltage component superimposed on the DC voltage component, delay control is performed to increase the predetermined time, so the ripple generated in the output voltage by simple control Can be reduced.
  • the power supply control unit determines the on-timing of the switching element so as to delay the on-timing of the switching element compared to when the power supplied to the load is high.
  • count variable zero cross switching control is performed to increase the predetermined number of times compared to when the power supplied to the load is high.
  • delay control is performed to increase the predetermined time compared to when the power supplied to the load is high.
  • the power supply control unit when the power supplied to the load is large, (1) when the detected value of the input voltage becomes larger due to the AC voltage component superimposed on the DC voltage component, the detected value of the input voltage Compared to when it becomes smaller due to the AC voltage component superimposed on the component, the on-timing of the switching element is determined so as to delay the on-timing of the switching element, and the switching element is controlled to switch,
  • the power supplied to the load is small, (2) a control method for switching control of the switching element at a constant switching cycle, (3) regardless of the AC voltage component in which the detected value of the input voltage is superimposed on the DC voltage component,
  • a control method that counts the number of zero current signals indicating the timing at which the current flowing through the reactor becomes zero, determines the timing at which the count reaches a predetermined number as the ON timing of the switching element, and controls the switching of the switching element , At least one control may be performed. According to this, when the power supplied to the load is large, the ripple generated in the output voltage can be reduced.
  • the power supply control unit determines the on-time of the switching element based on the output voltage detection value and the target voltage value of the power supply main circuit unit, a desired output voltage can be obtained.
  • FIG. FIG. 18 is a circuit block diagram showing a power conversion device according to Embodiment 2 of the present invention.
  • the load is an LED (Light Emitting Diode) module 50 as compared with the first embodiment.
  • the load 5 in FIG. 1 is changed to the LED module 50, and an output voltage detection unit. 8 is changed to the output current detection unit 80, the output voltage detection value Vosen is changed to the output current detection value Isen, and the target voltage value Voref input to the on-time generation unit 32 is changed to the target current value Ioref.
  • the difference was made.
  • the output current detection unit 80 includes a current detection resistor (not shown), and detects a potential difference generated between both ends of the current detection resistor as a voltage conversion value Isen corresponding to the current flowing through the LED module 50.
  • the LED module 50 has a configuration in which all LED chips are connected in series in FIG. 18, the LED module 50 is not limited to a series connection, and may be a parallel connection or a series-parallel connection, or may be a single LED.
  • LED is connected as load here, you may change not to LED but to organic electroluminescence (organic EL), a laser diode, etc.
  • the control is changed from the control for adjusting the output voltage to the target voltage to the control for adjusting the output current to the target current.
  • the on-time generation unit 32 derives the on-time of the switching element 11 based on the output current detection value Iosen and the target current value Ioreef. That is, the on-time generating unit 32 calculates the difference between the output current detection value Isen and the target current value Ioref, and determines the on-time of the switching element 11 so that the difference becomes zero. If comprised in this way, control of the output current which flows into the LED module 50 can be performed by control similar to Embodiment 1.
  • the power supply control unit 3 determines that the input voltage detection value Vinsen becomes a DC voltage component when the input voltage detection value Vinsen becomes larger due to the AC voltage component superimposed on the DC voltage component. Since the switching control is performed by determining the on-timing of the switching element 11 so as to delay the on-timing of the switching element 11 as compared with the time when it becomes smaller due to the superimposed AC voltage component, the ripple of the output current can be reduced. .
  • the load is an LED
  • the ripple generated in the output current can be reduced by the variable count ZCS control or the delay control described in the first embodiment, the occurrence of light flickering can be prevented.
  • the dimming function can be achieved if the target current value Ioref that is normally input from outside is made variable by the dimming function. realizable.
  • the output current can be adjusted to the target current, Effects similar to those described in Embodiment 1 can be obtained. In particular, the ripple generated in the output current can be reduced.

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Abstract

Provided is a power conversion device provided with a power supply main circuit unit (2) and a power supply control unit (3). The power supply main circuit unit (2) has a switching element (11) and a reactor (12) and performs power conversion on an input voltage having an AC voltage component superimposed on a DC voltage component to output the converted input voltage to a load. The power supply control unit (3) determines the turn-on timing of the switching element (11) so as to delay the turn-on timing of the switching element (11) when the sensed value (Vinsen) of the input voltage becomes large due to the AC voltage component superimposed on the DC voltage component as compared to when the sensed value (Vinsen) of the input voltage becomes small due to the AC voltage component superimposed on the DC voltage component.

Description

電力変換装置Power converter
　この発明は、直流／直流電力変換を行う電力変換装置に関するものである。 The present invention relates to a power conversion device that performs DC / DC power conversion.
　スイッチング素子とリアクトルとを備え、入力直流電圧を任意の大きさの直流電圧に変換する電力変換装置の高効率な制御法としてゼロクロススイッチング制御（以下、ＺＣＳ制御と称す）が知られている。ＺＣＳ制御は、スイッチング素子に流れる電流またはリアクトルに流れる電流が零となるタイミングを零電流信号として検出し、零電流信号を検出したタイミングでスイッチング素子をスイッチングさせる制御である。ＺＣＳ制御は、軽負荷時においてはスイッチング周波数が高周波化し、スイッチング損失が増大するという課題が存在する。 Zero cross switching control (hereinafter referred to as ZCS control) is known as a highly efficient control method for a power conversion device that includes a switching element and a reactor and converts an input DC voltage into a DC voltage of an arbitrary magnitude. The ZCS control is a control for detecting the timing when the current flowing through the switching element or the current flowing through the reactor becomes zero as a zero current signal and switching the switching element at the timing when the zero current signal is detected. The ZCS control has a problem that the switching frequency is increased at a light load, and the switching loss is increased.
　そこで、スイッチング周波数の高周波化を防止し、スイッチング損失を低減する方法が開示されている。例えば特許文献１では、零電流信号を検出してからスイッチング素子をスイッチングするまでの間に遅延時間を挿入する方法を開示している。また、例えば特許文献２では、検出した零電流信号の数をカウントして、零電流信号のカウント数が一定回数に達したタイミングでスイッチング素子をスイッチングする方法を開示している。 Therefore, a method for preventing an increase in switching frequency and reducing switching loss is disclosed. For example, Patent Document 1 discloses a method of inserting a delay time between detection of a zero current signal and switching of a switching element. For example, Patent Document 2 discloses a method of counting the number of detected zero current signals and switching the switching element at a timing when the number of zero current signals reaches a certain number.
特許５８２８１０６号Patent 5828106 特開２０１４－１３１４５５号JP 2014-131455 A
　上記特許文献１および上記特許文献２は電力変換装置の入力電圧である入力直流電圧に交流電圧成分が重畳した場合についての検討がなされていない。そのため、入力直流電圧に交流電圧成分が重畳した場合、出力電圧に大きなリップルが発生するという課題があった。 In Patent Document 1 and Patent Document 2, the case where an AC voltage component is superimposed on an input DC voltage that is an input voltage of a power converter is not studied. Therefore, when an AC voltage component is superimposed on the input DC voltage, there is a problem that a large ripple occurs in the output voltage.
　この発明は、上記のような課題を解決するためになされたものであり、入力直流電圧に交流電圧成分が重畳した場合でも出力電圧のリップルを低減することができる電力変換装置を提供することを目的とする。 The present invention has been made to solve the above-described problems, and provides a power conversion device capable of reducing ripple of an output voltage even when an AC voltage component is superimposed on an input DC voltage. Objective.
　この発明に係る電力変換装置は、スイッチング素子と、リアクトルとを有し、直流電圧成分に交流電圧成分が重畳した入力電圧を電力変換して負荷に出力する電源主回路部と、
上記入力電圧の検出値が直流電圧成分に重畳する交流電圧成分により大きくなる時は、上記入力電圧の検出値が直流電圧成分に重畳する交流電圧成分により小さくなる時に比べて、上記スイッチング素子のオンタイミングを遅らせるように上記スイッチング素子のオンタイミングを決定する電源制御部を備えたものである。 A power conversion device according to the present invention includes a power supply main circuit unit that has a switching element and a reactor, converts an input voltage in which an AC voltage component is superimposed on a DC voltage component, and outputs the power to a load.
When the detected value of the input voltage increases due to the AC voltage component superimposed on the DC voltage component, the switching element is turned on more than when the detected value of the input voltage decreases due to the AC voltage component superimposed on the DC voltage component. The power supply control part which determines the ON timing of the said switching element so that timing may be delayed is provided.
　この発明の電力変換装置によれば、入力直流電圧に交流電圧成分が重畳した場合においても出力電圧のリップルを低減することができる。 According to the power conversion device of the present invention, output voltage ripple can be reduced even when an AC voltage component is superimposed on an input DC voltage.
この発明の実施の形態１による電力変換装置を示す回路ブロック図である。It is a circuit block diagram which shows the power converter device by Embodiment 1 of this invention. この発明の実施の形態１による入力電源の構成例を示す回路ブロック図である。It is a circuit block diagram which shows the structural example of the input power supply by Embodiment 1 of this invention. この発明の実施の形態１による電源主回路部の動作を説明する図である。It is a figure explaining the operation | movement of the power main circuit part by Embodiment 1 of this invention. この発明の実施の形態１による電源主回路部の動作を説明する図である。It is a figure explaining the operation | movement of the power main circuit part by Embodiment 1 of this invention. この発明の実施の形態１による電源主回路部の動作を説明する図である。It is a figure explaining the operation | movement of the power main circuit part by Embodiment 1 of this invention. この発明の実施の形態１による電源制御部の制御動作を示すフローチャートである。It is a flowchart which shows the control operation of the power supply control part by Embodiment 1 of this invention. この発明の実施の形態１による入力電圧検出値と比較閾値との比較を表す図である。It is a figure showing the comparison with the input voltage detection value by Embodiment 1 of this invention, and a comparison threshold value. この発明の実施の形態１によるカウント可変ＺＣＳ制御適用時のシミュレーション結果を表す図である。It is a figure showing the simulation result at the time of count variable ZCS control application by Embodiment 1 of this invention. この発明の実施の形態１によるカウント可変ＺＣＳ制御不適用時のシミュレーション結果を表す図である。It is a figure showing the simulation result at the time of count variable ZCS control non-application by Embodiment 1 of this invention. この発明の実施の形態１による入力電圧検出値と比較閾値との他の比較例を表す図である。It is a figure showing the other comparative example of the input voltage detection value by Embodiment 1 of this invention, and a comparison threshold value. この発明の実施の形態１による電力変換装置の他の例を示す回路ブロック図である。It is a circuit block diagram which shows the other example of the power converter device by Embodiment 1 of this invention. この発明の実施の形態１によるカウント可変ＺＣＳ制御適用時のシミュレーション結果を表す図である。It is a figure showing the simulation result at the time of count variable ZCS control application by Embodiment 1 of this invention. この発明の実施の形態１によるカウント可変ＺＣＳ制御不適用時のシミュレーション結果を表す図である。It is a figure showing the simulation result at the time of count variable ZCS control non-application by Embodiment 1 of this invention. この発明の実施の形態１による電力変換装置の他の例を示す回路ブロック図である。It is a circuit block diagram which shows the other example of the power converter device by Embodiment 1 of this invention. この発明の実施の形態１による電力変換装置の他の例を示す回路ブロック図である。It is a circuit block diagram which shows the other example of the power converter device by Embodiment 1 of this invention. 図１５の電力変換装置の電源主回路部の動作を説明する図である。It is a figure explaining operation | movement of the power main circuit part of the power converter device of FIG. この発明の実施の形態１による電力変換装置の他の例を示す回路ブロック図である。It is a circuit block diagram which shows the other example of the power converter device by Embodiment 1 of this invention. この発明の実施の形態２による電力変換装置を示す回路ブロック図である。It is a circuit block diagram which shows the power converter device by Embodiment 2 of this invention.
実施の形態１．
　図１はこの発明の実施の形態１による電力変換装置１を示す回路ブロック図である。本実施の形態１の電力変換装置１は、電源主回路部２と、電源制御部３とを備えている。電源主回路部２は、スイッチング素子１１、ダイオード１３、リアクトル１２を有するコンバータ６と、コンバータ６の出力電圧を平滑化するコンデンサＣｏを備えている。電源主回路部２は、コンバータ６の入力側に入力電源４が、コンデンサＣｏの出力側に負荷５がそれぞれ接続される。 Embodiment 1 FIG.
1 is a circuit block diagram showing a power conversion apparatus 1 according to Embodiment 1 of the present invention. The power conversion device 1 according to the first embodiment includes a power supply main circuit unit 2 and a power supply control unit 3. The power supply main circuit unit 2 includes a converter 6 having a switching element 11, a diode 13, and a reactor 12, and a capacitor Co that smoothes the output voltage of the converter 6. In the power supply main circuit unit 2, an input power supply 4 is connected to the input side of the converter 6, and a load 5 is connected to the output side of the capacitor Co.
　入力電源４は、交流電圧成分および直流電圧成分を含む電圧Ｖｉｎ（以降、入力電圧Ｖｉｎ若しくは脈動電圧Ｖｉｎと称す）を出力する装置である。入力電源４は脈動電圧Ｖｉｎを出力するものであればよく、図２に示すように、交流電源４１が出力する交流電圧Ｖａｃをダイオードブリッジ回路４２により全波整流し、その後、ＰＦＣ（Ｐｏｗｅｒ　Ｆａｃｔｏｒ　Ｃｏｒｒｅｃｔｉｏｎ）回路４３により電力変換を行うという構成としてもよい。なお、図２において、Ｃ１、Ｃ２はコンデンサを示す。
　また、入力電源４として、ＰＦＣ回路４３を用いずに交流電圧Ｖａｃをダイオードブリッジ回路４２で全波整流した電圧を出力する構成としてもよい。
　さらに、入力電源４として、ダイオードブリッジ回路４２を用いずに交流電圧Ｖａｃを直接直流電圧に変換する交流／直流コンバータ（図示せず）を用いる構成としてもよい。
　なお、実施の形態１では、図１に示すように、脈動電圧Ｖｉｎを発生させる入力電源４を、交流電源４Ａと直流電源４Ｂが直列接続された回路図として示す。 The input power supply 4 is a device that outputs a voltage Vin (hereinafter referred to as an input voltage Vin or a pulsating voltage Vin) including an AC voltage component and a DC voltage component. The input power supply 4 only needs to output a pulsating voltage Vin, and as shown in FIG. 2, the AC voltage Vac output from the AC power supply 41 is full-wave rectified by a diode bridge circuit 42, and then PFC (Power Factor Correction). The circuit 43 may perform power conversion. In FIG. 2, C1 and C2 indicate capacitors.
The input power supply 4 may be configured to output a voltage obtained by full-wave rectifying the AC voltage Vac by the diode bridge circuit 42 without using the PFC circuit 43.
Furthermore, as the input power supply 4, an AC / DC converter (not shown) that directly converts the AC voltage Vac into a DC voltage without using the diode bridge circuit 42 may be used.
In the first embodiment, as shown in FIG. 1, the input power supply 4 for generating the pulsating voltage Vin is shown as a circuit diagram in which an AC power supply 4A and a DC power supply 4B are connected in series.
　コンバータ６は、入力電圧（脈動電圧）Ｖｉｎを入力し、目標とする出力電圧Ｖｏに直流／直流電力変換する電力変換器であり、例えばスイッチング素子１１、リアクトル１２、ダイオード１３を備える降圧チョッパ回路から構成される。なお、コンバータ６はスイッチング素子とリアクトルを有し、直流／直流電力変換を行う回路であればよく、例えば、昇圧チョッパ回路、昇降圧チョッパ回路、Ｈブリッジ型昇降圧回路、ＳＥＰＩＣ（Ｓｉｎｇｌｅ　Ｅｎｄｅｄ　Ｐｒｉｍａｒｙ　Ｉｎｄｕｃｔｏｒ　Ｃｏｎｖｅｒｔｅｒ）コンバータ、フライバックコンバータ、またはＣｕｋコンバータであってもよい。また、スイッチング素子１１は、後述する電源制御部３で生成したスイッチング素子駆動信号Ｇａ（以下、ゲート信号Ｇａと称す）により駆動されるＦＥＴ（Ｆｉｅｌｄ　Ｅｆｆｅｃｔ　Ｔｒｎｓｉｓｔｏｒ）素子、ＩＧＢＴ（Ｉｎｓｕｌａｔｅｄ　Ｇａｔｅ　Ｂｉｐｏｌａｒ　Ｔｒａｎｓｉｓｔｏｒ）素子などである。また、ダイオード１３を、ＦＥＴ素子またはＩＧＢＴ素子などのスイッチング素子Ｑ１（図示せず）に変更し、スイッチング素子１１およびスイッチング素子Ｑ１のオンオフを逆論理で動作させる同期整流方式としてもよい。 The converter 6 is a power converter that inputs an input voltage (pulsation voltage) Vin and converts DC / DC power to a target output voltage Vo. For example, the converter 6 includes a step-down chopper circuit including a switching element 11, a reactor 12, and a diode 13. Composed. The converter 6 may be any circuit that has a switching element and a reactor and performs DC / DC power conversion. For example, the converter 6 may be a step-up chopper circuit, a step-up / step-down chopper circuit, an H-bridge type step-up / step-down circuit, a SEPIC (Single Ended Primary Inductor). Converter), flyback converter, or Cuk converter. The switching element 11 includes a FET (Field Effect Transistor) element and an IGBT (Insulated Gate Bipolar Transistor) element driven by a switching element drive signal Ga (hereinafter referred to as a gate signal Ga) generated by a power supply control unit 3 to be described later. Etc. Further, the diode 13 may be changed to a switching element Q1 (not shown) such as an FET element or an IGBT element, and a synchronous rectification method may be employed in which the switching element 11 and the switching element Q1 are turned on / off by reverse logic.
　電源主回路部２は、入力電圧検出部７、出力電圧検出部８、零電流検出部９を備える。入力電圧検出部７は、入力電圧（脈動電圧）Ｖｉｎの大きさを入力電圧検出値Ｖｉｎｓｅｎとして検出するものであり、例えば図１に示すように、２つ以上の直列に接続された分圧抵抗を備える。出力電圧検出部８は、直流化された出力電圧ｖｏの大きさを出力電圧検出値Ｖｏｓｅｎとして検出するものであり、例えば図１に示すように、２つ以上の直列に接続された分圧抵抗を備える。零電流検出部９は、リアクトル１２に流れる電流の零点を検出するためのものであり、例えば図１に示すように、リアクトル１２に対して逆極性の補助巻線が設けられている。零電流検出部９の補助巻線から得られる電圧ＶＬｓｅｎは後述する電源制御部３の零電流信号生成部３１に出力され、零電流信号生成部３１はリアクトル１２の電流の零点を検出して零電流信号ＺＣＤを出力する。 The power main circuit unit 2 includes an input voltage detection unit 7, an output voltage detection unit 8, and a zero current detection unit 9. The input voltage detector 7 detects the magnitude of the input voltage (pulsation voltage) Vin as an input voltage detection value Vinsen. For example, as shown in FIG. 1, two or more voltage dividing resistors connected in series Is provided. The output voltage detection unit 8 detects the magnitude of the DC output voltage vo as an output voltage detection value Vosen. For example, as shown in FIG. 1, two or more voltage dividing resistors connected in series Is provided. The zero current detection unit 9 is for detecting the zero point of the current flowing through the reactor 12. For example, as shown in FIG. 1, an auxiliary winding having a reverse polarity with respect to the reactor 12 is provided. The voltage VLsen obtained from the auxiliary winding of the zero current detection unit 9 is output to a zero current signal generation unit 31 of the power supply control unit 3 to be described later, and the zero current signal generation unit 31 detects the zero point of the current of the reactor 12 to zero. The current signal ZCD is output.
　なお、零電流検出部９は、リアクトル１２に流れる電流の零点を検出できる構成であれば、補助巻線を用いる方法でなくてもよく、例えば、リアクトル１２のローサイドに電流検出抵抗を設置し、電流検出抵抗の両端に発生する電圧からリアクトル１２の電流の零点を検出する方法でもよい。 The zero current detection unit 9 may not be a method using an auxiliary winding as long as it can detect the zero point of the current flowing through the reactor 12, for example, a current detection resistor is installed on the low side of the reactor 12, A method of detecting the zero point of the current of the reactor 12 from the voltage generated at both ends of the current detection resistor may be used.
　次に、電源制御部３について説明する。電源制御部３は、零電流信号生成部３１と、オン時間生成部３２と、オンタイミング生成部３３と、スイッチング駆動部３４を備える。零電流信号生成部３１は、前述のように、零電流検出部９から得られる電圧ＶＬｓｅｎに基づいて、リアクトル１２に流れる電流が零になるタイミングを表す零電流信号ＺＣＤを出力する。オン時間生成部３２は、出力電圧検出値Ｖｏｓｅｎおよび目標電圧値Ｖｏｒｅｆに基づいて、ゲート信号ＧａをＨｉｇｈ（以下、“Ｈ”と記す）に維持する時間、すなわちスイッチング素子１１のオン時間を導出する。オンタイミング生成部３３は、零電流信号ＺＣＤ、入力電圧検出値Ｖｉｎｓｅｎおよび出力電圧検出値Ｖｏｓｅｎに基づいてカウント可変ＺＣＳ制御を行い、ゲート信号Ｇａを“Ｈ”とするタイミング、すなわちスイッチング素子１１のオンタイミングを決定する。カウント可変ＺＣＳ制御は、入力電圧（脈動電圧）Ｖｉｎに重畳している交流電圧成分に基づいてゲート信号Ｇａを“Ｈ”とするタイミングを決定する制御である。カウント可変ＺＣＳ制御については後に詳述する。スイッチング駆動部３４は、オン時間生成部３２からのオン時間と、オンタイミング生成部３３からのオンタイミングを入力し、スイッチング素子１１を動作させるゲート信号Ｇａを生成する。 Next, the power supply control unit 3 will be described. The power supply control unit 3 includes a zero current signal generation unit 31, an on time generation unit 32, an on timing generation unit 33, and a switching drive unit 34. As described above, the zero current signal generation unit 31 outputs the zero current signal ZCD representing the timing when the current flowing through the reactor 12 becomes zero based on the voltage VLsen obtained from the zero current detection unit 9. Based on the output voltage detection value Vosen and the target voltage value Voref, the on-time generation unit 32 derives a time for maintaining the gate signal Ga at High (hereinafter referred to as “H”), that is, an on-time of the switching element 11. . The on-timing generator 33 performs count variable ZCS control based on the zero current signal ZCD, the input voltage detection value Vinsen, and the output voltage detection value Vosen, and the timing when the gate signal Ga is set to “H”, that is, the switching element 11 is turned on. Determine timing. The count variable ZCS control is control for determining the timing at which the gate signal Ga is set to “H” based on the AC voltage component superimposed on the input voltage (pulsation voltage) Vin. The count variable ZCS control will be described in detail later. The switching drive unit 34 receives the on-time from the on-time generation unit 32 and the on-timing from the on-timing generation unit 33, and generates a gate signal Ga that operates the switching element 11.
　次に、図３を用いて電源主回路部２の回路動作、特にＺＣＳ制御の回路動作を説明する。図３は、スイッチング駆動部３４が出力するゲート信号Ｇａ、リアクトル１２に流れるリアクトル電流ｉＬ、零電流信号生成部３１が出力する零電流信号ＺＣＤの関係を横軸を時間として表している。
　ゲート信号Ｇａが“Ｈ”となり、スイッチング素子１１がオンすると、図１において、入力電源４、スイッチング素子１１、リアクトル１２、負荷５、入力電源４の順に電流が流れ、リアクトル電流ｉＬは増加する。リアクトル電流ｉＬが増加する期間は零電流信号ＺＣＤが“Ｈ”となる。 Next, the circuit operation of the power supply main circuit unit 2, particularly the circuit operation of ZCS control will be described with reference to FIG. FIG. 3 shows the relationship between the gate signal Ga output from the switching drive unit 34, the reactor current iL flowing through the reactor 12, and the zero current signal ZCD output from the zero current signal generating unit 31 as time on the horizontal axis.
When the gate signal Ga becomes “H” and the switching element 11 is turned on, in FIG. 1, a current flows in the order of the input power supply 4, the switching element 11, the reactor 12, the load 5, and the input power supply 4, and the reactor current iL increases. During the period when the reactor current iL increases, the zero current signal ZCD becomes “H”.
　ゲート信号ＧａがＬｏｗ（以下、“Ｌ”と記す）となり、スイッチング素子１１がオフとなると、リアクトル１２、負荷５、ダイオード１３、リアクトル１２の順に電流が流れ、リアクトル電流ｉＬは零まで減少する。リアクトル電流ｉＬが零まで減少する期間は零電流信号ＺＣＤが“Ｌ”となる。 When the gate signal Ga becomes Low (hereinafter referred to as “L”) and the switching element 11 is turned off, current flows in the order of the reactor 12, the load 5, the diode 13, and the reactor 12, and the reactor current iL decreases to zero. During the period when the reactor current iL decreases to zero, the zero current signal ZCD becomes “L”.
　ここで、上記リアクトル電流ｉＬが増加する期間と上記リアクトル電流ｉＬが零まで減少する期間は、負荷５に供給する電力が小さくなるほど短くなる。 Here, the period during which the reactor current iL increases and the period during which the reactor current iL decreases to zero become shorter as the power supplied to the load 5 decreases.
　リアクトル電流ｉＬが零まで立ち下がると、リアクトル１２のインダクタンス成分とスイッチング素子１１の寄生容量とによりＬＣ共振が発生し、このＬＣ共振による共振電流がリアクトル電流ｉＬに流れる。リアクトルに共振電流が流れる期間において、リアクトル電流ｉＬが零となりかつ立ち上がるタイミングで零電流信号ＺＣＤは“Ｈ”となる。零電流信号ＺＣＤが“Ｈ”となるタイミングでゲート信号を“Ｈ”とすることで、スイッチング素子１１のスイッチングで発生するスイッチング損失を低減することができる。 When the reactor current iL falls to zero, LC resonance occurs due to the inductance component of the reactor 12 and the parasitic capacitance of the switching element 11, and the resonance current due to this LC resonance flows to the reactor current iL. During the period in which the resonant current flows through the reactor, the reactor current iL becomes zero and the zero current signal ZCD becomes “H” at the timing of rising. By setting the gate signal to “H” at the timing when the zero current signal ZCD becomes “H”, the switching loss generated by switching of the switching element 11 can be reduced.
　次に、カウント可変ＺＣＳ制御の概要を説明する。カウント可変ＺＣＳ制御では、リアクトル１２に共振電流が流れる期間において零電流信号ＺＣＤの“Ｈ”への立上りをカウントし、カウント数が所定の回数に達したタイミングでゲート信号Ｇａを“Ｈ”とする。このとき、脈動電圧Ｖｉｎに重畳した交流電圧成分に基づいてゲート信号Ｇａを“Ｈ”とするまでのカウント数を可変させる。具体的には、脈動電圧Ｖｉｎの電圧値が重畳する交流電圧成分により大きくなる時はゲート信号Ｇａを“Ｈ”とするまでのカウント数を増加させる。また、脈動電圧Ｖｉｎの電圧値が重畳する交流電圧成分により小さくなる時はゲート信号Ｇａを“Ｈ”とするまでのカウント数を減少させる。 Next, an outline of the variable count ZCS control will be described. In the variable count ZCS control, the rising of the zero current signal ZCD to “H” is counted during the period in which the resonance current flows through the reactor 12, and the gate signal Ga is set to “H” when the count reaches a predetermined number. . At this time, the number of counts until the gate signal Ga is set to “H” is varied based on the AC voltage component superimposed on the pulsating voltage Vin. Specifically, when the voltage value of the pulsating voltage Vin increases due to the superimposed AC voltage component, the number of counts until the gate signal Ga is set to “H” is increased. Further, when the voltage value of the pulsation voltage Vin becomes smaller due to the superimposed AC voltage component, the number of counts until the gate signal Ga becomes “H” is decreased.
　図４および図５はカウント可変ＺＣＳ制御の動作説明図である。図４は、零電流信号ＺＣＤをカウントして、カウント数が２回となったタイミングでゲート信号Ｇａを“Ｈ”としている。図５は、零電流信号ＺＣＤをカウントして、カウント数が３回となったタイミングでゲート信号Ｇａを“Ｈ”としている。零電流信号ＺＣＤのカウント数を多くしてゲート信号Ｇａを“Ｈ”とする図５に示す方が、零電流信号ＺＣＤのカウント数を少なくしてゲート信号Ｇａを“Ｈ”とする図４に示す方に比べ、ゲート信号Ｇａを“Ｌ”とする期間が増え、ゲート信号Ｇａのデューティ比が小さくなっていることがわかる。つまり、脈動電圧Ｖｉｎが重畳する交流電圧成分により大きくなる時は、零電流信号ＺＣＤのカウント数を大きくすることで、ゲート信号Ｇａのデューティ比を小さくし、出力電圧の増大を抑える。また、脈動電圧Ｖｉｎが重畳する交流電圧成分により小さくなる時は、零電流信号ＺＣＤのカウント数を小さくすることで、ゲート信号Ｇａのデューティ比を大きくし、出力電圧の減少を抑える。以上の動作により、出力電圧に発生するリップル成分を低減することができる。 4 and 5 are operation explanatory diagrams of the count variable ZCS control. In FIG. 4, the zero current signal ZCD is counted, and the gate signal Ga is set to “H” at the timing when the count number becomes two. In FIG. 5, the zero current signal ZCD is counted, and the gate signal Ga is set to “H” at the timing when the count number becomes three. 5 in which the count number of the zero current signal ZCD is increased and the gate signal Ga is set to “H”, the count number of the zero current signal ZCD is decreased and the gate signal Ga is set to “H” in FIG. It can be seen that the period during which the gate signal Ga is set to “L” is increased and the duty ratio of the gate signal Ga is reduced as compared with the one shown. That is, when the pulsation voltage Vin increases due to the superimposed AC voltage component, the duty ratio of the gate signal Ga is reduced by increasing the count number of the zero current signal ZCD, thereby suppressing an increase in output voltage. When the pulsating voltage Vin is reduced by the superimposed AC voltage component, the count number of the zero current signal ZCD is reduced to increase the duty ratio of the gate signal Ga and suppress the decrease in the output voltage. With the above operation, a ripple component generated in the output voltage can be reduced.
　また、カウント可変ＺＣＳ制御は負荷５に供給する電力に応じて、零電流信号ＺＣＤのカウント数を可変する。具体的には、軽負荷時は、高負荷時に比べて零電流信号ＺＣＤのカウント数を増加させる。これにより、負荷５に供給する電力が小さくなり、上記リアクトル電流ｉＬが増加する期間および減少する期間が短くなっても、スイッチング周波数が高周波化することを防止することができる。なお、零電流信号ＺＣＤのカウント数は、スイッチング周波数が高周波化しないように設定すればどのように設定してもよく、例えば負荷５の電力によらずにスイッチング周波数がほとんど同じとなるように設定してもよいし、例えば負荷５に供給する電力が小さい時は負荷に供給する電力が大きい時よりスイッチング周波数が低減されるように設定してもよい。 Further, the variable count ZCS control varies the count number of the zero current signal ZCD according to the power supplied to the load 5. Specifically, at the time of light load, the count number of the zero current signal ZCD is increased compared with the case of high load. As a result, the power supplied to the load 5 is reduced, and it is possible to prevent the switching frequency from increasing even when the period during which the reactor current iL increases and the period during which the reactor current iL decreases are shortened. The count number of the zero current signal ZCD may be set in any way as long as the switching frequency is set not to increase. For example, the switching frequency is set to be almost the same regardless of the power of the load 5. Alternatively, for example, when the power supplied to the load 5 is small, the switching frequency may be set to be lower than when the power supplied to the load is large.
　次に、電源制御部３の詳細について説明する。なお、電源制御部３は、全部がＩＣ（Ｉｎｔｅｒｔｅｄ　Ｃｉｒｃｕｉｔ）を用いない一般のデジタル制御回路（デジタル制御回路と同機能をもつソフトウェアによる回路も含まれる）でもよく、またその構成要素の一部がデジタル制御回路であっても良い。さらに、全部がデジタル制御回路を用いないアナログ制御回路であっても良い。本実施の形態では、マイコンを用いるデジタル制御回路とした構成について記述する。 Next, details of the power supply control unit 3 will be described. The power supply control unit 3 may be a general digital control circuit (including a circuit using software having the same function as the digital control circuit) that does not use an IC (Interconnected Circuit), and some of the components thereof It may be a digital control circuit. Furthermore, an analog control circuit that does not use a digital control circuit may be used. In this embodiment, a configuration of a digital control circuit using a microcomputer is described.
　オン時間生成部３２は、出力電圧検出値Ｖｏｓｅｎと目標電圧値Ｖｏｒｅｆの差分を演算し、その差分が零になるようにスイッチング素子１１のオン時間を決定する。オン時間の演算は、ＰＩ制御（比例積分制御）、ＰＩＤ制御（比例微分積分制御）等の古典制御、あるいはＨ∞（Ｈ－ｉｎｆｉｎｉｔｙ）制御等の現代制御など、出力電圧検出値Ｖｏｓｅｎと目標電圧値Ｖｏｒｅｆの差分を零とするように制御する方法であればどんな制御を用いてもよい。オン時間生成部３２のオン時間の演算により、出力電圧Ｖｏを任意の目標電圧値Ｖｏｒｅｆに調整することができる。 The on-time generator 32 calculates the difference between the output voltage detection value Vosen and the target voltage value Voref, and determines the on-time of the switching element 11 so that the difference becomes zero. The on-time is calculated using the output voltage detection value Vosen and the target voltage, such as PI control (proportional integral control), PID control (proportional derivative integral control), or other modern control, or H∞ (H-infinity) control. Any control may be used as long as the control is performed so that the difference between the values Voref is zero. The output voltage Vo can be adjusted to an arbitrary target voltage value Voref by calculating the on-time of the on-time generator 32.
　オンタイミング生成部３３は、零電流信号ＺＣＤ、入力電圧検出値Ｖｉｎｓｅｎおよび出力電圧検出値Ｖｏｓｅｎを用いて、カウント可変ＺＣＳ制御を行い、ゲート信号Ｇａのオンタイミングを生成する。 The on-timing generator 33 performs count variable ZCS control using the zero current signal ZCD, the input voltage detection value Vinsen, and the output voltage detection value Vosen, and generates the on-timing of the gate signal Ga.
　オンタイミング生成部３３の動作を図６のフローチャートを用いて説明する。なお、図６において符号Ｓは処理ステップを意味する。 The operation of the on-timing generator 33 will be described with reference to the flowchart of FIG. In FIG. 6, the symbol S means a processing step.
　まず、オンタイミング生成部３３は制御処理を開始すると、電源主回路部２の入力電圧検出部７により入力電圧（脈動電圧）Ｖｉｎを検出して得られる入力電圧検出値Ｖｉｎｓｅｎ、および出力電圧検出部８により出力電圧Ｖｏを検出して得られる出力電圧検出値Ｖｏｓｅｎを取り込む（ステップＳ１）。 First, when the on-timing generation unit 33 starts control processing, the input voltage detection value Vinsen obtained by detecting the input voltage (pulsation voltage) Vin by the input voltage detection unit 7 of the power supply main circuit unit 2, and the output voltage detection unit The output voltage detection value Vosen obtained by detecting the output voltage Vo is acquired by 8 (step S1).
　次に、出力電圧検出値Ｖｏｓｅｎとあらかじめ分かっている負荷５の抵抗値から負荷５の供給電力を算出し、負荷５の供給電力に基づいて基準カウントｃｎｔを決定する（ステップＳ２）。基準カウントｃｎｔは１以上の整数であり、負荷５の供給電力が小さい時ほど数値が大きくなるように設定する。なお、当該ステップＳ２の実施位置は図６に示した位置でなくてもよく、後述するステップＳ３、またはステップＳ４の後にステップＳ２を実施してもよい。なお、負荷５に流れる電流の電流検出回路を追加して、負荷５に流れる電流の検出値と出力電圧検出値Ｖｏｓｅｎを用いて負荷５の供給電力を算出する構成としてもよい。 Next, the supply power of the load 5 is calculated from the output voltage detection value Vosen and the resistance value of the load 5 known in advance, and the reference count cnt is determined based on the supply power of the load 5 (step S2). The reference count cnt is an integer equal to or greater than 1, and is set so that the numerical value increases as the power supplied to the load 5 decreases. Note that the execution position of step S2 may not be the position shown in FIG. 6, and step S2 may be executed after step S3 or step S4 described later. It is also possible to add a current detection circuit for the current flowing through the load 5 and calculate the power supplied to the load 5 using the detection value of the current flowing through the load 5 and the output voltage detection value Vosen.
　次に、入力電圧検出値Ｖｉｎｓｅｎの平均値を算出することにより、入力電圧検出値Ｖｉｎｓｅｎの直流電圧成分を算出し、算出した結果を比較閾値Ｖｃｏｍｐと設定する（ステップＳ３）。なお、ステップＳ３はオンタイミング生成部３３の制御周期ごとに行う必要はなく、比較閾値Ｖｃｏｍｐを一度設定した後はステップＳ３を省略してもよい。また、比較閾値Ｖｃｏｍｐは入力電圧検出値Ｖｉｎｓｅｎから算出する必要はなく、入力電源４の直流電圧成分の大きさが予めわかっている場合は、その値を比較閾値Ｖｃｏｍｐに設定しておいても良い。例えば、入力電源４がＡＣ／ＤＣコンバータである場合は、ＡＣ／ＤＣコンバータの目標出力電圧を比較閾値Ｖｃｏｍｐとしてあらかじめ設定しておいてもよい。 Next, the DC voltage component of the input voltage detection value Vinsen is calculated by calculating the average value of the input voltage detection value Vinsen, and the calculated result is set as the comparison threshold value Vcomp (step S3). Note that step S3 need not be performed every control cycle of the on-timing generation unit 33, and step S3 may be omitted after the comparison threshold value Vcomp is set once. Further, the comparison threshold value Vcomp need not be calculated from the input voltage detection value Vinsen. If the magnitude of the DC voltage component of the input power supply 4 is known in advance, the value may be set as the comparison threshold value Vcomp. . For example, when the input power supply 4 is an AC / DC converter, the target output voltage of the AC / DC converter may be set in advance as the comparison threshold value Vcomp.
　次に、ステップＳ４において、ステップＳ３で算出した比較閾値Ｖｃｏｍｐと入力電圧検出値Ｖｉｎｓｅｎとの大小比較を行う。図７は比較閾値Ｖｃｏｍｐと入力電圧検出値Ｖｉｎｓｅｎとの大小比較を説明するための図である。図７において、入力電圧検出値Ｖｉｎｓｅｎが比較閾値Ｖｃｏｍｐ以上の期間Ｔ１を斜線を付して表し、入力電圧検出値Ｖｉｎｓｅｎが比較閾値Ｖｃｏｍｐより小さい期間Ｔ２と区別している。 Next, in step S4, the comparison threshold Vcomp calculated in step S3 is compared with the input voltage detection value Vinsen. FIG. 7 is a diagram for explaining a comparison between the comparison threshold value Vcomp and the input voltage detection value Vinsen. In FIG. 7, a period T1 in which the input voltage detection value Vinsen is equal to or greater than the comparison threshold Vcomp is indicated by hatching, and is distinguished from a period T2 in which the input voltage detection value Vinsen is smaller than the comparison threshold Vcomp.
　ステップＳ４における比較閾値Ｖｃｏｍｐと入力電圧検出値Ｖｉｎｓｅｎとの大小比較により、入力電圧検出値Ｖｉｎｓｅｎが比較閾値Ｖｃｏｍｐより小さい期間Ｔ２は、基準カウントｃｎｔから減少補正値ｘ１を減算した値をターンオンカウントＺＣＤｃｎｔに設定する（ステップＳ５）。入力電圧検出値Ｖｉｎｓｅｎが比較閾値Ｖｃｏｍｐ以上の期間Ｔ１は、基準カウントｃｎｔに増加補正値ｘ２を加算した値をターンオンカウントＺＣＤｃｎｔに設定する（ステップＳ６）。ここで、減少補正値ｘ１と増加補正値ｘ２はともに０以上の整数であるが、減少補正値ｘ１と増加補正値ｘ２が同時に０となることはない。また、減少補正値ｘ１は基準カウントｃｎｔ未満の値をもつ。そのため、ターンオンカウントＺＣＤｃｎｔが零および負の値となることはない。 As a result of the comparison between the comparison threshold value Vcomp and the input voltage detection value Vinsen in step S4, during the period T2 when the input voltage detection value Vinsen is smaller than the comparison threshold value Vcomp, a value obtained by subtracting the decrease correction value x1 from the reference count cnt is set as the turn-on count ZCDcnt. Set (step S5). During a period T1 where the input voltage detection value Vinsen is equal to or greater than the comparison threshold Vcomp, a value obtained by adding the increase correction value x2 to the reference count cnt is set as the turn-on count ZCDcnt (step S6). Here, the decrease correction value x1 and the increase correction value x2 are both integers of 0 or more, but the decrease correction value x1 and the increase correction value x2 do not become 0 at the same time. The decrease correction value x1 has a value less than the reference count cnt. Therefore, the turn-on count ZCDcnt never becomes zero or negative.
　次に、電源制御部３の零電流信号生成部３１はリアクトル電流ｉＬが零となるタイミングを表す零電流信号ＺＣＤを出力して、オンタイミング生成部３３は零電流信号ＺＣＤを検出する（ステップＳ７）。そして、零電流信号ＺＣＤの検出をカウントして、カウント数がターンオンカウントＺＣＤｃｎｔに達したタイミングでゲート信号Ｇａを“Ｈ”とするタイミング、すなわちスイッチング素子１１のオンタイミングを決定する（ステップＳ８）。
　以上の説明が、オンタイミング生成部３３の動作（図６のフローチャート）の説明である。以上のように、動作させることによりカウント可変ＺＣＳ制御を実現することができる。 Next, the zero current signal generation unit 31 of the power supply control unit 3 outputs a zero current signal ZCD indicating the timing when the reactor current iL becomes zero, and the on timing generation unit 33 detects the zero current signal ZCD (step S7). ). Then, the detection of the zero current signal ZCD is counted, and when the count number reaches the turn-on count ZCDcnt, the timing when the gate signal Ga is set to “H”, that is, the ON timing of the switching element 11 is determined (step S8).
The above description is the description of the operation of the on-timing generation unit 33 (the flowchart of FIG. 6). As described above, the count variable ZCS control can be realized by operating.
　実際に、Ｍｙｗａｙプラス社の回路シミュレーションを使用して、本実施の形態のカウント可変ＺＣＳ制御の効果確認を行った。今回のシミュレーションでは、直流電圧３００Ｖと交流電圧２０Ｖ（１００Ｈｚ）を直列接続し、入力電圧とした。また、比較閾値Ｖｃｏｍｐを３００Ｖ、基準カウントｃｎｔを３、減少補正値ｘ１を１、増加補正値ｘ２を１、目標電圧値Ｖｏｒｅｆを２００Ｖと設定した。 Actually, the effect of the count variable ZCS control of the present embodiment was confirmed using circuit simulation of Myway Plus. In this simulation, a DC voltage of 300 V and an AC voltage of 20 V (100 Hz) were connected in series to obtain an input voltage. Further, the comparison threshold Vcomp is set to 300V, the reference count cnt is set to 3, the decrease correction value x1 is set to 1, the increase correction value x2 is set to 1, and the target voltage value Voref is set to 200V.
　図８および図９は、カウント可変ＺＣＳ制御適用時および不適用時のシミュレーション結果を表す図である。図８および図９において、上段の図は入力電圧検出値Ｖｉｎｓｅｎと比較閾値Ｖｃｏｍｐの波形を表し、中段の図は出力電圧Ｖｏの波形を表し、下段の図はターンオンカウントＺＣＤｃｎｔを表している。
　図８は入力電圧検出値Ｖｉｎｓｅｎと比較閾値Ｖｃｏｍｐを比較し、入力電圧検出値Ｖｉｎｓｅｎが比較閾値Ｖｃｏｍｐ以上（Ｖｉｎｓｅｎ＞＝Ｖｃｏｍｐ）時はターンオンカウントＺＣＤｃｎｔが４に、入力電圧検出値Ｖｉｎｓｅｎが比較閾値Ｖｃｏｍｐより小さい（Ｖｉｎｓｅｎ＜Ｖｃｏｍｐ）時はターンオンカウントＺＣＤｃｎｔが２になっていることが確認できる。また、図９は入力電圧検出値の大きさに関係なく常にターンオンカウントＺＣＤｃｎｔを２となるように設定した場合のシミュレーション結果である。 8 and 9 are diagrams showing simulation results when the count variable ZCS control is applied and when it is not applied. 8 and 9, the upper diagram shows the waveform of the input voltage detection value Vinsen and the comparison threshold value Vcomp, the middle diagram shows the waveform of the output voltage Vo, and the lower diagram shows the turn-on count ZCDcnt.
FIG. 8 compares the input voltage detection value Vinsen and the comparison threshold Vcomp. When the input voltage detection value Vinsen is equal to or higher than the comparison threshold Vcomp (Vinsen> = Vcomp), the turn-on count ZCDcnt is 4, and the input voltage detection value Vinsen is the comparison threshold Vcomp. It can be confirmed that the turn-on count ZCDcnt is 2 when it is smaller (Vinsen <Vcomp). FIG. 9 shows simulation results when the turn-on count ZCDcnt is always set to 2 regardless of the magnitude of the input voltage detection value.
　図８のシミュレーション結果は、図９のシミュレーション結果より、出力電圧Ｖｏの脈動が小さくなっていることが確認できる。出力電圧Ｖｏの最大値と最小値の差を出力電圧Ｖｏの平均値で割ることで算出される出力電圧Ｖｏのリップル率は、図８のシミュレーション結果では０．０６８、図９のシミュレーション結果では０．１３１である。したがって、カウント可変ＺＣＳ制御の出力電圧リップル低減効果が確認できた。 The simulation result in FIG. 8 confirms that the pulsation of the output voltage Vo is smaller than the simulation result in FIG. The ripple rate of the output voltage Vo calculated by dividing the difference between the maximum value and the minimum value of the output voltage Vo by the average value of the output voltage Vo is 0.068 in the simulation result of FIG. 8, and 0 in the simulation result of FIG. 131. Therefore, the output voltage ripple reduction effect of the variable count ZCS control was confirmed.
　なお、本実施の形態では、図７に示すように、入力電圧検出値Ｖｉｎｓｅｎと入力電圧検出値Ｖｉｎｓｅｎにより算出される比較閾値Ｖｃｏｍｐの比較により、ターンオンカウントＺＣＤｃｎｔを決定した。しかしながら、ターンオンカウントＺＣＤｃｎｔは、入力電圧（脈動電圧）の直流電圧成分に重畳する交流電圧成分に基づいて決定すればどのように定めてもよい。例えば、図１０に示すように、比較閾値としてＶｃｏｍｐ１とＶｃｏｍｐ２を設けて、これら比較閾値Ｖｃｏｍｐ１、Ｖｃｏｍｐ２と、入力電圧検出値Ｖｉｎｓｅｎを比較しても良い。図１０に示す例の場合、ターンオンカウントＺＣＤｃｎｔは脈動電圧Ｖｉｎの１周期間に３つで可変となる。すなわち、入力電圧検出値Ｖｉｎｓｅｎが比較閾値Ｖｃｏｍｐ１より小さい期間Ｔ３０、入力電圧検出値Ｖｉｎｓｅｎが比較閾値Ｖｃｏｍｐ２より小さくかつ比較閾値Ｖｃｏｍｐ１以上の期間Ｔ２０、入力電圧検出値Ｖｉｎｓｅｎが比較閾値Ｖｃｏｍｐ２以上の期間Ｔ１０において、それぞれターンオンカウントＺＣＤｃｎｔが順に大きくなるように決定する。 In the present embodiment, as shown in FIG. 7, the turn-on count ZCDcnt is determined by comparing the input voltage detection value Vinsen and the comparison threshold value Vcomp calculated from the input voltage detection value Vinsen. However, the turn-on count ZCDcnt may be determined in any way as long as it is determined based on the AC voltage component superimposed on the DC voltage component of the input voltage (pulsation voltage). For example, as shown in FIG. 10, Vcomp1 and Vcomp2 may be provided as comparison threshold values, and the comparison threshold values Vcomp1 and Vcomp2 may be compared with the input voltage detection value Vinsen. In the case of the example shown in FIG. 10, the turn-on count ZCDcnt is variable by three during one cycle of the pulsating voltage Vin. That is, in a period T30 in which the input voltage detection value Vinsen is smaller than the comparison threshold Vcomp1, a period T20 in which the input voltage detection value Vinsen is smaller than the comparison threshold Vcomp2 and greater than or equal to the comparison threshold Vcomp1, and a period T10 in which the input voltage detection value Vinsen is greater than or equal to the comparison threshold Vcomp2. The turn-on count ZCDcnt is determined so as to increase in order.
　また、本実施の形態ではコンバータ６として図１に示す降圧チョッパ回路を用いる構成で説明を行ったが、コンバータ６はスイッチング素子とリアクトルを有し、ＤＣ／ＤＣ変換を行う回路であればどのような回路を用いてもよい。例えば、図１１に示すようにコンバータ６として昇圧チョッパ回路を用いる構成としてもよい。 In this embodiment, the step-down chopper circuit shown in FIG. 1 is used as the converter 6. However, the converter 6 includes a switching element and a reactor, and any circuit that performs DC / DC conversion can be used. A simple circuit may be used. For example, a booster chopper circuit may be used as the converter 6 as shown in FIG.
　図１１に示すように、コンバータ６として昇圧チョッパ回路を用いる構成とした場合も、これまで説明したコンバータ６に降圧チョッパ回路を用いる構成と同様にカウント可変ＺＣＳ制御を行うことができる。すなわち、入力電圧（脈動電圧）Ｖｉｎに重畳する交流電圧成分に応じてターンオンカウントＺＣＤｃｎｔを可変することで出力電圧Ｖｏのリップルを低減することができる。 As shown in FIG. 11, even when the booster chopper circuit is used as the converter 6, the variable count ZCS control can be performed similarly to the configuration using the step-down chopper circuit for the converter 6 described so far. That is, the ripple of the output voltage Vo can be reduced by varying the turn-on count ZCDcnt according to the AC voltage component superimposed on the input voltage (pulsation voltage) Vin.
　コンバータ６として、図１１の昇圧チョッパ回路を用いる構成とした場合について、Ｍｙｗａｙプラス社の回路シミュレーションを使用して、本実施の形態のカウント可変ＺＣＳ制御の効果確認を行った。今回のシミュレーションは直流電圧１００Ｖと交流電圧２０Ｖ（１００Ｈｚ）を直列接続し、入力電圧とした。また、比較閾値Ｖｃｏｍｐを１００Ｖ、基準カウントｃｎｔを３、減少補正値ｘ１を１、増加補正値ｘ２を１、目標電圧値Ｖｏｒｅｆを２００Ｖと設定した。 As the converter 6, the effect of the variable count ZCS control of the present embodiment was confirmed using a circuit simulation of Myway Plus Co., in the case of using the boost chopper circuit of FIG. In this simulation, a DC voltage of 100 V and an AC voltage of 20 V (100 Hz) were connected in series to obtain an input voltage. In addition, the comparison threshold Vcomp is set to 100V, the reference count cnt is set to 3, the decrease correction value x1 is set to 1, the increase correction value x2 is set to 1, and the target voltage value Voref is set to 200V.
　図１２および図１３は、コンバータ６として図１１の昇圧チョッパ回路を用いた場合の、カウント可変ＺＣＳ制御適用時および不適用時のシミュレーション結果である。図１２および図１３において、上段の図は入力電圧検出値Ｖｉｎｓｅｎと比較閾値Ｖｃｏｍｐの波形を表し、中段の図は出力電圧Ｖｏの波形を表し、下段の図はターンオンカウントＺＣＤｃｎｔを表している。 12 and 13 show simulation results when the variable count ZCS control is applied and when it is not applied when the step-up chopper circuit of FIG. 11 is used as the converter 6. 12 and 13, the upper diagram shows the waveform of the input voltage detection value Vinsen and the comparison threshold Vcomp, the middle diagram shows the waveform of the output voltage Vo, and the lower diagram shows the turn-on count ZCDcnt.
　図１２はカウント可変ＺＣＳ制御適用時のシミュレーション波形であり、入力電圧検出値Ｖｉｎｓｅｎが比較閾値Ｖｃｏｍｐ以上（Ｖｉｎｓｅｎ＞＝Ｖｃｏｍｐ）の時はターンオンカウントＺＣＤｃｎｔが４に、入力電圧検出値Ｖｉｎｓｅｎが比較閾値Ｖｃｏｍｐより小さい（Ｖｉｎｓｅｎ＜Ｖｃｏｍｐ）時はターンオンカウントＺＣＤｃｎｔが２になっていることが確認できる。また、図１３は入力電圧検出値Ｖｉｎｓｅｎに関わらず、常にターンオンカウントＺＣＤｃｎｔを２と設定した時のシミュレーション波形である。図１２のカウント可変ＺＣＳ制御適用時の方が図１３の不適用時の場合より、出力電圧Ｖｏの脈動が小さくなっていることが確認できる。出力電圧Ｖｏの最大値と最小値の差を出力電圧Ｖｏの平均値で割ることで算出される出力電圧Ｖｏのリップル率は、図１２の場合は０．０４３、図１３の場合は０．０６９であった。したがって、コンバータ６として昇圧チョッパ回路を用いる構成とした場合も、カウント可変ＺＣＳ制御による出力電圧リップル低減効果が確認できた。 FIG. 12 shows a simulation waveform when the variable count ZCS control is applied. When the input voltage detection value Vinsen is equal to or higher than the comparison threshold Vcomp (Vinsen> = Vcomp), the turn-on count ZCDcnt is 4, and the input voltage detection value Vinsen is the comparison threshold Vcomp. It can be confirmed that the turn-on count ZCDcnt is 2 when it is smaller (Vinsen <Vcomp). FIG. 13 is a simulation waveform when the turn-on count ZCDcnt is always set to 2 regardless of the input voltage detection value Vinsen. It can be confirmed that the pulsation of the output voltage Vo is smaller when the count variable ZCS control of FIG. 12 is applied than when the count variable ZCS control is not applied of FIG. The ripple rate of the output voltage Vo calculated by dividing the difference between the maximum value and the minimum value of the output voltage Vo by the average value of the output voltage Vo is 0.043 in the case of FIG. 12, and 0.069 in the case of FIG. Met. Therefore, even when the booster chopper circuit is used as the converter 6, the output voltage ripple reduction effect by the variable count ZCS control can be confirmed.
　また、本実施の形態では、図１に示すように、零電流検出部９および零電流信号生成部３１を用いてリアクトル１２に流れる電流の零点を零電流信号ＺＣＤとして検出し、カウント可変ＺＣＳ制御を行ったが、これに限らない。すなわち、スイッチング素子１１に加わる電圧が零となるタイミングを零電圧信号ＺＶＤとして検出し、零電流信号ＺＣＤの替わりに零電圧信号ＺＶＤを使用してもよい。この場合、図１に示す零電流検出部９および零電流信号生成部３１の替わりに、図１４に示すように、スイッチング素子１１に加わる電圧を検出する零電圧検出部９０およびスイッチング素子１１に加わる電圧が零となるタイミングを零電圧信号ＺＶＤとして出力する零電圧信号生成部３１０を用いることになる。その他の構成および動作は、上記の説明と同様である。 Further, in the present embodiment, as shown in FIG. 1, the zero point of the current flowing through the reactor 12 is detected as the zero current signal ZCD using the zero current detecting unit 9 and the zero current signal generating unit 31, and the count variable ZCS control is performed. However, this is not a limitation. That is, the timing when the voltage applied to the switching element 11 becomes zero may be detected as the zero voltage signal ZVD, and the zero voltage signal ZVD may be used instead of the zero current signal ZCD. In this case, instead of the zero current detector 9 and the zero current signal generator 31 shown in FIG. 1, the zero voltage detector 90 and the switching element 11 for detecting the voltage applied to the switching element 11 are applied as shown in FIG. The zero voltage signal generator 310 that outputs the timing when the voltage becomes zero as the zero voltage signal ZVD is used. Other configurations and operations are the same as those described above.
　さらに、本実施の形態では、スイッチング素子のオンタイミングを零電流信号ＺＣＤのカウント数を用いて決定する制御法について説明したが、入力電圧に重畳する交流電圧成分に応じてスイッチング素子のオンタイミングを決定しさえすれば、零電流信号ＺＣＤをカウントしない構成で実現してもよい。例えば、スイッチング素子のオンタイミングを所定時間が経過したタイミングに設定すると共に、入力電圧に重畳する交流電圧成分により当該所定時間を可変にする制御法で実現してもよい。 Furthermore, in the present embodiment, the control method for determining the ON timing of the switching element using the count number of the zero current signal ZCD has been described. However, the ON timing of the switching element is set according to the AC voltage component superimposed on the input voltage. As long as it is determined, the zero current signal ZCD may not be counted. For example, the ON timing of the switching element may be set to a timing at which a predetermined time has elapsed, and may be realized by a control method in which the predetermined time is made variable by an AC voltage component superimposed on the input voltage.
　以下、入力電圧に重畳する交流電圧成分により所定時間を可変にする制御について、図１５の電力変換装置の回路図および図１６の回路動作図に基づいて説明する。図１５において、電力変換装置１の電源主回路部２および電源制御部３の構成は図１の構成と基本的に同じであるが、電源制御部３の制御動作、特にオンタイミング生成部３３Ａの動作が異なる。 Hereinafter, control for varying the predetermined time by the AC voltage component superimposed on the input voltage will be described based on the circuit diagram of the power conversion device in FIG. 15 and the circuit operation diagram in FIG. In FIG. 15, the configurations of the power supply main circuit unit 2 and the power supply control unit 3 of the power conversion device 1 are basically the same as those of FIG. The operation is different.
　図１５において、電源制御部３は、零電流検出部９から得られる電圧ＶＬｓｅｎに基づいてリアクトル１２に流れる電流が零になるタイミングを示す零電流信号ＺＣＤを出力する零電流信号生成部３１と、出力電圧検出値Ｖｏｓｅｎおよび目標電圧値Ｖｏｒｅｆに基づいてスイッチング素子１１のオン時間を導出するオン時間生成部３２と、零電流信号ＺＣＤに基づいて所定時間経過したタイミングをスイッチング素子１１のオンタイミングとして決定するオンタイミング生成部３３Ａと、オン時間生成部３２からのオン時間とオンタイミング生成部３３Ａからのオンタイミングを入力してスイッチング素子１１を動作させるゲート信号Ｇａを生成するスイッチング駆動部３４を備えている。 In FIG. 15, the power supply control unit 3 includes a zero current signal generation unit 31 that outputs a zero current signal ZCD indicating a timing at which the current flowing through the reactor 12 becomes zero based on the voltage VLsen obtained from the zero current detection unit 9; An on-time generator 32 for deriving an on-time of the switching element 11 based on the output voltage detection value Vosen and the target voltage value Voref, and a timing at which a predetermined time has elapsed based on the zero current signal ZCD is determined as the on-timing of the switching element 11. An on-timing generation unit 33A that receives the on-time from the on-time generation unit 32 and the on-timing from the on-timing generation unit 33A, and generates a gate signal Ga that operates the switching element 11. Yes.
　図１６において、オンタイミング生成部３３Ａは、スイッチング素子１１がオフした後の１回目の零電流信号ＺＣＤの立上りタイミングｔ１から時間測定を開始し、測定した時間が所定時間Ｔｄに達したタイミングによりスイッチング素子１１をオンするオンタイミングを決定する。スイッチング素子１１のオンタイミングを決定するための所定時間Ｔｄは入力電圧に重畳される交流電圧成分により決定する。すなわち、入力電圧の検出値Ｖｉｎｓｅｎが直流電圧成分に重畳する交流電圧成分により大きくなる時は、入力電圧の検出値Ｖｉｎｓｅｎが直流電圧成分に重畳する交流電圧成分により小さくなる時に比べて、所定時間Ｔｄを長くする遅延制御を行う。 In FIG. 16, the on-timing generator 33A starts time measurement from the first rising timing t1 of the zero current signal ZCD after the switching element 11 is turned off, and switching is performed at the timing when the measured time reaches the predetermined time Td. The on-timing for turning on the element 11 is determined. The predetermined time Td for determining the ON timing of the switching element 11 is determined by an AC voltage component superimposed on the input voltage. That is, when the detected value Vinsen of the input voltage becomes larger due to the AC voltage component superimposed on the DC voltage component, the predetermined time Td than when the detected value of the input voltage Vinsen becomes smaller due to the AC voltage component superimposed on the DC voltage component. Delay control to increase
　図１５および図１６により説明した遅延制御を行うことにより、零電流信号ＺＣＤを用いる構成と同様の動作を実現できるとともに、出力電圧リップルの低減効果を得ることができる。なお、時間測定を開始するタイミングは零電流信号ＺＣＤに基づくものでなく、例えば、図１４で説明した零電圧信号ＺＶＤに基づくものであっても良い。また、スイッチング素子１１がオンするタイミングまたはスイッチング素子１１がオフするタイミングとしても良い。 By performing the delay control described with reference to FIGS. 15 and 16, it is possible to realize the same operation as the configuration using the zero current signal ZCD and to obtain the effect of reducing the output voltage ripple. The timing for starting the time measurement is not based on the zero current signal ZCD, but may be based on the zero voltage signal ZVD described in FIG. 14, for example. Alternatively, the timing when the switching element 11 is turned on or the timing when the switching element 11 is turned off may be used.
　スイッチング素子１１がオンまたはオフするタイミングから時間測定を開始する電力変換装置の例を図１７に示す。図１７において、スイッチング検出部３５は、スイッチング駆動部３４からのゲート信号Ｇａに基づいてスイッチング素子１１のオンまたはオフのタイミングを検出する。オンタイミング生成部３３Ｂは、スイッチング素子１１のオンまたはオフしたタイミングから時間測定を開始し、測定した時間が所定時間に達したタイミングでスイッチング素子１１をオンするオンタイミングを決定する。その他の動作は図１５および図１６で説明した内容と同様である。 FIG. 17 shows an example of a power converter that starts time measurement from the timing when the switching element 11 is turned on or off. In FIG. 17, the switching detection unit 35 detects the on / off timing of the switching element 11 based on the gate signal Ga from the switching drive unit 34. The on-timing generation unit 33B starts time measurement from the timing when the switching element 11 is turned on or off, and determines the on-timing for turning on the switching element 11 when the measured time reaches a predetermined time. Other operations are the same as those described in FIGS. 15 and 16.
　以上のように、実施の形態１によれば、スイッチング素子と、リアクトルとを有し、直流電圧成分に交流電圧成分が重畳した入力電圧を電力変換して負荷に出力する電源主回路部と、入力電圧の検出値が直流電圧成分に重畳する交流電圧成分により大きくなる時は、入力電圧の検出値が直流電圧成分に重畳する交流電圧成分により小さくなる時に比べて、スイッチング素子のオンタイミングを遅らせるようにスイッチング素子のオンタイミングを決定する電源制御部を備えたので、出力電圧に発生するリップルを低減することができる。 As described above, according to the first embodiment, the power supply main circuit unit that has the switching element and the reactor, converts the input voltage in which the AC voltage component is superimposed on the DC voltage component, and outputs the power to the load, When the detected value of the input voltage increases due to the AC voltage component superimposed on the DC voltage component, the on-timing of the switching element is delayed compared to when the detected value of the input voltage decreases due to the AC voltage component superimposed on the DC voltage component. As described above, since the power supply control unit that determines the ON timing of the switching element is provided, the ripple generated in the output voltage can be reduced.
　また、電源制御部は、入力電圧の検出値と比較閾値とを比較し、入力電圧の検出値が比較閾値以上の時は、比較閾値より小さい時に比べて、スイッチング素子のオンタイミングを遅らせるようにスイッチング素子のオンタイミングを決定するようにしたので、簡単な制御により出力電圧に発生するリップルを低減することができる。 Further, the power supply control unit compares the detected value of the input voltage with the comparison threshold value, and delays the on-timing of the switching element when the detected value of the input voltage is equal to or greater than the comparison threshold value compared to when it is smaller than the comparison threshold value. Since the ON timing of the switching element is determined, ripple generated in the output voltage can be reduced by simple control.
　さらに、比較閾値を入力電圧の直流電圧成分としたので、簡単な制御により出力電圧に発生するリップルを低減することができる。 Furthermore, since the comparison threshold value is a DC voltage component of the input voltage, ripple generated in the output voltage can be reduced by simple control.
　また、電源制御部は、リアクトルに流れる電流が零になるタイミングを示す零電流信号を出力する零電流信号生成部およびスイッチング素子に加わる電圧が零になるタイミングを示す零電圧信号を出力する零電圧信号生成部のうちいずれか一方と、零電流信号および零電圧信号のうちいずれか一方の回数をカウントし、カウント数が所定回数に達したタイミングをスイッチング素子のオンタイミングとして決定するオンタイミング生成部と、オンタイミング生成部で決定したオンタイミングでスイッチング素子をターンオンするスイッチング駆動部を備え、入力電圧の検出値が直流電圧成分に重畳する交流電圧成分により大きくなる時は、上記入力電圧の検出値が上記直流電圧成分に重畳する交流電圧成分により小さくなる時に比べて、上記所定回数を大きくするカウント可変ゼロクロススイッチング制御を行うようにしたので、出力電圧に発生するリップルを低減することができると共に、リアクトルに流れる電流が零となるタイミングまたはスイッチング素子に加わる電圧が零になるタイミングでスイッチング素子をオンするため、スイッチング損失の低減およびスイッチングノイズの低減を図ることができる。 The power supply control unit outputs a zero current signal that outputs a zero current signal indicating the timing when the current flowing through the reactor becomes zero, and a zero voltage that outputs a zero voltage signal indicating the timing when the voltage applied to the switching element becomes zero An on-timing generator that counts the number of times either one of the signal generators and one of the zero-current signal and the zero-voltage signal and determines the timing when the count reaches a predetermined number as the on-timing of the switching element And a switching drive unit that turns on the switching element at the on-timing determined by the on-timing generation unit, and when the detected value of the input voltage becomes larger due to the AC voltage component superimposed on the DC voltage component, the detected value of the input voltage Compared to when the voltage becomes smaller due to the AC voltage component superimposed on the DC voltage component, Since variable count zero-crossing switching control is performed to increase the predetermined number of times, the ripple generated in the output voltage can be reduced, and the timing at which the current flowing through the reactor becomes zero or the voltage applied to the switching element becomes zero. Since the switching element is turned on at the timing, switching loss and switching noise can be reduced.
　また、電源制御部は、リアクトルに流れる電流が零になるタイミングを示す零電流信号を出力する零電流信号生成部、スイッチング素子に加わる電圧が零になるタイミングを示す零電圧信号を出力する零電圧信号生成部、およびスイッチング素子がオンまたはオフするタイミングを検出するスイッチング検出部のうちいずれか一つと、零電流信号、零電圧信号、およびスイッチング素子のオンまたはオフするタイミングのうちいずれか一つから所定時間経過したタイミングをスイッチング素子のオンタイミングとして決定するオンタイミング生成部と、オンタイミング生成部で決定したオンタイミングでスイッチング素子をターンオンするスイッチング駆動部を備え、入力電圧の検出値が直流電圧成分に重畳する交流電圧成分により大きくなる時は、入力電圧の検出値が直流電圧成分に重畳する交流電圧成分により小さくなる時に比べて、所定時間を長くする遅延制御を行うようにしたので、簡単な制御により出力電圧に発生するリップルを低減することができる。 Further, the power supply control unit outputs a zero current signal that indicates a timing when the current flowing through the reactor becomes zero, and a zero voltage that outputs a zero voltage signal that indicates the timing when the voltage applied to the switching element becomes zero From any one of the signal generation unit and the switching detection unit that detects the timing at which the switching element is turned on or off, and the zero current signal, the zero voltage signal, and the timing at which the switching element is turned on or off An on-timing generator that determines when a predetermined time has elapsed as an on-timing of the switching element, and a switching drive unit that turns on the switching element at the on-timing determined by the on-timing generator, and the detected value of the input voltage is a DC voltage component Larger due to AC voltage component superimposed on When the detected value of the input voltage becomes smaller due to the AC voltage component superimposed on the DC voltage component, delay control is performed to increase the predetermined time, so the ripple generated in the output voltage by simple control Can be reduced.
　また、電源制御部は、負荷への供給電力が低い場合は、負荷への供給電力が高い場合に比べて、スイッチング素子のオンタイミングを遅らせるようにスイッチング素子のオンタイミングを決定する。また、負荷への供給電力が低い場合は、負荷への供給電力が高い場合に比べて、所定回数を大きくするカウント可変ゼロクロススイッチング制御を行う。さらに、負荷への供給電力が低い場合は、負荷への供給電力が高い場合に比べて、所定時間を長くする遅延制御を行う。その結果、負荷への供給電力が変動した場合においても、スイッチング周波数が高周波化することを防止し、スイッチング損失の増大を防ぐことができる。 In addition, when the power supplied to the load is low, the power supply control unit determines the on-timing of the switching element so as to delay the on-timing of the switching element compared to when the power supplied to the load is high. When the power supplied to the load is low, count variable zero cross switching control is performed to increase the predetermined number of times compared to when the power supplied to the load is high. Furthermore, when the power supplied to the load is low, delay control is performed to increase the predetermined time compared to when the power supplied to the load is high. As a result, even when the power supplied to the load fluctuates, it is possible to prevent the switching frequency from increasing and prevent an increase in switching loss.
　また、電源制御部は、負荷への供給電力が大きい場合は、（１）入力電圧の検出値が直流電圧成分に重畳する交流電圧成分により大きくなる時は、入力電圧の検出値が上記直流電圧成分に重畳する交流電圧成分により小さくなる時に比べて、スイッチング素子のオンタイミングを遅らせるようにスイッチング素子のオンタイミングを決定して、スイッチング素子をスイッチング制御するとともに、
　負荷への供給電力が小さい場合は、（２）スイッチング素子を一定のスイッチング周期でスイッチング制御する制御法、（３）入力電圧の検出値が直流電圧成分に重畳する交流電圧成分によらずに、リアクトルに流れる電流が零になるタイミングを示す零電流信号の回数をカウントし、カウント数が定められた回数に達したタイミングをスイッチング素子のオンタイミングとして決定して、スイッチング素子をスイッチング制御する制御法、のうち少なくとも一つの制御を行うようにしても良い。
　これによれば、負荷への供給電力が大きい場合、出力電圧に発生するリップルを低減することができる。 In addition, the power supply control unit, when the power supplied to the load is large, (1) when the detected value of the input voltage becomes larger due to the AC voltage component superimposed on the DC voltage component, the detected value of the input voltage Compared to when it becomes smaller due to the AC voltage component superimposed on the component, the on-timing of the switching element is determined so as to delay the on-timing of the switching element, and the switching element is controlled to switch,
When the power supplied to the load is small, (2) a control method for switching control of the switching element at a constant switching cycle, (3) regardless of the AC voltage component in which the detected value of the input voltage is superimposed on the DC voltage component, A control method that counts the number of zero current signals indicating the timing at which the current flowing through the reactor becomes zero, determines the timing at which the count reaches a predetermined number as the ON timing of the switching element, and controls the switching of the switching element , At least one control may be performed.
According to this, when the power supplied to the load is large, the ripple generated in the output voltage can be reduced.
　また、電源制御部は、電源主回路部の出力電圧検出値と目標電圧値に基づいてスイッチング素子のオン時間を決定するようにしたので、所望の出力電圧を得ることができる。 Further, since the power supply control unit determines the on-time of the switching element based on the output voltage detection value and the target voltage value of the power supply main circuit unit, a desired output voltage can be obtained.
実施の形態２．
　図１８はこの発明の実施の形態２による電力変換装置を示す回路ブロック図である。図１８において、図１と同一もしくは対応する構成部分には同一の符号を付す。この実施の形態２は、実施の形態１に対して、負荷をＬＥＤ（Ｌｉｇｈｔ　Ｅｍｉｔｔｉｎｇ　Ｄｉｏｄｅ）モジュール５０とした場合であり、図１の負荷５がＬＥＤモジュール５０に変更された点、出力電圧検出部８が出力電流検出部８０に変更された点、出力電圧検出値Ｖｏｓｅｎが出力電流検出値Ｉｏｓｅｎに変更された点、オン時間生成部３２に入力される目標電圧値Ｖｏｒｅｆが目標電流値Ｉｏｒｅｆに変更された点が異なる。なお、出力電流検出部８０は、例えば、図示しない電流検出抵抗を設置し、電流検出抵抗の両端間に発生する電位差をＬＥＤモジュール５０に流れる電流に対応した電圧変換値Ｉｏｓｅｎとして検出する。また、ＬＥＤモジュール５０は、図１８ではＬＥＤチップを全て直列に接続した構成としているが、直列接続した場合に限らず並列接続や直並列接続としてもよく、１個のＬＥＤであっても良い。さらに、ここでは負荷としてＬＥＤを接続しているが、ＬＥＤでなく、有機エレクトロルミネッセンス（有機ＥＬ）、レーザーダイオード等に変更しても良い。 Embodiment 2. FIG.
FIG. 18 is a circuit block diagram showing a power conversion device according to Embodiment 2 of the present invention. In FIG. 18, the same or corresponding components as those in FIG. The second embodiment is a case where the load is an LED (Light Emitting Diode) module 50 as compared with the first embodiment. The load 5 in FIG. 1 is changed to the LED module 50, and an output voltage detection unit. 8 is changed to the output current detection unit 80, the output voltage detection value Vosen is changed to the output current detection value Isen, and the target voltage value Voref input to the on-time generation unit 32 is changed to the target current value Ioref. The difference was made. For example, the output current detection unit 80 includes a current detection resistor (not shown), and detects a potential difference generated between both ends of the current detection resistor as a voltage conversion value Isen corresponding to the current flowing through the LED module 50. Moreover, although the LED module 50 has a configuration in which all LED chips are connected in series in FIG. 18, the LED module 50 is not limited to a series connection, and may be a parallel connection or a series-parallel connection, or may be a single LED. Furthermore, although LED is connected as load here, you may change not to LED but to organic electroluminescence (organic EL), a laser diode, etc.
　ここで、ＬＥＤは通常、その特性から電流制御が適している。そのため、本実施の形態では、出力電圧を目標電圧に調整する制御から出力電流を目標電流に調整する制御へと変更している。図１８において、オン時間生成部３２は、出力電流検出値Ｉｏｓｅｎおよび目標電流値Ｉｏｒｅｆに基づいてスイッチング素子１１のオン時間を導出する。すなわち、オン時間生成部３２は、出力電流検出値Ｉｏｓｅｎと目標電流値Ｉｏｒｅｆの差分を演算し、その差分が零になるようにスイッチング素子１１のオン時間を決定する。このように構成すれば、実施の形態１と同様の制御により、ＬＥＤモジュール５０に流れる出力電流の制御を行うことができる。 Here, LED is usually suitable for current control due to its characteristics. Therefore, in the present embodiment, the control is changed from the control for adjusting the output voltage to the target voltage to the control for adjusting the output current to the target current. In FIG. 18, the on-time generation unit 32 derives the on-time of the switching element 11 based on the output current detection value Iosen and the target current value Ioreef. That is, the on-time generating unit 32 calculates the difference between the output current detection value Isen and the target current value Ioref, and determines the on-time of the switching element 11 so that the difference becomes zero. If comprised in this way, control of the output current which flows into the LED module 50 can be performed by control similar to Embodiment 1. FIG.
　また、電源制御部３は、実施の形態１で説明した通り、入力電圧の検出値Ｖｉｎｓｅｎが直流電圧成分に重畳する交流電圧成分により大きくなる時は、入力電圧の検出値Ｖｉｎｓｅｎが直流電圧成分に重畳する交流電圧成分により小さくなる時に比べて、スイッチング素子１１のオンタイミングを遅らせるようにスイッチング素子１１のオンタイミングを決定してスイッチング制御を行っているので、出力電流のリップルを低減することができる。 Further, as described in the first embodiment, the power supply control unit 3 determines that the input voltage detection value Vinsen becomes a DC voltage component when the input voltage detection value Vinsen becomes larger due to the AC voltage component superimposed on the DC voltage component. Since the switching control is performed by determining the on-timing of the switching element 11 so as to delay the on-timing of the switching element 11 as compared with the time when it becomes smaller due to the superimposed AC voltage component, the ripple of the output current can be reduced. .
　特に、負荷をＬＥＤとした場合、ＬＥＤに流れる電流に大きなリップルが重畳していると、防犯カメラやビデオカメラなどに光ちらつきが写りこむという問題が発生する。実施の形態２では、実施の形態１で説明したカウント可変ＺＣＳ制御または遅延制御により出力電流に発生するリップルの低減を実現できるので、光ちらつきの発生を防止することができる。また、電力変換装置がＬＥＤの光量を調整するための調光機能を搭載する場合は、通常外部から入力される目標電流値Ｉｏｒｅｆを調光機能により可変可能な構成とすれば、調光機能が実現できる。 In particular, when the load is an LED, if a large ripple is superimposed on the current flowing through the LED, there is a problem that light flickering appears in a security camera or a video camera. In the second embodiment, since the ripple generated in the output current can be reduced by the variable count ZCS control or the delay control described in the first embodiment, the occurrence of light flickering can be prevented. In addition, when the power conversion device is equipped with a dimming function for adjusting the light quantity of the LED, the dimming function can be achieved if the target current value Ioref that is normally input from outside is made variable by the dimming function. realizable.
　以上のように、実施の形態２によれば、出力電流検出値と目標電流値に基づいてスイッチング素子のオン時間を決定するようにしたので、出力電流を目標電流に調整することができるとともに、実施の形態１で説明した効果と同様の効果を得ることができる。特に、出力電流に発生するリップルを低減することができる。 As described above, according to the second embodiment, since the ON time of the switching element is determined based on the output current detection value and the target current value, the output current can be adjusted to the target current, Effects similar to those described in Embodiment 1 can be obtained. In particular, the ripple generated in the output current can be reduced.
　なお、本発明は、その発明の範囲内において、各実施の形態を自由に組み合わせることや、各実施の形態を適宜、変形、省略することが可能である。 In the present invention, it is possible to freely combine the respective embodiments within the scope of the invention, and to appropriately modify and omit the respective embodiments.

Claims (14)

  1. スイッチング素子と、リアクトルとを有し、直流電圧成分に交流電圧成分が重畳した入力電圧を電力変換して負荷に出力する電源主回路部と、
    上記入力電圧の検出値が直流電圧成分に重畳する交流電圧成分により大きくなる時は、上記入力電圧の検出値が直流電圧成分に重畳する交流電圧成分により小さくなる時に比べて、上記スイッチング素子のオンタイミングを遅らせるように上記スイッチング素子のオンタイミングを決定する電源制御部を備えた電力変換装置。     A power supply main circuit unit that has a switching element and a reactor, converts the input voltage in which the AC voltage component is superimposed on the DC voltage component, and outputs it to the load;
    When the detected value of the input voltage increases due to the AC voltage component superimposed on the DC voltage component, the switching element is turned on more than when the detected value of the input voltage decreases due to the AC voltage component superimposed on the DC voltage component. The power converter device provided with the power supply control part which determines the ON timing of the said switching element so that timing may be delayed.
  2. 上記電源制御部は、上記入力電圧の検出値と比較閾値とを比較し、上記入力電圧の検出値が上記比較閾値以上の時は、上記比較閾値より小さい時に比べて、上記スイッチング素子のオンタイミングを遅らせるように上記スイッチング素子のオンタイミングを決定する請求項１に記載の電力変換装置。 The power supply control unit compares the detected value of the input voltage with a comparison threshold value, and when the detected value of the input voltage is equal to or greater than the comparison threshold value, the on-timing of the switching element is smaller than when it is smaller than the comparison threshold value. The power conversion device according to claim 1, wherein the on-timing of the switching element is determined so as to delay the delay.
  3. 上記比較閾値は、上記入力電圧の直流電圧成分とする請求項２に記載の電力変換装置。 The power converter according to claim 2, wherein the comparison threshold is a DC voltage component of the input voltage.
  4. 上記電源制御部は、上記リアクトルに流れる電流が零になるタイミングを示す零電流信号を出力する零電流信号生成部および上記スイッチング素子に加わる電圧が零になるタイミングを示す零電圧信号を出力する零電圧信号生成部のうちいずれか一方と、上記零電流信号および上記零電圧信号のうちいずれか一方の回数をカウントし、カウント数が所定回数に達したタイミングを上記スイッチング素子のオンタイミングとして決定するオンタイミング生成部と、上記オンタイミング生成部で決定した上記オンタイミングで上記スイッチング素子をターンオンするスイッチング駆動部を備え、
    上記入力電圧の検出値が直流電圧成分に重畳する交流電圧成分により大きくなる時は、上記入力電圧の検出値が上記直流電圧成分に重畳する交流電圧成分により小さくなる時に比べて、上記所定回数を大きくする制御を行う請求項１から請求項３のいずれか１項に記載の電力変換装置。     The power supply control unit outputs a zero current signal indicating a timing when the current flowing through the reactor becomes zero and a zero voltage signal indicating a timing when the voltage applied to the switching element becomes zero. One of the voltage signal generators and the number of either the zero current signal or the zero voltage signal are counted, and the timing at which the count reaches a predetermined number is determined as the ON timing of the switching element. An on-timing generator, and a switching driver that turns on the switching element at the on-timing determined by the on-timing generator,
    When the detected value of the input voltage increases due to the AC voltage component superimposed on the DC voltage component, the predetermined number of times is larger than when the detected value of the input voltage decreases due to the AC voltage component superimposed on the DC voltage component. The power converter according to any one of claims 1 to 3, wherein control for increasing the power is performed.
  5. 上記電源制御部は、上記リアクトルに流れる電流が零になるタイミングを示す零電流信号を出力する零電流信号生成部、上記スイッチング素子に加わる電圧が零になるタイミングを示す零電圧信号を出力する零電圧信号生成部、および上記スイッチング素子がオンまたはオフするタイミングを検出するスイッチング検出部のうちいずれか一つと、上記零電流信号、上記零電圧信号、および上記スイッチング素子のオンまたはオフするタイミングのうちいずれか一つから所定時間経過したタイミングを上記スイッチング素子のオンタイミングとして決定するオンタイミング生成部と、上記オンタイミング生成部で決定した上記オンタイミングで上記スイッチング素子をターンオンするスイッチング駆動部を備え、
    上記入力電圧の検出値が直流電圧成分に重畳する交流電圧成分により大きくなる時は、上記入力電圧の検出値が上記直流電圧成分に重畳する交流電圧成分により小さくなる時に比べて、上記所定時間を長くする遅延制御を行う請求項１から請求項３のいずれか１項に記載の電力変換装置。     The power supply control unit outputs a zero current signal indicating a timing when the current flowing through the reactor becomes zero, and outputs a zero voltage signal indicating a timing when the voltage applied to the switching element becomes zero. Any one of a voltage signal generation unit and a switching detection unit that detects a timing at which the switching element is turned on or off, and a timing at which the zero current signal, the zero voltage signal, and the switching element are turned on or off. An on-timing generator that determines a timing after a predetermined time from any one as an on-timing of the switching element; and a switching driver that turns on the switching element at the on-timing determined by the on-timing generator;
    When the detected value of the input voltage is increased by the AC voltage component superimposed on the DC voltage component, the predetermined time is longer than when the detected value of the input voltage is decreased by the AC voltage component superimposed on the DC voltage component. The power converter according to any one of claims 1 to 3, wherein delay control for increasing the length is performed.
  6. 上記電源制御部は、上記負荷への供給電力が低い場合は、上記負荷への供給電力が高い場合に比べて、上記スイッチング素子のオンタイミングを遅らせるように上記スイッチング素子のオンタイミングを決定する請求項１から請求項３のいずれか１項に記載の電力変換装置。 The power supply control unit determines the on-timing of the switching element so that the on-timing of the switching element is delayed when the power supplied to the load is low compared to when the power supplied to the load is high. The power conversion device according to any one of claims 1 to 3.
  7. 上記電源制御部は、上記負荷への供給電力が低い場合は、上記負荷への供給電力が高い場合に比べて、上記所定回数を大きくする制御を行う請求項４に記載の電力変換装置。 The power converter according to claim 4, wherein the power supply control unit performs control to increase the predetermined number of times when the power supplied to the load is low compared to when the power supplied to the load is high.
  8. 上記電源制御部は、上記負荷への供給電力が低い場合は、上記負荷への供給電力が高い場合に比べて、上記所定時間を長くする遅延制御を行う請求項５に記載の電力変換装置。 The power converter according to claim 5, wherein the power supply control unit performs delay control to increase the predetermined time when the power supplied to the load is low compared to when the power supplied to the load is high.
  9. 上記電源制御部は、上記負荷への供給電力が大きい場合、上記入力電圧の検出値が直流電圧成分に重畳する交流電圧成分により大きくなる時は、上記入力電圧の検出値が上記直流電圧成分に重畳する交流電圧成分により小さくなる時に比べて、上記スイッチング素子のオンタイミングを遅らせるように上記スイッチング素子のオンタイミングを決定して、上記スイッチング素子をスイッチング制御し、
    上記負荷への供給電力が小さい場合、上記スイッチング素子を一定のスイッチング周期でスイッチング制御する制御法、および、上記入力電圧の検出値が直流電圧成分に重畳する交流電圧成分によらずに、上記リアクトルに流れる電流が零になるタイミングを示す零電流信号の回数をカウントし、カウント数が定められた回数に達したタイミングを上記スイッチング素子のオンタイミングとして決定して、上記スイッチング素子をスイッチング制御する制御法のうち少なくとも一つの制御を行う請求項１に記載の電力変換装置。     When the power supplied to the load is large and the detected value of the input voltage is increased by the AC voltage component superimposed on the DC voltage component, the power supply control unit converts the detected value of the input voltage to the DC voltage component. Compared to when it becomes smaller due to the superimposed AC voltage component, the on-timing of the switching element is determined so as to delay the on-timing of the switching element, and the switching element is subjected to switching control,
    When the power supplied to the load is small, the reactor is controlled regardless of the control method for switching control of the switching element at a constant switching cycle, and the AC voltage component in which the detected value of the input voltage is superimposed on the DC voltage component. Control for switching control of the switching element by counting the number of zero current signals indicating the timing when the current flowing through the counter reaches zero, and determining the timing when the count reaches the predetermined number as the on-timing of the switching element The power conversion device according to claim 1, wherein at least one of the methods is controlled.
  10. 上記電源制御部は、上記電源主回路部の出力電圧検出値と目標電圧値に基づいて上記スイッチング素子のオン時間を決定する請求項１から請求項９のいずれか１項に記載の電力変換装置。 10. The power conversion device according to claim 1, wherein the power supply control unit determines an ON time of the switching element based on an output voltage detection value and a target voltage value of the power supply main circuit unit. .
  11. 上記電源制御部は、上記電源主回路部の出力電流検出値と目標電流値に基づいて上記スイッチング素子のオン時間を決定する請求項１から請求項９のいずれか１項に記載の電力変換装置。 10. The power conversion device according to claim 1, wherein the power supply control unit determines an ON time of the switching element based on an output current detection value and a target current value of the power supply main circuit unit. 11. .
  12. 上記電源主回路部は、上記負荷として、ＬＥＤ、有機エレクトロルミネッセンスおよびレーザーダイオードのうちいずれか一つが接続されている請求項１１に記載の電力変換装置。 The power converter according to claim 11, wherein the power main circuit unit is connected with any one of an LED, an organic electroluminescence, and a laser diode as the load.
  13. 上記電源主回路部は、降圧チョッパ回路から構成される請求項１から請求項１２のいずれか１項に記載の電力変換装置。 The power conversion device according to any one of claims 1 to 12, wherein the power supply main circuit unit includes a step-down chopper circuit.
  14. 上記電源主回路部は、昇圧チョッパ回路から構成される請求項１から請求項１２のいずれか１項に記載の電力変換装置。 The power converter according to any one of claims 1 to 12, wherein the power supply main circuit unit includes a step-up chopper circuit.
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