JP2006280120A - Inverter power supply unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that a bigger power loss is caused, by hard switching when an inverter circuit is turned off, in an inverter power supply unit of a conventional phase shift control system. <P>SOLUTION: The inverter power supply unit includes a dc power circuit which outputs a dc voltage, the inverter circuit forming a bridge, a phase shift control circuit in which a shift period consisting of first conduction, a first cycle, second conduction and a second cycle is provided, and phase shift control is performed to control an output, and an output conversion circuit which converts to an output corresponding to a load, wherein a fifth switching element between the dc power circuit and the inverter circuit, an auxiliary capacitor provided in parallel at an input side of the inverter circuit, and a power switching driving circuit are provided, in which the driving circuit conducts the fifth switching element during a first conduction period, and conducts up to the same length as the first conduction period during a second conduction period. At a point of time when the auxiliary capacitor is discharged sufficiently, the first conduction and the second conduction finish. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an inverter power supply device for a high frequency power supply that supplies power to a load, and in the phase shift control system that controls the switching element of the inverter unit using phase shift, soft switching that reduces the switching loss value of the inverter unit It is about technology.

  FIG. 12 is a block diagram of a conventional arc machining power supply apparatus employing a phase shift control system. In the figure, a direct current power source includes a primary rectifier circuit DR1 that rectifies the output of a three-phase alternating current commercial power source AC and converts it into a direct current voltage, and a smoothing capacitor C1 that smoothes the electric power converted into direct current by the primary rectifier circuit DR1. A circuit is formed.

  The bridge-connected inverter circuit shown in FIG. 12 is formed by the first switching element TR1 to the fourth switching element TR4, and includes the first switching element TR1 and the fourth switching element TR4 that form opposite sides. The second switching element TR2 and the third switching element TR3 are subjected to phase shift control by a phase shift circuit PS described later to convert a DC voltage into a high-frequency AC voltage.

  The first reverse conduction diode D1 to the fourth reverse conduction diode D4 are respectively connected in parallel with the reverse polarity to the first switching element TR1 to the fourth switching element TR4.

  The main transformer INT converts the high-frequency AC voltage on the primary side into a voltage suitable for arc machining. The secondary rectifier circuit DR2 rectifies the output of the main transformer INT, converts it into a DC voltage for arc machining, and supplies a DC voltage between the torch 1 and the workpiece 2 through the DC reactor DCL.

  The output current detection circuit ID outputs an output current detection signal Id. The error amplification circuit ER compares the output current setting signal Ir of the output current setting circuit IR with the output current detection signal Id of the output current detection circuit ID, and outputs the value of the error amplification signal Er = Ir−Id.

  The feedback control circuit FS is formed of a triangular wave oscillator OSC and a comparison circuit CP, and outputs a feedback control signal Fs of a pulse signal generated by comparing the error amplification signal Er and the reference triangular wave signal Osc.

  The phase shift circuit PS responds to the feedback control signal Fs from the feedback control circuit FS with the first switching element driving signal Ps1, the third switching element driving signal Ps3, the second switching element driving signal Ps2, and the fourth switching element driving signal Ps2. The phase of the switching element drive signal Ps4 is shifted by 180 degrees, and the phase of the first switching element drive signal Ps1 and the second switching element drive signal Ps2 is adjusted to control the output.

  FIG. 13 is a diagram for explaining an operation mode of the arc machining power supply device of the prior art shown in FIG. 12, and FIG. 14 is a waveform diagram for explaining the operation.

  14A shows the waveform of the first switching element drive signal Ps1, the waveform of FIG. 14B shows the waveform of the second switching element drive signal Ps2, and the waveform of FIG. The waveform shows the waveform of the third switching element drive signal Ps3, and the waveform in FIG. 4D shows the waveform of the fourth switching element drive signal Ps4. The waveform in FIG. 5E shows the primary voltage Vt of the primary winding of the main transformer INT, and the waveform in FIG. 5F shows the primary current It of the primary winding of the main transformer INT. Show.

  The phase shift period shown in FIG. 14 is formed with a first half cycle (t1 to t3) and a second half cycle (t3 to t5). The first half period is formed by a first conduction period T1 (t1 to t2), a first circulation period T2 (t2 to t22), and a first regeneration period (t22 to t3). The first circulation period T2 includes a first dead time period (t2 to t21). The latter half period is formed by the second conduction period T3 (t3 to t4), the second circulation period T4 (t4 to t42), and the second regeneration period (t42 to t5). The second circulation period T4 includes a second dead time period (t4 to t42).

(1) First conduction period T1
At time t = t1 shown in FIG. 14, the phase shift circuit PS conducts the first switching element TR1 and starts the first conduction period T1. The first conduction period T1 ends at time t2 determined by the feedback control signal generated by comparing the error amplification signal Er and the reference triangular wave signal. During the first conduction period T1, since the first switching element TR1 and the fourth switching element TR4 are in the conduction state, the primary winding indicated by the dotted line in FIG. 13 (1) is provided in the primary winding of the main transformer INT. The current It is energized, the primary voltage Vt shown in FIG. 14E is applied to both ends of the primary winding, the secondary voltage is generated in the secondary winding, and the voltage is transformed.

(2) First circulation period T2
The first circulation period T2 starts at time t = t2. Then, at time t21 when a predetermined first dead time period has elapsed, the second switching element TR2 changes to a conductive state. This dead time period is provided in order to prevent an arm short circuit from occurring due to the intersection of the cutoff of the fourth switching element TR4 and the conduction of the second switching element TR2. During the first dead time period, as shown in FIG. 13 (2), the energy stored in the leakage inductance of the main transformer INT is discharged through the second reverse conducting diode D2, and the state shown in FIG. The primary current It shown in FIG. At this time, the primary side of the main transformer INT is short-circuited, and the primary voltage Vt shown in FIG.

  At the end of the first dead time period at time t = t21, the second switching element TR2 is changed to a conductive state. At this time, as shown in FIG. 132 (2), a primary current flows through the second reverse conducting diode D2, and the second switching element TR2 conducts in a short-circuited state, so that it can be turned on with zero voltage. There is no loss.

  The time t = t22 is a time point just before a predetermined first regeneration period from the time point (t3) when the first half period of the phase shift period elapses, and the first switching element TR1 is changed to the cut-off state to change to the first circulation period. T2 ends. During the period from time t21 to time t22, as shown in FIG. 13B, the first switching element TR1 and the second switching element TR2 are in the conductive state, and the primary current It is the first switching element TR1. Circulate through the main transformer INT and the second reverse conducting diode D2. At this time, the primary voltage Vt of the main transformer INT is clamped near zero voltage by the first switching element TR1 and the second switching element TR2 as shown in FIG.

  At time t = t22, the first regeneration period starts and the first switching element TR1 changes to the cut-off state. When the first switching element TR1 is cut off, the energy stored in the leakage inductance is regenerated to the power source through the second reverse conducting diode D2 and the third reverse conducting diode D3. At this time, when the third switching element TR3 is made conductive, switching with zero voltage is possible. Then, when the first regeneration period elapses and the first half period of the phase shift period ends, the third switching element TR3 changes to a conductive state. During the first regeneration period, the arm short circuit is prevented and the energy stored in the leakage inductance of the main transformer INT is regenerated to the DC power supply circuit through the second reverse conducting diode D2 and the third reverse conducting diode D3. Then, the primary voltage Vt shown in FIG. 14E is applied to both ends of the primary winding of the main transformer INT.

(3) Second conduction period T3
At time t = t3 shown in FIG. 14, the phase shift circuit PS conducts the third switching element TR1 and starts the second conduction period T2. Then, at time t4 determined by the feedback control signal generated by comparing the error amplification signal Er and the reference triangular wave signal, the second conduction period T2 ends. During the second conduction period T3, the second switching element TR2 and the third switching element TR3 are in the conduction state, and therefore the primary winding indicated by the dotted line in FIG. 13 (1) is provided in the primary winding of the main transformer INT. The current It is energized, the primary voltage Vt shown in FIG. 14E is applied to both ends of the primary winding, the secondary voltage is generated in the secondary winding, and the voltage is transformed.

(4) Second circulation period T4
The second circulation period T4 starts at time t = t4. Then, at a time t41 when a predetermined second dead time period has elapsed, the fourth switching element TR4 changes to a conductive state. This dead time period is provided in order to prevent the occurrence of an arm short circuit due to the intersection of the cutoff of the second switching element TR2 and the conduction of the fourth switching element TR4. During this second dead time period, as shown in FIG. 13 (2), the energy stored in the leakage inductance of the main transformer INT is discharged through the fourth reverse conducting diode D4, and the state shown in FIG. The primary current It shown in FIG. At this time, the primary side of the main transformer INT is short-circuited, and the primary voltage Vt shown in FIG.

  At the end of the second dead time period at time t = t41, the fourth switching element TR4 is changed to a conductive state. At this time, as shown in FIG. 13 (2), a primary current flows through the fourth reverse conducting diode D4, and the fourth switching element TR4 conducts in a short-circuited state, so that it can be turned on with zero voltage. There is no loss.

  Time t = t42 is a time point that is a short time before the predetermined second regeneration period from the time point (t5) when the latter half of the phase shift period elapses, and changes the third switching element TR3 to the cutoff state. During the period from time t41 to time t42, as shown in FIG. 13B, the third switching element TR3 and the fourth switching element TR4 are in the conductive state, and the primary current It is supplied from the third switching element TR3. Circulates through the main transformer INT and the fourth reverse conducting diode D4. At this time, the primary voltage Vt of the main transformer INT is clamped near zero voltage by the third switching element TR3 and the fourth switching element TR4 as shown in FIG.

  At time t = t42, the second regeneration period starts and the third switching element TR3 changes to the cut-off state. Then, when the second regeneration period elapses and the latter half of the phase shift period ends, the first switching element TR1 changes to a conductive state. This regeneration period is provided to prevent an arm short circuit. During the second regeneration period, the energy stored in the leakage inductance of the main transformer INT is regenerated to the DC power supply circuit through the first reverse conducting diode D1 and the fourth reverse conducting diode D4, and the main transformer The primary voltage Vt shown in FIG. 14E is applied to both ends of the INT primary winding. (Patent Document 1)

  Moreover, in the arc control power supply device of the PWM control system shown in Patent Document 2 of Prior Art 2, the DC power supply circuit that outputs a DC voltage, and the first switching element TR1 and the first switching element TR1 are opposed to each other. An inverter circuit that forms a bridge from the fourth switching element TR4, the second switching element TR2 and the third switching element TR3 opposite to the second switching element TR2 to convert the DC voltage into a high-frequency AC voltage; A main transformer that converts the high-frequency AC voltage into a voltage suitable for arc machining, a rectifier circuit that rectifies the output of the main transformer and outputs a DC voltage, and the DC power supply circuit and the inverter circuit. A fifth switching element TR5 (power switching switching element) that opens and closes the output of the DC power supply circuit, and And an auxiliary capacitor C2 provided in parallel on the input side of the data circuit to turn on the input voltage and the output voltage of the fifth switching element TR5 at substantially the same voltage, and for feedback control of the output of the arc machining power supply device. An output control circuit that outputs a first output control signal and a second output control signal that are shifted from each other by a half cycle, and the fifth output when the first output control signal or the second output control signal changes to a high level. When the switching element TR5 is turned on and the first output control signal or the second output control signal changes to a low level, the power switching drive circuit that shuts off the fifth switching element TR5, and the first output control signal Changes to the high level, the first switching element TR1 and the fourth switching element TR4 are brought into conduction, and the first output element is turned on. The first switching element TR1 and the fourth switching element TR4 are shut off after the auxiliary capacitor discharge time during which the force control signal changes to the low level and the auxiliary capacitor C2 discharges considerably, and then the first switching element TR4 is cut off. When the second output control signal changes to the high level, the second switching element TR2 and the third switching element TR3 are made conductive, and the second output control signal changes to the low level, so that the auxiliary capacitor C2 becomes considerably high. An arc machining power supply apparatus comprising: an inverter drive circuit that shuts off the second switching element TR2 and the third switching element TR3 after the discharge time of the auxiliary capacitor to be discharged has elapsed; In the device, the loss at the time of turn-off of the inverter circuit is reduced. Shift switching technique is disclosed. (Patent Document 2)

JP 2004-74258 A JP 2003-31408 A

  In the arc shift power supply apparatus of the phase shift control system described above, when each switching element of the inverter circuit is turned on, the turn-on loss is not caused because the turn-on is performed with zero voltage. However, at the time of turn-off, it cannot be turned off at zero voltage, and a large loss occurs at the time of turn-off. If the frequency of the inverter circuit is increased while the loss at turn-off occurs from the above, the number of switchings per unit time increases, the loss per unit time increases, and it is difficult to achieve high frequency of the inverter circuit. . If the frequency is forcibly increased, it is necessary to strengthen the cooling mechanism and the like, resulting in a large power supply device.

  In the prior art 2, since the soft switching method is employed, each switching element of the inverter circuit is turned off at zero voltage because the switching element is turned off at zero voltage. Will occur. This turn-on loss makes it difficult to increase the frequency of the inverter circuit.

  Then, it is providing the inverter power supply device which solves said subject.

  In order to solve the above-described problems, a first invention is a DC power supply circuit that outputs a DC voltage, a first switching element and a second switching element that are connected to a plus-side output of the DC power supply circuit, and the above An inverter circuit for forming a bridge from the fourth switching element facing the first switching element and the third switching element facing the second switching element to convert the DC voltage into a high-frequency AC voltage; A phase shift period having one cycle of the first conduction period, the first circulation period, the first regeneration period, the second conduction period, the second circulation period, and the second regeneration period is provided, and a load voltage or current and a predetermined voltage are provided. Alternatively, an error amplification circuit that amplifies the current setting signal and outputs a feedback control signal, and the feedback control signal is used as an input to start the first conduction period. In point, the fourth switching element is in a conductive state from the previous period, the first switching element is changed to a conductive state, and the fourth switching element is changed to a cutoff state at a time determined by the feedback control signal. The second switching element is changed to a conducting state when the first dead time period elapses from the start of the first circulation period after the first conducting period ends, and the phase shift When the first half cycle elapses, the first switching element is changed to the cut-off state at a time just before a predetermined first regeneration period from the time when the first half cycle of the period elapses. To end the first regeneration period, and then change the third switching element to the conductive state at the start of the second conductive period, and The second switching element is changed to a cut-off state at a time determined by a clock control signal to end the second conduction period, and then a second dead time period predetermined from the start time of the second circulation period. When the time elapses, the fourth switching element is changed to a conductive state, and the third switching element is cut off at a time point that is a predetermined second regeneration period before the second half period of the phase shift period elapses. A phase shift control circuit that terminates the second recycle period and ends the second regeneration period and performs phase shift control when the second half period elapses, and loads the converted high-frequency AC voltage An inverter power supply device comprising an output conversion circuit for converting to an output according to the above, and provided between the DC power supply circuit and the inverter circuit to open and close the DC voltage A fifth switching element, an auxiliary capacitor provided in parallel on the input side of the inverter circuit, a period from the start time of the first conduction period to a time point determined by the feedback control signal, and the start of the second conduction period During the period from the time point to the time point determined by the feedback control signal, the power switching drive circuit for bringing the fifth switching element into a conductive state and the auxiliary capacitor charged at the start of the second regeneration period include the fifth switching element. An auxiliary capacitor timed output circuit for outputting an auxiliary capacitor timed signal when the auxiliary capacitor charged at the start of the first regeneration period and the auxiliary capacitor charged at the start of the first regeneration period are substantially discharged. The feedback control signal, which is an input signal of the shift control circuit, is connected to the auxiliary controller. An inverter power supply apparatus characterized by replacing the capacitors timed signal.

  According to a second aspect of the present invention, there is provided a first charging time point at which the auxiliary capacitor is substantially charged within the regeneration period from the start time of the second regeneration period, and the auxiliary capacitor within the regeneration period from the start time of the first regeneration period. A charging-supporting auxiliary capacitor timed circuit that outputs an auxiliary capacitor timed signal at a second charging time corresponding to the time when the power is switched, and the power switching drive circuit is determined by the feedback control signal from the first charging time of the auxiliary capacitor timed signal And a power switching drive circuit that brings the fifth switching element into a conductive state during a period from the second charging time of the auxiliary capacitor timing signal to a time determined by the feedback control signal. The inverter power supply device according to Item 1.

  According to a third aspect of the present invention, in the inverter power supply apparatus according to claim 1 or 2, wherein the auxiliary capacitor is considerably discharged or charged by detecting the voltage or current of the auxiliary capacitor. is there.

  According to a fourth aspect of the invention, the output conversion circuit includes a main transformer that converts the high-frequency AC voltage into a voltage suitable for arc machining, and a secondary rectifier circuit that rectifies the output of the main transformer and outputs a DC voltage. The inverter power supply device according to claim 1, wherein the inverter power supply device is used for arc machining.

  According to a fifth aspect of the present invention, there is provided a main transformer that converts the high-frequency AC voltage into a voltage suitable for arc machining, and a secondary rectifier circuit that rectifies the output of the main transformer and outputs a DC voltage. 4. The inverter according to claim 1, comprising a secondary inverter circuit that converts the output of the secondary rectifier circuit into a low-frequency AC output and outputs the low-frequency AC output, and is used for AC arc machining. It is a power supply device.

  According to the first invention, in the phase shift control system, the fifth switching element (power switching switching element) is cut off before the second switching element TR2 and the fourth switching element TR4 are cut off from conduction. As a result, the supply of the DC voltage from the DC power supply circuit is stopped, so that the second switching element TR2 and the fourth switching element TR4 of the inverter circuit can be turned off at zero voltage, and the value of the turn-off loss is greatly reduced. it can. Therefore, the switching loss value of the inverter circuit can be reduced, and the frequency can be increased. As a result, the power supply device can be reduced in size and weight.

  According to the second invention, the fifth switching element (power switching switching element) is turned on when the auxiliary capacitor is considerably charged, so that it can be turned on with zero voltage. The turn-on loss of the switching element 5 does not occur.

  According to the third aspect of the invention, an inverter is used to detect the discharge voltage or the charge voltage of the auxiliary capacitor and set the auxiliary capacitor discharge time or the auxiliary capacitor charge time when the voltage is equal to or lower than a predetermined reference value or higher than the reference value. Each element of the circuit can be accurately cut off at zero voltage, and the fifth switching element can be turned on accurately at zero voltage.

  According to the fourth invention, when the power conversion circuit of the inverter power supply device is replaced with a main transformer that converts high-frequency voltage suitable for arc machining and a secondary rectifier circuit that rectifies the output of the main transformer, arc machining It can be used as a DC power supply for arc machining used in

  According to the fifth invention, the power converter circuit of the inverter power supply apparatus is converted into a high-frequency voltage suitable for arc machining, a secondary rectifier circuit that rectifies the output of the main transformer, and a secondary rectifier circuit are reduced. If it replaces with the secondary inverter circuit converted into a frequency alternating current output, it can be used as an AC power supply device for arc processing used for AC arc processing.

[Embodiment 1]
Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is an electrical connection diagram of a typical switching regulator of the inverter power supply device of the present invention, and the operation of the soft switching method of phase shift control will be described with reference to FIG. In the figure, the same reference numerals as those in the electric connection diagram of the arc machining power supply device of the prior art perform the same operations, and therefore, the description thereof will be omitted and different operations will be described.

  The fifth switching element TR5 is a power switching switching element connected in series between the smoothing capacitor C1 and the auxiliary capacitor C2 shown in FIG. 1, and controls the supply of a DC voltage from the DC power supply circuit. In addition, the auxiliary capacitor C2 generates an electromotive force due to energy accumulated by the wiring and leakage inductance of the main transformer INT, and charges the auxiliary capacitor C2. At this time, if the voltage exceeds the rated voltage of the fifth switching element TR5, the element is destroyed. However, the fifth reverse conducting diode D5 bypasses the leakage inductance energy to the smoothing capacitor C1 to prevent the generation of a high voltage.

  The auxiliary capacitor C2 connected in parallel to the input side of the inverter circuit switches the input voltage and the output voltage of the fifth switching element TR5 with substantially the same voltage (zero voltage), and the auxiliary capacitor C2 is bridge-connected by having the auxiliary capacitor C2. Each switching element of the inverter circuit can also be turned off at zero voltage.

  The output conversion circuit includes a converter that converts a high-frequency AC voltage on the primary side into a voltage suitable for a load, a secondary rectifier circuit DR2 that rectifies the high-frequency AC voltage and converts it to a DC voltage, and rectifies and converts the DC voltage. It is formed of a DC reactor DCL and a secondary smoothing capacitor C3 that are smoothed to attenuate the ripple component and supply the load to the load.

  The output voltage detection circuit VD detects the output voltage. The error amplification circuit ER performs error amplification on the output voltage setting signal Vr of the output voltage setting device VR and the output voltage detection signal Vd of the output voltage detection circuit VD, and outputs an error amplification signal Er.

  The feedback control circuit FS is formed of a triangular wave oscillator OSC and a comparison circuit CP, and outputs a feedback control signal Fs of a pulse generated by comparing the error amplification signal Er and the reference triangular wave signal Osc.

  The power open / close drive circuit CR sets the power open / close drive signal Cr to the high level when it becomes high level in response to the feedback control signal Fs, and sets the power open / close drive signal Cr to the low level when it goes low.

  As shown in FIG. 2, the auxiliary capacitor timed output circuit DD is formed by a first OR gate OR1 and a first timed circuit TI1. The first time circuit TI1 starts operation when the power switching drive signal Cr becomes low level, and outputs a first time signal Ta of a predetermined time period in which the voltage of the auxiliary capacitor C2 is considerably discharged. The upper first OR gate OR1 performs an OR logic on the power switching drive signal Cr and the first time limit signal Ta and outputs the result as an auxiliary capacitor time limit signal Dd.

  The phase shift control circuit PSA provides a phase shift between the first switching element driving signal Pa1 and the fourth switching element driving signal Pa4, and the second switching element driving signal Pa2 and the third switching element driving signal Pa3. The phase shift control circuit PSA determines a first conduction period and a second conduction period according to the auxiliary capacitor time limit signal Dd.

  FIG. 5 is a waveform timing chart for explaining the operation of the electrical connection diagram of the inverter power supply device (representative example switching regulator) according to the first embodiment of the present invention shown in FIG. The waveform in FIG. 6A shows the waveform of the first switching element drive signal Pa1, the waveform in FIG. 5B shows the waveform of the second switching element drive signal Pa2, and the waveform in FIG. The waveform of the third switching element drive signal Pa3 is shown, the waveform of FIG. 11D shows the waveform of the fourth switching element drive signal Pa4, and the waveform of FIG. 9E shows the waveform of the power switching drive signal Cr. Indicates. The waveform in (F) shows the terminal voltage Vc2 of the auxiliary capacitor, the waveform in (G) shows the auxiliary capacitor time limit signal Dd, and the waveform in (H) shows the collector-voltage of the first switching element TR1. The emitter-to-emitter voltage V2 is shown. The waveform in FIG. 11I shows the collector current I1 of the first switching element TR1, and the waveform in FIG. 10J shows the collector-emitter voltage V2 of the second switching element TR2. The waveform of (K) in the figure shows the collector current I2 of the second switching element TR2. The waveform in FIG. 5L shows the collector current I5 of the fifth switching element TR5, and the waveform in FIG. 4M shows the collector-emitter voltage V5 of the fifth switching element TR5.

  The phase shift period shown in FIG. 5 is formed with a first half cycle (t1 to t3) and a second half cycle (t3 to t5). The first half period is formed by a first conduction period T1 (t1 to t2), a first circulation period T2 (t2 to t22), and a first regeneration period (t22 to t3). The first conduction period T1 includes an auxiliary capacitor time period (t12 to t2), and the first circulation period T2 includes a first dead time period (t2 to t21). The latter half period is formed by the second conduction period T3 (t3 to t4), the second circulation period T4 (t4 to t5), and the second regeneration period (t42 to t5). The second conduction period T3 includes an auxiliary capacitor time period (t32 to t4), and the second circulation period T4 includes a second dead time period (t41 to t42).

(1) First conduction period T1
At time t = t1 shown in FIG. 5, the phase shift control circuit PSA conducts the first switching element TR1 to start the first conduction period T1, and the power switching drive circuit CR conducts the fifth switching element TR5. To start. Then, at the time t12 determined by the feedback control signal generated by comparing the error amplification signal Er and the reference triangular wave signal, the fifth switching element TR5 is cut off. During the period from t1 to t12 of the first conduction period, the first switching element TR1 and the fourth switching element TR4 are in the conduction state, so that the primary winding of the main transformer INT is connected to the primary winding of FIG. A primary current It indicated by a dotted line is energized, a primary voltage Vt is applied to both ends of the primary winding, a secondary voltage is generated in the secondary winding, and the voltage is transformed.

  When the fifth switching element TR5 is cut off at time t = t12, the power supply is cut off and the auxiliary capacitor C2 starts discharging, and the voltage of the auxiliary capacitor terminal voltage VC2 becomes zero as shown in FIG. And decrease. At this time, at time t = t12, the fifth switching element TR5 is cut off at the same potential and no turn-off loss occurs. Subsequently, the auxiliary capacitor timed output circuit DD sets the auxiliary capacitor timed signal Dd shown in FIG. 5 (G) to the low level at the time t = t2 when the fifth switching element TR5 is cut off, and the phase shift is performed. Input to the control circuit PSA. The phase shift control circuit PSA discriminates that the auxiliary capacitor C2 is considerably discharged when the auxiliary capacitor time limit signal Dd becomes low level at time t = t2, and shuts off the fourth switching element TR4 and first conduction period T1. Ends. At this time, since the auxiliary capacitor is discharged to substantially zero, the fourth switching element TR4 is cut off at zero voltage and no turn-off loss occurs.

(2) First circulation period T2
The first circulation period T2 starts at time t = t2. Then, at time t21 when a predetermined first dead time period has elapsed, the second switching element TR2 changes to a conductive state. This dead time period is provided in order to prevent an arm short circuit from occurring due to the intersection of the cutoff of the fourth switching element TR4 and the conduction of the second switching element TR2. During the first dead time period, as shown in FIG. 4 (2), the energy accumulated in the leakage inductance of the main transformer INT is discharged through the second reverse conducting diode D2, and the primary current It is Energize continuously. At this time, the primary side of the main transformer INT is short-circuited and the primary voltage Vt is not applied.

  At the end of the first dead time period at time t = t21, the second switching element TR2 is changed to a conductive state. At this time, as shown in FIG. 3 (2), a primary current flows through the second reverse conducting diode D2, and the second switching element TR2 conducts in a short-circuited state, so that it can be turned on with zero voltage. There is no loss.

  The time t = t22 is a time point just before a predetermined first regeneration period from the time point (t3) when the first half period of the phase shift period elapses, and the first switching element TR1 is changed to the cut-off state to change to the first circulation period. Exit. During the period from time t21 to time t22, as shown in FIG. 3B, the first switching element TR1 and the second switching element TR2 are in the conductive state, and the primary current It is the first switching element TR1. Circulate through the main transformer INT and the second reverse conducting diode D2. At this time, the primary voltage Vt of the main transformer INT is clamped near zero voltage by the first switching element TR1 and the second switching element TR2.

  At time t = t22, the first regeneration period starts and the first switching element TR1 changes to the cut-off state. At this time, since the terminal voltage of the auxiliary capacitor is substantially zero voltage as shown in FIG. 5F, the first switching element TR1 can be cut off with zero voltage and no turn-off loss occurs. Then, when the first regeneration period elapses and the first half period of the phase shift period ends, the third switching element TR3 changes to a conductive state. During the first regeneration period, the arm short circuit is prevented and the energy stored in the leakage inductance of the main transformer INT is regenerated to the DC power supply circuit through the second reverse conducting diode D2 and the third reverse conducting diode D3. Then, the auxiliary capacitor C2 is charged with electric charge as shown in FIG.

(3) Second conduction period T3
At time t = t3 shown in FIG. 5, the phase shift control circuit PSA conducts the third switching element TR3 and starts the second conduction period T3, and the power switching drive circuit CR conducts the fifth switching element TR5. To start. Then, at the time t32 determined by the feedback control signal generated by comparing the error amplification signal Er and the reference triangular wave signal, the fifth switching element TR5 is cut off. Since the second switching element TR2 and the third switching element TR3 are in a conducting state during the period from t3 to t32 of the second conduction period, the primary winding of the main transformer INT is connected to the primary winding of FIG. 3 (4). A primary current It indicated by a dotted line is energized, a primary voltage Vt is applied to both ends of the primary winding, a secondary voltage is generated in the secondary winding, and the voltage is transformed.

  When the fifth switching element TR5 is cut off at time t = 32, the supply of power is cut off and the auxiliary capacitor C2 starts discharging, and the voltage of the auxiliary capacitor terminal voltage VC2 becomes zero as shown in FIG. 5 (F). And decrease. At this time, at time t = t32, the fifth switching element TR5 is cut off at the same potential and no turn-off loss occurs. Subsequently, the auxiliary capacitor timed output circuit DD sets the auxiliary capacitor timed Dd shown in FIG. 5 (G) to the low level at the time t = t4 when the fifth switching element TR5 is substantially discharged, and the phase shift control circuit DD. Input to PSA. At time t = t4, the phase shift control circuit PSA discriminates that the auxiliary capacitor C2 is considerably discharged when the auxiliary capacitor time limit signal Dd becomes low level, and shuts off the second switching element TR2, and the second conduction period T3. Ends. At this time, since the auxiliary capacitor is discharged to substantially zero, the third switching element TR3 is cut off at zero voltage and no turn-off loss occurs.

(4) Second circulation period T4
The second circulation period T4 starts at time t = t4. Then, at the time t41 when the predetermined second dead time period has elapsed, the fourth switching element TR4 changes to the conductive state. This dead time period is provided in order to prevent the occurrence of an arm short circuit due to the intersection of the cutoff of the second switching element TR2 and the conduction of the fourth switching element TR4. During the second dead time period, as shown in FIG. 4 (5), the energy accumulated in the leakage inductance of the main transformer INT is discharged through the fourth reverse conducting diode D4, and the primary current It is Energize continuously. At this time, the primary side of the main transformer INT is short-circuited and the primary voltage Vt is not applied.

  At the end of the second dead time period at time t = t41, the fourth switching element TR4 is changed to a conductive state. At this time, as shown in FIG. 4 (5), the primary current flows through the fourth reverse conducting diode D4, and the fourth switching element TR4 conducts in a short-circuited state, so that it can be turned on with zero voltage. There is no loss.

  Time t = t42 is a time point before a predetermined second regeneration period from time point t5 when the latter half of the phase shift period elapses, and the third switching element TR3 is changed to a cutoff state. During the period from time t41 to time t42, as shown in FIG. 4 (5), the third switching element TR3 and the fourth switching element TR4 are in the conductive state, and the primary current It is supplied from the third switching element TR3. Circulates through the main transformer INT and the fourth reverse conducting diode D4. At this time, the primary voltage Vt of the main transformer INT is clamped near zero voltage by the third switching element TR3 and the fourth switching element TR4.

  At time t = t42, the second regeneration period starts and the third switching element TR3 changes to the cut-off state. At this time, since the terminal voltage of the auxiliary capacitor is substantially zero voltage as shown in FIG. 5F, the third switching element TR3 can be cut off with zero voltage, and no turn-off loss occurs. Then, when the second regeneration period elapses and the latter half of the phase shift period ends, the first switching element TR1 changes to a conductive state. During this regeneration period, the arm short circuit is prevented and the energy stored in the leakage inductance of the main transformer INT is regenerated to the DC power supply circuit through the first reverse conduction diode D1 and the fourth reverse conduction diode D4. The auxiliary capacitor C2 is charged as shown in FIG.

[Embodiment 2]
In the second embodiment of the present invention, the power switching drive circuit CR shown in FIG. 1 is replaced with the charge-compatible power switching drive circuit CRV shown in FIG. 6, and the same reference numerals as those in the electrical connection diagram shown in FIG. Since the same operation is performed, a description thereof will be omitted and a different operation will be described.

  The charge-compatible power switching drive circuit CRV shown in FIG. 6 is formed of a charge-compatible auxiliary capacitor time circuit and a power switching drive circuit, and the charge-compatible auxiliary capacitor time circuit includes a second OR circuit OR2 and a second time circuit TI2. And the inverter switching circuit NOT2, and the power switching drive circuit is formed of the inverter circuit NOT1 and the flip-flop circuit FF. The second OR circuit OR2 performs an OR logic between the first switching element drive signal Pa1 and the third switching element drive signal Pa3, and the second time limit circuit TI2 operates when the OR signal Or2 becomes Low level. The auxiliary capacitor charging signal Tb for a predetermined period during which the voltage of the auxiliary capacitor C2 is considerably charged is output. The flip-flop circuit FF sets the output to a high level when the inverted signal of the auxiliary capacitor charging signal Tb becomes a high level, and sets the output to a low level when the inverted signal of the feedback control signal Fs becomes a high level. Output as an open / close drive signal Crv.

  Next, the operation of the second embodiment will be described with reference to the waveform diagram shown in FIG. When the third switching element drive signal Pa3 becomes a low level, the auxiliary capacitor C2 generates an electromotive force due to the energy accumulated by the leakage inductance of the main transformer INT. As shown in FIG. Start charging C2. The charging-capable auxiliary capacitor timing circuit obtains the first charging point in time t = t11 shown in FIG. 7 (F) and sets the charging-compatible power switching drive signal Crv shown in FIG. 7 (H) to the high level. The fifth switching element TR5 is conducted. Subsequently, when the feedback control signal Fs becomes a low level at time t = t12, the charge-compatible power switching drive signal Crv is set to a low level, and the fifth switching element TR5 is cut off. At this time, the voltage of the auxiliary capacitor C2 starts discharging. Further, the first switching element TR1 may be made conductive while the fifth switching element TR5 is made conductive.

  Subsequently, when the first switching element drive signal Pa1 becomes a low level, the auxiliary capacitor C2 generates an electromotive force due to the energy accumulated by the leakage inductance of the main transformer INT, as shown in FIG. Charging of the auxiliary capacitor C2 is started. Then, the charging-capable auxiliary capacitor timing circuit obtains the second charging time point at time t = t31 shown in FIG. 7 (F) and sets the charging-compatible power switching drive signal Crv shown in FIG. 7 (H) to the high level. The fifth switching element TR5 is conducted. Subsequently, when the feedback control signal Fs becomes a low level at time t = t32, the charge-compatible power switching drive signal Crv is set to a low level, and the fifth switching element TR5 is cut off. At this time, the voltage of the auxiliary capacitor C2 starts discharging. In addition, the fifth switching element TR5 may be turned on and the third switching element TR3 may be turned on.

[Embodiment 3]
FIG. 8 is an electrical connection diagram according to the third embodiment of the present invention. In the figure, the same reference numerals as those of the connection diagram shown in the first embodiment shown in FIG.

  The primary voltage detection circuit CV is connected in parallel to both ends of the auxiliary capacitor C2, detects the charge voltage and the discharge voltage of the terminal voltage of the auxiliary capacitor, and outputs it as the primary voltage detection signal Cv.

  9 is obtained by replacing the power switching drive circuit CR and the auxiliary capacitor time limit DD shown in FIG. 1 with the charge / discharge compatible power switching drive circuit CDV shown in FIG.

  The charge / discharge compatible power switching drive circuit CDV shown in FIG. 9 includes a NOT circuit 1, a flip-flop circuit FF, an OR circuit OR2, a primary voltage-corresponding second time limit circuit TV2, a NOT circuit 2 a first comparison circuit CP1, and a first comparison circuit CP1. The reference voltage setting circuit VR1 detects the charging voltage of the auxiliary capacitor C2 and outputs a charge detection-compatible power switching drive signal Cdv. The second comparison circuit CP2, the second reference voltage setting circuit VR2, An auxiliary capacitor discharge signal Ddv corresponding to discharge detection is output according to the circuit configuration of the first time limit circuit TV1 corresponding to the primary voltage and the OR circuit OR3.

  The first comparison circuit CP1 compares the value of the primary voltage detection signal Cv with the value of the first reference voltage setting signal Vr1 set in advance by the first reference voltage setting circuit VR1, and the first comparison circuit CP1 Is greater than the reference voltage setting signal Vr1, the first comparison signal Cp1 is set to the Low level. At this time, the terminal voltage of the auxiliary capacitor C2 is charged to a predetermined value. The second time limit circuit TV2 corresponding to the primary voltage starts operating when the output of the second OR circuit 2 becomes low level, and stops the operation when the first comparison signal Cp1 becomes low level. Then, the output is set to the low level. The flip-flop circuit FF sets the output to the high level when the inverted signal of the time limit signal Tv2 becomes the high level, and sets the output to the low level when the inverted signal of the power switching drive signal Cr becomes the high level. A power open / close drive signal Cdv is output.

  The second comparison circuit CP2 compares the value of the primary voltage detection signal Cv with the value of the predetermined second reference voltage setting signal Vr2 set by the second reference voltage setting circuit VR2, and the second comparison circuit CP2 When it is smaller than the reference voltage setting signal Vr2, the second comparison signal Cp2 is set to the Low level. At this time, the terminal voltage of the auxiliary capacitor C2 is discharged to a predetermined value. The first time limit circuit TV1 corresponding to the primary voltage starts operation when the feedback control signal Fs becomes low level and sets the output to high level, and stops operation when the second comparison signal Cp becomes low level and outputs the output low. To level. The third OR circuit 3 performs an OR logic of the feedback control signal Fs and the time limit signal Tv2, and outputs the result as a discharge detection-compatible auxiliary capacitor discharge signal Ddv. In addition, a primary current detection circuit CT (not shown) is provided between the contact between the first switching element and the third switching element and the transformer INT instead of the primary voltage detection circuit CV. The detection signal Ct may be used instead of the primary voltage detection signal Cv.

  Next, the operation of the third embodiment will be described with reference to the waveform diagram shown in FIG. When the third switching element drive signal Pa3 becomes a low level, the auxiliary capacitor C2 generates an electromotive force due to the energy accumulated by the leakage inductance of the main transformer INT. As shown in FIG. Start charging C2. Subsequently, the first comparison circuit CP1 compares the value of the primary voltage detection signal Cv with the value of the first reference voltage setting signal Vr1, and if it is greater than the first reference voltage setting signal Vr1, the first comparison circuit CP1 The comparison signal Cp1 is set to low level. At this time, it is determined that the terminal voltage of the auxiliary capacitor C2 is charged to a predetermined value, and at the time t = t11, the charging detection-corresponding power switching drive signal Cdv is set to the High level, and the fifth switching element TR5 is turned on. Subsequently, when the feedback control signal Fs becomes a low level at time t = t12, the charge detection corresponding power switching drive signal Cdv is set to a low level, and the fifth switching element TR5 is cut off. At this time, the voltage of the auxiliary capacitor C2 starts discharging. Further, the first switching element TR1 may be made conductive while the fifth switching element TR5 is made conductive.

  At time t = t12, the voltage of the auxiliary capacitor C2 starts discharging, and the second comparison circuit CP2 compares the value of the primary voltage detection signal Cv with the value of the second reference voltage setting signal Vr2, and When the reference voltage setting signal Vr2 is smaller than 2, the second comparison signal Cp2 is set to the Low level. At this time, it is determined that the terminal voltage of the auxiliary capacitor C2 is discharged to a predetermined value. At time t = 13, the discharge detection-supporting auxiliary capacitor discharge signal Ddv is set to low level and input to the phase shift control circuit PSA. The phase shift control circuit PSA sets the fourth switching element drive signal Pa4 to the low level according to the discharge detection-supporting auxiliary capacitor discharge signal Ddv.

[Embodiments 4 and 5]
FIG. 11 is an electrical connection diagram of Embodiments 4 and 5 of the present invention. In the figure, the same reference numerals as those of the electrical connection diagram shown in FIG.

  The secondary side output conversion circuit shown in FIG. 1 rectifies the output of the main transformer and the main transformer for converting the high frequency AC voltage on the primary side shown in FIG. When the DC rectifier circuit that outputs the current and the DC reactor that rectifies and smoothes the DC voltage to attenuate the ripple component and supply the load to the load can be configured, the DC power supply device for arc machining used for arc machining can be configured. It becomes possible to perform welding.

  If the secondary power conversion circuit is replaced with the main transformer, secondary rectifier circuit, DC reactor, and secondary inverter circuit for converting to a low-frequency AC output suitable for arc machining, AC arc machining Therefore, it is possible to construct an AC power supply device for arc machining used in the above, and to perform AC arc welding.

It is an electrical connection figure of the inverter power supply device of Embodiment 1 of this invention. FIG. 2 is a detailed diagram of an auxiliary capacitor discharge detection circuit shown in FIG. 1. It is a 1/2 figure explaining the operation mode of an inverter power supply device. It is a 2/2 figure explaining the operation mode of an inverter power supply device. It is a wave form diagram explaining operation | movement of an inverter power supply device. 6 is a detailed diagram of a charge-compatible power switching drive circuit according to Embodiment 2. FIG. FIG. 6 is a waveform diagram for explaining the operation of the second embodiment. It is an electrical connection figure of the inverter power supply device of Embodiment 3. 6 is a detailed diagram of a charge / discharge compatible power switching drive circuit according to Embodiment 3. FIG. FIG. 10 is a waveform diagram for explaining the operation of the third embodiment. It is an electrical connection diagram of Embodiment 4 and Embodiment 5. It is an electrical connection figure of the power supply apparatus for arc processing of a prior art. It is a figure explaining the operation mode of the power supply device for arc processing. It is a wave form diagram explaining the operation mode of the power supply device for arc processing.

Explanation of symbols

C1 smoothing capacitor C2 auxiliary capacitor C3 secondary smoothing capacitor CR power switching drive circuit CV primary voltage detection circuit CDV charge / discharge compatible power switching drive circuit CRV charging compatible power switching drive circuit CP1 first comparison circuit CP2 second comparison circuit DD Auxiliary capacitor timing circuit D1 1st reverse conducting diode D2 2nd reverse conducting diode D3 3rd reverse conducting diode D4 4th reverse conducting diode D5 5th reverse conducting diode DCL DC reactor DR1 Primary rectifier circuit DR2 2 Secondary rectifier circuit ER Error amplifier circuit FS Feedback control circuit FF Flip-flop circuit ID Output current detection circuit IR Output current setting circuit IN2 Secondary inverter circuit INT Main transformer NOT1 First NOT circuit NOT2 Second NOT circuit OR1 First OR circuit O 2 Second OR circuit OR3 Third OR circuit PS Phase shift circuit PSA Phase shift control circuit TS Start switch TI1 First time circuit TI2 Second time circuit TR1 First switching element TR2 Second switching element TR3 Second 3 switching element TR4 4th switching element TR5 5th switching element TV1 primary voltage corresponding first time limit circuit TV2 primary voltage corresponding second time limit circuit VD output voltage detection circuit VR output voltage setting circuit VR1 first Reference voltage setting circuit VR2 Second reference voltage setting circuit

Cr Power open / close drive signal Cv Primary voltage detection signal Crv Charging compatible power open / close drive signal Cdv Charge detection compatible power open / close drive signal Dd Auxiliary capacitor time limit signal Ddv Discharge detection compatible auxiliary capacitor discharge signal Er Error amplification signal Id Output current detection signal Ir Output current setting signal Pa1 First switching element driving signal Pa2 Second switching element driving signal Pa3 Third switching element driving signal Pa4 Fourth switching element driving signal Vd Output voltage detection signal Vr Output voltage setting signal

Claims (5)

A DC power supply circuit that outputs a DC voltage, a first switching element and a second switching element connected to a positive output of the DC power supply circuit, and a fourth switching element opposite to the first switching element; An inverter circuit that forms a bridge from the third switching element opposite to the second switching element and converts the DC voltage to a high-frequency AC voltage; a first conduction period; a first circulation period; a first regeneration period; A phase shift period with one cycle of the second conduction period, the second circulation period, and the second regeneration period is provided, and a feedback control signal is output by amplifying an error between a load voltage or current and a predetermined voltage or current setting signal. And the feedback control signal as an input, and at the start of the first conduction period, is the fourth switching element in the previous period? The first switching element is changed to a conductive state in a conductive state, and the fourth switching element is changed to a cut-off state at a time determined by the feedback control signal to end the first conductive period. The second switching element is changed to a conductive state when a predetermined first dead time period elapses from the start time of the first circulation period, and is predetermined from the time when the first half period of the phase shift period elapses. At the time just before the first regeneration period, the first switching element is changed to a cut-off state to end the first circulation period, and when the first half period has elapsed, the first regeneration period is ended, The third switching element is changed to a conductive state at the start of the second conduction period, and the second switching element is determined at a time determined by the feedback control signal. The switching element is changed to a cut-off state to end the second conduction period. Subsequently, when a predetermined second dead time period elapses from the start of the second circulation period, the fourth switching element is turned on. Change to the conducting state, and change the third switching element to the cut-off state at a time just before the predetermined second regeneration period from the time when the latter half period of the phase shift period elapses, and the second circulation period ends. A phase shift control circuit for ending the second regeneration period and performing phase shift control when the latter half period has elapsed, and an output conversion circuit for converting the converted high-frequency AC voltage into an output corresponding to a load. In the inverter power supply device provided,
A fifth switching element provided between the DC power supply circuit and the inverter circuit to open and close the DC voltage; an auxiliary capacitor provided in parallel on the input side of the inverter circuit; and a start point of the first conduction period A power switching drive circuit for bringing the fifth switching element into a conductive state during a period from the start time of the second conduction period to a time point determined by the feedback control signal and a time point determined by the feedback control signal; The time when the auxiliary capacitor charged at the start of the second regeneration period is considerably discharged by the cutoff of the fifth switching element and the time when the auxiliary capacitor charged at the start of the first regeneration period is considerably discharged And an auxiliary capacitor timed output circuit for outputting an auxiliary capacitor timed signal at Inverter power supply the feedback control signal is the input signal of the preparative control circuit, characterized in that replacing the auxiliary capacitor timed signal.   A first charging time when the auxiliary capacitor is charged considerably during the regeneration period from the start time of the second regeneration period and a first charging time when the auxiliary capacitor is charged considerably within the regeneration period from the start time of the first regeneration period. A charge-capable auxiliary capacitor timing circuit for outputting an auxiliary capacitor timing signal at the time of two charging, and a period from the first charging time of the auxiliary capacitor timing signal to a time determined by the feedback control signal and the auxiliary switching circuit 2. The inverter power supply circuit according to claim 1, wherein the inverter power supply is a power switching drive circuit that brings the fifth switching element into a conductive state during a period from a second charging time of a capacitor time signal to a time determined by the feedback control signal. apparatus.   3. The inverter power supply apparatus according to claim 1, wherein the auxiliary power supply device determines that the auxiliary capacitor has been considerably discharged or charged by detecting a voltage or current of the auxiliary capacitor.   The output conversion circuit includes a main transformer that converts the high-frequency AC voltage into a voltage suitable for arc machining, and a secondary rectifier circuit that rectifies the output of the main transformer and outputs a DC voltage, and is used for arc machining. The inverter power supply device according to claim 1, wherein the inverter power supply device is characterized in that: The output converter circuit converts the high-frequency AC voltage into a voltage suitable for arc machining, a secondary rectifier circuit that rectifies the output of the main transformer and outputs a DC voltage, and an output of the secondary rectifier circuit The inverter power supply device according to claim 1, wherein the inverter power supply device is used for AC arc machining.

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