TW201545447A - Power converter with both of positive gain and negative gain and dynamic voltage restorer using the same - Google Patents

Abstract

A power converter with both of positive gain and negative gain and a dynamic voltage restorer (DVR) using the same are provided in the present invention. The DVR compensates the voltage swell and the voltage sag by an extra series transformer. The primary winding of the transformer is coupled to the current source type AC to AC converter of the present invention. The plus-minus and the magnitude of the voltage gain of the AC to AC converter is determined by the duty cycle of the PWM provided to the AC to AC converter. Therefore, if the voltage swell occurs, the compensation voltage with negative gain is generated by the AC to AC converter, and if the voltage sag occurs, the compensation voltage with positive gain is generated by the AC to AC converter.

Description

Positive and negative voltage gain power converter and dynamic voltage restorer using same

The present invention relates to the application of a power converter, and more particularly to an AC-to-AC converter, a DC-to-DC converter, and a dynamic voltage restorer using the same.

In recent years, due to the strict quality requirements of electronic equipment in industrial automation, such as voltage dips, voltage surges, and harmonic requirements. In general, voltage dips are the most common disturbances in power systems, accounting for more than 90% of various power quality problems, mainly due to startup and short-circuit faults of large motor loads; voltage surges occur in switched large capacitors. Or when large load removal and single phase ground faults occur. The sudden drop of output voltage has a great impact on the system. Today's high-tech equipment such as computer communication systems, measuring instruments and production machines are sensitive to voltage changes. Even if the voltage changes only 3~5 cycles, it may cause the equipment to crash. Shadow The production of the factory. It can be seen that in the high-tech industry in Taiwan Science Park, computer automation equipment with great voltage sensitivity is adopted, so stable output voltage and power quality are necessary investment and demand.

The cause of voltage anomalies can be divided into the following states according to different degrees of change and duration: 1. low-frequency decaying ringwave, high-frequency impulse and ringwave, 3. Steady tolerance, 4. Voltage swell, 5. Voltage sag, 6. Dropout. For example: the voltage rises to an output voltage rms value of more than 120% and lasts for more than 0.5 seconds. The voltage dip can be divided into two sections, one is that the voltage is within 90% of the rms value (<10%) and lasts for more than 10 seconds after the output voltage drops, and the second is the rms voltage after the falling. Within 85% (<15%) for more than 0.5 seconds. The reversal is divided into two categories, with a voltage dip of more than 30% or a complete voltage interruption. Immediately after the event occurs, it returns to a normal state with a duration of less than 20ms.

Dynamic Voltage Restorer (DVR) is an important method to solve the above problems such as voltage dips and voltage surges in recent years. It compensates for variations in the supply voltage in series to achieve better system efficiency and stable output voltage. Figure 1 is a circuit diagram of a prior art dynamic voltage restorer. Referring to FIG. 1, the dynamic voltage restorer includes a transformer 101, an energy storage component 102, and a DC-to-AC converter 103. In addition, in the first figure, the AC equivalent impedance ZAC is indicated. In this dynamic voltage restorer, The additional DC-to-AC converter 103 generates a compensation voltage and compensates for the input voltage through the transformer 101. However, limited by the capacity of the energy storage element 102, its compensation time, cost, and circuit volume will be limited.

An object of the present invention is to provide a dynamic voltage restorer that compensates for a power supply voltage by an AC-to-AC converter having a positive and negative voltage gain and a compensation transformer connected in series with a voltage source to achieve an instant voltage regulation function.

Another object of the present invention is to provide an AC-to-AC converter with positive and negative gains that reflects a positive or negative voltage gain in accordance with the duty cycle of the supplied pulse.

Another object of the present invention is to provide a DC-to-DC converter that reflects a positive or negative voltage gain according to a duty cycle of a supplied pulse wave, and the DC-to-DC converter has a high rise. The pressure ratio makes it more applicable.

In view of this, the present invention provides a dynamic voltage restorer suitable for compensating for an output voltage dip and an output voltage surge. The dynamic voltage restorer includes a transformer and a current source type AC to AC converter. . The transformer includes a primary side coil and a secondary side coil, wherein the first end of the secondary side coil is coupled to a first alternating current end, and the second end of the secondary side coil is configured to provide a compensation input voltage. The AC-to-AC converter includes a single-ended primary inductor converter (SEPIC), a power supply control circuit, and a current feedback circuit. Single-ended primary inductance conversion The device includes a first input terminal, a second input terminal, a first output terminal, a second output terminal, and a front end inductor. The first input end of the single-ended primary inductor converter is coupled to the first AC terminal, the second input end of the single-ended primary inductor converter is coupled to the second AC terminal, and the first output end of the single-ended primary inductor converter is coupled to the transformer The first end of the primary-side coil is coupled to the second end of the primary-side coil of the transformer, wherein the first end of the front-end inductor is coupled to the single-ended primary inductor The first input.

The power control circuit is configured to provide at least one pulse to the single-ended primary inductor converter for power conversion. The first end of the current feedback circuit is coupled to the second end of the front end inductor, and the second end of the current feedback circuit is coupled to the second output end of the single-ended primary inductor converter, wherein the current feedback circuit is used to connect the single end The current between the first output and the second output of the primary inductor converter is fed back to the front end inductance of the single-ended primary inductor converter in accordance with a particular ratio. The AC-to-AC converter determines whether the input voltage has a positive or negative gain on the output voltage according to the duty cycle of the pulse supplied to the single-ended primary inductor converter.

The invention provides a current source type AC to AC converter. The current source type AC to AC converter is suitable for compensating for a dynamic voltage restorer of output voltage dip and output voltage surge. The dynamic voltage restorer comprises a transformer, the transformer comprises a primary side coil and a secondary side coil, the first end of the secondary side coil is coupled to a first alternating current end, and the second end of the secondary side coil is used to provide a compensation input Voltage, this current source type AC to AC converter includes a single-ended primary inductor converter (SEPIC), A power control circuit and a current feedback circuit. The single-ended primary inductor converter includes a first input terminal, a second input terminal, a first output terminal, a second output terminal, and a front end inductor. The first input end of the single-ended primary inductor converter is coupled to the first AC terminal, the second input end of the single-ended primary inductor converter is coupled to the second AC terminal, and the first output end of the single-ended primary inductor converter is coupled to the transformer The first end of the primary side coil is coupled to the second end of the primary side coil of the transformer. The first end of the front end inductor is coupled to the first input of the single-ended primary inductor converter.

The power control circuit is configured to provide at least one pulse to the single-ended primary inductor converter for power conversion. The first end of the current feedback circuit is coupled to the second end of the front end inductor, and the second end of the current feedback circuit is coupled to the second output end of the single-ended primary inductor converter. The current feedback circuit is configured to feed back the current between the first output end and the second output end of the single-ended primary inductance converter to the front end inductance of the single-ended primary inductance converter according to a specific ratio. The current source type AC-to-AC converter determines whether the input voltage has a positive or negative gain on the output voltage according to the duty cycle of the pulse supplied to the single-ended primary inductor converter.

According to a current source type AC-to-AC converter and a dynamic voltage restorer using the same according to a preferred embodiment of the present invention, the single-ended primary inductor converter further includes an electronic switch, a first capacitor, and a second inductor. a unidirectional conduction element and a second capacitor. The electronic switch includes a first end, a second end, and a control end. The first end of the electronic switch is coupled to the second end of the front end inductor, the second end of the electronic switch is coupled to the second AC end, and the control end of the electronic switch is coupled to the power control circuit to receive the pulse wave. The first capacitor includes a first end and a second end, wherein the first end of the first capacitor is coupled to the first end of the electronic switch. The second inductor includes a first end and a second end, wherein the first end of the second inductor is coupled to the second end of the first capacitor, and the second end of the second inductor is coupled to the first end of the single inductor Two inputs. The unidirectional conduction element includes a first end and a second end, wherein the first end of the unidirectional conduction element is coupled to the first end of the second inductor, wherein the conduction direction of the unidirectional conduction element is One end is turned on to the second end. The second capacitor includes a first end and a second end, wherein the first end of the second capacitor is coupled to the second end of the unidirectional conductive element, and the second end of the second capacitor is coupled to the single-ended primary inductor The second output.

According to a current source type AC-to-AC converter and a dynamic voltage restorer using the same according to a preferred embodiment of the present invention, the current feedback circuit includes a feedback inductor. The feedback inductor includes a first end and a second end, wherein the first end of the feedback inductor is coupled to the second end of the front end inductor, and the second end of the feedback capacitor is coupled to the single end main inductor The second output. In another embodiment, the unidirectional conduction element is replaced with an electronic switch.

The present invention provides a current source type DC-to-DC converter comprising a single-ended primary inductance converter (SEPIC), a power supply control circuit, and a current feedback circuit. The single-ended primary inductor converter includes a first input terminal, a second input terminal, a first output terminal, a second output terminal, and a front end inductor. The first input end of the single-ended primary inductor converter is coupled to the positive terminal of the DC power supply, and the second input end of the single-ended primary inductor converter is coupled to the negative terminal of the DC power supply, The first output of the primary inductor converter and the second output of the single-ended primary inductor converter output an output voltage, wherein the first end of the front end inductor is coupled to the first input of the single-ended primary inductor converter. The power control circuit is configured to provide at least one pulse to the single-ended primary inductor converter for power conversion. The current feedback circuit includes a first end and a second end. The first end of the current feedback circuit is coupled to the second end of the front end inductor, and the second end of the current feedback circuit is coupled to the second output end of the single-ended primary inductor converter, wherein the current feedback circuit is used to connect the single end The current between the first output and the second output of the primary inductor converter is fed back to the front end inductance of the single-ended primary inductor converter in accordance with a particular ratio.

The spirit of the present invention is to use the existing single-ended primary inductance converter (SEPIC) with a current sampling parallel hybrid feedback network (Shunt-Series Feedback) to feedback the output current to the input end of the single-ended primary inductance converter. , developed a new form of power converter. This power converter can have a high step-up ratio when applied to DC-to-DC conversion. In addition, when used in AC-to-AC conversion, this power converter can have both positive and negative voltage gains. Accordingly, an AC-to-AC converter implemented in accordance with the teachings of the present invention is suitable for use in a dynamic voltage restorer that compensates for AC output voltage dips and output voltage spikes.

The above and other objects, features and advantages of the present invention will become more <RTIgt;

101‧‧‧Transformer

102‧‧‧ energy storage components

103‧‧‧DC to AC converter

ZAC‧‧‧ AC equivalent impedance

Vcan‧‧‧ AC compensation voltage

Vac‧‧‧AC input voltage

201‧‧‧AC to AC converter

202‧‧‧Power controller and drive circuit

203‧‧‧Transformer

204‧‧‧Auxiliary power circuit

Vo‧‧‧ output voltage

Vin‧‧‧Input voltage

50‧‧‧Single-ended primary inductor converter

51‧‧‧Power Control Circuit

52‧‧‧Return circuit

501‧‧‧ front end inductor

502, 601‧‧‧ electronic switch

503‧‧‧first capacitor

504‧‧‧second inductance

505‧‧‧ unidirectional conduction element

506‧‧‧second capacitor

507‧‧‧ load capacitance

508‧‧‧Load resistor

521‧‧‧Responsive inductance

602‧‧‧Shut capacitor

Figure 1 is a circuit diagram of a prior art dynamic voltage restorer.

FIG. 2 is a circuit diagram of a dynamic voltage restorer according to a preferred embodiment of the present invention.

FIG. 3A is a circuit diagram of a prior art single-ended primary-inductor converter (SEPIC).

FIG. 3B is a diagram showing the input voltage and output voltage transfer function of the prior art.

FIG. 4A is a diagram showing the input current and output current transfer function of the current source type AC to AC converter 201 according to a preferred embodiment of the present invention.

FIG. 4B is a diagram showing the input voltage and output voltage transfer function of the voltage source type AC to AC converter 201 according to a preferred embodiment of the present invention.

FIG. 5A is a circuit diagram of a current source type DC-DC power converter according to a preferred embodiment of the present invention.

FIG. 5B is an equivalent circuit diagram of a current source type DC-DC power converter according to FIG. 5A according to a preferred embodiment of the present invention.

FIG. 6 is a circuit diagram of a current source type AC to AC converter according to a preferred embodiment of the present invention.

FIG. 7 is a diagram showing a gain function of a current source type power converter according to a preferred embodiment of the present invention.

FIG. 8A is a waveform diagram of input voltage and output voltage of a current source type AC-to-AC converter when the pulse wave duty cycle is equal to 0.2 according to an embodiment of the present invention.

FIG. 8B is a waveform diagram of the input voltage and the output voltage of the current source type AC-to-AC converter when the pulse wave duty cycle is equal to 0.4 according to an embodiment of the present invention.

FIG. 8C is a waveform diagram of the input voltage and the output voltage of the current source type AC-to-AC converter when the pulse wave duty cycle is equal to 0.7 according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of a dynamic voltage restorer according to a preferred embodiment of the present invention. Referring to FIG. 2, in this embodiment, the AC converter 201 is directly exchanged to implement a compensation mechanism for the input voltage. It uses an AC input voltage or output voltage in conjunction with a low frequency transformer to compensate for its low or excessive voltage. The architecture is shown in Figure 2. This method is highly efficient and has no shortcomings of the first method described above. Although it does not provide its required output voltage when the power supply is interrupted, it can be implemented with other emergency power generation equipment. In this embodiment, the dynamic voltage restorer (DVR) requires a compensated output voltage change and a fast response, so that the AC-to-AC converter is directly converted, and the dynamic voltage restorer includes an AC-to-AC converter 201, The power controller and drive circuit 202 and the transformer 203. In addition, in order to maintain the operation of the power controller and drive circuit 202, an additional auxiliary power circuit 204 is required. In addition, in the first In the figure 2, the AC equivalent impedance ZAC is indicated.

Further, in order to explain the spirit of the present invention, in this embodiment, the ratio of the primary side to the secondary side of the transformer is assumed to be 1:n. In this embodiment, to achieve the up and down variation of the compensated output voltage required by the dynamic voltage restorer (DVR), the AC to AC converter needs to have both a positive voltage gain and a negative voltage gain. In this embodiment, in order to solve the problem of output voltage dip and voltage surge, the compensation voltage V _out required for the AC to AC converter is as shown in the following formula (1):

Where Vo is the output voltage, Vin is the input voltage, G(D) is the gain of the AC to AC converter, and n is the ratio of the turns of the low frequency transformer. It can be known from equation (1) that the voltage V _out required to be compensated for the voltage dip is positive, whereas the voltage V _out is negative when the voltage is suddenly raised. That is, the gain G(D) of the AC to AC converter must be positive or negative. Since the duty cycle D of the pulse wave ranges from 0 to 1, in order to obtain a positive or negative value, in this embodiment, the duty cycle of the pulse wave is 0.5 as the demarcation point. When the duty cycle D<0.5, G(D) is a positive value, and when the duty cycle D>0.5, G(D) is a negative value. It can be seen from the above that if the denominator or the numerator of the gain transfer function G(D) is 1-2D, the above requirements are met.

FIG. 3A is a circuit diagram of a prior art single-ended primary-inductor converter (SEPIC). FIG. 3B is a diagram showing the input voltage and output voltage transfer function of the prior art. Please refer to FIG. 3A and FIG. 3B simultaneously. In this embodiment, the transfer function with 1-2D is first derived based on the single-ended primary inductor converter. The single-ended primary inductor converter of Figure 3A is of the current source type, and the relationship between the input current and the output current of the single-ended primary inductor converter is (1-D)/D as shown in Fig. 3B. If the circuit feedback is used, the output current Io is added by the feedback to the If voltage and the input current Ii, and is obtained by the Mason gain formula of the control theory:

4A and 4B are diagrams showing input voltage and output voltage transfer functions of the current source type AC to AC converter 201 according to a preferred embodiment of the present invention. Please refer to Fig. 4A and Fig. 4B at the same time. By using a single-ended primary inductor converter with feedback of twice the output current, the voltage gain of the molecule is -(1-2D).

FIG. 5A is a circuit diagram of a current source type DC-DC power converter according to a preferred embodiment of the present invention. Referring to FIG. 5, the current source type DC-to-DC converter includes a single-ended primary inductor converter 50, a power control circuit 51, and a feedback circuit 52. In this embodiment, the single-ended primary inductor converter 50 includes a front end inductor 501, an electronic switch 502, a first capacitor 503, a second inductor 504, a unidirectional conductive element 505, and a second capacitor 506. The feedback circuit 52 is implemented by a feedback inductor 521 for feeding back the output current Io to the single-ended primary The input of the inductive converter 50. In addition, this circuit diagram additionally shows a load capacitor 507 and a load resistor 508. It can be seen by those skilled in the art that the current source type power converter of this embodiment utilizes the concept of shunt-series feedback (Current-Sampling Shunt-mixing), which is doubled. The output current Io is fed back to the input. FIG. 5B is an equivalent circuit diagram of a current source type DC-DC power converter according to FIG. 5A according to a preferred embodiment of the present invention. Please refer to FIG. 5A and FIG. 5B at the same time. If the components of FIG. 5A are arranged, the circuit as shown in FIG. 5B can be obtained.

FIG. 6 is a circuit diagram of a current source type AC to AC converter according to a preferred embodiment of the present invention. Referring to FIG. 5B and FIG. 6 simultaneously, in this embodiment, the unidirectional conduction element 505 is replaced by an electronic switch 601. In addition, the electronic switch 502 and the electronic switch 601 are implemented in the form of a bidirectional AC switch. Since the present invention compensates for the input alternating current, the circuit of the converter of Fig. 6 is an alternating current type converter, so that the electronic switch 502 and the unidirectional conductive element 505 are changed by a bidirectional switch. The bidirectional AC switch is implemented by a power transistor and four diodes, and the coupling relationship is as shown in the figure.

The current source type AC to AC converter conduction period and input/output transfer function can be divided into the following three intervals: 1, 0 < D < 0.5, the gain is negative and is buck; 2, 0.5 < D < 0.67, gain Positive value and step-down; 3, 0.67<D<1, gain is positive and is liter Pressure.

FIG. 7 is a diagram showing a gain function of a current source type power converter according to a preferred embodiment of the present invention. Referring to Fig. 7, from the above analysis, the gain function G(D) of the power converter can achieve a relatively high gain multiple at 0.67 < D < 1, but the gain function is not positive or negative symmetry. Therefore, the power supply control circuit 51 must obtain a pulse width required for the power converter by using a linear proportional-integrated (PI) Proportional-Integral digital controller or a nonlinear fuzzy controller via an offline look-up table. The duty cycle D of the modulation (PWM) signal.

FIG. 8A is a waveform diagram of input voltage and output voltage of a current source type AC-to-AC converter when the pulse wave duty cycle is equal to 0.2 according to an embodiment of the present invention. FIG. 8B is a waveform diagram of the input voltage and the output voltage of the current source type AC-to-AC converter when the pulse wave duty cycle is equal to 0.4 according to an embodiment of the present invention. FIG. 8C is a waveform diagram of the input voltage and the output voltage of the current source type AC-to-AC converter when the pulse wave duty cycle is equal to 0.7 according to an embodiment of the present invention. Please refer to the analysis of the 8A, 8B, 8C, 7 and the transfer function, and the simulation results can verify the correctness of the above transfer function and the feasibility of the circuit.

In addition, please refer to FIG. 5, which is in the form of a DC-to-DC converter. From the above derivation, it can be seen from the ordinary knowledge in the art that the DC-DC converter has a duty cycle of 0.8< There is a very high boost ratio (gain) between D<1. Generally, in order to obtain a high multiple boost ratio, those skilled in the art will Using a coupled inductor to achieve a high boost ratio is a common method in the art, but the leakage inductance of the transformer causes the voltage stress of the switch to become large and the efficiency is lowered. In this example, the topology of the entire DC converter is changed using a non-coupled inductor to achieve a high boost ratio.

In addition, in the above embodiment, although the feedback voltage is fed back to the input terminal with a double output voltage, those skilled in the art should know that a power converter having both positive gain and negative gain is obtained. The feedback voltage does not have to use twice the output voltage. For example, by supplying 1.5 times output current, 0.5 times output current, and 0.7 times output current in parallel shunt mode, a power converter having both positive gain and negative gain G(D) can be obtained. Therefore, the invention is not limited thereto.

In summary, the spirit of the present invention is to use the existing single-ended primary inductance converter (SEPIC) with a current sampling parallel hybrid feedback network (Shunt-Series Feedback) to return the output current to the single-ended primary inductance. At the input of the converter, a new form of power converter has been developed. This power converter can have a high step-up ratio when applied to DC-to-DC conversion. In addition, when used in AC-to-AC conversion, this power converter can have both positive and negative voltage gains. Accordingly, an AC-to-AC converter implemented in accordance with the teachings of the present invention is suitable for use in a dynamic voltage restorer that compensates for AC output voltage dips and output voltage spikes.

The specific embodiments of the present invention are intended to be illustrative only and not to limit the invention to the above embodiments, without departing from the spirit of the invention and the following claims. The scope of the situation, the implementation of all kinds of changes, are The scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims.

50‧‧‧Single-ended primary inductor converter

51‧‧‧Power Control Circuit

52‧‧‧Return circuit

501‧‧‧ front end inductor

502, 601‧‧‧ electronic switch

503‧‧‧first capacitor

504‧‧‧second inductance

505‧‧‧ unidirectional conduction element

506‧‧‧second capacitor

507‧‧‧ load capacitance

508‧‧‧Load resistor

521‧‧‧Responsive inductance

Claims (13)

A dynamic voltage restorer is adapted to compensate for an output voltage dip and an output voltage surge, comprising: a transformer comprising a primary side coil and a secondary side coil, wherein the first end of the secondary side coil is coupled to a first An AC terminal, the second end of the secondary side coil is configured to provide a compensation input voltage; and a current source type AC to AC converter includes: a single-ended primary inductance converter (SEPIC), including a first An input terminal, a second input terminal, a first output terminal, a second output terminal, and a front end inductor L1, wherein the first input end of the single-ended primary inductor converter is coupled to the first AC terminal, the single The second input end of the primary inductance converter is coupled to a second AC end, and the first output end of the single-ended primary inductance converter is coupled to the first end of the primary side coil of the transformer, the single-ended primary inductance converter The second output end is coupled to the second end of the primary side coil of the transformer, wherein the first end of the front end inductor is coupled to the first input end of the single-ended primary inductor converter; a power control circuit is provided to provide At least one Transmitting the single-ended primary inductor converter for power conversion; and a current feedback circuit comprising a first end and a second end, wherein the first end of the current feedback circuit is coupled to the front end inductor The second end of the current feedback circuit is coupled to the second output end of the single-ended primary inductor converter, wherein the current feedback circuit is configured to use the first output end of the single-ended primary inductor converter And the current between the second output is fed back to the front end of the single-ended primary inductor converter according to a specific ratio Sense, wherein the current source type AC to the AC converter determines the gain of the input voltage to be positive or negative according to the duty cycle of the pulse wave supplied to the single-ended primary inductor converter. The dynamic voltage restorer of claim 1, wherein the single-ended primary inductor converter comprises: a first electronic switch, comprising a first end, a second end, and a control end, wherein The first end of the first electronic switch is coupled to the second end of the front end, the second end of the first electronic switch is coupled to the second AC end, and the control end of the first electronic switch is coupled to the power control circuit; The first capacitor Cf includes a first end and a second end, wherein the first end of the first capacitor is coupled to the first end of the electronic switch, and the second inductor L2 includes a first end and a first end a second end, wherein the first end of the second inductor is coupled to the second end of the first capacitor, and the second end of the second inductor is coupled to the second input end of the single-ended primary inductor converter; The second electronic switch includes a first end and a second end, wherein the first end of the second electronic switch is coupled to the first end of the second inductor, and the control end of the second electronic switch is coupled to the power control a second capacitor C1 includes a first end and a second end, The first end of the second capacitor is coupled to the second end of the second electronic switch, and the second end of the second capacitor is coupled to the second output end of the single-ended primary inductor converter. The dynamic voltage recovery device of claim 2, wherein the current feedback circuit comprises: a feedback inductor Lf, comprising a first end and a second end, wherein the feedback inductor is first The second end of the feedback capacitor is coupled to the second output end of the single-ended primary inductor converter. The dynamic voltage restorer of claim 2, wherein the first electronic switch comprises: a power transistor comprising a gate, a first source drain and a second source drain, wherein The gate of the power transistor is coupled to the control end of the first electronic switch; a first unidirectional conductive component includes a first end and a second end, wherein the first unidirectional conductive component The first end of the first unidirectional conduction element is coupled to the first end of the first electronic switch, wherein the first unidirectional conduction element is coupled to the first source of the first unidirectional conduction element The current direction is the first end of the first unidirectional conduction element to the second end of the first unidirectional conduction element; and the second unidirectional conduction element includes a first end and a second end, wherein The first end of the second unidirectional conductive element is coupled to the second end of the first unidirectional conductive element, and the second end of the second unidirectional conductive element is coupled to the second source of the power transistor a drain, wherein a current direction of the second unidirectional conductive element is the second unidirectionality Conducting the first end of the component to a second end of the second unidirectional conducting element; a third unidirectional conducting element comprising a first end and a second end, wherein the first end of the third unidirectional conducting element is coupled to the a first source drain of the power transistor, the second end of the third unidirectional conductive element is coupled to the second end of the first electronic switch, wherein a current direction of the third unidirectional conductive element is the first a first end of the three unidirectional conducting element to the second end of the third unidirectional conducting element; and a fourth unidirectional conducting element comprising a first end and a second end, wherein the fourth The first end of the unidirectional conductive element is coupled to the second end of the third unidirectional conductive element, and the second end of the fourth unidirectional conductive element is coupled to the second source drain of the power transistor, wherein The current direction of the fourth unidirectional conduction element is the first end of the fourth unidirectional conduction element to the second end of the fourth unidirectional conduction element. The dynamic voltage restorer of claim 2, wherein the second electronic switch comprises: a power transistor comprising a gate, a first source drain, and a second source drain, wherein The gate of the power transistor is coupled to the control end of the first electronic switch; a first unidirectional conductive component includes a first end and a second end, wherein the first unidirectional conductive component The first end of the first unidirectional conduction element is coupled to the first end of the second electronic switch, wherein the first unidirectional conduction element is coupled to the first source of the first unidirectional conduction element The current direction is the first end of the first unidirectional conduction element to the first a second end of the unidirectional conductive element; a second unidirectional conductive element includes a first end and a second end, wherein the first end of the second unidirectional conductive element is coupled to the first single a second end of the second unidirectional conductive element is coupled to the second source drain of the power transistor, wherein a current direction of the second unidirectional conductive element is the first end a first end of the unidirectional conductive element to the second end of the second unidirectional conductive element; a third unidirectional conductive element comprising a first end and a second end, wherein the third single The first end of the directional conductive element is coupled to the first source drain of the power transistor, and the second end of the third unidirectional conductive element is coupled to the second end of the second electronic switch, wherein the third The current direction of the unidirectional conduction element is a first end of the third unidirectional conduction element to a second end of the third unidirectional conduction element; and a fourth unidirectional conduction element includes a first end And a second end, wherein the first end of the fourth unidirectional conductive element is coupled to the third unidirectional guide The second end of the fourth unidirectional conductive element is coupled to the second source drain of the power transistor, wherein the current direction of the fourth unidirectional conductive element is the fourth one-way The first end of the conductive element is to the second end of the fourth unidirectional conductive element. A current source type AC-to-AC converter suitable for compensating for a dynamic voltage restorer of output voltage dip and output voltage surge, the dynamic voltage restorer comprising a transformer comprising a primary side coil and a secondary side a coil, the first end of the secondary side coil is coupled to a first alternating current The second end of the secondary side coil is configured to provide a compensation input voltage. The current source type AC to AC converter comprises: a single-ended primary inductance converter (SEPIC), including a first input end, and a first input end a second input terminal, a first output terminal, a second output terminal, and a front end inductor L1, wherein the first input end of the single-ended primary inductor converter is coupled to the first AC terminal, and the single-ended primary inductance conversion The second input end is coupled to a second AC end, the first output end of the single-ended primary inductive converter is coupled to the first end of the primary side coil of the transformer, and the second output of the single-ended primary inductive converter The second end of the primary side coil of the transformer is coupled to the first end of the single-ended primary inductor converter; the power control circuit is configured to provide at least one pulse wave The single-ended primary inductor converter is configured to perform power conversion; and a current feedback circuit includes a first end and a second end, wherein the first end of the current feedback circuit is coupled to the front end of the inductor Two ends, the current feedback The second end of the circuit is coupled to the second output end of the single-ended primary inductance converter, wherein the current feedback circuit is used between the first output end and the second output end of the single-ended primary inductance converter Current is fed back to the front end inductor of the single-ended primary inductor converter according to a specific ratio, wherein the current source type AC-to-AC converter is in accordance with the duty cycle of the pulse supplied to the single-ended primary inductor converter The size determines whether the input voltage has a positive or negative gain on the output voltage. Current source type communication as described in item 6 of the patent application scope The AC converter, wherein the single-ended primary inductor converter includes: a first electronic switch, including a first end, a second end, and a control end, wherein the first end of the first electronic switch is coupled The second end of the first electronic switch is coupled to the second AC end, and the control end of the first electronic switch is coupled to the power control circuit; a first capacitor Cf includes a first end And a second end, wherein the first end of the first capacitor is coupled to the first end of the electronic switch; the second inductor L2 includes a first end and a second end, wherein the second inductor The first end is coupled to the second end of the first capacitor, the second end of the second inductor is coupled to the second input end of the single-ended primary inductor converter; and the second electronic switch includes a first end and a second end, wherein the first end of the second electronic switch is coupled to the first end of the second inductor, the control end of the second electronic switch is coupled to the power control circuit; and the second capacitor C1 includes a a first end and a second end, wherein the first end of the second capacitor is coupled A second terminal of the second electronic switch, the second capacitor second end coupled to the second output terminal of the single-ended primary inductor converter. The current source type AC-to-AC converter as described in claim 6 , wherein the current feedback circuit comprises: a feedback inductor Lf, including a first end and a second end, wherein the back The first end of the inductor is coupled to the second end of the front end inductor, and the second end of the feedback capacitor is coupled to the second output of the single-ended primary inductor converter. The current source type AC-to-AC converter as described in claim 7 , wherein the first electronic switch comprises: a power transistor, including a gate, a first source drain, and a second source; a first unidirectional conduction element includes a first end and a second end, wherein the first one-way is connected to the control terminal of the first electronic switch; The first end of the first unidirectional conductive element is coupled to the first end of the first electronic switch, wherein the first end is coupled to the first end of the first electronic switch The current direction of the directional conduction element is the first end of the first unidirectional conduction element to the second end of the first unidirectional conduction element; and the second unidirectional conduction element includes a first end and a a second end, wherein the first end of the second unidirectional conductive element is coupled to the second end of the first unidirectional conductive element, and the second end of the second unidirectional conductive element is coupled to the power a second source drain of the crystal, wherein a current direction of the second unidirectional conductive element is a first end of the second unidirectional conductive element to a second end of the second unidirectional conductive element; a third unidirectional conductive element comprising a first end and a second end, wherein the first The first end of the three-way conductive element is coupled to the first source drain of the power transistor, and the second end of the third one-way conductive element is coupled to the second end of the first electronic switch, wherein a current direction of the third unidirectional conduction element is a first end of the third unidirectional conduction element to a second end of the third unidirectional conduction element; a fourth unidirectional conductive element includes a first end and a second end, wherein the first end of the fourth unidirectional conductive element is coupled to the second end of the third unidirectional conductive element, The second end of the fourth unidirectional conduction element is coupled to the second source drain of the power transistor, wherein the current direction of the fourth unidirectional conduction element is the first end of the fourth unidirectional conduction element To the second end of the fourth unidirectional conduction element. The current source type AC-to-AC converter according to claim 7, wherein the second electronic switch comprises: a power transistor, including a gate, a first source drain, and a second source. a first unidirectional conduction element includes a first end and a second end, wherein the first one-way is connected to the control terminal of the first electronic switch; The first end of the first conductive element is coupled to the first source of the power transistor, and the second end of the first unidirectional element is coupled to the first end of the second electronic switch, wherein the first The current direction of the directional conduction element is the first end of the first unidirectional conduction element to the second end of the first unidirectional conduction element; and the second unidirectional conduction element includes a first end and a a second end, wherein the first end of the second unidirectional conductive element is coupled to the second end of the first unidirectional conductive element, and the second end of the second unidirectional conductive element is coupled to the power a second source drain of the crystal, wherein a current direction of the second unidirectional conductive element is a first end of the second unidirectional conductive element to a second end of the second unidirectional conductive element; a third unidirectional conduction element includes a first end and a second end, wherein the first end of the third unidirectional conduction element is coupled to the first source drain of the power transistor, the third The second end of the unidirectional conductive element is coupled to the second end of the second electronic switch, wherein the current direction of the third unidirectional conductive element is the first end of the third unidirectional conductive element to the first a second end of the three unidirectional conductive element; and a fourth unidirectional conductive element, including a first end and a second end, wherein the first end of the fourth unidirectional conductive element is coupled to the first end a second end of the third unidirectional conducting element, the second end of the fourth unidirectional conducting element is coupled to the second source drain of the power transistor, wherein the current direction of the fourth unidirectional conducting element is a first end of the fourth unidirectional conduction element to a second end of the fourth unidirectional conduction element. A current source type DC-to-DC converter includes: a single-ended primary inductor converter (SEPIC) including a first input terminal, a second input terminal, a first output terminal, a second output terminal, and a The front end inductor L1, wherein the first input end of the single-ended primary inductor converter is coupled to the positive end of the DC power supply, and the second input end of the single-ended primary inductor converter is coupled to the negative end of the DC power supply, the single The first output end of the primary inductance converter and the second output end of the single-ended primary inductance converter output an output voltage, wherein the first end of the front end inductor is coupled to the first input of the single-ended primary inductance converter a power control circuit for providing at least one pulse to the single-ended primary inductor converter for power conversion; a current feedback circuit includes a first end and a second end, wherein the first end of the current feedback circuit is coupled to the second end of the front end inductor, and the second end of the current feedback circuit is coupled to the second end a second output of the single-ended primary inductor converter, wherein the current feedback circuit is configured to return current between the first output terminal and the second output terminal of the single-ended primary inductor converter according to a specific ratio The front end inductance of the single-ended primary inductor converter is granted. The current source type DC-DC converter according to claim 11, wherein the single-ended primary inductor converter further includes: an electronic switch including a first end, a second end, and a control end The first end of the electronic switch is coupled to the second end of the front end inductor, the second end of the electronic switch is coupled to the second AC end, and the control end of the electronic switch is coupled to the power control circuit to receive the a first capacitor Cf includes a first end and a second end, wherein the first end of the first capacitor is coupled to the first end of the electronic switch; and the second inductor L2 includes a first And a second end, wherein the first end of the second inductor is coupled to the second end of the first capacitor, and the second end of the second inductor is coupled to the second input end of the single-ended primary inductor converter a unidirectional conductive element includes a first end and a second end, wherein the first end of the unidirectional conductive element is coupled to the first end of the second inductor, wherein the unidirectional conductive element The conduction direction is that the first end is turned on to the second end; a second capacitor C1 The second end includes a first end and a second end, wherein a first terminal of the second capacitor is coupled to the unidirectional conductive element, the The second end of the second capacitor is coupled to the second output of the single-ended primary inductor converter. The current source type DC-DC converter according to claim 12, wherein the current feedback circuit comprises: a feedback inductor Lf, comprising a first end and a second end, wherein the back The first end of the inductor is coupled to the second end of the front end inductor, and the second end of the feedback capacitor is coupled to the second output of the single-ended primary inductor converter.