Power conversion device and control method thereof
First Claim
1. A power conversion device, for converting a direct-current (DC) voltage to an alternating current corresponding to an alternating-current (AC) voltage according to the AC voltage, comprising:
- a power conversion unit, for converting the DC voltage to a high-frequency current having two envelops corresponding to the waveform of the AC voltage, the power conversion unit comprising;
a DC to AC conversion circuit, for converting the DC voltage to a converted voltage, wherein the amplitude of the converted voltage is substantially equal to the level of the DC voltage, and the duty cycle of the converted voltage corresponds to the absolute value of the instantaneous value of the AC voltage, wherein the DC to AC conversion circuit comprises a full-bridge inverter having four active switch elements, the four active switch elements are turned on correspondingly under control of a pulse width modulation (PWM) control signal, and the four active switch elements being turned on correspondingly are for converting the DC voltage to the converted voltage; and
an immitance conversion circuit, for converting the converted voltage to the high-frequency current by way of resonance;
an output unit, comprising;
an inductive circuit, for providing two induced currents according to the high-frequency current, wherein one induced current and the high-frequency current are in phase, and the other induced current and the high-frequency current are in antiphase;
a full-wave rectifying circuit, for full-wave rectifying the two induced currents;
an inverter circuit, for alternatively transferring the two full-wave rectified induced currents so as to output an output current; and
a filter circuit, for filtering the output current to provide the alternating current; and
a control unit, for providing the PWM control signal according to an instantaneous value of the AC voltage;
wherein, the control unit obtains an alternating current command according to a product of the absolute value of the phasor of the AC voltage and a DC current command, and the alternating current command corresponds to an instantaneous value of the alternating current;
wherein, the control unit further obtains a feed-forward signal according to a product of the alternating current command and a gain value, the feed-forward signal represents an angle, and the gain value corresponds to a ratio between effective values of the AC voltage and the alternating current; and
wherein, the control unit further provides the PWM control signal according to an angular frequency and the angle represented by the feed-forward signal, and the angular frequency corresponds to a resonance frequency of the immitance conversion circuit.
1 Assignment
0 Petitions
Accused Products
Abstract
A power conversion device is provided for converting a DC voltage to an alternating current corresponding to an AC voltage according to the AC voltage, which includes a power conversion unit and an output unit. The power conversion unit converts the DC voltage to a high-frequency current having two envelops corresponding to the waveform of the AC voltage. The output unit includes an inductive circuit, a full-wave rectifying circuit, an inverter circuit and a filter circuit. The inductive circuit provides two induced currents according to the high-frequency current, wherein one induced current and the high-frequency current are in phase, and the other induced current and the high-frequency current are in antiphase. The full-wave rectifying circuit full-wave rectifies the two induced currents. The inverter circuit alternatively transfers the two full-wave rectified induced currents, and thus output an output current. The filter circuit filters the output current to provide the alternating current.
-
Citations
20 Claims
-
1. A power conversion device, for converting a direct-current (DC) voltage to an alternating current corresponding to an alternating-current (AC) voltage according to the AC voltage, comprising:
-
a power conversion unit, for converting the DC voltage to a high-frequency current having two envelops corresponding to the waveform of the AC voltage, the power conversion unit comprising; a DC to AC conversion circuit, for converting the DC voltage to a converted voltage, wherein the amplitude of the converted voltage is substantially equal to the level of the DC voltage, and the duty cycle of the converted voltage corresponds to the absolute value of the instantaneous value of the AC voltage, wherein the DC to AC conversion circuit comprises a full-bridge inverter having four active switch elements, the four active switch elements are turned on correspondingly under control of a pulse width modulation (PWM) control signal, and the four active switch elements being turned on correspondingly are for converting the DC voltage to the converted voltage; and an immitance conversion circuit, for converting the converted voltage to the high-frequency current by way of resonance; an output unit, comprising; an inductive circuit, for providing two induced currents according to the high-frequency current, wherein one induced current and the high-frequency current are in phase, and the other induced current and the high-frequency current are in antiphase; a full-wave rectifying circuit, for full-wave rectifying the two induced currents; an inverter circuit, for alternatively transferring the two full-wave rectified induced currents so as to output an output current; and a filter circuit, for filtering the output current to provide the alternating current; and a control unit, for providing the PWM control signal according to an instantaneous value of the AC voltage; wherein, the control unit obtains an alternating current command according to a product of the absolute value of the phasor of the AC voltage and a DC current command, and the alternating current command corresponds to an instantaneous value of the alternating current; wherein, the control unit further obtains a feed-forward signal according to a product of the alternating current command and a gain value, the feed-forward signal represents an angle, and the gain value corresponds to a ratio between effective values of the AC voltage and the alternating current; and wherein, the control unit further provides the PWM control signal according to an angular frequency and the angle represented by the feed-forward signal, and the angular frequency corresponds to a resonance frequency of the immitance conversion circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
-
-
16. A control method applied in a power conversion device, wherein the power conversion device converts a direct-current (DC) voltage to an alternating current corresponding to an alternating-current (AC) voltage according to a pulse width modulation (PWM) control signal and an output control signal, the method is for providing the PWM control signal and the output control signal, and the method comprises:
-
obtaining an alternating current command according to a product of the absolute value of the phasor of the AC voltage and a DC current command, the alternating current command corresponding to an instantaneous value of an alternating current; obtaining a feed-forward signal according to a product of the alternating current command and a gain value, the feed-forward signal representing an angle, and the gain value corresponding to a ratio between effective values of the AC voltage and the alternating current; providing the PWM control signal according to an angular frequency and the angle represented by the feed-forward signal, the angular frequency corresponding to a resonance frequency of the power conversion device; and providing the output control signal according to an instantaneous value of the AC voltage. - View Dependent Claims (17, 18, 19, 20)
-
Specification