IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0874054
(2015-10-02)
|
등록번호 |
US-9325247
(2016-04-26)
|
발명자
/ 주소 |
|
출원인 / 주소 |
|
대리인 / 주소 |
|
인용정보 |
피인용 횟수 :
3 인용 특허 :
23 |
초록
▼
A power converter including a transformer, a resonant circuit including the transformer and a resonant capacitor having a characteristic resonant frequency and period, and output circuitry connected to the transformer for delivering a rectified output voltage to a load. Primary switches drive the re
A power converter including a transformer, a resonant circuit including the transformer and a resonant capacitor having a characteristic resonant frequency and period, and output circuitry connected to the transformer for delivering a rectified output voltage to a load. Primary switches drive the resonant circuit, a clamp switch is connected to shunt the resonant capacitor, and a switch controller operates the primary switches and the clamp switch in a series of converter operating cycles. The converter operating cycles include power transfer intervals including resonant intervals during which a resonant current at the characteristic resonant frequency flows through a winding of the transformer; and a clamp interval during which the clamp switch provides a low impedance shunt across the resonant capacitor holding the resonant capacitor at a voltage at or near zero volts. The operating cycles may also include energy recycling intervals for charging and discharging capacitances within the converter.
대표청구항
▼
1. A method of converting power between an input source and a load, where the load may vary over a normal operating range, comprising: providing a transformer;forming a resonant circuit including the transformer and a resonant capacitor and having a characteristic resonant frequency and period;provi
1. A method of converting power between an input source and a load, where the load may vary over a normal operating range, comprising: providing a transformer;forming a resonant circuit including the transformer and a resonant capacitor and having a characteristic resonant frequency and period;providing output circuitry connected to the transformer for delivering a rectified output voltage to the load;providing two or more primary switches to drive the resonant circuit;providing a clamp switch to clamp the resonant capacitor;providing a switch controller to operate the primary switches and the clamp switch in a series of converter operating cycles, each converter operating cycle characterized by:(a) two power transfer intervals of essentially equal duration during which one or more of the primary switches are ON, a magnetizing current flows in a winding of the transformer, and power is transferred between the input and the output via the transformer, each power transfer interval comprising: (i) first and second resonant intervals, each having a duration less than the characteristic resonant period, during which a resonant current flows through a winding of the transformer at the characteristic resonant frequency; and(ii) a clamp interval occurring after the first resonant interval and before the second resonant interval and having a clamp duration during which the clamp switch is ON and provides a low impedance shunt across the resonant capacitor. 2. The method of claim 1 wherein the converter operating cycles further comprise one or more energy-recycling intervals, during which the primary switches are OFF and currents in the converter are used to charge and discharge capacitances in the converter. 3. The method of claim 2 wherein the energy recycling intervals further comprise a duration which may be adjusted by adjusting the clamp duration. 4. The method of claim 3 wherein the duration of the energy recycling intervals may be adjusted as a function of the power delivered to the load. 5. The method of claim 4 wherein the duration of the energy recycling intervals may be increased in response to a decrease in the power delivered to the load. 6. The method of claim 1 wherein the switch controller adjusts the clamp duration. 7. The method of claim 6 wherein the switch controller adjusts the clamp duration as a function of power delivered to the load. 8. The method of claim 7 wherein the clamp duration is reduced in response to a decrease in the power delivered to the load. 9. A method for improving the efficiency of a Sine Amplitude Converter of the kind which comprises switches for driving a resonant circuit comprising a resonant capacitor, the resonant circuit having a characteristic resonant frequency and period, and which delivers an output current comprising a series of resonant unidirectional output current pulses, each pulse having a period substantially equal to one-half of the characteristic resonant period, the method comprising: providing a clamp switch connected to shunt the resonant capacitor; andproviding a controller to operate the switches and the clamp switch to extend the period of each unidirectional output current pulse by providing a non-resonant clamp interval, having a clamp duration, during the output current pulse;the controller operating the switches and the clamp switch in a series of converter operating cycles, each converter operating cycle characterized by: (a) two power transfer intervals of essentially equal duration during which one or more of a plurality of primary switches driving the resonant circuit are ON, a magnetizing current flows in a winding of a transformer, and power is transferred between an input source and an output circuit via the transformer, each power transfer interval comprising: (i) first and second resonant intervals, each having a duration less than the characteristic resonant period, during which a resonant current flows through a winding of the transformer at the characteristic resonant frequency; and(ii) a clamp interval occurring after the first resonant interval and before the second resonant interval and having a clamp duration during which the clamp switch is ON and provides a low impedance shunt across the resonant capacitor. 10. The method of claim 9 further comprising: turning the clamp switch ON at a time when the voltage across the resonant capacitor is at or near zero volts to provide a low impedance shunt across the resonant capacitor for the clamp duration. 11. A power conversion apparatus for converting power between an input source and a load, where the load may vary over a normal operating range, comprising: a transformer;a resonant circuit including the transformer and a resonant capacitor and having a characteristic resonant frequency and period;output circuitry connected to the transformer for delivering a rectified output voltage to the load;two or more primary switches to drive the resonant circuit;a clamp switch to clamp the resonant capacitor; anda switch controller to operate the primary switches and the clamp switch in a series of converter operating cycles, each converter operating cycle comprising:(a) two power transfer intervals of essentially equal duration during which one or more of the primary switches are ON, a magnetizing current flows in a winding of the transformer, and power is transferred between the input and the output via the transformer, each power transfer interval comprising: (i) first and second resonant intervals, each having a duration less than the characteristic resonant period, during which a resonant current flows through a winding of the transformer at the characteristic resonant frequency; and(ii) a clamp interval occurring after the first resonant interval and before the second resonant interval and having a clamp duration during which the clamp switch is ON and provides a low impedance shunt across the resonant capacitor. 12. The power conversion apparatus of claim 11 wherein the converter operating cycles further comprise one or more energy-recycling intervals during which the primary switches are OFF and currents in the converter are used to charge and discharge capacitances in the converter. 13. The power conversion apparatus of claim 12 wherein the switch controller is configured to adjust the duration of the energy recycling interval by adjusting the clamp duration. 14. The power conversion apparatus of claim 13 wherein the switch controller is configured to adjust the duration of the energy recycling interval as a function of the power delivered to the load. 15. The power conversion apparatus of claim 14 wherein the switch controller is configured to increase the duration of the energy recycling interval in response to a decrease in the power delivered to the load. 16. The power conversion apparatus of claim 11 wherein the switch controller is configured to adjust the clamp duration. 17. The power conversion apparatus of claim 16 wherein the switch controller is configured to adjust the clamp duration as a function of power delivered to the load. 18. The power conversion apparatus of claim 17 wherein the switch controller is configured to reduce the clamp duration in response to a decrease in the power delivered to the load. 19. A method of converting power between an input source and a load, where the load may vary over a normal operating range, comprising: forming a resonant circuit including an inductor and a resonant capacitor and having a characteristic resonant frequency and period;providing output circuitry connected to the resonant circuit for delivering a rectified output voltage to the load;providing a primary switch to drive the resonant circuit;providing a clamp switch to clamp the resonant capacitor;providing a switch controller to operate the primary switch and the clamp switch in a series of converter operating cycles, each converter operating cycle characterized by:(a) one or more power transfer intervals each having (i) a first and a second resonant interval, each having a duration less than the characteristic resonant period, during which a resonant current flows through the inductor at the characteristic resonant frequency and power is transferred between the input and the output via the resonant circuit; and(ii) a clamp interval, having a clamp duration, during which the clamp switch is ON and provides a low impedance shunt across the resonant capacitor and power is transferred between the input and the output via the inductor. 20. A method of converting power between an input source and a load, where the load may vary over a normal operating range, comprising: forming a resonant circuit including an inductor and a resonant capacitor and having a characteristic resonant frequency and period;providing output circuitry connected to the resonant circuit for delivering a rectified output voltage to the load;providing a primary switch to drive the resonant circuit;providing a clamp switch to clamp the resonant capacitor;providing a switch controller to operate the primary switch and the clamp switch in a series of converter operating cycles, each converter operating cycle characterized by:(a) one or more power transfer intervals each having (i) a first resonant interval, having a duration approximately equal to one quarter of the characteristic resonant period, during which a resonant current flows through the inductor at the characteristic resonant frequency and power is transferred between the input and the output via the resonant circuit; and(ii) a clamp interval, having a clamp duration, during which the clamp switch is ON and provides a low impedance shunt across the resonant capacitor and power is transferred between the input and the output via the inductor. 21. A method of converting power between an input source and a load, where the load may vary over a normal operating range, comprising: forming a resonant circuit including an inductor and a resonant capacitor and having a characteristic resonant frequency and period;providing output circuitry connected to the resonant circuit for delivering an output current at a unipolar voltage to the load;providing a primary switch to drive the resonant circuit;providing a clamp switch to clamp the resonant capacitor;providing a switch controller to operate the primary switch and the clamp switch in a series of converter operating cycles, each converter operating cycle characterized by:(a) one or more power transfer intervals each having (i) a first resonant interval, having a duration less than the characteristic resonant period, during which the output current changes sinusoidally from zero to a first value at the characteristic resonant frequency; and(ii) a clamp interval immediately following the first resonant interval, having a clamp duration, during which the clamp switch is ON and provides a low impedance shunt across the resonant capacitor, and the output current continues to flow. 22. The method of claim 21 wherein the output current changes from the first value at the beginning of the clamp interval to a second value at the end of the clamp interval. 23. The method of claim 22 wherein the first value is essentially equal to the second value. 24. The method of claim 23 wherein each power transfer interval further comprises (iii) a second resonant interval, having a duration less than the characteristic resonant period, during which the output current changes sinusoidally from the second value to zero at the characteristic resonant frequency. 25. The method of claim 22 wherein the first value is less than the second value.
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