Voltage clamped parallel resonant converter with controllable duty cycle
First Claim
1. A parallel resonant converter for transferring electrical power between a power source and a load, comprising:
- a first switch circuit for coupling the source to the load;
a link circuit for generating link signal pulses connected between the source and the first switch circuit, said link circuit containing a parallel resonant tank circuit with a resonant capacitor connected in parallel to the first switch circuit; and
the link circuit containing link switches which are electronically switched to generate a train of link voltage pulses that are transmitted to the output terminals of the first switch circuit with each voltage pulse consisting of a zero and non-zero segment and both segments being continuously and independently controllable in duration by said link switches.
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Accused Products
Abstract
A high efficiency static voltage clamped parallel resonant converter for converting power between two AC and/or DC circuits includes a link circuit between an input switch circuit and an output switch circuit. The link circuit comprises a parallel resonant circuit and link switch elements which are switched to generate a unipolar train of link voltage pulses. All of the switches are "soft-switched" on and off at substantially zero voltage or zero current. Each link voltage pulse consists of a zero segment and a non-zero segment. The duty cycle of these voltage pulses is controllable by the link switches and such that the duration of the zero and non-zero segments are independently controllable. Pulse width modulation (PWM) and pulse area modulation (PAM) can be applied for reduced filtering requirements and maintaining high efficiency for operation at fractional load conditions. The link voltage is clamped to a maximum voltage during the non-zero segment of each link voltage pulse. Resonant oscillation due to the resonant circuit is active only during the transitions between the zero and non-zero voltage levels of the link voltage pulses. As a result, all converter components will be exposed to voltage and current levels which are higher than the load voltage and current levels by just a small fraction.
82 Citations
20 Claims
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1. A parallel resonant converter for transferring electrical power between a power source and a load, comprising:
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a first switch circuit for coupling the source to the load; a link circuit for generating link signal pulses connected between the source and the first switch circuit, said link circuit containing a parallel resonant tank circuit with a resonant capacitor connected in parallel to the first switch circuit; and the link circuit containing link switches which are electronically switched to generate a train of link voltage pulses that are transmitted to the output terminals of the first switch circuit with each voltage pulse consisting of a zero and non-zero segment and both segments being continuously and independently controllable in duration by said link switches. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of operating a parallel resonant converter to transfer electrical power between a power source and a load, wherein the load voltage waveforms are synthesized by the converter, including the steps of:
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generating link voltage pulses having zero voltage segments and non-zero voltage segments in a link circuit; transmitting the link voltage pulses to the output terminals of a first switch circuit connected between the link circuit and the load; controlling the duration of the zero and non-zero segments of each link voltage pulse so that the duty cycle of such pulses may be controlled continuously during the generation of said link signals; and limiting the maximum voltage of said link voltage pulses to a predetermined voltage. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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Specification