摘要:
A flyback converter has a main switch coupling a primary winding of a transformer between supply terminals, a duty cycle of the main switch controlling an output of the converter derived from a secondary winding of the transformer. Soft (zero voltage) switching of the main switch is facilitated by a snubber capacitor in parallel with the main switch. An auxiliary circuit coupled in parallel with the snubber capacitor and main switch includes a series-connected auxiliary switch, capacitor, and inductor coupled via another inductor to a full wave rectifier arrangement for recovering energy from the snubber capacitor. Resonant circuits provided by the auxiliary circuit facilitate soft switching of the auxiliary switch for low power loss and high frequency operation. The switches can be MOSFETs with reverse-poled diodes in parallel with their drain-source paths.
摘要:
In a power factor corrected AC-to-DC power supply system, a DC-to-DC power converter is coupled to the output of an AC-to-DC power converter in order to produce a regulated DC output signal from a rectified AC input signal. The AC-to-DC power converter and the DC-to-DC power converter each includes a switch for controlling the operation of their respective power converter. The AC-to-DC converter includes an inductor. The system provides power factor correction for minimizing harmonic distortion by including a controller that receives the regulated DC output voltage as a feedback signal, and in response, produces a series of drive pulses having predetermined constant duty cycle. These pulses are simultaneously fed to each switch, to operate the respective converters alternately between ON and OFF states. When the AC-to-DC converter is driven by a fixed duty cycle of the series of pulses, power factor correction is improved since the current flowing through the inductor is substantially proportional to the waveform of the rectified AC input signal. By preselecting the value of the inductor, the AC-to-DC converter is operable in a discontinuous mode when the instantaneous rectified AC input signal is low and in a continuous mode when the instantaneous rectified AC input signal is high.
摘要:
Provided are methods, circuits, and systems for obtaining power from a power generator such as a photovoltaic cell or a fuel cell. The methods, circuits, and systems comprise converting substantially DC output power from the power generator into a high frequency AC voltage while rejecting or minimizing oscillations in the output power from the power generator; converting the high frequency AC voltage into a high frequency substantially sinusoidal voltage or current; and converting the high frequency substantially sinusoidal AC voltage or current into (i) a DC voltage or current, and (ii) a low frequency substantially sinusoidal AC voltage or current; wherein the high frequency substantially sinusoidal AC voltage or current is isolated from the DC voltage or current or the low frequency substantially sinusoidal AC voltage or current.
摘要:
Resonant DC/DC converters are disclosed. The DC/DC converters according to the present invention include a bridged inverter, a resonant circuit, a high frequency transformer and a rectifying circuit. The high frequency transformer has a tertiary winding. The resonant circuit consists of a series resonant branch connected to the transformer primary winding and a parallel resonant branch connected across the tertiary winding. The converters require less capacitive components and lend themselves well to miniaturization.
摘要:
The invention provides a digital active EMI filter that removes, minimizes, or reduces unwanted interference (i.e., EMI noise) generated by a power circuit such as, for example, a power converter. Digital active filtering includes digital sampling of the incident noise signal amplitude and frequency, discrete time conversion of the EMI noise source, processing (e.g., inverting) the digital signal, and then constructing an analog output signal (i.e., an EMI compensation signal) which is injected to the input of the power circuit. A digital EMI filter as described herein may be used in both differential-mode and common-mode configurations, and overcomes limitations of passive and active analog EMI filters.
摘要:
A resonant power converter circuit stage can be configured to: i) receive a rectified voltage derived from an AC input voltage; ii) convert the rectified voltage to an internal voltage based on the application of a duty cycle that varies depending on the input voltage and the output dynamic load, and iii) convert the internal voltage to a DC output voltage for driving the dynamic load based on application of a switching frequency that varies depending on a dynamic load. The efficiency of the power converter system can be increased by setting the internal DC voltage magnitude to be load adaptive. Variation of the internal DC voltage depending on the dynamic load enables the resonant converter circuit to operate at a switching frequency near its optimum resonance frequency. This method results in constant power converter system efficiency over a wide range of loading. In order to further increase the light load efficiency interleaved resonant power converters with load, adaptive internal DC voltage are used.
摘要:
A controller circuit in a power supply system is configured to simultaneously control both a voltage regulator circuit and a dynamic power supply circuit. The controller circuit monitors voltage produced by the voltage regulator circuit. The voltage regulator circuit conveys power from a voltage source to a dynamic load such as a microprocessor, whose power consumption can change rapidly change during operation. Depending on a state (e.g., current value, trend, etc.) of the monitored voltage applied to the load by the voltage regulator circuit, the controller circuit can initiate activation of the dynamic power supply circuit in parallel with the voltage regulator circuit to selectively supply additional power to the load. Supplying additional power to the dynamic load during heavy load conditions prevents the regulated voltage supplied to the load from falling below a threshold value.
摘要:
A power supply system includes multiple power converter phases. A controller (e.g., a processor device, ASIC) monitors an output voltage generated by a combination of multiple power converter phases that supply power to a load. Based on the monitoring, the controller determines: i) a magnitude of an error signal representing a relative difference between the output voltage and a predetermined setpoint value, and ii) a rate-of-change associated with the output voltage. The controller compares the rate-of-change to threshold criteria. In response to detecting that the rate-of-change associated with the output voltage exceeds a threshold value, the controller adjusts a time of turning on of a phase switch (e.g., a power switch configured to convey an input voltage to an inductor that in turn delivers energy to the load) in one or more of the multiple power converter phases depending on the magnitude of the error signal.
摘要:
A constant frequency full resonant mode dc/dc converter is provided, suitable for use in low voltage, high current dc power distribution systems. The converter comprises a full-bridge inverter, a resonant circuit, an output transformer, an output diode rectifier, a dc output filter, and a control circuit. The resonant circuit consists of a series branch and a parallel branch. The components of the resonant circuit are selected such that a sinusoidal voltage waveform is achieved across the parallel branch, and an overall lagging current is obtained at the output of the full-bridge inverter for a desired range of output voltage control and no-load to full-load operating conditions.
摘要:
An AC/DC converter is provided, suitable for use in an advanced single phase, sine wave voltage, high frequency power distribution system, such as that used on a 20 kHz Space Station Primary Electrical Power Distribution System. The converter comprises a transformer, a resonant network, a current controler, a diode rectifier and an output filter. The voltage source is converted into a sinusoidal current source. The output of this current source is rectified by the diode rectifier and is controlled by the current controller. The controlled rectified current is then filtered by the output filter to obtain a constant voltage across the load.