One-stage power factor correction (PFC) with output electrical isolation. The converter has a configuration of combining a boost circuit and a forward circuit in one power stage. To relieve the voltage spike caused by the leakage inductance of the power transformer, two bulk storage capacitors are used. The same power switch is shared by the PFC circuit and the power conversion circuit. Due to its simplified power stage and control circuit, this converter presents a better efficiency (87%), lower cost and higher reliability. Detailed steady state analysis results show this novel converter has both good power factor correction and excellent regulation capabilities. With PSPICE simulation and experimental results, a measured power factor of 0.99 was obtained by this single switch converter.
This invention relates to AC to DC converters. This invention is a Continuation-In-Part of U.S. Provisional Patent Application 60/050,476 titled "AC/DC Converters" filed Jun. 23, 1997.
An electronic converter having an input circuit and an output circuit which, in addition to the converter function, carries out power-factor correction. A control circuit opens and closes an electronic switch as a function of the output voltage from the converter circuit and the voltage which is dropped across a current measurement sensor. The circuit has a logic ground LM and a power ground PM at different electrical potentials.
A rectifier circuit matched for power factor correction. A first diode (D1), a second diode (D2), a third diode (D3) and a fourth diode (D4) are in a bridge arrangement. A first pole (10) and a second pole (12) of the bridge arrangement are connected to a source (U) which has at least one AC voltage component. An inductance (L1) is arranged in series with the third pole (14) or the fourth pole (16) of the bridge arrangement. A capacitance (C1) is connected between the first pole (10) and the second pole (12), and two of the four diodes (D1, D2, D3, D4) are in the form of fast diodes.
The invention relates to a circuit for power-factor correction having a rectifier (14) which can be connected on the input side to an AC voltage source (10) and which is connected on the output side to at least one series circuit comprising a capacitor (CS1) and a diode (DS1), with the diode (DS1) being arranged such that the capacitor (CS1; CS2) cannot be charged through the diode (DS1; DS2) by the output signal from the rectifier (14), a first and a second electronic switch (T1, T2) connected in series as part of a half bridge or full bridge, each having a freewheeling diode (DF1; DF2) connected in parallel with the switch (T1; T2) and, with the [lacuna] formed by the junction point between the first and second switches (T1, T2) [lacuna] an output connection of the half bridge or full bridge is on the one hand connected via an inductance (L) to a point on the connection of the capacitor (CS1) and diode (DS1) of each series circuit comprising a capacitor (CS1) and a diode (DS1), and on the other hand forms a connection for a load (LD), and the signal at this connection during operation is at a considerably higher frequency than the output signal from the AC voltage source (10), an energy-storage capacitor (CS) which is connected in parallel with the two switches (T1, T2) and at least one further diode (DP1; DP2) which is arranged between the energy-storage capacitor (CS) and the rectifier (14) in such a manner that the energy-storage capacitor (CS) cannot be discharged through the rectifier (14).
To provide an AC/DC converter including a resonant converter which reliably supplies a constant DC power supply voltage (U.sub.out) in a wide output power range, while using a minimal number of components, and in which the input impedance of the AC/DC converter should have a minimal reactive impedance, both a capacitive (C2) and an inductive (n3) coupling of the resonant converter (8) to a point (5) between the resonant converter (8) and a rectifier arrangement (1) is provided. The rectifier arrangement is used for rectifying an AC voltage (U.sub.in) applied to the AC/DC converter.
A regulated, switch mode power converter is described. An embodiment of the present invention provides regulated, switch mode power conversion from alternating current to direct current utilizing a single transistor and associated switching scheme. Embodiments of the present invention are useful in a variety of applications, including, for example, photo control applications.
