The secondary circuit of this converter comprises a series of inductance L 1 and a capacitor C o parallel to the output; the secondary current is rectified by a diode D and applied to a load represented by a resistor R o connected to output terminals 12 and In the primary circuit, switching means S is connected in series with the primary winding This switching means S constitutes a periodic switching means, for instance a field-effect transistor FET, that is controlled by a control circuit The magnetizing inductance L m and the overall stray or parasitic capacitance C s are shown in dotted lines.
According to the present invention, the value of the input inductance L in is much greater than the total series inductance between C in and C o. The input capacitance C in is much lower than the corresponding value of the output capacitor C o.
The input capacitor C in and the series inductance L s which includes the leakage inductance of the transformer and the output inductance L 1 form a resonat circuit the period of which is:. According to the present invention, this period T is shorter than the closed or on period of the periodic switching means S. The curve 2c represents the voltage across the switch S; according to the present invention, the resonance period of the circuit constituted by the magnetizing inductance L m and the overall stray or parasitic capacitance C s is shorter than the open or off period of the periodic switching means.
As a result, the voltage across the switch S presents the shape of a half sinusoid 23; this voltage returns to zero before the new closing operation of the switch S; as a result, there is no loss in the parasitic elements L m and C s. The magnetizing current I m that is flowing through the magnetizing inductance L m must be added to the current I s of the primary winding 21 for obtaining the total primary current I p.
This means that when the current I s comes to zero after the half-sinusoid 22, the magnetizing current I m remains.
In fact, since the magnetizing current is very low, the switching losses due to the closing of the switch S are very low. In fact, according to the present invention, the quasi-resonance involves all the parasitic capacitance, i.
All these parasitic capacitances can be combined to provide a total equivalent capacitance C s connected a shown in FIG. Tuning capacitor C t includes the input capacitance C in. In this embodiment, the components that are equivalent to those of FIG. The push-pull converter uses a transformer 30 comprising a primary winding with a mid-point connection 31; the periodic switching means are constituted by two switches S1 and S2, each of these being connected in series with one end of the primary winding of the transformer Here's a way to reduce switching errors caused by leakage inductance inconsistencies in a quasi-resonant power converter.
I was working on a quasi-resonant power converter that in extremely simplified form, looked like the following sketch:. A push-pull pair of power MOSFETs would turn on and turn off in the usual alternation and when each one would turn on, its drain to source current, Ids, would rise and fall back down again along a sinusoidal curve.
That waveform contour arose from an LC resonance, but because switching events were involved, the process was actually quasi-resonant. The fly in the ointment was that the two halves of the primary winding were not exactly alike. From the way that they had been constructed, their leakage inductances were ever so slightly different, which led to switching errors as in the following sketch:. Description Customer Reviews 1. The EG driver board is a driver module dedicated to the inverter's pre-stage push-pull quasi-resonant boost.
It provides battery undervoltage buzzer and undervoltage shutdown. Strelkov, V. Quasi resonant converter for autonomous power supply. Download citation. Received : 07 April Revised : 25 November Accepted : 27 November Published : 02 February Issue Date : March Anyone you share the following link with will be able to read this content:. Sorry, a shareable link is not currently available for this article. Provided by the Springer Nature SharedIt content-sharing initiative. Skip to main content.
Search SpringerLink Search. Abstract Quasiresonant converters QRCs are increasingly being used in autonomous power supply systems. References 1. View author publications.
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