초록 ▼

An inverter has a resonant circuit composed of a parallel connected inductor and capacitor and a filter capacitor connected in series with the inductor which has a capacitance substantially greater than the resonant capacitor. A half bridge or full bridge switching circuit formed of pairs of gate co

An inverter has a resonant circuit composed of a parallel connected inductor and capacitor and a filter capacitor connected in series with the inductor which has a capacitance substantially greater than the resonant capacitor. A half bridge or full bridge switching circuit formed of pairs of gate controlled switching devices is connected to a DC power supply and to the resonant circuit and filter capacitor, with the switching devices being switched to provide a relatively high frequency, e.g., 20 KHz or higher, resonant current in the resonant circuit. The filter capacitor is of a size such that the high frequency component of the current flowing in the resonant circuit does not result in a substantial voltage at the switching frequency appearing across the filter capacitor. In addition to the high frequency switching current in the resonant circuit, the switching frequency and the duration of switching is adjusted in a controlled manner such that a lower frequency AC component appears in the current flowing in the resonant circuit and through the filter capacitor such that a voltage at the lower frequency component appears across the filter capacitor.

대표청구항 ▼

Quasi-resonant current mode power conversion apparatus comprising: (a) a resonant circuit having a resonant inductor and a resonant capacitor connected in a parallel configuration with respect to each other; (b) a filter capacitor connected in series with the resonant inductor and having substantial

Quasi-resonant current mode power conversion apparatus comprising: (a) a resonant circuit having a resonant inductor and a resonant capacitor connected in a parallel configuration with respect to each other; (b) a filter capacitor connected in series with the resonant inductor and having substantially greater capacitance than the resonant capacitor, the output voltage across the filter capacitor being the output voltage of the power conversion apparatus; (c) a switching circuit including at least two switching devices, which are controllable to be turned on and off, connected together at a node to which the resonant inductor and capacitor are connected; (d) control means for switching the switching devices to cause a stable resonant oscillation in the resonant circuit when the switching circuit is provided with a supply voltage such that a high frequency AC resonant voltage oscillation is maintained across the resonant circuit and a lower frequency sinusoidal oscillation is maintained across the filter capacitor, the control means switching the switching devices on and off when the inductor current reaches selected minimum and maximum envelope values such that the average value of the inductor current yields a desired waveform which is at a substantially lower frequency than the frequency of switching of the switching devices.