| 摘要 |
1. AC/AC-converter with DC-intermediate circuit for feeding an ohmic-inductive or inductive load (L), with a rectifier (G), a DC-regulating circuit, a filter capacitor (D4) which feeds the load (L) through a DC/AC-converter (S1 - S4), and with auxiliary circuits comprising an oscillator for controlling the switching means of the DC/AC-converter in order to feed the load with the voltage delivered by the DC/AC-converter, characterized in that it comprises a smoothing capacitor (C2) capable to be charged on the one hand as a function of the current in the load and on the other hand at slow rate by the rectifier for producing a substantially constant under no load however intermittent supply voltage for the auxiliary circuits which control the DC/AC-converter, and in that the DC-regulating circuit comprises a blocking converter (S7, T5, Ck, Rk, D8 ; S7, T5, T4, C5) which is connected to the output of the rectifier (G) delivering a full-wave rectified voltage, said blocking converter being periodically switched on by a signal of a control circuit (5, 6, 7) having a frequency higher than the frequency which feeds the converter and a constant pulse width, for controlling the current delivered by the rectifier (G) for loading the filter capacitor (C4), so that the current drawn from the mains is maintained at least substantially sinusoidal. |
