| 摘要 |
<p>The chopper capacitance (C1) is connected across the uncontrolled rectifier output (Ve) via a protective diode (D5) and an inductance (L1). A MOS power transistor (Q1) is connected between the diode/inductance node and the earthed rectifier terminal. Inductance, diode and MOST constitute a voltage raising circuit. The output (Vs) is taken from the secondary of a transformer (T1) with an extension primary winding (T1') controlling a second MOST(Q1'), operating synchronously with the first. This is connected across the capacitor (C1), in series with a further diode (D4), producing the normal virtually constant chopped current, while the inductance circuit contributes an additional power factor related component. The combined wave-form closely follows that of the current input to the uncontrolled rectifier.</p> |
