| 摘要 |
<p>A modulation method for a pulse width modulator in the inverter section (11) of a frequency converter provided with a voltage intermediate circuit, said frequency converter comprising a single-phase mains bridge (10) to be connected to a single-phase alternating current source (U L , N), a direct-voltage intermediate circuit and a controlled load bridge (11) for feeding a three-phase alternating voltage (U R , U S , U T ) of varying frequency and amplitude into a load (13), for controlling the semiconductor switches of the inverter section, in which low-capacitance direct-voltage intermediate circuit the waveform of the intermediate-circuit voltage in a normal load situation follows the absolute value of the supply network voltage, and wherein the modulation is implemented using an estimate value of the intermediate-circuit voltage to control the semiconductor switches of the inverter section.</p> |
