| 摘要 |
An electricity supply apparatus has an input for receiving a direct current electricity supply,and has a converter arranged to convert the electricity supply received by the input to generate, at an output, a voltage waveform of alternating polarity, which alternates in repeated cycles. A value A is given by the integral over a half cycle of the voltage waveform of the difference between: (i) the square of the instantaneous voltage; and (ii) the average value of the square of the voltage, the integral being taken only when the square of the instantaneous voltage exceeds the average value of the square of the voltage. A value B is given by the integral over a half cycle of the voltage waveform of the square of the instantaneous voltage. The ratio A:B is not greater than 0.2. The converter may be arranged to generate the voltage waveform such that it is in anti-phase with a substantially sinusoidally alternating electricity supply. |
