A Bipolar, High Precision, Low Ripple Power Supply

A ±600 V, ±50 Amp high precision SCR power supply has been developed for use in the Energy Doubler Correction system. The bipolar output is accomplished by means of a dual converter with circulating current for smooth zero-crossing current transitions. Absolute accuracy better than ±.025% is achieved with a high precision transductor, current reference, and other high quality components. Stability is better than 2.5 ppm/°C and voltage ripple is less than 30 mV peak to peak. Low ripple is achieved through the use of bipolar series-pass transistor bank. The dual converter (plus a passive filter) acts as a pre-regulator for the transistor bank, which has a dynamic range of 30 volts. Ripple attenuation of the transistor bank is a minimum of 60 dB from DC to 2 kHz. Microvolt level noise and pickup in the power supply regulator ultimately set the ripple level in the power supply output. A special "active ground" circuit is included to filter the common mode ripple which is inherent in SCR supplies.