Constant amplitude constant frequency sinusoidal output inverter - has DC supply into rectifier bridge via resonant inductor and capacitor across bridge plus referenced outputs

摘要

The circuitry supplies a constant amplitude constant frequency sinusoidal ac output from a dc source. The inverter output is very tolerant to load value changes. The output frequency of the inverter is determined by an inductor in the dc source side of the rectifier bridge and by the capacitor across the centre of the bridge and across which the output potential is formed. The current through the capacitor is formed by a relationship between bridge charging currents which are time dependent, and the output current. The ac output current and the input dc are not subject to variation caused by commutators in the 'no current' switch state since they are inverted by diode circuitry. A regulator circuit maintains the time integral of the difference between the input current and the load current to zero. The dc supply to the rectifier bridge is via an electronic switching circuit and the actual current through the capacitor is referred to the reference from a reference signal source prior to being fed to output regulator circuits. A harmonic oscillator is used to provide the references for comparison with the capacitor current.