Excitation system by contactless power transfer system with the primary series capacitor method

For power transfer to the rotor circuit of excitation-type synchronous motors, we propose a contactless power transfer system with a primary series capacitor (S topology) to compensate for the leakage reactance. This system does not contain secondary resonant and smoothing capacitors and can reduce the number of components in the rotor circuit. The value of the primary resonant capacitor is determined such that the input power factor is set to one for the operating frequency. The rotating shaft of the rotor is covered with an aluminum sheet to reduce the loss due to the leakage flux. Power transfer tests were performed. A high efficiency of 91.8% was achieved when power was transferred to the rotor circuit of the synchronous motor.