Generalized Analysis of Load-Independent ZCS Parallel-Resonant Inverter

Load‐independent inverse class‐E ZVS inverter and its application to wireless power transfer systems

“…It is seen from Figure 12(a) that both the original and load‐independent inverters kept the output voltage constant at light loads. The original inverter kept the output voltage constant at light load without load‐independent design due to the parallel resonant filter characteristics [16]. We also see from Figure 12(a) that the output voltage of the WPT system with the original inverter decreased as the output power increased, which is a natural characteristic of the class‐E switching circuits [2].…”

“…The CV‐type load‐independent parallel‐resonant inverter was proposed in ref. [16]. Besides, the CC‐type ZVS parallel resonant inverter was presented in ref.…”

“…While the load‐independent inverse class‐E inverter in refs. [16] and [17] can keep the CV with ZCS, the proposed inverter achieves the CC, satisfying the ZVS condition against load variations. Besides, a WPT system with the proposed inverter was designed and implemented.…”

“…The load-independent operation, which is a particular operating mode of the resonant inverter, has a possibility to solve the above problems. The load-independent class-E inverter [13][14][15][16][17][18] consistently achieves both the soft switching and the constant output current (CC) or constant output voltage (CV) at any load resistances. About 30 years ago, the first proposal for the load-independent class-E inverter was made [13].…”

“…Therefore, the class-E type topology is suitable for realising load-independent operation. The load-independent mode has been applied to class-E [14], inverse class-E [16,17], and class-EF [19] inverters until now. In recent years, the load-independent operation has been attracting attention because this characteristic is suitable for the WPT systems [19][20][21][22][23][24][25][26][27][28][29].…”