A comparative performance analysis of zero voltage switching class e and selected enhanced class E inverters

This paper presents a comparative analysis of the class E and selected enhanced class E inverters, namely, the second and third harmonic group of class EFn, E/Fn and the class E Flat Top inverter. The inverters are designed under identical specifications and evaluated against the variation of switching frequency (f), duty ratio (D), capacitance ratio (k), and the load resistance (RL).

To offer a comparative understanding, the performance parameters, namely, the power output capability, efficiency, peak switch voltage and current, peak resonant capacitor voltages, and the peak current in the lumped network, are determined quantitatively. It is found that the class EF2 and E/F3 inverters, in general, have higher efficiency and comparable power output capability with respect to the class E inverter.

More specifically, the class EF2 (parallel LC and in series to the load network) and E/F3 (parallel LC and in series to the load network) maintain 90% efficiency compared to 80% for class E inverter at the optimum operating condition. Furthermore, the peak switch voltage and current in these inverters are on average 20–30% lower than the class E and other versions for k > 1.

The analysis also shows that the class EF2 and E/F3 inverters should be operated in the stretch of 1 < k < 5 and D = 0.3–0.6 at the optimum load to sustain the high-performance standard.