Parallel inverter switching frequency per device In a classic parallel inverter (class-B type commutation), how many times is each thyristor turned on during each output cycle?

Introduction / Context:
A parallel inverter uses commutating components in a parallel resonant path to turn SCRs off and generate an AC output across the load. Understanding device gating counts per cycle is useful for gate-drive timing and loss estimation.

Given Data / Assumptions:

• Idealized parallel inverter producing a quasi-square AC output.
• Two main SCRs that conduct alternately each half-cycle.

Concept / Approach:

In each half cycle of the output, one SCR conducts while the commutation network prepares to transfer conduction to the other device. Thus, over one full output cycle (two half cycles), each SCR is gated once and conducts for one half cycle.

Step-by-Step Solution:

Verification / Alternative check:

Typical timing diagrams for parallel inverters show one gate pulse per device per cycle, with natural commutation via the resonant components.

Why Other Options Are Wrong:

Options suggesting more than one turn-on per device per cycle do not reflect the standard two-device, square-wave operation without PWM.

Common Pitfalls:

Confusing parallel inverters with high-frequency PWM inverters where devices may commutate multiple times per fundamental cycle.

Final Answer:

Each thyristor is turned on once during each cycle