Output voltage waveform of a single-phase half-bridge inverter (unmodulated) What is the basic shape of the line-to-neutral output voltage for a half-bridge inverter using equal DC-link capacitors and 180° conduction (no PWM)?

Introduction / Context:
The half-bridge inverter is a fundamental single-phase topology that produces an AC output from a DC link. Without pulse-width modulation (PWM) or filtering, the raw output waveform is set by the switching pattern rather than the load alone.

Given Data / Assumptions:

• Two switches with complementary gating (180° conduction).
• Split DC link with midpoint to form the neutral.
• No output filter; unmodulated operation.

Concept / Approach:

When the top device conducts, the output node is tied to +Vdc/2; when the bottom device conducts, it is tied to −Vdc/2. With ideal devices and hard switching, the output toggles between two constant levels. Thus the time-domain output voltage is a two-level square wave (line-to-neutral). A sinusoidal output would require modulation plus filtering.

Step-by-Step Solution:

Verification / Alternative check:

Fourier analysis of the square wave shows odd harmonics; adding an LC filter or PWM can approximate a sinusoid, but the native inverter output remains square.

Why Other Options Are Wrong:

(a) and (c) would require specific modulation or filtering; (d) incorrectly attributes shape to load; (e) sawtooth is not produced by standard half-bridge switching.

Common Pitfalls:

Confusing inverter output before filtering with the filtered load voltage; assuming load inductance alone makes it sinusoidal.

Final Answer:

Square