For a full wave bridge inverter, the output voltage (Vo).

Question

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$V_o = V_s$ for $0 < t < \frac{T}{2}$

Explanation: In a single-phase full-bridge inverter, the output voltage waveform switches between $+V_s$ and $-V_s$ depending on which pair of switches is triggered. During the interval $0

Working Principle: The full-bridge inverter uses four controlled switches arranged in a bridge topology. By alternating the conduction of switch pairs (S1-S4 and S2-S3) with a period $T$, a square wave output is generated across the load. When S1 and S4 are gated, the load terminal sees $+V_s$; when S2 and S3 are gated, the load terminal sees $-V_s$. This ensures the load receives an alternating voltage despite being supplied by a DC source.

Key Formulas: $V_{o(rms)} = V_s$ — The RMS output voltage for a square wave inverter; $f = \frac{1}{T}$ — Relationship between frequency and switching period

Key Points: Full-bridge inverters provide twice the output voltage compared to half-bridge configurations for the same DC source.; The output voltage is a square wave with peak magnitude equal to the DC supply voltage $V_s$.; Requires four switches (IGBTs or MOSFETs) with corresponding anti-parallel diodes.

Advantages: Higher output voltage capability; Better utilization of DC source

Disadvantages: Higher switch count compared to half-bridge; Requires more complex gate drive circuitry

Applications: Uninterruptible Power Supplies (UPS); Variable Frequency Drives (VFD)

Additional Info: Option A is incorrect because $V_s/2$ is the output of a half-bridge inverter.. Option D is incorrect because the period defined is for one half-cycle, not a phase-shifted representation.

Answer: B is correct — For a full-bridge inverter, the output voltage is equal to the DC source voltage $V_s$ during the conduction interval of the first pair of switches ($0

Exam Tip: Always remember that in bridge inverters, the full DC bus voltage is applied to the load, whereas in half-bridge, only half the bus voltage is available due to the capacitive center tap.

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