Choppers converts

Question

Choppers converts

Examoogle · Accepted Answer

DC to DC

Explanation: A chopper is a static power electronic device that converts a fixed DC input voltage into a variable DC output voltage. It acts as a DC equivalent of an AC transformer, providing variable DC output by varying the duty cycle of the switching element.

Working Principle: The chopper functions by rapidly switching a power semiconductor device (like a MOSFET, IGBT, or SCR) ON and OFF between the DC source and the load. By modulating the ratio of the 'ON' time to the total switching period (duty cycle), the average output voltage is controlled. The load voltage remains DC, but its magnitude is effectively adjusted based on the duty cycle $D = \frac{T_{ON}}{T_{ON} + T_{OFF}}$.

Key Formulas: $V_{avg} = D \cdot V_s$ — Average output voltage where $D$ is duty cycle; $D = \frac{T_{ON}}{T}$ — Duty cycle definition where $T = T_{ON} + T_{OFF}$

Key Points: Choppers provide high efficiency in DC voltage regulation.; Used extensively in electric traction for speed control of DC motors.; Categorized as Step-down (Buck), Step-up (Boost), or Buck-Boost choppers.; The output waveform is a pulsed DC voltage which is often smoothed using an LC filter.

Advantages: High efficiency due to switching operation; Compact size and lower weight compared to linear regulators; Regenerative braking capability in DC drives

Disadvantages: Generates electromagnetic interference (EMI) due to high-frequency switching; Requires complex control circuitry for duty cycle modulation

Applications: Electric vehicles and battery-powered systems; DC motor speed control in industrial drives; Switch-mode power supplies (SMPS)

Additional Info: Option A (AC to DC) describes a Rectifier.. Option B (DC to AC) describes an Inverter.. Option D (AC to AC) describes an AC Voltage Controller or Cycloconverter.

Answer: C is correct — Choppers are power electronic circuits specifically designed to convert a fixed DC voltage to a variable DC voltage output.

Exam Tip: Remember the mnemonic: 'Rectifier' (AC-DC), 'Inverter' (DC-AC), 'Chopper' (DC-DC), and 'Cycloconverter' (AC-AC) to quickly identify power electronics conversion functions.

Related Questions

Discussion (0)