A single phase half wave controlled SCR converter with a commutating diode an RL Load at an average load voltage of 150V at firing angle of 60 .The supply voltage to the converter is?

Question

Answer

Single Phase Half Wave Controlled SCR Converter with Commutating Diode and RL Load

Problem Statement

A half wave controlled SCR converter with a commutating diode and RL load is operating at an average load voltage of 150V and a firing angle of 60 degrees. What is the supply voltage to the converter?

Solution

The half wave controlled SCR converter with a commutating diode and RL load can be represented by the following circuit diagram:

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Calculating the Load Voltage

The load voltage for an RL load can be calculated using the following formula:

V_L = V_m * (1 - e^{-R/L * t})

Where V_m is the peak voltage of the AC supply, R is the load resistance, L is the load inductance, and t is the time.

For a half wave controlled SCR converter, the average load voltage can be calculated using the following formula:

V_L,avg = V_m / π * (1 - cos(α))

Where α is the firing angle.

Substituting the given values, we get:

150 = V_m / π * (1 - cos(60))

V_m = 150 * π * 2 / √3

V_m = 546.76V

Calculating the Supply Voltage

The supply voltage can be calculated by adding the voltage drop across the SCR and the commutating diode to the peak load voltage.

The voltage drop across the SCR can be calculated using the following formula:

V_SCR = V_T * ln(I_L / I₀)

Where V_T is the voltage drop across the SCR, I_L is the load current, and I₀ is the holding current.

The voltage drop across the commutating diode can be assumed to be negligible.

Assuming a typical value of V_T = 1V and I₀ = 10mA, we can calculate the load current as:

I_L = V_L / R

I_L = 150 / 10

I_L = 15A

Substituting the values, we get:

V

Answer

Similar Electrical Engineering (EE) Doubts

A single-phase half-wave controlled converter with resistive load is operated from a 120 V, 50 Hz supply. If the average output voltage is 25% of the maximum possible output voltage, the firing angle of the thyristor would be equal to

For a single-phase half-wave-controlled converter system, sketch waveforms for load voltage and load current for (i) RL load and (ii) RL load with freewheeling diode across RL. From a comparison of these waveforms, discuss the advantages of using a freewheeling diode?

For the waveform (as shown below), which of the options is true?

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