Single Phase Full Wave Controlled Rectifier with RL Load | New Topic 2025

In this note, we are going to know about Single Phase Full Wave Controlled Rectifier with RL Load. Welcome to Poly Notes Hub, a leading destination for engineering notes for diploma and degree engineering students.

Author Name: Arun Paul.

What is Single Phase Full Wave Controlled Rectifier with RL Load?

A Single Phase Full Wave Controlled Rectifier with an RL Load is an AC to DC converter that converts a single-phase AC input voltage to a controlled DC output voltage via thyristors (SCRs). This sort of converter is widely used in applications that require controlled DC power, such as motor drives, battery charging, and power supplies.

Circuit Diagram of Single Phase Full Wave Controlled Rectifier with RL Load

• Input Voltage Source: A 1 phase AC voltage source.
• Thyristors (SCRs): 4 Thyristors or SCRs (T1, T2, T3, T4) arranged in a full bridge connection.
• Load: RL load (Resistive and Inductive) connected across the output terminals of the bridge circuit.
• Control Circuit: Provides gate pulses to the thyristors to control the output voltage by varying the firing angle.

Working Principle of Single Phase Full Wave Controlled Rectifier with RL Load

In a single phase full wave controlled rectifier with RL load, the operation can be explained separately for the positive and negative half cycles of the AC input voltage.

During the positive half cycle, the AC input voltage is positive, and thyristors T1 and T2 are forward-biased. At the firing angle α, gate pulses are provided to T1 and T2, turning them on. Current then flows through T1, the load, and T2, delivering power to the load. The output voltage across the load follows the input voltage from the firing angle α until the end of the positive half cycle at π. The inductive nature of the load causes the current to lag behind the voltage, which ensures that the current continues to flow even beyond π, until it naturally commutates.

In the negative half cycle, the AC input voltage reverses polarity, making thyristors T3 and T4 forward biased. At a firing angle π+α, gate pulses are applied to T3 and T4, turning them on. Current flows through T3, the load, and T4, again delivering power to the load. The output voltage follows the negative half of the input voltage from π+α to 2π. As in the positive half cycle, the inductive load ensures that the current lags, allowing for continuous conduction even after the input voltage crosses zero.

By controlling the firing angle α, the average DC output voltage can be regulated, making the converter suitable for applications like DC motor drives and controlled DC power supplies.

Advantages of Single Phase Full Wave Controlled Rectifier with RL Load

Here are some advantages of Single Phase Full Wave Controlled Rectifier with RL Load –

1. It has wide range of output voltage control ability.
2. Is has High efficiency due to controlled conduction of SCRs.

Disadvantages of Single Phase Full Wave Controlled Rectifier with RL Load

Here are some disadvantages of Single Phase Full Wave Controlled Rectifier with RL Load –

1. This type of circuit has high harmonic content in the input current.
2. It requires complex control circuitry to generate gate pulses.

Applications of Single Phase Full Wave Controlled Rectifier with RL Load

Here are some applications of Single Phase Full Wave Controlled Rectifier with RL Load –

1. DC motor drives.
2. Battery charging.
3. Power supplies with controlled DC output.