The integral cycle control method is a technique used in AC voltage controllers to regulate the power delivered to the load. It is commonly employed in applications where precise control of the average power is required. Let's understand how this method works and why the correct answer is option 'A'.


The integral cycle control method operates by controlling the conduction angle of the thyristors in the AC voltage controller. The conduction angle refers to the portion of each half-cycle of the input AC waveform during which the thyristors are allowed to conduct. By adjusting the conduction angle, the average power delivered to the load can be controlled.


The control strategy of the integral cycle control method involves the following steps:

1. Measure the load voltage: The AC voltage controller continuously monitors the load voltage using an appropriate sensing mechanism.

2. Compare with reference voltage: The measured load voltage is compared with a reference voltage, which represents the desired output voltage level. This reference voltage can be set using a feedback control system or predetermined based on the application requirements.

3. Determine the error: The difference between the measured load voltage and the reference voltage is calculated to determine the error signal.

4. Adjust the conduction angle: Based on the error signal, the conduction angle of the thyristors is adjusted. If the load voltage is lower than the reference voltage, the conduction angle is increased to deliver more power to the load. Conversely, if the load voltage is higher than the reference voltage, the conduction angle is decreased to reduce the power delivered to the load.

5. Repeat the process: The control loop continuously monitors the load voltage, compares it with the reference voltage, and adjusts the conduction angle accordingly. This iterative process ensures that the average power delivered to the load remains controlled and regulated.


The integral cycle control method offers several advantages, which include:

- Precise control of average power: By adjusting the conduction angle, the method enables precise control of the average power delivered to the load.

- Smooth and continuous control: The control loop ensures that the power variations are gradual, avoiding abrupt changes that can cause instability or damage to the load.

- Compatibility with various loads: The integral cycle control method can be applied to different types of loads, such as resistive, inductive, and capacitive loads.

- Cost-effective implementation: The method can be implemented using simple and cost-effective circuitry, making it suitable for a wide range of applications.

Therefore, the correct answer to the given question is option 'A' - the average power delivered to the load is controlled in the integral cycle control method of the AC voltage controller.