Tighter control with digital burst firing

 

In the past it has been common for thyristors to control power delivery by using time proportioning power switching. This simply means that the power is switched to the load for time t with a total cycle time of T. Where the ratio t/T equates to the percentage power demand from the analogue input to the thyristor (see fig. 1).

 

Burst Firing Time Graph

This method of burst-fire power delivery has two main drawbacks; firstly, the cycle time is usually fixed by the product/manufacturer, which affects the control resolution. Secondly, and depending on the defined cycle time and power demand, there can be significant periods of ‘off-time’, which in turn will result in ineffective power supply to the load elements, especially those with lower thermal inertia.

 Burst Firing Cycle Time

 

 

Industry strives for improved process control; we know this results in improved efficiency and reduced costs, so why should this logic stop with the sensing and control functions within the process? Power switching can also play its part.

 

The CD Automation range of  thyristors has been designed with a unique digital algorithm, which determines  the smoothest power delivery over a user definable cycle time. This intelligent firing gives the ability to control with a resolution of up to 0.2% with a minimum ‘off-time’ of 20mS, both ensuring the power delivery control is as accurate and efficient as any other link in the process control.

 

Digital Burst Firing is available on all CD Automation Thyristor Power Controllers. Refer to our Thyristor home page for more information or view our Thyristor Application Product Selector, alternatively simply complete the 'Contact us' form to the left including your question and we will be pleased to help .