Stabilizing the Buck Converter With a First-Order-Filter-Based Time Delay Feedback Controller

Abstract

A first-order-filter-based time delay feedback (TDF) controller is proposed to stabilize the buck converter when operating with non-linear phenomena, such as bifurcation and chaos. Compared with the existing second-order filter method, the proposed controller needs only two parameters. This is similar to the ideal TDF controller and it makes the design of the controller simpler. The discrete model of the converter is used to compute one of the two parameters, which is known as the feedback gain. The frequency domain comparison of the proposed controller and the ideal TDF controller shows that the proposed controller is almost non-invasive, because it does not change the dc component of the converter and only changes slightly the harmonic at the switching frequency. The proposed controller has another structure called the extended controller, which needs three parameters. By increasing the third parameter, the feedback gain needs a larger value to stabilize the converter. The benefit of the proposed controller lies in the fact that it does not need the digital circuit that was thought to be necessary for the TDF control of the converter. Simulated and experimental waveforms verify the computation results. The added feedback signal is small enough when the switch turns on.

Keywords

• Analog circuit
• bifurcation
• chaos
• controller
• dc-dc power converter
• delay system