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A method for estimating and compensating the zero introduced by the capacitor equivalent series resistance (ESR) in the buck converter transfer function is introduced. The method is well-suited for practical implementation with digital controllers. The ESR zero is estimated by online measurement of the output voltage ripple and the power stage corner frequency. Accordingly, the coefficients of the...
The combination of non-linear control and linear control proposed in [1] has a very fast transient response (voltage step from 1 V to 1.5 V in 2 mus). In order to achieve this fast transient response the non-linear scheme is based on measuring the current of the output capacitor of a Buck converter. The design of this current sensor is complex due to parasitic effects such as component tolerances...
Achieving faster dynamic response is one of the big challenges for the future microprocessor voltage regulators (VR). It is well known that the system bandwidth needs to be higher to get a faster dynamic response but the system bandwidth is usually limited by the phase shift near the switching frequency. In this paper, the existing theories for this phase shift and efforts to achieve a faster transient...
Multiphase interleaved buck converter is a widely used topology to power high current microprocessor load in voltage regulator (VR) applications. The current in each phase of the VR is required to be balanced under static and dynamic load conditions without high amplitude beat frequency oscillation. A voltage mode controlled phase current balancing technique is presented in this paper followed by...
In radio systems linear power amplifiers (class A, B or AB) are usually used as a solution for the power amplifier stage. These amplifiers have high linearity, but suffer from low efficiency when the transmitted signal has low peak-to-average power ratio. The Kahn envelope elimination and restoration (EER) technique is used to enhance efficiency of RF transmitters, by combining highly efficient, nonlinear...
This paper proposes a group of high performance filters for fundamental positive / negative sequences and harmonics detection under varied grid conditions based on a basic filter cell. The filter cell is demonstrated to be equivalent to a band-pass filter in the stationary frame, and is easily implemented using a multi-state-variable structure. To achieve high performance in different grid conditions,...
This paper analyzes the tuning of the phase locked loops (PLLs) employed in the control of power converters when there is distortion in the AC mains. The pros and cons of different optimization approaches are studied. In a general way, PLLs with a low bandwidth (low-gain PLLs) are required when handling with distorted. This paper proves that the tuning of low-gain PLLs have more than one trade-off...
When a power factor corrector (PFC) is designed with a relatively fast output-voltage feedback loop, the static and the dynamic behaviour of the power stage is different to that obtained with a slow output-voltage feedback loop. This is because of the influence of the voltage ripple that is present on the control signal. This voltage ripple generates a parasitic feedback loop, which is different to...
Digital power supplies have gained traction as they provide programmability, ease of use, and higher performance. Powerful modern processors can be leveraged to implement complex control algorithms that lead to higher efficiency and faster transient response. One of the major barriers in adopting digital control for isolated power supplies is the need to send digital rather than analog information...
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