The first two installments of the article “Understanding The Right Half Plane Zero” derived the origins of the right half-plane zero and discovered how it could affect converter dynamics. If we know where it hides, we still need to explain how to deal with it when it comes to compensation. Compensating a converter means shaping the loop-gain ac response T(s) via a compensation network – usually an operational amplifier and a gang of RC elements – featuring a specific small-signal response G(s). Within this response, the designer will adequately place poles and zeros to locally boost the phase in the vicinity of the crossover frequency and make sure enough phase and gain margins exist in all operat- ing conditions. The object here is where to place these poles and zeros when a vicious RHPZ plagues the design. These issues are discussed in the third part of this series, in this article titled “Compensating The RPHZ In A CCM Boost Converter: The Analytical Way.”
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