Boost DC/DC converter nonlinearity and RHP-zero: Survey of the control-to-output transfer function linearization methods

Abstract

This invited paper is dedicated to both the nonlinear behavior of a step-up DC/DC converter, and to its linearization. It explains the nonlinear DC and AC control-to-output transfer function and its RHP-zero. The explanation is based on linearized models developed in the paper. These models are suitable for SPICE-like environment, and allow to obtain accurate symbolic equations in Matlab format. The linearization methods based on tri-state PWM and predistortion are also described. The description is followed by a Matlab algorithm allowing fast computation of the voltagemode PID controller for pre-distorted PWM modulator. As a result, a linearized converter operating in wide duty-cycle range is designed with voltage mode feedback loop. B. Nonlinear Dynamic (transient) Response The dynamic response is governed by the operating point given by V IN , V OUT , I OUT and D. As an example, the Bode-plot of the control-to-output transfer function for three values of D is shown in Fig. 3. Here, each duty-cycle exhibits a different frequency characteristic, and thus a different transient response.

Analysis and Comparison of DC-DC Boost Converter and Interleaved DC-DC Boost Converter

“…A boost converter is a converter with a voltage output in excess of its voltage input [12]. The traditional DC-DC boost converter circuit diagram is seen in Figure 2.…”

“…For to be positive, this is a necessary condition. Therefore, (12) determines the boundary between continuous and discontinuous inductor current.…”

Low‐complexity inductance estimation for switched‐mode power converters using peak‐current mode control

“…Additionally, due to the triangular inductor current being symmetrical around zero, the dead times also have a very small influence on the measurement accuracy. This is due to the alternately conducting low-and highside switch body diodes, mutually cancelling their contributions to the volt-second balance of the inductor [18]. Consequently, the following mathematical description is based on idealised equations, which in the case of zero (or very low) current load are very close to the real converter behaviour.…”

“…Additionally, due to the triangular inductor current being symmetrical around zero, the dead times also have a very small influence on the measurement accuracy. This is due to the alternately conducting low‐ and high‐side switch body diodes, mutually cancelling their contributions to the volt–second balance of the inductor [18].…”

“…The optimal ratio can be refined during the converter design process, based on the trade‐off between the current‐sensor accuracy, and the deviation of V OUT from its ideal value (4) or (9) [18].…”