Modeling, Control, and Implementation of DC–DC Converters for Variable Frequency Operation

Abstract

In this paper, novel small-signal averaged models for dc-dc converters operating at variable switching frequency are derived. This is achieved by separately considering the on-time and the off-time of the switching period. The derivation is shown in detail for a synchronous buck converter and the model for a boost converter is also presented. The model for the buck converter is then used for the design of two digital feedback controllers, which exploit the additional insight in the converter dynamics. First, a digital multiloop PID controller is implemented, where the design is based on loop-shaping of the proposed frequency-domain transfer functions. And second, the design and the implementation of a digital LQG state-feedback controller, based on the proposed time-domain state-space model, is presented for the same converter topology. Experimental results are given for the digital multiloop PID controller integrated on an application-specified integrated circuit in a 0.13 μm CMOS technology, as well as for the statefeedback controller implemented on an FPGA. Tight output voltage regulation and an excellent dynamic performance is achieved, as the dynamics of the converter under variable frequency operation are considered during the design of both implementations.

Energy-Regenerative Braking Control of Electric Vehicles Using Three-Phase Brushless Direct-Current Motors

“…After the perturbation process and instantaneous variable separation, the averaged small signal model of the system [20,24] would be:…”

“…to improve the DC-link voltage of the power converter, a bidirectional DC-DC power converter is used for boosting control [20,21]; (3) braking energy is recovered by using the driving power converter itself for charging control, the energy-regeneration control is achieved by using different control strategy, this can be found in [22,23]. For Category (1), the additional energy-storing components need to be charged and discharged via a DC-DC power converter, status of the ultra-capacitor (such as full charged or under-voltage) needs to be acquired, thus, voltage and current sensors must be installed in the controller, in this way, the braking energy is temporarily stored in the ultra-capacitor pack, this scheme makes the whole system more complicated, moreover, due to the high price of ultra-capacitor pack, the cost of the controller would be more expensive than a conventional controller.…”

Data-Driven Modeling of a Commercial Photovoltaic Microinverter

“…White-box models (first principle models), which require significant knowledge of converter structure and parameters, have been developed both to capture the switching operation [9] of the converter and to represent the averaged behavior of the converter [10,11]. At the same time, black-box experimental models (datadriven models) have been developed [12][13][14] using system identification approaches.…”

Approach to the Modeling of LDO-Assisted DC-DC Voltage Linear Regulators

“…Previous researches have been done to minimize the existing impediments such as low efficiency and high power dissipation [5,6]. Other researches have proposed topologies to optimize the performance of buck converter or improve the control techniques [7,8,9]. Another have optimized the design using push-pull linear regulator [10].…”