Víctor Repecho

Switching Frequency Regulation in Sliding Mode Control by a Hysteresis Band Controller

Fixing the switching frequency is a key issue in sliding mode control implementations. This paper presents a hysteresis band controller capable of setting a constant value for the steady-state switching frequency of a sliding mode controller in regulation and tracking tasks. The proposed architecture relies on a piecewise linear modeling of the switching function behavior within the hysteresis band, and consists of a discrete-time integral-type controller that modifies the amplitude of the hysteresis band of the comparator in accordance with the error between the desired and the actually measured switching period. For tracking purposes, an additional feedforward action is introduced to compensate the time variation of the switching function derivatives at either sides of the switching hyperplane in the steady state. Stability proofs are provided, and a design criterion for the control parameters to guarantee closed-loop stability is subsequently derived. Numerical simulations and experimental results validate the proposal.

Fixed switching frequency sliding mode control using an hysteresis band controller

This paper presents a hysteresis band controller in charge of fixing the switching frequency of a sliding mode controller. The proposed control measures the switching period of the control signal and modifies the hysteresis band of the comparator to regulate the switching frequency of the sliding motion. The switching frequency control system is modelled and a design criterion of the control parameters is derived to guarantee the closed loop stability.

G2V and V2G operation 20 kW battery charger

This paper presents a bidirectional on-board battery charger for Electric Vehicles designed to perform both Grid to Vehicle (G2V) and Vehicle to Grid (V2G) operation. The charger can also operate with single or three-phase power grid connection, regulates the battery charging current and presents input unity power factor. A high frequency three-phase transformer has been included in the charger, this providing galvanic isolation.

Fixed Switching Period Discrete-Time Sliding Mode Current Control of a PMSM

A fixed switching period sliding mode control (SMC) for permanent-magnet synchronous machines (PMSMs) is presented. The aim of this paper is to design an SMC that improves the traditional PI-based field-oriented control transient response, as well as to reduce the switching frequency variations of the direct torque control. Such SMC requires a decoupling method of the control actions, which also brings constant switching functions slopes. These constant slopes allow to calculate the required hysteresis band value to control the switching frequency. The digital implementation degrades the performance of the hysteresis comparator, and as a consequence, the previously calculated band becomes inaccurate to regulate the switching frequency. In order to recover the analogue hysteresis band comparator performance, a predictive algorithm is proposed. Finally, a set of experimental results with constant switching frequency during a torque reversal and speed control tests are provided.

Sliding mode control of a voltage source inverter with switching frequency regulation

This work presents the study of a switching frequency regulation of a sliding mode control under tracking control scheme. A variable hysteresis band with an additional control loop is proposed and the equivalent system is developed in order to analyse the stability. Sufficient stability conditions are found for the resulting discrete-time, time varying system, using a feed forward term. The technique is applied to a voltage source inverter tracking a time varying voltage reference. Simulation results are presented in order to confirm the goodness of the switching frequency control loop.

Sliding mode control of a three-phase three-wire LCL rectifier

This paper presents a dynamic analysis and the control design for a three-phase three-wire unity power factor rectifier with a LCL filter. The control algorithm is based on the sliding mode control techniques that provides good tracking performance and robustness with respect to parameter variations, and a PI controller to regulate the DC voltage. The sliding control design uses a decoupling matrix to solve the algebraic constraint on the grid currents. The control law has been tested in numerical simulations with satisfactory results.

Sliding Mode abc current control for PMSM drives with an enhanced high frequency injection algorithm for sensorless operation

A high frequency injection (HF) based sensorless Sliding Mode Control (SMC) for Permanent Magnet Synchronous Machines (PMSMs) is designed. An analytical analysis, which demonstrates that the HF band is perturbed under sensorless operation, is addressed. Further increase of the sensorless control dynamics is achieved by removing the perturbed signals by means of compensation terms, which also estimate the PMSM αβ inductance value. Numerical simulation results are presented, confirming the proper speed sensorless control at low speed reversal with load impact.

Sliding Mode Control of Power Converters with Switching Frequency Regulation

This chapter deals with the development of a hysteresis band controller in charge of fixing the switching frequency of a sliding mode controller. The proposed control measures the switching period of the control signal and modifies the hysteresis band of the comparator in order to regulate the switching frequency of the sliding motion. The switching frequency control system is modelled and a design criterion for the control parameters is derived to guarantee closed loop stability. The technique is applied to power electronics. Specifically, DC-to-DC and DC-to-AC power converters are considered, a sliding mode controller providing robustness in the face of load disturbances and input voltage variations is designed and, finally, the stability analysis of these systems when the switching frequency is regulated is also presented. A set of numerical simulations will confirm the achievement of fixed switching frequency, robustness of the controller, and stability of the closed-loop system.

Robust sliding mode control of a DC/DC Boost converter with switching frequency regulation

Abstract This paper presents the design of a hysteresis band controller to regulate the switching frequency in a sliding mode controlled nonlinear Boost power converter. The proposed architecture relies on a piecewise linear modeling of the switching function behavior within the hysteresis band, and consists of a continuous-time integral-type controller that modifies the amplitude of the hysteresis band of the comparator in accordance with the error between the desired and the actually measured switching period. The study provides the dynamical models of the converter operating in sliding mode and the switching frequency control loop. Moreover, the design of the parameters of both the sliding mode control and the switching frequency controller guarantee the fulfilment of the desired output voltage regulation of the Boost converter and the steady state setting of the switching frequency with a known, taylored dynamics. A Boost power converter prototype has been built to validate the proposal. Experimental results confirm the predicted good performance of the controllers, as well as the robustness with respect to changes in the switching frequency reference and the system parameters.

Sliding mode control of a m-phase DC/DC buck converter with chattering reduction and switching frequency regulation

This paper presents a sliding mode control for a multiphase synchronous buck converter with chattering reduction, which is capable to operate with fixed switching frequency at steady state. The system works with a Master-Slave configuration. The chattering reduction is achieved using interleaved control action, while the switching frequency is regulated using a variable hysteresis band comparator for the Master phase. Experimental results show that interleaving operation, robust output regulation and fixed switching frequency at steady state are properly achieved.