Adaptive pulse width modulation design for power converters based on affine switched systems

Abstract

In this work we propose a novel adaptive switching strategy for the design of pulse width modulation signals in power converters. Instead of an uncertain averaged model of the power converter, an uncertain switched model is considered, which can better represent the actual power converter dynamics. Uncertainties in the power converters parameters are handled via an adaptive control approach, and all circuit parameters of the switched model are assumed to be unknown (including the load and parasitic effects). After defining the pulse width modulation in terms of a reverse mode-dependent dwell time, an elementarytime-unit Lyapunov function is used to derive a set of linear matrix inequalities (LMIs) based on global uniformly ultimately boundedness of the switched system. The LMIs are solved in an adaptive fashion using an exploitation-exploration mechanism: exploitation is achieved by solving the LMIs based on the estimated switched model, while exploration is achieved by a persistently exciting input voltage source, which guarantees convergence of the estimated parameters to the true system parameters.

Global Practical Stabilization of Discrete-time Switched Affine Systems via Switched Lyapunov Functions and State-dependent Switching Functions

“…The problem of practical stabilization of switched systems without common equilibria or in particular case of switched affine systems has been investigated in the last years either in a general problem formulation or as in the case of particular problems most notably those related to the switching power converters [12], [35], [36]. There are very few works for the global practical stabilization of discrete-time switched affine systems via multiple Lyapunov functions and using state-dependent switching functions.…”

“…Proof: Since the conditions in Relation (43) are the same as the conditions (12) in Theorem 12, the proof that the set V in Eq. 3is invariant under switching Algorithm 9 for the system (2) is similar to the first part of the proof the Theorem 12 from (20)- (27).…”

Design of a Continuous Signal Generator Based on Sliding Mode Control of Three-Phase AC-DC Power Converters

“…For more details on the implementation issues, please see references [20][21][22][23]. Remark: The proposed control strategy offers an alternative to some other sliding mode controllers designs considering adaptive pulse width modulation [24], sub-optimal regulation [25], and multitype restrictive [26] approaches which have been applied on DC-DC power converters to obtain arbitrary signals. However, not one of them has been tested on the AC-DC device.…”

Active Power Filtering Embedded in the Frequency Control of an Offshore Wind Farm Connected to a Diode-Rectifier-Based HVDC Link

“…Finally, in accordance with Equations (8) and (19), the system's harmonic currents flowing into the capacitor bank (C) contain triple-order harmonics in the dq reference frame. Therefore, the THD of the offshore ac-grid voltage can be reduced by elimination of the triple harmonic components of the capacitor bank current in the dq reference frame.…”

“…The authors in [18] used an average value model of the diode rectifier to derive the proposed control. However, it is illustrated in [19] that a hybrid switched model better represents the actual power converter dynamics; leading to the uncertainties in the power converters' parameters being handled by an adaptive control approach.…”