A sliding mode control based multi-functional power converter for electric vehicles and energy applications

Abstract

In this paper, a sliding mode control based multifunctional power converter is presented for electric vehicles and renewable energy applications. The proposed power converter is a multi-functional converter, which has capabilities of buckboost, bidirectional functions and even fault tolerance. Each mode of operation of the proposed system were analyzed and to validate the system, a prototype test-bed is built and tested using a Digital Signal Processor (DSP). The results show that the proposed system could be applicable for energy(fuel cell/wind/solar) and electric vehicle application. Index Termss-Fault Tolerance, Multi-Functional and Sliding Mode Control

Control of a Charger/Discharger DC/DC Converter with Improved Disturbance Rejection for Bus Regulation

“…In conclusion, the system is able to reach the surface Ψ = 0 when the restrictions presented in (20), (21), (24) and (25) are fulfilled.…”

“…A particular case for (20) occurs for a step perturbation in the DC bus current, which is the fastest (and strongest) perturbation possible: in this case, restriction (20) is not fulfilled in the very short time t step ≈ 0 in which the step occurs because di dc dt → ∞, but after that short time, the current is almost constant, i.e., di dc dt ≈ 0. Considering that Section 4 will demonstrate that k i must be negative (36) for stability reasons, expression (20) is modified to define the maximum magnitude of k i that ensures the reachability of the surface, presented in (21), which corresponds to the most restrictive case:…”

“…Another important application in which batteries are extensively used is the construction of stand-alone renewable power systems, which are common solutions for remote energy generation and urban/distributed energy systems for pollution reduction [13,14]. A common structure of such power systems based on renewable generators and batteries is presented in Figure 1 [15][16][17][18][19][20][21][22]. Such an architecture has a renewable energy source as the main energy generator, e.g., photovoltaic modules or fuel cell, interacting with a unidirectional DC/DC converter that is responsible for optimizing the source operating conditions.…”

“…The charger/discharger converter is controlled to regulate the DC bus voltage within safe limits and simultaneously impose a given energy flow between the battery and the DC bus. Due to safety implications for the source and load, there are many research papers focused on regulating the DC bus voltage using charger/discharger converters: some of them are based on linear control [16,[23][24][25][26], others are based on intelligent control [13,[27][28][29][30][31][32], and others are based on non-linear control strategies [15,[17][18][19][20][21][22]. In particular, sliding-mode controllers (SMCs) have been widely used for this application to ensure global stability, robustness to parameter tolerances, higher bandwidth compared with classical linear controllers [17,22,33], and reduced implementation cost and complexity compared with intelligent controllers [31,34].…”

“…Another solution based on SMC was reported in [21]. That work was aimed at controlling a buck-boost charger/discharger converter with a cascade structure: an outer voltage loop based on a PI structure defines the reference of an inner current loop based on an SMC, in which the sliding surface is formed by the inductor current error.…”