Cuk Converter With Sliding Mode Control — Simulation & Power Modeling

Abstract — Cuk Converter With Sliding Mode Control

Creative Commons Attribution (CC BY) license ( https://creativecommons.org/licenses/by/4.0/ ). This paper presents a robust nonlinear current-mode control approach for a pulse-width modulated DC-DC Cuk converter in a simple analog form. The control scheme is developed based on the reduced-state sliding-mode current control technique, in which a simplified equivalent control equation is derived using an averaged power converter model in continuous conduction mode. The proposed controller does not require an output capacitor current sensor and double proportional-integral compensators as in conventional sliding-mode current controllers; thus, the cost and complexity of the practical implementation is minimized without degrading the control performance. The simplified nonlinear controller rejects large disturbances, provides fast transient response, and maintains a constant switching frequency. The nonlinear control scheme is developed using an analog circuit with minimal added components, which is suitable for low-cost industrial applications. The control law derivation, control circuit design, controller gains selection, and stability analysis are provided. The proposed control methodology is verified via simulating the closed-loop nonlinear power converter model in MATLAB/SIMULINK under abrupt changes in load current and input voltage. The simulation results show that the proposed control scheme provides robust tracking performance, a low percentage overshoot, fast transient response, and a wide operating range. The maximum percentage overshoot and settling time of the closed-loop power converter response during line disturbance are 5.6% and 20 ms, respectively, whereas the percentage overshoot and settling time during load disturbance are 2.8% and 15 ms, respectively.

Analytical & State-Space Control Methodology

Keywords: analog control circuit, constant switching frequency, DC-DC Cuk converter, simplified nonlinear control, sliding-mode current control Figure 2: Power Converter Circuit Schematic & Electrical Interfacing for Cuk Converter With Sliding Mode Control Switched-mode DC-DC converters are key parts in modern power systems through which the DC input voltage is stepped up or down to meet the load voltage requirement. The DC-DC Cuk converter has been studied in the literature due to its excellent features, such as ripple-free input and output currents and wide conversion ratio . However, the fourth-order dynamics of the DC-DC Cuk converter affect its bandwidth and transient response in the presence of line and load variations, which occur during normal operation condition. Hence, a robust control circuit is required to enhance the power converter response and track the desired reference voltage under large disturbances. In addition, the structure of the controller should be cost-effective and attractive for industrial applications . In the literature, nonlinear control techniques have been proposed for such a type of power converter [ 3 , 4 , 5 , 6 , 7 , 8 ]. For instance, a cascaded system that incorporates a DC-DC boost converter supplying buck, Cuk, and SEPIC converters has been studied . The nonlinear behavior of the cascaded system has been investigated with a two-loop controller, which contains inner current and outer voltage loops. In , a three-phase inverter-based Cuk converter with a proportional-integral (PI) controller has been introduced. However, the performance of such control techniques and their robustness under large line and load disturbances has not been discussed.

Simulink Waveforms & Power Quality Findings

In [ 5 , 6 , 7 , 8 , 9 , 10 , 11 ], robust control methods have been studied with the DC-DC Cuk converter. For instance, a control algorithm based on fuzzy logic has been implemented with a photovoltaic (PV) system, in which a DC motor is fed via a Cuk power converter . Another controller has been proposed in , using a passivity-based control method. A state-observer-based nonlinear sensorless controller has been applied to the boost and Cuk converters with unknown load conductance . In , a down-sampled repetitive controller with a fractional-order phase-lead compensation has been utilized with the Cuk converter. Modern optimization algorithms have been integrated with the SMC method to control a hybrid interleaved boost-Cuk converter . An ant colony-optimized maximum power-point tracking (MPPT) control system that employs a single Cuk converter as an impedance power adapter has been given in . A fuzzy logic-based MPPT control technique for buck-boost, Cuk, SEPIC, and ZETA DC-DC converters has been studied for PV applications . Despite the robust tracking performance of the aforementioned controllers, their practical implementation is complicated and requires expensive platforms such as dSPACE and DAQCard-6062E, which are not attractive for low-cost industrial applications.

Scope & Practical Applications

• High-efficiency DC-DC converters and isolated resonant topologies (LLC / DAB)
• Sinusoidal and Space Vector PWM inverters for grid integration & industrial motor drives
• MOSFET / IGBT gate driver optimization with active Miller-clamp shoot-through protection
• Power quality conditioning with Total Harmonic Distortion (THD) strictly compliant with IEEE 519
• Complete Simscape .SLX model files, parameter calculation scripts, and IEEE dissertation reports