Digital current‐limited sliding‐mode control for synchronous buck converter with curved switching surface

SummaryThe output current of the fast control power supply for the Experimental Advanced Superconducting Tokamak (EAST) excites the load coil. Magnetic field can be quickly generated by the fast output current to control the balance of plasma vertical displacement. In order to improve the output current speed of EAST fast control power supply and its ability to resist external disturbance, an improved discrete integral sliding mode control method combining gray prediction and variable gain sliding mode observer is proposed. A sliding mode disturbance observer is used to observe the total disturbance on the load side, and feedforward compensation control is performed on the total disturbance. To further suppress chattering and accelerate convergence speed, a high‐order term is added to the traditional discrete exponential reach law, and a gain adaptive observer is designed to adaptively adjust the observer gain based on the observed current error and the tracking current error. In the current sampling process, an improved gray prediction structure is added, and the original current sequence of gray prediction is improved based on the principle of new information priority, improving the accuracy of predicted current, compensating for the inherent delay in digital control, and further improving the output current response speed. Simulation and experimental verification show that the proposed disturbance suppression improved discrete integral sliding mode fast current tracking control strategy has faster output current response speed and strong antidisturbance performance.

“…The discrete exponential reach law is widely used because of good control performance. It can be expressed as follows 23 :…”

Section: Dismc With High Order Termsmentioning

confidence: 99%

“…The discrete exponential reach law is widely used because of good control performance. It can be expressed as follows 23 :

s ((), k goodbreak+ 1) goodbreak= ((), 1 goodbreak- {qT}_{s}) s ((), k) goodbreak- ε T_{s} sgn ((), s ((), k))

where Ɛ > 0, 0 < 1 − qT s < 1, and sgn( s ) is symbolic function.…”

Section: Dismc With High Order Termsmentioning

confidence: 99%

Disturbance supression improved discrete sliding mode fast current tracking control of experimental advanced superconducting tokamak fast control power supply

Chen,

Huang,

Wang

2023

“…However, the inadequate switching control action would result in a steady-state error in the output voltage-integral SMC, which can minimize SSE. 18,19 Double integral SMC has a quicker response for a wide range of operating conditions with a significant reduction in SSE. 20,21 The MPC provides a solution for trajectory optimization; however, because MPC calculates its control input from the system dynamic model, differences between the actual system and dynamic model can degrade the performance of MPC.…”

Section: Introductionmentioning

confidence: 99%

“…The FF‐SMC with constant‐frequency continuous switching action can overcome the chattering and variable‐switching‐frequency limitations of HM‐based SMC. However, the inadequate switching control action would result in a steady‐state error in the output voltage—integral SMC, which can minimize SSE 18,19 . Double integral SMC has a quicker response for a wide range of operating conditions with a significant reduction in SSE 20,21 .…”

Section: Introductionmentioning

confidence: 99%

Bidirectional quasi‐Z‐source DC‐DC converter with Lyapunov function‐based controller in stand‐alone photovoltaic‐connected system

Battula

Garg

Lenka

et al. 2022

This article proposes a bidirectional quasi-Z-source DC-DC converter (BQZSDC) to integrate distributed energy storage system with a stand-alone photovoltaic (PV)-connected system. The operational challenges like control and energy management of the renewable-driven stand-alone systems have been an interest of research. However, the challenge is managing the renewable energy source and the distributed energy storage system and simultaneously catering to the loads. This article analyzes the performance of a BQZSDC with a Lyapunov function-based controller for regulating DC link voltage (load voltage) and battery current. A duty-ratio feedforward control unit and a Lyapunov function-based feedback control unit are used to develop the controller. The duty-ratio feedforward control unit is used to reduce the burden on the feedback controller. The closed-loop system is exponentially stable with the feedback controller, offering excellent transient responsiveness even under large disturbances. Simulations in MATLAB/Simulink show that the controller functions satisfactorily in achieving regulation objectives. Finally, experimental results validate the performance of the proposed controller.

“…Digital control makes it easily possible to change the control parameters, adapt to different operating conditions, and implement complex control algorithms. New high‐performance microcontrollers have also made digital controllers more functional and flexible than analog controllers 4–8 …”

Section: Introductionmentioning

confidence: 99%

Digital peak current mode control of isolated current‐fed push‐pull DC‐DC converter with slope compensation

Ghalebani

Teymoori

2021

The isolated current‐fed push‐pull dc‐dc converter has some practical advantages such as improved cross regulation characteristics, reduced output noise, and good overall efficiency. Although detailed insight on this converter is available in the literature, the use of digital peak current mode with slope compensation control methodology has not been explicitly presented. This paper discusses digital peak current mode control of a current‐fed push‐pull converter with a novel double digital pulse‐by‐pulse current limiting scheme. Push‐pull topology is implemented on the primary side of an isolation transformer in a dc‐dc bidirectional converter. Achieving this control solution of isolated push‐pull converter is attractive especially in controlling battery power flow in smart micro‐grids. By using a digitally controlled push‐pull converter, the ability to change controller parameters and the use of droop control methods for storage are easier. Furthermore, current mode control provides capability of equal current sharing between parallel converters and eliminates the transformer saturation problem that is common in push‐pull topology. Using continuous time model of the converter, a Type II compensator is designed and implemented in discrete time domain. Digital slope compensation is applied to eliminate the high frequency oscillations caused by current feedback loop. The control method and slope compensation are implemented on STM32F303 mixed‐signal microcontroller. On‐chip analog comparator disabled the PWM output if the sensed current exceeds the reference current until next PWM cycle. The digital controller performance is confirmed by 13 W hardware implementation including fast transient response and stable operation.