Switching Control for Power Converters
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Solution Overview
Problem
Current double loop control methods for power electronic converters, such as Proportional-Integral (PI) control and predictive control, face limitations in dynamic performance and switching frequency, particularly in achieving a balance between steady-state accuracy and transient response.
Innovation Solution
A switching type control method based on double loop predictive control is introduced, where deadbeat control is used in the outer loop for steady-state accuracy and finite control set model predictive control is employed in the inner loop for transient states, ensuring a fixed switching frequency and rapid system transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If deadbeat control is used in the outer loop, then steady-state accuracy is improved, but dynamic response performance deteriorates
Solution Approach 1:
The control system dynamically switches between deadbeat control and finite control set model predictive control based on system state. Deadbeat control is applied in steady-state for high accuracy, while finite control set model predictive control is applied in transient states for fast dynamic response. This dynamic adaptation resolves the contradiction between steady-state accuracy and dynamic response performance.
2Speed
If finite control set model predictive control is used in the inner loop, then dynamic response is improved, but switching frequency becomes non-fixed
Solution Approach 1:
The system dynamically selects the control strategy based on whether it is in a transient or steady state. During transient states, finite control set model predictive control provides fast dynamic response with variable switching frequency. During steady states, deadbeat control maintains fixed switching frequency. This dynamic selection resolves the contradiction between dynamic response and switching frequency stability.
3Stability of the object's composition
If traditional PI control is used in the outer loop, then system stability is maintained, but overall system performance deteriorates
Solution Approach 1:
The invention changes the control parameter from traditional PI control to deadbeat control in the outer loop. Deadbeat control provides superior steady-state accuracy and enables fixed switching frequency operation. Combined with finite control set model predictive control in the inner loop, this parameter change significantly improves overall system performance while maintaining stability through the coordinated dual-loop structure.
4Stability of the object's composition
If modulation unit is added to deadbeat control, then switching frequency is fixed, but dynamic performance is limited
Solution Approach 1:
The control system is segmented into two independent loops: outer loop using deadbeat control for steady-state accuracy and fixed switching frequency, and inner loop using finite control set model predictive control for fast dynamic response. This segmentation allows each loop to optimize for its specific function, resolving the contradiction between fixed switching frequency and dynamic performance.
Data Source
AI summary
A switching type control method based on a double loop predictive control is provided. A deadbeat control is adopted by the outer loop control. The switching type control method is adopted by the inner loop control. When the system is in the steady state, the deadbeat control by an inner loop is adopted to ensure the steady state accuracy of the system and to achieve the fixed switching frequency. When the system is in the transient state, it is switched to the finite control set model predictive control by the inner loop to ensure the rapid transition of the system to the steady state.