Voltage Source Inverter Control with Dynamic Current Limiting
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Solution Overview
Problem
The existing voltage control methods for inverters, which connect an outer voltage loop and an inner current loop in series, result in complex parameter design and limited bandwidth, affecting the stability and response speed of the system.
Innovation Solution
A voltage control method where the voltage loop and double current loops run in parallel, with the current loop dynamically limiting the amplitude of the voltage loop, allowing separate design of loop parameters and improving stability and response speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the voltage loop and current loop are connected in series, then the system can implement dual control on voltage and current, but the parameter design becomes complex and system stability is affected
Solution Approach 1:
The patent divides the control system into independent voltage loop and current loop modules that operate in parallel rather than series. Each loop has its own controller and can be designed independently, eliminating the coupling complexity while maintaining dual control functionality through separate control paths.
Solution Approach 2:
The patent implements dynamic switching between voltage loop control and current loop control based on system conditions. The controller dynamically selects which loop to activate, allowing the system to adapt to different operating modes (voltage source mode vs. current source mode) without the complexity of simultaneous series control.
2Adaptability or versatility
If the voltage loop and current loop are connected in series, then dual control is achieved, but the bandwidth of the voltage loop is limited and system response speed is affected
Solution Approach 1:
By segmenting the control into parallel independent loops, each loop can operate at its optimal bandwidth without being constrained by the other. The voltage loop can achieve higher bandwidth for fast voltage response, while the current loop handles current regulation, eliminating the bandwidth limitation imposed by series connection.
Solution Approach 2:
The dynamic switching mechanism allows the system to use the voltage loop for high-speed voltage regulation when needed, without being bottlenecked by the current loop's bandwidth limitations. This dynamic allocation of control functions restores the voltage loop's full bandwidth potential.
3Adaptability or versatility
If the voltage loop and current loop are connected in series, then dual control is implemented, but the parameter design complexity increases
Solution Approach 1:
The parallel architecture segments the control design into independent modules with well-defined interfaces. Each loop can be designed, tuned, and implemented separately using standard control design procedures, significantly reducing the overall design complexity compared to coupled series control.
Solution Approach 2:
The dynamic switching logic simplifies the design by allowing each loop to be optimized for its specific function without needing to account for the complex interactions that would arise in series control. This modular dynamic approach makes parameter design more straightforward and systematic.
Data Source
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AI summary
This application provides a voltage control method, an inverter, and a voltage control apparatus, to help improve a response speed and stability of a system. The method is applied to a voltage source inverter. The voltage source inverter includes a bus capacitor, a bidirectional power tube, a filter inductor, and a filter capacitor. The method includes: respectively obtaining a first feedback current and a first feedback voltage from an output end of the filter inductor and an output end of the filter capacitor; obtaining a first duty cycle and a second duty cycle based on the first feedback current, a maximum current reference value, and a minimum current reference value in a current loop; obtaining a third duty cycle based on the first feedback voltage and a voltage reference value in a voltage loop; and selecting one of the first duty cycle, the second duty cycle, and the third duty cycle, and controlling the bidirectional power tube, so that a duty cycle of the bidirectional power tube is between the first duty cycle and the second duty cycle.