Nonlinear DC Voltage Control in Converter-Inverter Power Stages
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Solution Overview
Problem
Existing power converters experience significant fluctuations in DC voltage on the output side due to fluctuations in the load of the inverter, which can lead to instability and inefficiency.
Innovation Solution
A power converter with a control unit that calculates a control difference between a target DC voltage and a feedback DC voltage, performs a nonlinear operation process on this difference, and uses the resulting operation value to control the converter, thereby stabilizing the DC voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional voltage control is used in the power converter, then the control structure is simple, but the DC voltage fluctuates significantly when the inverter load changes
Solution Approach 1:
The patent applies parameter changes by implementing a nonlinear operation process that dynamically adjusts the control difference based on the relationship between converter output current and inverter input current. The control difference is modified using a nonlinear function that considers the operating point of the system, allowing the controller to adapt its response characteristics according to the actual power flow conditions. This resolves the contradiction by improving voltage stability through adaptive parameter adjustment without requiring a completely complex control architecture.
Solution Approach 2:
The patent employs feedback mechanisms by continuously monitoring the DC voltage and comparing it with the target voltage to generate a control difference. This control difference is then processed through the nonlinear operation and fed back to adjust the converter's output. The feedback loop ensures that voltage fluctuations are detected and corrected in real-time, improving reliability while maintaining a manageable control structure through systematic feedback processing.
2Reliability
If the converter output current is not adjusted according to inverter input current, then the control is simple, but the DC voltage fluctuates when load changes
Solution Approach 1:
The patent applies preliminary action by pre-defining the nonlinear operation characteristics and the relationship between converter output current and inverter input current. The control system is prepared in advance with the appropriate control strategy that accounts for load variations. When load changes occur, the pre-established nonlinear control mechanism automatically adjusts the converter output current according to the inverter input current requirements, improving voltage stability without complicating the real-time operation.
3Reliability
If nonlinear operation process is applied to control difference, then DC voltage fluctuation is reduced, but calculation complexity increases
Solution Approach 1:
The patent applies local quality by implementing the nonlinear operation process specifically on the control difference rather than the entire control system. The nonlinear function is applied locally to the voltage error signal, providing enhanced voltage stabilization where it is most needed while keeping the rest of the control structure relatively simple. This localized approach reduces DC voltage fluctuation without requiring complex nonlinear processing throughout the entire control architecture.
Data Source
AI summary
A power converter includes a converter, an inverter, and a control unit. The converter converts electric power supplied from a power supply side to DC power. The inverter is provided on an output side of the converter. The control unit is configured to calculate a control difference between a target value for a target control voltage in a DC section provided on the output side of the converter and a feedback value using a DC voltage of the DC section as the feedback value, to perform a nonlinear operation process on the control difference, and to calculate an operation value based on a result of the nonlinear operation process and control the converter using the operation value.