Converter Terminal Voltage Control to Minimize Generator Current
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Solution Overview
Problem
Existing converter technologies face issues with low utilization of DC voltage, overmodulation, and efficiency due to a constant control target value for field weakening voltage, which fails to adapt to changes in DC voltage and operating conditions, leading to suboptimal generator-side current management.
Innovation Solution
A method and device for controlling the generator-side terminal voltage of a converter by determining an upper limit based on the DC bus voltage and searching for an optimal value within a preset interval to minimize the generator-side current, dynamically adjusting the target voltage to optimize current usage and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a constant control target value for field weakening voltage is used, then the control system is simple to implement, but the utilization of DC voltage becomes low in some working conditions
Solution Approach 1:
The patent implements dynamic adjustment of the control target value for field weakening voltage based on real-time operating conditions. The controller continuously monitors generator speed, DC bus voltage, and other parameters to dynamically update the reference voltage, enabling the system to adapt to varying working conditions and maximize DC voltage utilization across different operational scenarios.
Solution Approach 2:
The patent changes the control parameter from a fixed constant value to a dynamically variable reference voltage. By adjusting the field weakening voltage reference based on operating conditions (such as generator speed and power output), the system optimizes DC voltage utilization without requiring complete redesign of the control architecture.
2Device complexity
If a constant control target value for field weakening voltage is used, then the control strategy is simple, but overmodulation occurs in some working conditions
Solution Approach 1:
The patent employs feedback mechanisms where the controller continuously monitors the actual terminal voltage and compares it with the dynamically adjusted reference voltage. This feedback loop enables real-time detection of overmodulation conditions and automatic adjustment of control parameters to prevent overmodulation, ensuring reliable operation across all working conditions.
Solution Approach 2:
By making the control target value dynamic rather than constant, the system can adapt to changing operating conditions that may lead to overmodulation. The controller adjusts the reference voltage in real-time based on generator speed and load conditions, preventing the system from entering overmodulation regions.
3Device complexity
If a constant control target value for field weakening voltage is used, then the control implementation is straightforward, but the efficiency of the electric transmission chain becomes low
Solution Approach 1:
The patent optimizes energy efficiency by dynamically adjusting the field weakening voltage reference to match optimal operating points. By changing the control parameter from fixed to variable, the system minimizes resistive losses and improves overall transmission chain efficiency without requiring complex additional hardware.
Solution Approach 2:
The dynamic control strategy enables the system to operate at optimal efficiency points across varying load and speed conditions. By continuously adjusting the field weakening voltage reference, the system minimizes energy losses in the transmission chain, improving overall efficiency while maintaining straightforward control implementation.
4Device complexity
If the generator-side terminal voltage is not optimized, then the control system is simple, but the generator-side current is high leading to heat generation
Solution Approach 1:
The patent reduces heat generation by dynamically optimizing the generator-side terminal voltage through parameter adjustment. By changing the field weakening voltage reference based on operating conditions, the system minimizes excessive current flow and associated I²R losses, thereby reducing heat generation without requiring complex additional cooling systems.
Data Source
AI summary
The present application provides a method and device for controlling a generator-side terminal voltage of a converter, and a controller of the converter. The method includes: determining an upper limit of the generator-side terminal voltage based on a present voltage value of a direct-current (DC) bus of the converter, where the generator-side terminal voltage is a voltage of an output terminal of a generator, and the output terminal is connected to the converter; determining an optimal value of the generator-side terminal voltage that minimizes a present value of a generator-side current, where the generator-side current is a current of the output terminal of the generator; setting a target value of the generator-side terminal voltage based on the upper limit and the optimal value of the generator-side terminal voltage. The target value includes a control reference value of the generator-side terminal voltage.