Voltage Control Device Reactive Power Segmentation
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Solution Overview
Problem
The high cost of semiconductor devices like IGBTs used for voltage control in wind turbine generators and the underutilization of their fast response due to grid requirements, which demand responsiveness within a predetermined time frame.
Innovation Solution
A voltage control apparatus that separates reactive power control into two components: one handled by a switching device for active power fluctuations and another by a capacitor bank for power flow changes, allowing for responsive voltage control using less expensive equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If semiconductor devices such as IGBT are used for voltage control, then responsiveness is improved, but cost increases
Solution Approach 1:
The patent segments the reactive power control into two distinct components: a fast-response component handled by the switching device (IGBT) and a slow-response component handled by the capacitor bank. This segmentation allows each component to operate within its optimal performance range, reducing the need for expensive high-speed semiconductor devices while maintaining overall system responsiveness.
Solution Approach 2:
The patent replaces part of the expensive semiconductor device functionality with a cheaper capacitor bank that, while slower, can handle the non-time-critical portion of reactive power control. This substitution reduces overall system cost while maintaining adequate performance for grid requirements.
2Speed
If semiconductor devices are used for voltage control, then responsiveness is improved, but the fast response capability is not fully utilized due to grid time requirements
Solution Approach 1:
The patent applies partial action by having the switching device handle only the fast-response portion of reactive power control that actually requires high speed, while the capacitor bank handles the remaining portion where fast response is not necessary. This prevents over-engineering the system with excessive fast-response capability that would go unused.
3Speed
If reactive power control is handled by switching device only, then responsiveness is improved, but device complexity and cost increase
Solution Approach 1:
The control system is segmented into two independent control paths: one for fast-response reactive power (switching device) and one for slow-response reactive power (capacitor bank). This segmentation simplifies the control architecture by assigning specific functions to each component based on their inherent characteristics, reducing overall system complexity.
Data Source
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AI summary
An object is to provide voltage control having responsiveness without causing any problem in the operation of the utility grid, by using inexpensive equipment that has been conventionally used. Provided are a control-amount separating section (21) that separates, when it is determined that an interconnection-point voltage (Vr) at an interconnection point where a wind turbine (2) is connected to a utility grid (1) deviates from a target value, a target control amount for reactive power for matching the interconnection-point voltage (Vr) with the target value into a first control amount serving as a control amount for reactive power that is caused by a fluctuation in active power at the interconnection point and a second control amount serving as a control amount for reactive power that is caused by a change in a power flow in the utility grid (1); a wind-turbine control device (22) that controls the switching device on the basis of the first control amount; and a capacitor-bank control device (23) that controls the capacitor bank (5) on the basis of the second control amount.