Generator Brake System Using Semiconductor Switches for Wind Turbines
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In wind power generation systems, the frequent switching of switch contacts in generator brake systems leads to reduced switch lifespan and invalidation of brake protection, posing risks to the inverter system, especially during high wind speeds.
Innovation Solution
A generator brake system comprising a power conversion unit, a sensing unit, and a control unit that uses firmware or software to generate control signals to gradually reduce output voltage and activate switch units in a short circuit manner when the output voltage falls below a threshold, ensuring safe and accurate braking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hardware switches are used to provide brake protection for the generator, then the generator can be protected from fault current, but the switch contacts experience frequent switching leading to reduced lifespan and potential failure
Solution Approach 1:
The patent replaces the mechanical switch contact system with a semiconductor-based power conversion system controlled by firmware or software. The control unit monitors generator output voltage and current, and the power conversion unit uses semiconductor switches (IGBTs or MOSFETs) that can be controlled without mechanical contact, thereby eliminating wear and extending operational lifespan while maintaining brake protection functionality.
Solution Approach 2:
The patent changes the operating parameters of the switching system by controlling the semiconductor switches through PWM (Pulse Width Modulation) techniques. The control unit adjusts the switching duty cycle and frequency based on real-time generator output parameters, enabling smooth transition between operating states and reducing stress on the switching components, thus extending their operational life.
2Speed
If the generator is braked in a short circuit manner by turning on switch contacts, then braking can be achieved, but frequent switching of the switches reduces their life time and may cause failure
Solution Approach 1:
The patent replaces mechanical switch contacts with semiconductor switches in the power conversion unit that are controlled by the control unit through firmware or software. This substitution eliminates mechanical wear while maintaining the ability to quickly activate braking by turning on the semiconductor switches, thus achieving fast braking response without reducing component lifespan.
Solution Approach 2:
The patent implements dynamic control of the braking process by having the control unit continuously monitor generator parameters and adjust the switching signals to the power conversion unit accordingly. The braking process is controlled in real-time based on the generator's operating state, allowing for optimized switching patterns that reduce stress on components while maintaining rapid response capability.
3Reliability
If the output voltage is not controlled during braking, then the braking process may be unsafe or inaccurate, but controlling the voltage requires additional control mechanisms
Solution Approach 1:
The patent integrates multiple functions into the control unit and power conversion unit. The control unit not only controls the braking process but also monitors generator parameters, generates control signals, and manages the overall protection scheme. The power conversion unit serves both as a power management device and as the braking mechanism, eliminating the need for separate braking components and reducing overall system complexity while ensuring safe and accurate voltage control during braking.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach extends the lifespan of switch hardware by reducing wear and tear, ensuring accurate braking and safety during low-current operations, and preventing damage to the inverter system.
Implementation Method 1
a generator brake system for a permanent magnet generator (PMG)... converts the wind power into the electric power
Implementation Method 2
brake the generator in a short circuit manner by turning on at least one switch unit
Data Source
AI summary
The present invention provides a generator brake system for providing a brake control of a generator. The generator brake system includes a power conversion unit, a sensing unit, and a control unit. The power conversion unit receives an output voltage and an output current, generated from the generator, and the power conversion unit has at least one switch unit. The sensing unit receives the output voltage and the output current to generate a voltage signal and a current signal. The control unit receives the voltage signal and the current signal. When receiving a braking signal, the control unit generates at least one control signal for correspondingly turning on the at least one switch unit, thus braking the generator in a short circuit manner.