The Resistance in Wind Turbine
With the continuous growth of wind energy demand, the turbine components in accordance with the requirements are also increasing. The modern power electronic technology in wind turbine not only limit the number of components, and it also required the circuit can keep 20 years of service life in extreme temperature and vibration of hard environment.
Resistance
The electrical resistors in the wind turbines include the charger resistor, chopping resistor, breaker resistor and AC filter resistance. The charger resistance can limit surge current into DC link capacitance when the switch opens. In order to do so, the devices need high single pulse energy and high rated voltage. The adpedance of the resistor also limits surge current. Therefore, winding resistance is the best choice. The single pulse energy used for the charger resistance is usually 5 J.
When a chopper switch turned on, chopped resistance limits current. The chopper normally controls DC voltage with very high frequency. Therefore, resistance must be with high pressure and high rated repeatability pulse energy ability (equivalent to high rated continuous power). Chopping resistance must have low parasitic inductance, because it has to work in KHZ level high frequency situation, and it can get by film technology. The demand for high power rating in the small volume can be satisfied by resistor installed in the dissipation devices, which can be installed in the cooling system as the same as chopped switch.
Breaker resistance limits the electric current and voltage in order to prevent the pass of the low and high voltage. The requirements of wind turbines applications to this device including up to 4 MJ energy pulse capacity, 10 to 100 m Ω resistance, 1 ~ 20 mW power rating, maximum rated current of 10 to 20 kA, typical failure cycle for 200 ms.
In the RC filter, AC filter resistance and AC filter capacitor are used together. And AC filter resistance, used together with the inductance in the output transformer, can form RL filter. For AC filters capacitance, a high continuous rated power is needed. Corrugated ribbon structure increased the cooling effect.