Description
The proposed novel structure of a wind turbine-battery management-dump load-inverter integrated control system when compared to the traditional structure has the following advantages (by application of a single-phase 240V supply):

• Since the rated voltage output of the induction generator can be designed at high voltage of 270V as compatible with the output voltage of 240V, the wind turbine system works in a wide range of voltage level from about 50 (above the battery voltage) to 440V (at the highest wind speed acceptable to the system or the turbine) as determined by wind speeds.

• Since the generator can be designed at high rated voltages in contrast to traditional generators of low voltage systems, required by battery charging, the generator/converter efficiency is improved because the lower rated current at the same power rating reduces ohmic and switching losses.

• The highlight of the novel structure is that it provides two channels in parallel from the generator to the inverter. When the output voltage of the generator is higher than the rated voltage of the load, energy flow is transferred through the by-pass diode channel. Otherwise, when the output voltage of the generator is lower than the load voltage, energy flows through the buck-boost channel (battery charger, battery and boost chopper). The boost chopper is operational only when the wind speed is too low to drive the generator to its adequate output voltage. The system efficiency is indeed low when all the controller components are in full operation. With the addition of the by-pass channel as proposed in this innovative control system, the overall efficiency of the controller system is significantly higher than that of the traditional one because the by-pass diode eliminates the losses of many components at sufficient wind speed conditions.

The proposed system has three modes of operation:
Mode 1: Wind turbine powering the load without using the boost chopper and charging the batteries. The dump load is connected once the energy is excessive.

Mode 2: Wind turbine charging the batteries while the batteries are powering the load through the boost chopper.

Mode 3: Boost chopper shutting down at a low voltage to prevent the batteries from over-discharged.

State of Development
Prototype developed and laboratory tests completed.

Additional Information
The principal investigator and contributor to the main idea of this project is Liuchen Chang, a professor in the Department of Electrical and Computer Engineering at UNB.