Direct Connection Power optimisation and Power Conversion system
Patent Application Number: 0523186.7
The key to the success of the system is a unique newly patented PowerTrack™ control method, which is shown below. This system works on the basis that the brighter the sun, the greater the input or extract rate but the unique switching also results in 2½ times more power from the solar panel than can otherwise be achieved.
Technical characteristics
The problems associated with PV systems are that the electrical characteristics are constantly varying in terms of the current and voltage available (I and V) dependent upon the irradiance and the load applied on the system. Therefore, the potential electrical energy to be utilised also varies which is classed as non-optimised.
An I-V curve can be drawn for a photovoltaic arrangement at a given level of irradiance, on which a point can be found which gives the highest amperage and voltage. This is the optimum point of operation for the photovoltaic arrangement at that given irradiance level, from which any deviation will result in non-optimised operation.
The PowerTrack™ controller provides a method of controlling a ventilation arrangement of a fan and a PV system, by determining the optimum I-V point of the photovoltaic arrangement for the present level of irradiance and adjusting the fan to achieve the optimum I-V level, normally in terms of electrical load characteristics of the fan. The system includes a power converter to convert the electrical voltage of the electrical power from the photovoltaic arrangement.
Operation
The PowerTrack™ controller determines the optimum I-V point by using a power tracking (MPPT) device. The system defines whether the power produced by the PV arrangement is within two modes of operation:-
Operational Threshold
When the available electrical power at the photovoltaic arrangement is above the minimum operational threshold defined by the controller the fan is connected directly to the photovoltaic arrangement and allowed to operate with ordinary commutation and is not adjusted by the optimum I-V point tracker.
Power Conversion Threshold
However, when the available electrical power increases to the power conversion threshold, the PowerTrack™ converter is engaged to boost the voltage to the fan. To prevent the fan from drawing excess current and causing the photovoltaic array to deviate from its optimum I-V point, the controller causes the electrical load of the fan to be adjusted.
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