Methods and Means for Harmonics Compensation in Electrical Power Generation

Feeding more and more multiple non-linear and unsymmetrical power consumers (TV, Computers etc…) cause serious disturbances for the grid quality in terms of voltage harmonics and distortion power in particular in decentralised low power supplies like solar photovoltaic (PV) in households. The use of inverter-fed power devices with modern high speed micro-controllers and an intelligent management of the different powers to be generated can help improving the power quality under any operating conditions.
The invention provides a compensation algorithm implemented in a micro-controller combining the use of Finite Impulse Response (FIR) filters to extract the different harmonics from the original voltage signal and applies a Phase Locked Loop (PLL) to every extracted harmonic signal, which is finally compensated via a Proportional-Integral (PI) controller. All the PI controllers outputs are superposed in the final voltage source in such a way that they don’t conflict with each other, leading to a stable voltage source generation with a total harmonic distortion (THD) smaller than the limit of 8% requested by the global European power quality norm EN50160. The active harmonics compensator is able to compensate individually the strongest harmonics due to the feedback effect on the voltage source of any kind of non-linear load at partial-load as well as overload operation.
The compensation can be implemented on a self-sufficient single voltage generating power source running in stand-alone or grid-tied. It can also be shared and distributed on multiple voltage source inverters (VSI) of different powers connected on a utility grid. That allows an optimisation of the power production of each device, in particular supplied by variable renewable energy sources (solar PV, wind), taking into consideration its capacity currently available.