Finland Chenahoya electric control co., LTD., according to the market demand to develop CHHPA type harmonic purification device for the power side harmonic governance provides a perfect solution. CHHPA type harmonic purification plant is to use modern power electronic technology and digital signal processing (DSP) based on high-speed DSP technology into a new type of harmonic control device. It by instruction current arithmetic circuit and the compensation current generating circuit of two main parts. Instruction current arithmetic circuit real-time monitoring the current in the circuit, and converts analog current signal to digital signal, into the high speed digital signal processor (DSP) for signal processing, and the harmonic wave separation, and in the form of a pulse width modulation (PWM) signal to the compensation current generating circuit sends out the drive pulse, drive IGBT power modules, the generation and harmonic current amplitude is equal and opposite polarity and compensation current into the power grid, to compensate harmonic current or offset, take the initiative to eliminate electric power harmonic, so as to realize the electric power harmonic management.

The fundamental cause of harmonic is caused by nonlinear loads in power supply and distribution system. When current flows through the load, and the applied voltage is not a linear relation, to form non sinusoidal current, the circuit of harmonic. Electric power harmonic frequency is 50 hz integer times of sine wave voltage or current. Power plant or a voltage generator is frequency is 50 hz sine wave model, known as the fundamental wave, 50 hz, called the base wave frequency. The integer sine wave called a harmonic frequency is 50 hz. Harmonic expressed in multiples of fundamental wave, such as the frequency of 150 hz sine wave called three harmonic, called 5 times harmonic frequency of 250 hz sine wave, the frequency of 350 hz sine wave called seven times harmonic, and so on. In practical engineering, the harmonic surprising that most of the time harmonic, i.e., 3, 5, 7, 11, 13...