method and device for instabilitu00e4tserkennung and correction in a combined household heating and power unit

摘要

The present invention provides the method and apparatus of the unstable detection and correction of a kind of dchp unit. Stirling engine (1) includes the piston moved back and forth, which drives alternating current generator to generate electricity output (7). Current signal (7) is measured by electric current monitor (60) and generates Fast Fourier Transform value. It has been found that the FFT of current signal (7) is directly related with the operation stability of Stirling engine. Harmonic peaks in FFT increase the stroke length for indicating piston near or above safe maximum value. Corrective action can be thus taken, such as reduces the heat for inputing to Stirling engine. The invention also discloses a variety of stroke length detectors (110), they are used in combination or are used alone with the fft analysis of current signal (7). The present invention also together with the accelerometer on the shell for being mounted on Stirling engine, discloses photoswitch and mechanical switch and analog sensor.