Generally studied extraction methods of rotor position in low speed condition usually superimpose high frequency rotary sinusoidal voltage or pulse sinusoidal voltage on the fundamental signal. These two methods need to process the response current obtained by the high frequency voltage excitation through the band-pass filter(BPF) and the low-pass filter (HPF). The use of filters can cause time delay, reduce the highest frequency range that can be transmitted between the input and output signals of the control system. As a result, the extracted low speed rotor position lags behind the rotor position information detected by the actual position sensor. Thereby affecting the control system dynamic response speed. To avoid this impact, it is considered to replace high frequency rotary sinusoidal voltage or pulse sinusoidal voltage form with the square wave voltage form to extract information at low speed condition. This avoids the use of filters with its unique signal extraction method. A simulation model is established to test the effect of rotor position extraction algorithm after replacing the voltage form. Analysis of simulation results prove that the proposed method can converge in a short time and narrow the lag and value error between the rotor position information detected by the actual position sensor and the extracted low speed rotor position.