Sensorless brushless dc motor control - state observer method

 State observer method, calculation method of rotor position is will be coordinate transformation motor three-phase voltage, current, on the basis of the park equation one way to estimate the motor rotor position [2]. This method in recent electric motor 12v 500w years abroad far more [9]. The basic principle of this method to detect the rotor position signal is: the motor under a2b2c coordinate system of three-phase measured phase current and phase voltage conversion to represent the A2B hypothetical rotor position coordinates (the Angle of the two coordinate difference is $H); According to the coordinates of the current by parker equation to calculate the three-phase voltage value; Comparing the voltage and the front by converting the voltage difference, can have the function relationship between $U = f ($H).


The derivation can be found: when $H - > 0 $U ∝ $H, so can use a state observer to look at $U, thereby gaining $H, the rotor position signal. State observer method generally applies only to the induction electric potential for sine wave of permanent magnet brushless dc motor, and calculation of trival, high performance requirements of microcomputer. So although wholesalemotor.blogspot.com in this way has been put forward, in the late eighty s, many related articles published abroad, but is not very extensive application. Only in recent years, due to the development of the single chip computer technology, especially the high performance DSP (digital 3 phase ac induction motor signal processor) microprocessor application and popularization of this method has a certain applications. Abroad has been using TM S320C31, TM S320C30, ADMC330 DSP chip implements the approach of the permanent magnet brushless dc motor without position sensor control.