Control system for commutatorless motor

A control system for commutatorless motor comprising:

• a. a synchronous motor having polyphase armature winding and a field winding,
• b. a rectifying means for converting AC to DC,
• b'. an inverter means for converting the DC output of said rectifying means to AC to apply it to the armature winding of said synchronous motor,
• c. a position senser or detecting the position signal based on the rotational position of said synchronous motor,
• d. a voltage setup means for producing a constant exciting current reference determined in magnitude of the terminal voltage of said synchronous motor,
• e. first operational means for obtaining the magnitude of a nominal induced electromotive force of the vector sum of the armature reaction drop and the terminal voltage of said synchronous motor based on the signal proportional to the armature current and said constant exciting current reference produced from said voltage setup means,
• f. second operational means for obtaining the phase difference between the nominal induced electromotive force obtained by said first operational means and the terminal voltage of said synchronous motor,
• g. field control means for controlling the field current supplied to the field winding of said synchronous motor responsive to the magnitude of the nominal induced electromotive force produced by said voltage setup means,
• h. current phase reference means for producing a current phase reference leading the position signal of said position senser by the phase difference obtained by said second operational means, and
• i. current control means for controlling the firing phase of said frequency converter based on the current phase reference and current reference.

A control system for commutatorless motor comprising:

• a. a synchronous motor having polyphase armature winding and a field winding,
• b. a rectifying means for converting AC to DC,
• b'. an inverter means for converting the DC output of said rectifying means to AC to apply it to the armature winding of said synchronous motor,
• c. a position senser for detecting the position signal based on the rotational position of said synchronous motor,
• d. a voltage setup means for producing a constant exciting current reference determined in magnitude of the terminal voltage of said synchronous motor,
• e. first operational means for obtaining the magnitude of a nominal induced electromotive force of the vector sum of the armature reaction drop and the terminal voltage of said synchronous motor based on the signal proportional to the armature current and said constant exciting current reference produced from said voltage setup means,
• f. second operational means for obtaining the phase difference between the nominal induced electromotive force obtained by said first operational means and the terminal voltage of said synchronous motor,
• g. field control means for controlling the field current supplied to the field winding of said synchronous motor responsive to the magnitude of the nominal induced electromotive force produced by said voltage setup means,
• h. a power factor angle setup means for generating a power factor angle reference for instructing the power factor angle,
• h'. a current phase reference means for producing a current phase reference leading the position signal of said position senser by the phase difference of the sum of the phase difference obtained by said second operational means and said power factor angle reference,
• i. current control means for controlling the firing phase of said frequency converter based on the current phase reference and current reference.

A control system for commutatorless motor comprising:

• a. a synchronous motor having polyphase armature winding and a polyphase field winding,
• b. a frequency converter for supplying AC current of variable frequency to the armature winding of said synchronous motor,
• c. a position senser for detecting the position signal based on the rotational position of said synchronous motor,
• d. a voltage setup means for producing a constant exciting current reference determined in magnitude of the terminal voltage of said synchronous motor,
• e. first operational means for obtaining the magnitude of a nominal induced electromotive force of the vector sum of the armature reaction drop and the terminal voltage of said synchronous motor based on the signal proportional to the armature current and said constant exciting current reference produced from said voltage setup means,
• f. second operational means for obtaining the phase difference between the nominal induced electromotive force obtained by the first operational means and the terminal voltage of said synchronous motor,
• g. current phase reference means for producing a current phase reference leading the position signal of said position senser by the phase difference obtained by said second operational means,
• h. current control means for controlling the firing phase of said frequency converter based on the current phase reference and current reference,
• i. an oscillator for oscillating polyphase AC signal having the same number of phase as that of the field winding of said synchronous motor
• j. modulating means for modulating the polyphase AC signal by the nominal induced electromotive force obtained by said first operational means, and
• k. field control means for AC exciting the field winding of said synchronous motor based on the modulating signal of said modulating means.