Apparatus and method for controlling rotation speed of synchronous reluctance motor

An apparatus for controlling rotation speed of a synchronous reluctance motor, comprising:

• a position estimation unit for performing control of rotation speed of the synchronous reluctance motor by estimating the position angle of the rotor and rotation speed of the rotor according to the low or high speed areas of the synchronous reluctance motor;
• and
• a low speed control unit including:
• a signal injection unit for inputting a predetermined signal to a flux of a D-axis and obtaining the different between the flux value of a Q-axis which is finally observed in the synchronous reluctance motor and flux value of the Q-axis which was initially estimated, in the low speed area of the motor or in an initial driving;
• a high pass filter for performing filtering to remove signals of the direct current DC component among signals outputted from the signal injection unit 44a and outputting the resultant;
• a demodulation unit for receiving, demodulating the resultant value and outputting the signal of the DC component;
• a low pass filter for performing filtering to generate a signal of complete DC component, by removing erroneous components among the signals of the DC component and outputting the signal of the DC component;
• a PI control unit for performing PI control of the signal of the DC component and obtaining speed information according to low speed control of the motor;
• a second integrator for performing integration by
• receiving the speed information and obtaining position information according to the low speed control of the motor;
• and
• a switching unit for receiving the position information and outputting the information to the synchronization/fixed coordinate conversion unit.

An apparatus for controlling rotation speed of a synchronous reluctance motor, comprising:

• a position estimation unit for controlling rotation speed of the motor by estimating rotor position angle of the rotor and rotation speed of a rotor according to the low speed or high speed area of the synchronous reluctance motor;
• and
• a transient state stabilization unit including:
• a speed ratio adjustment unit for comparing the rotation speed of the rotor which was estimated in the position estimation unit in case of controlling the motor at high speed and outputted, and the rotation speed of the rotor which was estimated and outputted to a PI control unit in case of controlling the motor at low speed, in gear controlling of the motor, determining whether the motor is controlled at high or low speed, and stabilizing a transient state which is generated in the motor by having an overlapping region in case of converting from the high speed area to low speed area or from the low speed area to high speed area;
• a second integrator for integrating and outputting the speed information which was inputted from the speed ratio adjustment unit;
• and
• a switching unit for switching to control the motor at low or high speed by receiving the speed information and then outputting the speed information according to the low speed control or the speed information according to the high speed control respectively to the synchronization/fixed coordinate conversion unit.

An apparatus for controlling rotation speed of a synchronous reluctance motor, comprising:

• a fixed/synchronization coordinate conversion unit for detecting two phase currents among the three phase currents outputted to synchronous the reluctance motor and then outputting the currents to second and third comparators and a flux observer;
• the flux observer receiving the outputted two phase currents and the two voltages of the fixed coordinate system outputted to the synchronous reluctance motor, for outputting the corresponding flux;
• a position estimation unit for estimating the position angle of the rotor for high speed control of the synchronous reluctance motor and rotation speed of the rotor using the outputted flux;
• a low speed control unit receiving the rotation speed, for estimating the rotation speed of the rotor for low speed control of the synchronous reluctance motor and outputting the angle to the synchronization/fixed coordinate conversion unit;
• and
• a transient state stabilization unit for stabilizing a transient state which is generated according to the low speed control and a speed control algorithm, wherein the flex observer includes:
• a flux conversion unit receiving the two phase currents outputted from the fixed/synchronization coordinate conversion unit, for outputting the estimated flux according to the synchronous coordinate system;
• a fixed/synchronization flux conversion unit for converting the estimated flux according to the synchronization coordination system into an estimated flux value in the fixed coordinate system using the position angle of the rotor which is position information outputted from the position estimation unit for high speed control and outputting the flux value;
• a fourth comparator unit for comparing the voltage of the fixed coordinate system outputted from the synchronization/fixed coordinate conversion unit and the voltage corresponding to a multiplied value of the two phase currents and resistance at the stator side and outputting the corresponding voltage error, that is, an induced voltage;
• a first integrator for yielding the real flux and outputting the flux after integrating the outputted induced voltage;
• a sixth comparator unit for yielding difference between the estimated flux of the fixed coordinate system outputted from the synchronization/fixed flux conversion unit and the real flux outputted from the first integrator and outputting the difference;
• a gain generation unit for generating and outputting a gain value to reduce the difference between the outputted two fluxes, that is, the flux error;
• and
• a position estimation unit receiving the real flux outputted from the first integrator and the estimated flux outputted from the flux conversion unit, for yielding the position angle of the rotor for estimating the rotor position of the synchronous reluctance motor and outputting the angle.

A method for controlling rotation speed of a synchronous reluctance motor, comprising the steps of:

• comparing a speed reference value and real rotor speed value of the synchronous reluctance motor and then outputting the corresponding speed error;
• performing PI control for compensating the outputted speed error and outputting the corresponding electric current;
• receiving the outputted current, generating a voltage for a flux in the synchronous coordinate system and then outputting the voltage;
• generating a flux reference value and outputting the value;
• comparing the flux reference value and real flux, receiving the outputted flux reference value and then outputting the corresponding flux error;
• outputting a voltage for a torque in the synchronous coordinate, system after performing the PI control by receiving the outputted flux error;
• converting the two voltages of the synchronous coordinate system into two voltages of the fixed coordinate system by receiving the position angle of the rotor showing the real position of a rotor estimated in the high speed and low speed areas of the synchronous reluctance motor, converts the two voltages in the synchronous coordinate system into two voltages in the fixed coordinate system and output the voltages;
• converting the outputted two voltages of the fixed coordinate system into three phase voltages and outputting the voltages;
• inverting the outputted three phase voltages and then outputting a three phase electric currents for driving the synchronous reluctance motor;
• driving the synchronous reluctance motor by receiving the outputted three phase currents;
• detecting two phase currents among the three outputted phase currents;
• receiving the outputted two phase currents and the two voltages of the fixed coordinate system and outputting the corresponding flux;
• estimating the position angle of the rotor and rotation speed of the rotor for high speed control of the synchronous reluctance motor using the outputted flux;
• receiving the rotation speed, estimating the rotation speed of the rotor for low speed control of the synchronous reluctance motor and outputting the rotation speed;
• and
• stabilizing a transient state generated according to the low speed control and a speed control algorithm.