A motor includes a stator having a winding, and a rotor. The rotor rotates by receiving a rotational magnetic field generated by drive current supplied to the winding. The winding includes a first winding and a second winding, the first and second windings both being excited at the same timing by the drive current. The first winding and the second winding are connected in series. The rotor includes a first pole section and a second pole section. The second pole section faces the second winding at the rotation position of the rotor at which the first pole section faces the first winding. The magnetic force exerted on the stator by the second pole section is weaker than that exerted by the first pole section.

There is provided a motor control device which enables torque ripple suppressing control high in followability by executing direct voltage control. A motor control device includes a voltage command calculation unit 15 which calculates a d-axis voltage command value V.sub.d.sup.ref and a q-axis voltage command value V.sub.q.sup.ref from a d-axis current command value i.sub.d* and a q-axis current command value i.sub.q* of a motor 6, a feed forward command value calculation unit 23 which calculates a qi-axis voltage feed forward command value V.sup.qff* for generating a q-axis current ripple on the basis of spatial harmonic parameters and the frequency characteristics of a motor winding, and a subtraction unit 10 which subtracts the q-axis voltage feed forward command value V.sub.qff* calculated by the feed forward command value calculation unit 23 from the q-axis voltage command value V.sub.q.sup.ref calculated by the voltage command calculation unit 15.

There is provided a motor control device which enables torque ripple suppressing control high in followability by executing direct voltage control. A motor control device includes a voltage command calculation unit 15 which calculates a d-axis voltage command value V.sub.d.sup.ref and a q-axis voltage command value V.sub.q.sup.ref from a d-axis current command value i.sub.d* and a q-axis current command value i.sub.q* of a motor 6, a feed forward command value calculation unit 23 which calculates a qi-axis voltage feed forward command value V.sup.qff* for generating a q-axis current ripple on the basis of spatial harmonic parameters and the frequency characteristics of a motor winding, and a subtraction unit 10 which subtracts the q-axis voltage feed forward command value V.sub.qff* calculated by the feed forward command value calculation unit 23 from the q-axis voltage command value V.sub.q.sup.ref calculated by the voltage command calculation unit 15.

Control of an AC motor includes rotation over an operating speed range with the output from an inverter by operating the inverter at switching frequencies that vary in proportion to rotor speed. The operating speed range is parsed into a plurality of speed regions and the switching frequencies within each operating speed region may correspond to a respective pulse ratio that is different from the respective pulse ratio corresponding to an adjacent speed region.

Control of an AC motor includes rotation over an operating speed range with the output from an inverter by operating the inverter at switching frequencies that vary in proportion to rotor speed. The operating speed range is parsed into a plurality of speed regions and the switching frequencies within each operating speed region may correspond to a respective pulse ratio that is different from the respective pulse ratio corresponding to an adjacent speed region.

A parameterless and position-sensorless MTPA control of a permanent magnet synchronous motor including: using three rotating reference frames having different observation angles to parse the current vector; using a target current value and a preset current-rotor angle y that is between the current vector and the q.sub.r-axis of the (d.sub.r, q.sub.r) rotor reference frame to obtain the angles between the current vector, the voltage vector, and the rotor position; obtaining the target voltage value and the target voltage angle by using the obtained angles to obtain the target phase voltage values for regulation. The method is simple in controlling the motor, improves the control efficiency and reliability, and improves the control accuracy.

A parameterless and position-sensorless MTPA control of a permanent magnet synchronous motor including: using three rotating reference frames having different observation angles to parse the current vector; using a target current value and a preset current-rotor angle y that is between the current vector and the q.sub.r-axis of the (d.sub.r, q.sub.r) rotor reference frame to obtain the angles between the current vector, the voltage vector, and the rotor position; obtaining the target voltage value and the target voltage angle by using the obtained angles to obtain the target phase voltage values for regulation. The method is simple in controlling the motor, improves the control efficiency and reliability, and improves the control accuracy.

A controller is provided to drive an inverter circuit for a PMSM. The inverter circuit is connected to a battery through a DC link capacitor, and is driven in one safe state during a fault condition. The controller monitors at least one parameter with respective threshold value to drive the inverter circuit in one safe state comprising an active Short Circuit (SC) and a Freewheel (FW). While in FW state, the controller switches from the FW state to the SC state if the at least one parameter is above the respective threshold. While in SC state, the controller controls engine speed to bring the PMSM to a predetermined speed when the stator temperature is more than a threshold temperature value. The controller switches from the SC state to the FW state.

A method of setting up an electrical motor speed control in a fluidic system including a turbomachine, an electric motor having a number p of pole pairs rotating the turbomachine, a variable speed drive controlling the speed of the electric motor, a sensor measuring a parameter H, Q of the turbomachine, and a system controller receiving the sensor's measurements and controlling the operation of the fluidic system. The method includes driving the electric motor at a predetermined electrical frequency, Fe, such that the turbomachine rotates with a controlled rotational speed N, determining the point of intersection of the system curve of the fluidic system and of the performance curve of the turbomachine to obtain the turbomachine's nominal operating point, and thus the nominal value, Hn, Qn, of the turbomachine parameter, measuring, with the sensor, the current value, H, Q of the turbomachine parameter, calculating the controlled rotational speed N by inputting, into the Affinity Laws, the determined nominal value, Hn, Qn, the measured current value, H, Q, and the known nominal rotational speed, Nn, of the turbomachine, determining the number p of pole pairs of the electric motor based on the ratio of the electrical frequency Fe and the calculated controlled rotational speed N, and adapting the setup of the variable speed drive to match the determined number p of pole pairs.

A method for controller a multiphase electric machine includes, in response to a determination that a phase of the multiphase electric machine is in an open circuit condition, determining a desired torque to be generated by the multiphase electric machine and retrieving, based on the determination that the phase is in the open circuit condition and the desired torque, a set of current values to be applied to each of the other phases of the multiphase electric machine to achieve the desired torque. The method may also include applying respective current values of the set of current values to corresponding ones of the other phases of the multiphase electric machine, the set of current values being determined based on a model of the multiphase electric machine that includes the phase is in the open circuit condition.