Apparatus And Method For Generating Electromagnetic Torque In An Electric Machine

A method for generating electromagnetic torque in an N-phase electric machine, N being a positive integer, by means of N lines, each of the N lines including an input terminal, an output terminal, and at least a pair of thyristors, or of one thyristor and one diode, connected between the input terminal and the output terminal such that the cathode of one of the components in the thyristor or diode-thyristor pair is connected to the anode of the other one of the components in the thyristor or diode-thyristor pair and the cathode of said other one of the components in the thyristor or diode-thyristor pair is connected to the anode of said one of the components in the thyristor or diode-thyristor pair, wherein the N lines are connected between a mains and the electric machine, the method comprising the steps of:

• repeatedly or continuously determining at least the sign of a voltage over the thyristor or diode-thyristor pair in at least one of the N lines;
• repeatedly or continuously determining at least one parameter related to the electromagnetic field in said electric machine, and a time derivative thereof;
• and
• controlling the operation of the thyristor or diode-thyristor pair of said at least one of the N lines in response to (i) at least said determined sign of the voltage, (ii) at least the sign of said determined parameter related to the electromagnetic field in said electric machine, and (iii) at least the sign of the time derivative of said determined parameter related to the electromagnetic field in said electric machine.

A computer program product loadable into the internal memory of a computer and comprising software code portions for controlling a method for generating electromagnetic torque in an N-phase electric machine, when said product is run on a computer, N being a positive integer, by means of N lines, each of the N lines including an input terminal, an output terminal, and at least a pair of thyristors, or of one thyristor and one diode, connected between the input terminal and the output terminal such that the cathode of one of the components in the thyristor or diode-thyristor pair is connected to the anode of the other one of the components in the thyristor or diode-thyristor pair and the cathode of said other one of the components in the thyristor or diode-thyristor pair is connected to the anode of said one of the components in the thyristor or diode-thyristor pair, wherein the N lines are connected between a mains and the electric machine, the method comprising the steps of:

• repeatedly or continuously determining at least the sign of a voltage over the thyristor or diode-thyristor pair in at least one of the N lines;
• repeatedly or continuously determining at least one parameter related to the electromagnetic field in said electric machine, and a time derivative thereof;
• and
• controlling the operation of the thyristor or diode-thyristor pair of said at least one of the N lines in response to (i) at least said determined sign of the voltage, (ii) at least the sign of said determined parameter related to the electromagnetic field in said electric machine, and (iii) at least the sign of the time derivative of said determined parameter related to the electromagnetic field in said electric machine.