CPC H02P 9/14 (2013.01) | 11 Claims |
1. A method for controlling a generator-side terminal voltage of a converter, the method comprising:
determining an upper limit of the generator-side terminal voltage based on a present voltage value of a direct-current (DC) bus of the converter, wherein the generator-side terminal voltage is a voltage of an output terminal of a generator, and the output terminal of the generator is connected to the converter;
determining an optimal value of the generator-side terminal voltage from a preset optimal search interval, wherein the optimal value minimizes a present value of a generator-side current when compared with other values in the preset optimal search interval, wherein the generator-side current is a current of the output terminal of the generator; and
setting a target value of the generator-side terminal voltage based on the upper limit of the generator-side terminal voltage and the optimal value of the generator-side terminal voltage, wherein the target value is used to obtain a control reference value of the generator-side terminal voltage,
wherein determining the optimal value of the generator-side terminal voltage comprises:
determining whether a present value of the generator-side terminal voltage falls into the preset optimal search interval; and
responsive to the present value of the generator-side terminal voltage falling into the preset optimal search interval, searching in the preset optimal search interval for the optimal value of the generator-side terminal voltage that minimizes the present value of the generator-side current; and
wherein searching in the preset optimal search interval for the optimal value of the generator-side terminal voltage that minimizes the present value of the generator-side current comprises:
step (a): setting the target value of the generator-side terminal voltage to an initial value, and obtaining a value I0 of the generator-side current and a given torque value T0 of the generator after the generator-side terminal voltage is stable;
step (b): updating the target value of the generator-side terminal voltage as a sum of the initial value and ΔU, and when the generator-side terminal voltage is stable and the given torque value is T0, determining whether a value I1 of the generator-side current is less than I0, wherein when I1 is greater than I0, step (c) is performed, or, when I1 is less than I0, step (e) is performed;
step (c): updating the target value of the generator-side terminal voltage as a difference between the initial value and ΔU, and when the generator-side terminal voltage is stable and the given torque value is T0, determining whether a value I2 of the generator-side current is less than I0, wherein when I2 is greater than I0, the initial value is determined as the optimal value of the generator-side terminal voltage that minimizes the present value of the generator-side current, or, when I2 is less than I0, step (d) is performed;
step (d): reducing the target value of the generator-side terminal voltage by ΔU, and when the generator-side terminal voltage is stable and the given torque value is T0, determining whether the present value of the generator-side current is smaller than a previous value of the generator-side current, wherein when the present value of the generator-side current is not smaller than the previous value of the generator-side current, the target value of the generator-side terminal voltage is determined as the optimal value of the generator-side terminal voltage, or, when the present value of the generator-side current is smaller than the previous value of the generator-side current, step (d) is repeated; and
step (e): increasing the target value of the generator-side terminal voltage by ΔU, and when the generator-side terminal voltage is stable and the given torque value is T0, determining whether the present value of the generator-side current is smaller than the previous value of the generator-side current, wherein when the present value of the generator-side current is not smaller than the previous value of the generator-side current, the target value of the generator-side terminal voltage is determined as the optimal value of the generator-side terminal voltage or, when the present value of the generator-side current is smaller than the previous value of the generator-side current, step (e) is repeated,
wherein ΔU is greater than 0.
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