Control method for variable excitation synchronous motor MTPA based on multi-line fitting

Abstract

The invention relates to a control method for a variable excitation synchronous motor MTPA (Maximum Torque per Ampere) based on multi-line fitting, and provides a multi-line fitting method for a rectangular axis current solving module in a control structure drawing. An excitation magnetic chain is discretized in the variable scope; and then under each specific excitation magnetic chain, an electromagnetic torque is used as a single argument to carry out the quadratic polynomial fitting of a rectangular axis current solving function, and then a plurality of fitting curves under different excitation magnetic chains can be obtained. When the system runs, at the excitation magnetic chain at one moment, two closest fitting curves are selected firstly to carry out the current calculation of the rectangular axis respectively; then based on the two sets of values, the size of the excitation magnetic chain at the moment is used as a node to carry out linear interpolation, and the set value of the current value of the rectangular axis at the moment can be obtained; and finally, the control of the current ratio of the maximum torque of the variable excitation synchronous machine is completed.

Description

technical field [0001] The invention discloses a method for controlling the maximum torque-to-current ratio of a synchronous motor with variable excitation, specifically for synchronous motors with varying excitation currents, using a multi-line fitting method to control the maximum torque-to-current ratio (MTPA), and belongs to the technical field of AC motor transmission. Background technique [0002] Starting / generating integration is an important development direction of future aviation AC power system. At present, most aircraft AC power systems in my country use three-stage brushless synchronous motors (see figure 1 ) as a generator, this type of generator does not have the function of starting an aeroengine, and the engine is started by an independent starter. Such an engine-power supply system includes two sets of motors, which makes the volume and weight large, and the system is complex and the reliability is reduced. If on the basis of the original three-stage bru...

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Problems solved by technology

However, the motor is mainly designed to meet the power generation function, and there are the following problems in the motoring state: 1) In the static and low-speed state, the output voltage of the exciter is low, and the excitation current of the main generator is small, which seriously affects the load of the main generator Starting ability; 2) As the motor speed increases, the output voltage of the exciter gradually increases, and the excitation current of the main generator also gradually increases, that is, the excitation current of the main generator is always changing during the motor starting process

[0010] For formula (3), the function f 1 and f 2 The exact analytical form of is more difficult to determine and cannot be fitted by simple quadratic or cubic polynomials

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