Oil pump motor angle compensation method

Abstract

The invention relates to an oil pump motor angle compensation method. The method comprises the steps that S1, a permanent magnet synchronous motor achieves vector control through coordinate system conversion; s2, calibration compensation zero setting: S201, PWM is controlled by software to output a fixed direct current, so that an electrical zero position and a mechanical zero position coincide, and a first mechanical angle theta 1 is read; s202, positively controlling the electrical angle to rotate for a circle, and reading the next mechanical angle theta 2; s203, circularly reading for n times according to the step S202 to obtain mechanical angles theta n corresponding to n zero points; s204, one mechanical angle period of the oil pump motor is equally divided into 128 parts, and the angle is read once; and S205, compiling each read mechanical angle into a two-dimensional table, and performing table look-up through a dichotomy to compensate the angle delta. The optimal angle can be compensated according to different positions of the rotor, so that the method is suitable for oil pump motors suitable for various working condition scenes.

Description

Technical Field

[0001] The invention relates to the technical field of oil pump motors, in particular to an angle compensation method for an oil pump motor. Background Art

[0002] In order to achieve high-performance control of the oil pump motor, it is necessary to obtain accurate rotor position angles, which can be obtained by installing mechanical position sensors, such as resolvers, encoders, etc. However, errors in motor production, manufacturing, and installation can cause zero-point drift. Direct use of an uncalibrated oil pump may lead to control failure, unstable operation, or control errors. In order to make the mechanical angle detected by the encoder the same as the zero position of the motor electrical angle, manual calibration is required for compensation. At the same time, the calibration of existing technologies is only applicable to working conditions when the mechanical angle changes linearly. When the mechanical angle changes nonlinearly, the zero-point error calibration may still pass, but the compensated angle cannot meet the optimal performance output of each position. Therefore, the existing compensation method cannot be applied to motors in various working conditions. Summary of the invention

[0003] In view of the above problems, the present invention provides an oil pump motor angle compensation method suitable for compensating the angle of the motor rotor at various positions and improving the running stability of the motor.

[0004] The technical solution adopted by the present invention to solve the above technical problem is: a method for compensating the angle of an oil pump motor, comprising the following steps:

[0005] S1, realizes vector control of permanent magnet synchronous motor

[0006] The oil pump motor is a permanent magnet synchronous motor, which realizes vector control by converting its mathematical model in the ABC three-phase stationary coordinate system into the dq synchronous rotating coordinate system;

[0007] S2, calibration compensation zeroing

[0008] S201, control PWM through software to output a fixed DC, so that the electrical zero position coincides with the mechanical zero position, and read the first mechanical angle θ1;

[0009] S202, forward control electrical angle rotation for one circle, read the next mechanical angle θ2;

[0010] S203, loop through step S202 and read n times to obtain the mechanical angles θ corresponding to n zero points n ;

[0011] S204, after confirming that the angle information can be obtained, a mechanical angle cycle of the oil pump motor is divided into 128 equal parts, and the oil pump motor is controlled to read an angle once at each equal angle position, θ1, ..., θ128 ;

[0012] S205, compile each read mechanical angle into a two-dimensional table, and use the binary search method to look up the table to compensate the angle δ.

[0013] Preferably, step S1 specifically involves first converting from the ABC three-phase stationary coordinate system to, and then converting from the αβ two-phase stationary coordinate system to the dq synchronous rotating coordinate system.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] 1. Based on the calibration, the present invention divides the mechanical angle into several equal parts, reads the angle of each equal point, and compiles the compensation value based on the angle position, which can compensate the best angle according to the rotor at different positions, so as to be applicable to the oil pump motor in various positions of the rotor, that is, it can be applicable to various working conditions;

[0016] 2. The present invention makes the 0° of the mechanical angle coincide with the 0° of the electrical angle, and the 0° of other electrical angles coincide with the points where the mechanical period n (pole pair number) is equally divided, thereby achieving optimal output performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a coordinate transformation relationship diagram of the present invention (in the figure, 1a is the ABC three-phase stationary coordinate system, 1b is the αβ two-phase stationary coordinate system, and 1c is the dq synchronous rotating coordinate system);

[0018] Figure 2 It is a zero position relationship diagram;

[0019] Figure 3 is the linear angle calibration compensation diagram;

[0020] Figure 4 It is a nonlinear angle graph;

[0021] Figure 5 This is the schematic diagram of binary table lookup calibration. DETAILED DESCRIPTION

[0022] The following will be combined Figure 1-5 The present invention is described in detail. The exemplary embodiments and descriptions of the present invention are used to explain the present invention but are not intended to limit the present invention.

[0023] A method for compensating an oil pump motor angle comprises the following steps:

[0024] S1, realizes vector control of permanent magnet synchronous motor

[0025] The oil pump motor is a permanent magnet synchronous motor, which realizes vector control by converting its mathematical model in the ABC three-phase stationary coordinate system to the dq synchronous rotating coordinate system. Specifically, the ABC three-phase stationary coordinate system is first converted to the αβ two-phase stationary coordinate system, and then converted to the dq synchronous rotating coordinate system from the αβ two-phase stationary coordinate system. Figure 1 As shown, ideally, the zero position of the d-axis of the dq synchronous rotating coordinate system should be aligned with the A-axis of the ABC three-phase stationary coordinate system. However, due to factors such as installation errors, the actual relationship between the d-axis and the x-axis is as follows: Figure 2 As shown, Figure 2 δ is the angle between the encoder zero position and the A axis, which is the angle required for calibration and compensation.

[0026] S2, calibration compensation zeroing

[0027] S201, control PWM through software to output a fixed DC, so that the electrical zero position coincides with the mechanical zero position, and read the first mechanical angle θ1;

[0028] S202, forward control electrical angle rotation for one circle, read the next mechanical angle θ2;

[0029] S203, loop through step S202 and read n times to obtain the mechanical angles θ corresponding to n zero points n ;

[0030] S204, after confirming that the angle information can be obtained, a mechanical angle cycle of the oil pump motor is divided into 128 equal parts (the finer the division, the better the effect), and the oil pump motor is controlled to read the angle once at each equal angle position, θ1, ..., θ 128 ;

[0031] S205, compile each read mechanical angle into a two-dimensional table, and use the binary search method to look up the table to compensate the angle δ.

[0032] The existing calibration compensation algorithm can overcome most of the zero misalignment problems caused by some errors, such as Figure 3 As shown in the linear angle calibration compensation diagram, taking a nine-slot six-pole motor as an example, its pole pair number is 3, and the ideal angle curve is a solid line. In fact, due to the manufacturing or installation errors of the motor, the angle data read back by the encoder may be a dotted line, that is, there is a deviation between the mechanical angle and the zero position of the motor electrical angle. At this time, if the oil pump is directly operated, the oil pump may be out of control or have poor performance. In order for the oil pump to continue to work normally, manual calibration compensation is required, which can be compensated by the existing calibration compensation method. However, when the motor manufacturing error is large and the air magnetic density is uneven, the actual electrical angle may show nonlinear changes, such as Figure 4As shown, at this time, the existing zero-point error calibration method may still pass, but the compensation angle cannot meet the optimal performance output of each position. Based on this limitation, the present invention divides the mechanical angle into several parts on the basis of passing the calibration, and reads the angle of each divided point, and compiles it into a compensation value based on the angle position. It can compensate for the best angle according to the rotor at different positions, so that it is suitable for the rotor in various positions. Therefore, the compensation algorithm of the present invention can be applied to motors in various working scenarios, so that the motor can output the best performance at each position, thereby improving the stability of operation.

[0033] The technical solutions provided by the embodiments of the present invention are introduced in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the embodiments of the present invention. The description of the above embodiments is only applicable to help understand the principles of the embodiments of the present invention. At the same time, for those skilled in the art, according to the embodiments of the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A method for compensating an oil pump motor angle, characterized in that: The following steps are involved: S1, realizes vector control of permanent magnet synchronous motor The oil pump motor is a permanent magnet synchronous motor, which realizes vector control by converting its mathematical model in the ABC three-phase stationary coordinate system into the dq synchronous rotating coordinate system; S2, calibration compensation zeroing S201, control PWM through software to output a fixed DC, so that the electrical zero position coincides with the mechanical zero position, and read the first mechanical angle θ1; S202, forward control electrical angle rotation for one circle, read the next mechanical angle θ2; S203, loop through step S202 and read n times to obtain the mechanical angles θ corresponding to n zero points n ; S204, after confirming that the angle information can be obtained, a mechanical angle cycle of the oil pump motor is divided into 128 equal parts, and the oil pump motor is controlled to read an angle once at each equal angle position, θ1, ..., θ 128 ; S205, compile each read mechanical angle into a two-dimensional table, and use the binary search method to look up the table to compensate the angle δ.

2. The oil pump motor angle compensation method according to claim 1, characterized in that: Step S1 specifically involves first converting the ABC three-phase stationary coordinate system into the αβ two-phase stationary coordinate system, and then converting the αβ two-phase stationary coordinate system into the dq synchronous rotating coordinate system.

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