CN104283479A - Permanent magnet synchronous motor load torque monitoring system based on three-dimensional motor parameter tables - Google Patents

Abstract

The invention provides a permanent magnet synchronous motor load torque monitoring system based on three-dimensional motor parameter tables, and relates to the field of motor control. The influences of temperature on motor parameters are omitted in the current motor torque monitoring process, so that a large difference still exists between torque acquired through calculation and the actual value. According to the technical scheme, the system comprises an a-phase current sensor, a b-phase current sensor, a position sensor, a coordinate conversion unit, a temperature sensor, a rotor temperature calculation unit, a three-dimensional motor parameter storage unit and a load torque calculation unit. By the adoption of the technical scheme, the motor temperature sensor is arranged, the accuracy of load torque calculation is improved, the requirement for the calculation capacity of a chip is lowered, cost is reduced, and the response speed is high.

Description

Based on the permagnetic synchronous motor load torque monitoring system of three-dimensional parameter of electric machine table

Technical field

The present invention relates to Motor Control Field, is especially a kind of monitoring system of motor.

Background technology

Widely use permagnetic synchronous motor in electric automobile, it is that drive motors can provide accurate direct torque in full speed range and in full-load range to the major requirement of motor.In addition, the command torque given by contrast car load and the actual torque of drive motors system, indirectly can reflect the running status of drive motors system, infer whether have fault.In general, the measurement of torque, for electric automobile, is not only and is ensured the requirement of control performance, especially an important security features.

Accurately can obtain actual torque by torque measurement instrument, but be limited to cost control, the requirement such as weight and locus of electric automobile, this method is not applied to electric automobile field.Existing torque measurement is mainly realized by load torque observer, and its theory diagram as shown in Figure 1.The Obtaining Accurate of the parameter of electric machine is the necessary condition of load torque observer accurate surveying.Existing parameter of electric machine acquisition methods is mainly realized by on-line parameter identification, but this acquisition methods requires high to on-line parameter identification algorithm, adds the complexity of control system.Also have partial parameters on-line identification algorithm to consider the saturation characteristic of permanent magnet, improve the precision of torque observe, but these methods have ignored the impact of temperature on the parameter of electric machine, make calculating acquisition torque and reality still there is bigger difference.

Summary of the invention

The technical assignment of the technical problem to be solved in the present invention and proposition carries out improving to prior art and improves, and provides the permagnetic synchronous motor load torque monitoring system based on three-dimensional parameter of electric machine table, to improve the object of torque calculation accuracy.For this reason, the present invention takes following technical scheme.

Based on the permagnetic synchronous motor load torque monitoring system of three-dimensional parameter of electric machine table, it is characterized in that comprising:

A phase current transducer: for a phase current i _asample;

B phase current transducer: for b phase current i _bsample;

Position transducer: for detection rotor position θ;

Coordinate transformation unit: be connected with a phase current transducer and b phase current transducer, for according to a phase current i _a, b phase current i _b, rotor position calculates motor d shaft current i _dwith q shaft current i _q;

Temperature sensor: for measuring stator temperature t _s;

Temperature of rotor calculates unit: be connected with temperature sensor, for according to stator temperature t _scalculate motor rotor temperature t _r;

Three-dimensional parameter of electric machine memory cell: correspond to d shaft current i for storing _d, q shaft current i _qwith motor rotor temperature t _rmotor d axle inductance L _d, q axle inductance L _qwith permanent magnet flux linkage Ψ _f;

Load torque computing unit: calculate unit with coordinate transformation unit and temperature of rotor and be connected, for according to d shaft current i _d, q shaft current i _qinquire about three-dimensional parameter of electric machine memory cell with motor rotor temperature tr and obtain motor d axle inductance L _d, q axle inductance L _qwith permanent magnet flux linkage Ψ _f, and according to motor d axle inductance L _d, q axle inductance L _q, permanent magnet flux linkage Ψ _f, d shaft current i _d, q shaft current i _qcomputational load torque T _e.

The technical program establishes motor temperature sensor, improve the accuracy of computational load torque, on the other hand, during its load torque calculates, the used parameter of electric machine is by the running status of following motor in real time of tabling look-up, therefore the load torque obtained is observed to have higher precision and response speed faster, the parameter of electric machine sets in advance, reduces the computing capability requirement of chip, reduces costs.

As improving further and supplementing technique scheme, the present invention also comprises following additional technical feature.

Described temperature sensor is at least provided with the first temperature sensor, the second temperature sensor, and the first described temperature sensor, the second temperature sensor are embedded in motor stator side; Temperature of rotor calculates unit according to the first temperature sensor measurement temperature t _s1, the second temperature sensor measurement temperature t _s2and two temperature measuring points calculate acquisition motor rotor temperature t relative to the thermal resistance data of rotor _r.If multiple temperature sensor is conducive to the accuracy of the monitoring improving temperature.

In three-dimensional parameter of electric machine memory cell, three-dimensional parameter of electric machine manufacture method comprises the following steps:

1) to d shaft current i _d, q shaft current i _qwith temperature of rotor t _rcombine, carry out motor Finite Element Simulation Analysis repeatedly;

2) data of finite element analysis are carried out Data Analysis Services, generate d axle inductance L respectively _demulated data table, q axle inductance L _qemulated data table and permanent magnet flux linkage Ψ _femulated data table;

3) arrange emulated data table, continuous treatment is carried out to list data, connect continuousization processing mode and comprise interpolation calculation;

4) obtain initial three-dimensional parameter of electric machine table, be respectively d axle inductance L _dthree-dimensional parameter of electric machine table, q axle inductance L _qthree-dimensional parameter of electric machine table and permanent magnet flux linkage Ψ _fthree-dimensional parameter of electric machine table;

5) the actual measurement torque of motor under different running status and observation torque is recorded;

6) if observation torque with actual measurement torque error exceed allowed band, then need to carry out error correction to three-dimensional parameter of electric machine table, and repeat step 5) operation;

7) when the error requirement allowed band in of satisfied observation torque with actual measurement torque, final three-dimensional parameter of electric machine table is exported.

Coordinate transformation unit comprises two kinds in the mode of carrying out Coordinate Conversion: permanent amplitude transformation and invariable power conversion, and permanent amplitude transformation is calculated as shown in formula (1), and invariable power transformation calculations is for shown in formula (2):

$\left[\begin{array}{c}{i}_d\\ i_q\end{array}\right]=\frac{2}{3}\left[\begin{array}{cc}\cos \mathrm{\θ}& \sin \mathrm{\θ}\\ -\sin \mathrm{\θ}& \cos \mathrm{\θ}\end{array}\right]\left[\begin{array}{cc}\frac{3}{2}& 0\\ \frac{\sqrt{3}}{2}& \sqrt{3}\end{array}\right]\left[\begin{array}{c}{i}_a\\ i_b\end{array}\right]---\left(1\right)$

$\left[\begin{array}{c}{i}_d\\ i_q\end{array}\right]=\sqrt{\frac{2}{3}}\left[\begin{array}{cc}\cos \mathrm{\θ}& \sin \mathrm{\θ}\\ -\sin \mathrm{\θ}& \cos \mathrm{\θ}\end{array}\right]\left[\begin{array}{cc}\frac{3}{2}& 0\\ \frac{\sqrt{3}}{2}& \sqrt{3}\end{array}\right]\left[\begin{array}{c}{i}_a\\ i_b\end{array}\right]---\left(2\right)$

Motor rotor temperature t _rcomputing formula is:

$t_r=\frac{t_{s2}-t_{s1}}{R_{\mathrm{th}1}}\·R_{\mathrm{th}2}+t_{s2};$

In formula: R _th1and R _th2be respectively the thermal resistance data of two temperature measuring points relative to rotor.

Load torque computing unit computational load torque T _eformula be: T _e=1.5n _p(L _di _di _q-L _qi _di _q+ Ψ _fi _q); N in formula _pfor the magnetic of permagnetic synchronous motor is to number of poles.

Beneficial effect:.

Accompanying drawing explanation

Fig. 1 is the accurate Control loop system architecture diagram of existing torque.

Fig. 2 is structured flowchart of the present invention.

Fig. 3 is the flow chart of the three-dimensional parameter of electric machine table manufacture method of the embodiment of the present invention.

In figure: 1-b phase current transducer, 2-position transducer, 3-coordinate transformation unit, 4-first temperature sensor, 5-second temperature sensor, 6-temperature of rotor calculates unit, the three-dimensional parameter of electric machine table of 7-, 8-a phase current transducer, 9-load torque computing unit.

Embodiment

Below in conjunction with Figure of description, technical scheme of the present invention is described in further detail.

As shown in Figure 2, the present invention includes a phase current transducer 8, b phase current transducer 1, position transducer 2, coordinate transformation unit 3, load torque computing unit 9, first temperature sensor 4, second temperature sensor 5, temperature of rotor calculate unit 6 and store the three-dimensional parameter of electric machine memory cell of three-dimensional parameter of electric machine table 7, a phase current transducer 8 and b phase current transducer 1 detect the phase current i of two-phase _aand i _b, position transducer 2 detects rotor position, and the first temperature sensor 4 and the second temperature sensor 5 detect motor stator temperature t _s1and t _s2.

I _a, i _bbe input in coordinate transformation unit 3 with θ and calculate motor d shaft current i _dwith _qshaft current i _q.Coordinate transform has two kinds of forms: permanent amplitude transformation and invariable power conversion, and permanent amplitude transformation formula is:

$\left[\begin{array}{c}{i}_d\\ i_q\end{array}\right]=\frac{2}{3}\left[\begin{array}{cc}\cos \mathrm{\θ}& \sin \mathrm{\θ}\\ -\sin \mathrm{\θ}& \cos \mathrm{\θ}\end{array}\right]\left[\begin{array}{cc}\frac{3}{2}& 0\\ \frac{\sqrt{3}}{2}& \sqrt{3}\end{array}\right]\left[\begin{array}{c}{i}_a\\ i_b\end{array}\right]$

Invariable power transformation for mula is:

$\left[\begin{array}{c}{i}_d\\ i_q\end{array}\right]=\sqrt{\frac{2}{3}}\left[\begin{array}{cc}\cos \mathrm{\θ}& \sin \mathrm{\θ}\\ -\sin \mathrm{\θ}& \cos \mathrm{\θ}\end{array}\right]\left[\begin{array}{cc}\frac{3}{2}& 0\\ \frac{\sqrt{3}}{2}& \sqrt{3}\end{array}\right]\left[\begin{array}{c}{i}_a\\ i_b\end{array}\right]$

Temperature sensor 4 and temperature sensor 5 are embedded in motor stator side two temperature measuring points respectively, and its temperature detection result is expressed as t _s1and t _s2.Obtain these two temperature measuring points by theory calculate, simulation analysis or experiment measuring and be expressed as R relative to the thermal resistance data of rotor _th1and R _th2.By t _s1and t _s2be input to temperature of rotor calculating unit 6 and can calculate temperature of rotor t _r, that is:

$t_r=\frac{t_{s2}-t_{s1}}{R_{\mathrm{th}1}}\·R_{\mathrm{th}2}+t_{s2}$

I _d, i _qand t _rthree signals are input to three-dimensional parameter of electric machine table 7, and inquiry obtains d axle inductance L respectively _d, _qaxle inductance L _qwith permanent magnet flux linkage Ψ _f.Again by L _d, L _q, Ψ _f, i _dand i _qbe input in load torque computing unit 9 and calculate load torque T _e, torque calculation formula is:

T _e＝1.5n _p(L _di _di _q-L _qi _di _q+Ψ _fi _q)。

In Fig. 3, the manufacture method of the three-dimensional parameter of electric machine table 7 used in load torque observer comprises the following steps:

1) to d shaft current i _d, q shaft current i _qwith temperature of rotor t _rcarry out reasonable combination, carry out the motor Finite Element Simulation Analysis of abundant number of times.

2) by the statistical conversion of finite element analysis, and carry out data processing in a computer, generate d axle inductance L respectively _demulated data table, q axle inductance L _qemulated data table and permanent magnet flux linkage Ψ _femulated data table.

3) arrange emulated data table, in form, between adjacent cells lattice, realize the continuous treatment of list data by simple linear interpolation or other more excellent method.

4) obtain initial three-dimensional parameter of electric machine table, be respectively d axle inductance L _dthree-dimensional parameter of electric machine table, q axle inductance L _qthree-dimensional parameter of electric machine table and permanent magnet flux linkage Ψ _fthree-dimensional parameter of electric machine table.

5) the actual measurement torque of motor under different running status and observation torque is recorded.

6) if observation torque with actual measurement torque error exceed allowed band, then need to carry out error correction to three-dimensional parameter of electric machine table, and repeat step 5) operation.

7) when the error requirement allowed band in of satisfied observation torque with actual measurement torque, final three-dimensional parameter of electric machine table is exported.

The permagnetic synchronous motor load torque monitoring system based on three-dimensional parameter of electric machine table shown in above Fig. 2,3 is specific embodiments of the invention; substantive distinguishing features of the present invention and progress are embodied; can according to the use needs of reality; under enlightenment of the present invention; it is carried out to the equivalent modifications of the aspect such as shape, structure, all at the row of the protection range of this programme.

Claims (6)

1., based on the permagnetic synchronous motor load torque monitoring system of three-dimensional parameter of electric machine table, it is characterized in that comprising

A phase current transducer: for a phase current i _asample;

B phase current transducer: for b phase current i _bsample;

Position transducer: for detection rotor position θ;

Coordinate transformation unit: be connected with a phase current transducer and b phase current transducer, for according to a phase current i _a, b phase current i _b, rotor position calculates motor d shaft current i _dwith q shaft current i _q;

Temperature sensor: for measuring stator temperature t _s;

Temperature of rotor calculates unit: be connected with temperature sensor, for according to stator temperature t _scalculate motor rotor temperature t _r;

Three-dimensional parameter of electric machine memory cell: correspond to d shaft current i for storing _d, q shaft current i _qwith motor rotor temperature t _rmotor d axle inductance L _d, q axle inductance L _qwith permanent magnet flux linkage Ψ _f;

Load torque computing unit: calculate unit with coordinate transformation unit and temperature of rotor and be connected, for according to d shaft current i _d, q shaft current i _qwith motor rotor temperature t _rinquire about three-dimensional parameter of electric machine memory cell and obtain motor d axle inductance L _d, q axle inductance L _qwith permanent magnet flux linkage Ψ _f, and according to motor d axle inductance L _d, q axle inductance L _q, permanent magnet flux linkage Ψ _f, d shaft current i _d, q shaft current i _qcomputational load torque T _e.

2. the permagnetic synchronous motor load torque monitoring system based on three-dimensional parameter of electric machine table according to claim 1, it is characterized in that: described temperature sensor is at least provided with the first temperature sensor, the second temperature sensor, the first described temperature sensor, the second temperature sensor are embedded in motor stator side; Temperature of rotor calculates unit according to the first temperature sensor measurement temperature t _s1, the second temperature sensor measurement temperature t _s2and two temperature measuring points calculate acquisition motor rotor temperature t relative to the thermal resistance data of rotor _r.

3. the permagnetic synchronous motor load torque monitoring system based on three-dimensional parameter of electric machine table according to claim 1, is characterized in that: in three-dimensional parameter of electric machine memory cell, three-dimensional parameter of electric machine manufacture method comprises the following steps:

1) to d shaft current i _d, q shaft current i _qwith temperature of rotor t _rcombine, carry out motor Finite Element Simulation Analysis repeatedly;

2) data of finite element analysis are carried out Data Analysis Services, generate d axle inductance L respectively _demulated data table, q axle inductance L _qemulated data table and permanent magnet flux linkage Ψ _femulated data table;

3) arrange emulated data table, continuous treatment is carried out to list data, connect continuousization processing mode and comprise interpolation calculation;

4) obtain initial three-dimensional parameter of electric machine table, be respectively d axle inductance L _dthree-dimensional parameter of electric machine table, q axle inductance L _qthree-dimensional parameter of electric machine table and permanent magnet flux linkage Ψ _fthree-dimensional parameter of electric machine table;

5) the actual measurement torque of motor under different running status and observation torque is recorded;

6) if observation torque with actual measurement torque error exceed allowed band, then need to carry out error correction to three-dimensional parameter of electric machine table, and repeat step 5) operation;

7) when the error requirement allowed band in of satisfied observation torque with actual measurement torque, final three-dimensional parameter of electric machine table is exported.

4. the permagnetic synchronous motor load torque monitoring system based on three-dimensional parameter of electric machine table according to claim 1, it is characterized in that: coordinate transformation unit comprises two kinds in the mode of carrying out Coordinate Conversion: permanent amplitude transformation and invariable power conversion, permanent amplitude transformation is calculated as shown in formula (1), and invariable power transformation calculations is for shown in formula (2):

$\left[\begin{array}{c}{i}_d\\ i_q\end{array}\right]=\frac{2}{3}\left[\begin{array}{cc}\cos \mathrm{\θ}& \sin \mathrm{\θ}\\ -\sin \mathrm{\θ}& \cos \mathrm{\θ}\end{array}\right]\left[\begin{array}{cc}\frac{3}{2}& 0\\ \frac{\sqrt{3}}{2}& \sqrt{3}\end{array}\right]\left[\begin{array}{c}{i}_a\\ i_b\end{array}\right]---\left(1\right)$

$\left[\begin{array}{c}{i}_d\\ i_q\end{array}\right]=\sqrt{\frac{2}{3}}\left[\begin{array}{cc}\cos \mathrm{\θ}& \sin \mathrm{\θ}\\ -\sin \mathrm{\θ}& \cos \mathrm{\θ}\end{array}\right]\left[\begin{array}{cc}\frac{3}{2}& 0\\ \frac{\sqrt{3}}{2}& \sqrt{3}\end{array}\right]\left[\begin{array}{c}{i}_a\\ i_b\end{array}\right]---\left(2\right)$

5. the permagnetic synchronous motor load torque monitoring system based on three-dimensional parameter of electric machine table according to claim 2, is characterized in that: motor rotor temperature t _rcomputing formula is:

$t_r=\frac{t_{s2}-t_{s1}}{R_{\mathrm{th}1}}\·R_{\mathrm{th}2}+t_{s2};$

In formula: R _th1and R _th2be respectively the thermal resistance data of two temperature measuring points relative to rotor.

6. the permagnetic synchronous motor load torque monitoring system based on three-dimensional parameter of electric machine table according to claim 1, is characterized in that: load torque computing unit computational load torque T _eformula be: T _e=1.5n _p(L _di _di _q-L _qi _di _q+ Ψ _fi _q); N in formula _pfor the magnetic of permagnetic synchronous motor is to number of poles.