CN105071736A - Method for detecting position of sensorless rotor of PMSM for blower fan - Google Patents

Abstract

The invention provides a method for detecting the position of a sensorless rotor of a PMSM for a blower fan. The method includes the steps of converting three-phase current into two-phase d-axis q-axis current through Clarke conversion and Park conversion when a sensor detects the three-phase current of a motor, sending d-axis voltage generated by a d-axis current PI controller and containing rotor position error information to a phase-locked loop rotor position tracking proportional integral estimator, controlling gain parameter according to the PI in work frequency selection estimator of an inverter switch, and estimating the position and rotating speed of a rotor by controlling the d-axis current to be zero. Only permanent magnetic linkage is needed, no other motor parameters are needed, and the algorithm is simple. The position and rotating speed of a rotor can be accurately detected when the rotating speed reaches over 20% of the rated rotating speed. The method is applicable to PMSMs for heating ventilation and industrial purifying blower fans with wide power levels.

Description

A kind of blower fan permagnetic synchronous motor is without sensorless rotor position detection method

Technical field

The present invention relates to permagnetic synchronous motor, particularly relate to the permagnetic synchronous motor of the field matched with blower such as a kind of air-conditioning, factory building purification, building heating and ventilation project, communication base station, rail vehicle without sensorless rotor position detection method.

Background technology

In recent years, along with power electronic technology, variable frequency control and the fast development realizing complicated algorithm high-performance, low cost microprocessor, vector controlled permanent magnet synchronous machine (PMSM), there is the features such as high efficiency, low noise and accurate speeds control in wide speed, wide loading range, become the preferred motor of the field matched with blower such as air-conditioning, factory building purification, building heating and ventilation project, communication base station, rail vehicle.Based on the permagnetic synchronous motor of vector control, rotor-position and the speed of motor must be detected in real time.Conventional rotor-position detects and adopts mechanical pick-up device (encoder, solver and tachogenerator), but mechanical pick-up device has the problems such as installation, cable connection, fault, not only increase the volume of system and the moment of inertia of rotor, and reduce system reliability.In order to solve the various defects that mechanical pick-up device exists, be detected as the emphasis in order to study without sensorless rotor position.

At present, sensorless detection rotor-position method mainly contains the estimation algorithm utilizing the High Frequency Injection of motor saliency He utilize counter electromotive force of motor or magnetic linkage.High Frequency Injection has particular/special requirement to electric machine structure, needs rotor to have saliency, inapplicable to blower fan non-salient pole permanent magnet synchronous motor.Estimation algorithm mainly contains back electromotive force method, model reference adaptive method, sliding mode observer method, EKF method etc.Back electromotive force method utilizes motor fundamental voltage and current signal to calculate rotor-position and speed, and method is simple, is widely used, but very sensitive to the change of the parameter of electric machine, and adaptability is poor.Sliding mode observer method has good robustness, but during low speed, chattering phenomenon is more serious.EKF method needs to carry out complicated matrix inversion operation, and have higher calculation requirement to CPU, real-time is poor.Model reference adaptive method can only be adjusted to best at a certain velocity band, when rotating speed vibrates lower than easily causing the rotor-position of detection during this speed territory, and higher than easily causing the rotor-position detected to have larger delay during this speed territory.

Summary of the invention

For the deficiencies in the prior art, the invention provides a kind of blower fan permagnetic synchronous motor without sensorless rotor position detection method, the method proposed only needs permanent magnet flux linkage, without the need to other parameter of electric machine, algorithm is very simple, rotor-position and rotating speed can be detected exactly more than 20% rated speed, be applicable to the field blower fan permagnetic synchronous motors such as the wide in range HVAC of power grade, Industrial cleaning facility.

For achieving the above object, design of the present invention is: be input to phase-locked loop rotor-position tracking proportional integral estimation device by the rotor position error information direct-axis voltage that comprises exported by direct-axis current adjuster, controlling direct-axis current is zero, estimates rotor-position and rotating speed.

The following describes involved in the present invention without sensorless rotor position and velocity measuring principle.

Directly can measure unlike mechanical pick-up device because position-sensor-free rotor-position detects, but based on estimation, therefore between actual rotor position θ and estimated position θ e, certainly exist error delta θ.If actual rotor position two-phase static coordinate is alpha-beta, rotational coordinates is d-q coordinate system, and is r-δ coordinate system based on the rotational coordinates of estimation rotor-position, as shown in Figure 1.

According to PMSM characteristic, the PMSM stator voltage equation based on alpha-beta coordinate system is:

Definition transformation matrix

$T\left({\mathrm{\θ}}_e\right)=\left[\begin{array}{cc}\cos \left({\mathrm{\θ}}_e\right)& \sin \left({\mathrm{\θ}}_e\right)\\ -\sin \left({\mathrm{\θ}}_e\right)& \cos \left({\mathrm{\θ}}_e\right)\end{array}\right]---\left(2\right)$

Stator voltage then under r-δ coordinate system, electric current can be expressed as

$\left[\begin{array}{c}{V}_{\mathrm{\γ}}\\ V_{\mathrm{\δ}}\end{array}\right]=T\left({\mathrm{\θ}}_e\right)\left[\begin{array}{c}{V}_{\mathrm{\α}}\\ V_{\mathrm{\β}}\end{array}\right]---\left(3\right)$

$\left[\begin{array}{c}{i}_{\mathrm{\γ}}\\ i_{\mathrm{\δ}}\end{array}\right]=T\left({\mathrm{\θ}}_e\right)\left[\begin{array}{c}{i}_{\mathrm{\α}}\\ i_{\mathrm{\β}}\end{array}\right]---\left(4\right)$

Formula (1), (2), (4) are substituted into the PMSM voltage equation that formula (3) can obtain under r-δ coordinate system:

In formula, V α, V β, Vr, V δ are respectively stator winding alpha-beta axle and r-δ shaft voltage component; I α, i β, ir, i δ are respectively stator winding alpha-beta axle and r-δ shaft current component; Rs, Ls are respectively stator resistance and inductance; for the magnetic linkage that rotor permanent magnet magnetic pole produces; ω is rotor electrical angular speed.

Fig. 2 is vector control without position sensor PMSM block diagram, and in figure, forward direction coupled voltages is:

The electric current of measurement is substituted into formula (5) after CLARK and PARK conversion and can estimate ac-dc axis voltage under rotating coordinate system.

Formula (7) being deducted the error that formula (6) obtains ac-dc axis voltage is:

In formula, ω e is the rotor velocity of estimation.

As shown in Figure 2, direct-axis voltage error delta Vd is the output of direct-axis current pi regulator, and during stable state, id=id*, iq=iq*, can be obtained by formula (8):

Transform (9) can obtain rotor position error Δ θ:

If actual rotor position θ can be obtained, then can utilize the phase-locked loop structures of Fig. 3, obtain estimation rotational speed omega e and estimation rotor position e.

The transfer function that can be obtained phase-locked loop rotor speed and position estimation by Fig. 3 is:

${\mathrm{\θ}}_e\left(S\right)=\frac{K_p\·S+K_i}{S^{2+K_p}\·S+K_i}---\left(11\right)$

If the frequency range of phase-locked loop rotor speed and position estimation is ω v, in order to ensure quick dead-beat estimation rotor-position, getting damping ratio ξ is 1, then characteristic parameter is:

${\mathrm{\ω}}_v=\sqrt{K_i}---\left(12\right)$

$\mathrm{\ξ}=\frac{K_p}{2\·{\mathrm{\ω}}_v}=1---\left(13\right)$

Phase-locked loop rotor position estimation proportional gain kp and storage gain ki can be obtained be respectively according to formula (12), (13):

K _p＝2·ω _v(14)

$K_i={\mathrm{\ω}}_v^2---\left(15\right)$

The frequency range of usual speed ring gets 1/10 of PWM frequency, i.e. 50 ~ 200Hz.Consider the factors such as the non-linear of system inverter and current measurement errors, the frequency range of phase-locked loop rotor position estimation is generally the frequency range 2 ~ 6 times of speed ring.

In fact, actual rotor position θ is unknown, but applying equation (10) can obtain rotor position error information, namely extract from d axle PI current regulator output voltage, the block diagram of concrete rotor speed and position estimation is as the speed of Fig. 2 and position estimator part.

According to above-mentioned inventive concept, the present invention adopts following technical proposals:

(1) application sensors detects three-phase current ia, ib, ic of motor;

(2) utilize Clarke conversion and Park conversion that three-phase current ia, ib, ic are transformed to two-phase ac-dc axis current i d, iq;

(3) controlling direct-axis current id is zero, produces the direct-axis voltage comprising rotor position error information from direct-axis current PI controller;

(4) direct-axis voltage that direct-axis current PI controller produces is multiplied by after deliver to rotor-position follow the tracks of proportional integral estimation device obtain estimate rotational speed omega e, select estimation device proportional gain kp be 2 ω _v, storage gain ki is ω _vfor rotor-position follows the tracks of the frequency range of proportional integral estimation device, be chosen as 1/5 ~ 3/5 of inverter PWM frequency;

(5) rotational speed omega e rotor-position being followed the tracks of the estimation of proportional integral estimation device carries out integration and obtains estimating rotor position e.

The present invention compared with prior art, has following advantages:

(1) motor permanent magnet flux linkage is only needed, without the need to other parameter of electric machine, insensitive to the parameter of electric machine;

(2) do not rely on motor model, algorithm is simple, without the need to the CPU of high request, reduces production cost;

(3) estimate that the optimum configurations of device is very simple, be applicable to the matched with blower permagnetic synchronous motor large-scale production of different capacity grade.

Accompanying drawing explanation

Fig. 1 is different reference frame graph of a relation of the present invention;

Fig. 2 is ensorless control PMSM block diagram of the present invention;

Fig. 3 is phase-locked loop rotor speed of the present invention and position estimation block diagram.

Embodiment

Below in conjunction with accompanying drawing 2 and embodiment, the invention will be further described.

Blower fan permagnetic synchronous motor of the present invention is without sensorless rotor position detection method, phase-locked loop rotor-position tracking proportional integral estimation device is input to by the rotor position error information direct-axis voltage that comprises exported by direct-axis current adjuster, controlling direct-axis current is zero, estimates rotor-position and rotating speed.

See Fig. 2, said method comprising the steps of:

(1) application sensors detects three-phase current ia, ib, ic of motor;

(2) utilize Clarke conversion and Park conversion that three-phase current ia, ib, ic are transformed to two-phase ac-dc axis current i d, iq;

(3) controlling direct-axis current id is zero, produces the direct-axis voltage comprising rotor position error information from direct-axis current PI controller;

(4) direct-axis voltage that direct-axis current PI controller produces is multiplied by after deliver to rotor-position follow the tracks of proportional integral estimation device obtain estimate rotational speed omega e, select estimation device proportional gain kp be 2 ω _v, storage gain ki is ω _vfor rotor-position follows the tracks of the frequency range of proportional integral estimation device, be chosen as 1/5 ~ 3/5 of inverter PWM frequency;

(5) rotational speed omega e rotor-position being followed the tracks of the estimation of proportional integral estimation device carries out integration and obtains estimating rotor position e.

Above embodiment is used for illustrative purposes only, but not limitation of the present invention, person skilled in the relevant technique, without departing from the spirit and scope of the present invention, various conversion or modification can also be made, therefore all equivalent technical schemes also should belong to category of the present invention, should be limited by each claim.

Claims (1)

1. blower fan permagnetic synchronous motor is without a sensorless rotor position detection method, it is characterized in that, comprises the following steps:

(1) application sensors detects three-phase current ia, ib, ic of motor;

(2) utilize Clarke conversion and Park conversion that three-phase current ia, ib, ic are transformed to two-phase ac-dc axis current i d, iq;

(3) controlling direct-axis current id is zero, produces the direct-axis voltage comprising rotor position error information from direct-axis current PI controller;

(4) direct-axis voltage that direct-axis current PI controller produces is multiplied by after deliver to rotor-position follow the tracks of proportional integral estimation device obtain estimate rotational speed omega _e, the proportional gain kp selecting estimation device is 2 ω _v, storage gain ki is for rotor permanent magnet magnetic linkage, ω _vfor rotor-position follows the tracks of the frequency range of proportional integral estimation device, be chosen as 1/5 ~ 3/5 of inverter PWM frequency;

(5) rotor-position is followed the tracks of the rotational speed omega of proportional integral estimation device estimation _ecarry out integration to obtain estimating rotor position _e.