JPH0374191A - Sensorless asr control circuit pickup system - Google Patents

Abstract

PURPOSE:To perform speed estimation with established flux current component and to realize stable acceleration through smooth transfer by bringing the torque current command to zero, suppressing the flux current command below overcurrent and setting the initial frequency at a maximum value then performing speed estimation and establishing field flux component conditions thereafter applying torque component. CONSTITUTION:Rotary speed omegar is regulated and converged through PI control so that the torque component current of a motor 1 matches with the torque component current based on a torque command, and the regulated result is employed as an estimated speed. A sensorless ASR control circuit provides a pickup command to an ASR operating means 5 so that the torque current command I1* is zero. Flux current command I1* to be fed to a slip angular speed operating means 7 and a voltage vector operating means 8 is limited within a steady current level. PI operating value in a speed estimating means 4 is set such that omegar = fmax, and gate output of a PWM inverter is started.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a pick-up method for a sensorless ASR control circuit for an induction motor, and particularly to a pick-up method suitable for momentary power failures.

B6 Summary of the Invention The present invention uses a pick-up method for a sensorless ASR control circuit for an induction motor, in which the torque current command value is set to zero, the magnetic flux current command value is suppressed to below the overcurrent, and the frequency is set to the maximum value as an initial value. By estimating the speed and establishing the field magnetic flux component conditions, a torque component is added to estimate the speed based on the established magnetic flux current component, thereby providing a technology that achieves stable acceleration with smooth transition.

C1 The three elements of conventional technology control are responsiveness, precision, and stability, and the pursuit of stability in particular has enabled rapid feedback and quick calculation control due to the development of electronic technology.

The sensorless ASR of an induction motor, which controls the secondary magnetic flux and the secondary current perpendicular to it in a non-interfering manner, has superior performance to the DC motor in terms of the above-mentioned compatibility, but the accuracy and stability are one step ahead in terms of torque characteristics. Inferior.

The value of the secondary resistance used to calculate slip fluctuates due to temperature changes such as ambient temperature and rotor heat generation, but this changes the generated torque and is a major cause of loss of control stability. Various efforts have been made to address this issue.

The following equation is known as an equation for an induction motor in which a secondary circuit is expressed by a secondary magnetic flux λ.

Here, the α-β axis is a rotational coordinate fixed to the rotor.

In addition, in the above formula vI&+　V　αβ axis primary voltage in I, i□, I+1+αβ-axis primary current, λ, □λ□; αβ-axis secondary magnetic flux, R1, primary resistance, R2: secondary resistance, Ll; primary inductance, L2. secondary inductance, M: excitation inductance, ωs: [source angular velocity, ω": motor angular velocity, P: differential operator, That is, Lσ÷(LIL2-M”)/L2 It is.

Vector control is a method of linearizing the output torque with the torque current iId by setting the magnetic flux of the β-axis component in the secondary circuit to zero, and IB・(R2・M/L2)=(ω g −ω
If r) λ□ holds, λ,, = 0, so if the slip speed ωg(2ip= (ωS-ω') is known,
1ns-L2/(R2·M)(ωs-ωr,)λ.

A current such that 1. , if you run λ. −〇 holds true.

Also, in the equation in the fourth row of the above matrix, since λ□=0, f (a=λt, /vi + p (L t/n !M
-λtj Therefore, if iId is controlled by λ,,''/M so that f Ha=λ-,,'/M, λ□ becomes λ,,
= consL. The generated output torque T is T・(3/4・POI, E-M/L 2・λt,) x
t ta and the values in parentheses are made into constants, so the torque current and the generated torque are linearized.

Next, in order to perform vector control using the control voltage edge, the voltage V required to prevent the primary current i, □ i+a from flowing is determined.
When a is found, v,, -R1/M·λta -La-ωsmi,.

=rlli+a-Lcr・ωs-i,.

vl, =Ll・ωs−1□+(RI−Lσ・P)・i,
.

The circuit configuration to achieve this is shown in Figure 2, and its vector coordinates are shown in Figure 3, allowing non-interfering control of the primary current 11□i, which corresponds to the magnetic flux and torque commands. Established, the torque is i+.

can be controlled in proportion to

Problems that the D0 invention aims to solve By the way, with sensorless ASR, it goes without saying that speed is not directly detected, and the basis of speed estimation relies on current values, so in the event of a momentary power outage, the data inside the microcomputer will be erased. Therefore, the motor is often controlled as if it had stopped, even though the rotation is only slightly reduced. As a result, the ASR (automatic speed control) is canceled once the motor has stopped, or the v/
After picking up near the command speed in F mode, sensorless ASI? It is often time-consuming, as it requires control.

The present invention was created in view of these problems, and
The purpose of this invention is to provide a pick-up method for a sensorless ASR control circuit that accurately estimates the speed of the magnetic flux current component and achieves stable acceleration with smooth transition.

88 Means for Solving the Problem Means for solving the above problem R in the present invention is a sensorless ASR control circuit that estimates and controls the rotation speed of the induction motor by integrating the error of the command value and the detected value of the primary current. In the pick-up method, the torque current command value is set to zero,
This is based on the pick-up method of the sensorless ASR control circuit that suppresses the magnetic flux current command value to below the overcurrent, sets the frequency to the maximum initial value, then estimates the speed, establishes the field magnetic flux component conditions, and then adds the torque. do.

10 Effects The present invention aims to accurately estimate the speed of the magnetic flux current component by establishing the conditions for the motor field magnetic flux component and then adding the torque component, thereby achieving stable acceleration with a smooth transition to sensorless ASR. That is.

If the torque current command value is set to zero, the magnetic flux current command value is kept below the overcurrent, and the speed estimation component value is set to the maximum frequency value, and the inverter gate output is started, the power supply frequency will be lower than the actual rotation speed. When the current is high, the torque current flows in the induction motor in the acceleration direction, and in the opposite case, it flows in the deceleration direction. This current detection changes the output of the integrating amplifier, and
．． The speed ωr is estimated so that ,=0. When the software determines that the speed ωr has stabilized, the magnetic flux current is returned to the normal value, synchronous operation is started, the ASR speed loop is started, and the speed is accelerated to the command speed by ASR, and the pickup is completed.

G. Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing an example of a generally sensorless ASR control circuit of an induction motor suitable for implementing the present invention.

In the figure, 1 is an induction motor, 2 is a PWM inverter that controls the induction motor, and 3 is a Hall detector (HCT).
Rotating coordinate conversion means converts the three phases of motor currents 1u and Iv detected by the motor currents 1u and Iv into two phases, and 4 is a current command value i1. ′
5 is an ASR calculation means equipped with a PI amplifier that integrates the difference between the calculation means 4, 6 is a limiter, and 7 is the current command value f outputted via the limiter 6
+6" and the magnetic flux current value + +a", the slip speed ω5lip = (R2・1, , *) / (L2
・Slip angle calculation means for calculating the primary voltage from the current command value 11.' and the power supply current values i and I; 9 is the voltage vector calculation means for calculating the primary voltage from the current command value 11.' and the power supply current values i and I; and vl−, the phase of the primary voltage φv=
tan-'(v+, /v+*) and absolute value I V 1
l=vIm·1/cos(φV); 10 is a phase vector calculation means for calculating the P
This is a three-phase distributor that commands three-phase values to the WM inverter 2.

In the speed estimation of the control device, the rotational speed value ωr is adjusted and converged by PI control so that the motor torque current corresponds to the torque current based on the torque command, and the output thereof is used as the estimated value. The rotational coordinate conversion means 3 converts Iu detected by HOT or the like.

The three-phase motor current of Iv and Iw is converted into two-phase motor current, and the current ire is detected. This feedback detection current iea and the feedback torque current command i2. ′ is calculated by speed estimation.

Therefore, the operation will be explained with reference to FIG. 4. As the pickup operation in the sensorless ASR control j@ path shown in FIG. 1, the torque current command ■9. ' is picked up and commanded to the ASR calculation means 5 so that P of the speed estimation calculation means 4 is set to such an extent that it does not become a current.
■Set the calculated value ωr = fmax,
Assume that the gate output of the PWM inverter is started.

If the power supply frequency is higher than the actual number of rotations, a current corresponding to the torque flows in the induction motor l in the acceleration direction, and in the opposite case, it flows in the deceleration direction. With this current detection, the PI amplifier output of the speed estimation calculation means 4 changes, and the speed estimation calculation stage 1 4. Yo f,
Estimate J = 0 (Fig. 4 ■). When the software determines that ωr has stabilized, the magnetic flux current command is returned to the normal value, and 2
Continue i, , +=O until the next magnetic flux is established. From the start of pickup until the secondary magnetic flux is established, + , , @
=O, so ω512ip=08, and the estimated speed ωr directly becomes the output frequency.

Incidentally, by integrating this (direction ωS''), the upward magnetic flux position command angle θ is obtained, and the sum of θV and φV from the phase vector calculating means 9 is input to the three-phase arrangement 10. As shown in FIG. When the synchronous operation condition of IIn=0 and the secondary magnetic flux establishment condition of l + a = I
Start Sr side control and issue torque current command 11. By controlling ', the speed is accelerated to the commanded speed and the picking is completed as shown in j of FIG.

Note that the gain of each PI amplifier must be set low to avoid overshoot, but this can be easily achieved when calculation is performed using software.

As described above, the following effects are evident in the embodiments of the present invention.

(1) Regarding the steps ① to ② in Fig. 4 above, if the secondary time constant nt/1-t of the motor is known, synchronization detection and magnetic flux establishment can be performed at the same time.

As shown in Figure 5, this is the same as setting the command value of 111 to zero, but slowly increasing the value of 11' from zero to the normal command value of 11' at the time of the quadratic time constant. This can be achieved by By doing this, the current ripple at the start can be reduced and synchronization detection and magnetic flux establishment can be performed simultaneously, so that high-speed pickup can be realized.

(2) Since the torque component is added after establishing the conditions for the field magnetic flux component by setting the no-load synchronous operation, the operation becomes stable during acceleration after speed estimation.

H1 Effects of the Invention As stated above, according to the present invention, sensorless AS
It is possible to easily apply the R control circuit, perform speed estimation based on the established magnetic flux current component, and provide a pick-up method for a sensorless ASR control circuit that achieves stable acceleration with smooth transition.

[Brief explanation of drawings]

FIG. 1 is a block diagram of sensorless ASR, FIG. 2 is an explanatory diagram of vector calculation, FIG. 3 is an explanatory diagram of vector coordinates, and FIGS. 4 and 5 are diagrams of operation of an embodiment of the present invention. I...Induction type motive, 2...PWM inverter, 3.
...Rotating coordinate conversion means, 4...Speed estimation calculation means, 5
... ASR calculating means, 6... Limiter, 7... Slip angular frequency calculating means, 8... Claw seat vector calculating means, 9... Phase vector calculating means, IO... 3-phase distribution control. . 2 people not listed in Figure 2

Claims (1)

[Claims] (1) Sensorless AS that estimates and controls the rotational speed of the induction motor by integrating the error of the command value and detected value of the primary current
In the pick-up method of the R control circuit, the torque current command value is set to zero, the magnetic flux current command value is suppressed below the overcurrent, the frequency is set to the maximum value as the initial value, and then the speed is estimated and the field magnetic flux component conditions are established. This is a pick-up method for a sensorless ASR control circuit that is characterized by adding torque after that.