JPS6066687A - Control system of commutatorless motor - Google Patents

Abstract

PURPOSE:To prevent the control performance from decreasing in the basis of the continuation of an armature current at a light load time by forcibly reducing the magnetic flux command value of a magnetic flux control loop smaller than the prescribed value when the armature current becomes the certain level or lower. CONSTITUTION:When an armature current IM becomes a certain value IM1 or larger, it is designed to output the prescribed magnetic flux command phi*, while the certain value or smaller, it is designed to output a value decreasing proportionally to the current IM. Assume that an interrupting point of an armature current when the load becomes light while the magnetic flux command phi* remains as it is P1, the current interrupting point moves to the lower value as P2 if as the magnetic flux command value becomes smaller than phi*. Thus, even if the load becomes light, the interruption of the armature current can be avoided. In this manner, the decrease in the control performance on the basis of the interruption of the armature current can be prevented at the light load time.

Description

Detailed Description of the Invention [Technical field to which the invention pertains] This invention uses a passive inverter controlled by a voltage model as a converter on the motor side, and also compensates for armature reaction (r). A control method for a commutatorless motor (thyristor motor) equipped with a control loop inspired me.

[Prior art and its problems]

FIG. 1 is a diagram illustrating a conventional example of such a thyristor motor control device, FIG. 2 is a block diagram showing the configuration of the constant margin angle pulse generator in FIG. 1 in detail, and FIG. 3 is a waveform of each part in FIG. 2. FIG. In Fig. 1, 1 is the speed regulator (ASR), 2 is the current regulator (ACIL), 3 is the firing angle W1, 4 is the thyristor converter, and 5 is the speed electromotive force (
6 is a magnetic flux calculator (re''1 divider), 7 is a back electromotive force) calculator,
is a constant margin angle pulse generator, 8 is a pulse distributor, 9 is a thyristor motor (synchronous motor a), tO is a speed detection generator, 11 is a magnetic flux regulator (AΦ几), 12 is a field current regulator, 13 is a firing angle adjuster for a field thyristor, SEl is a speed setting device, SF3 is a magnetic flux setting device, and DCL is a DC smoothing reactor.

The alternating current power is converted to DC by the TIL source side converter 41, smoothed by the DC reactor DCL, and reconverted to AC by the motor side converter 42 to drive the SIRISK motor 9.
is driven. In this case, the speed setting device S
Speed setting signal (target value) r? from E1? * and electric motor 9
The actual speed value from the speed detection generator lO directly connected to
The detected value) n is compared and inputted to the speed H unit 1, and then the output signal, that is, the current command i* and the current detection IB signal i of the power supply side converter 41 are compared and the signal is input between the radio waves. This is achieved by inputting the signal to the ignition angle adjuster 2 and controlling the phase of the power supply side converter 41 via the firing angle adjuster 3 using the output signal.

On the other hand, the phase control of the motor-side converter 42 is performed using the motor terminal voltage vM and armature current Im obtained through a detector, and the armature resistance (几) and electric leakage reactance (L6
) by performing a predetermined calculation using the calculator 5 to calculate the back electromotive force E, which is then integrated by the integrator 6 (also referred to as a voltage model) to calculate the internal magnetic flux of the motor. Φ, this magnetic flux waveform is blunted as a reference, a constant margin angle pulse generator 7 generates a constant margin angle pulse with a predetermined pulse width, and this pulse is sent to the motor side converter 4 via a pulse distributor 8.
This is done by performing the ignition control in step 2.

The constant margin angle pulse generator 7 includes a phase advance circuit 71. which advances the position U by 90 degrees, as shown in detail in FIG. Comparator 72, commutation type force calculator (U calculator) 73
, a magnetic flux absolute value calculator 74, switches 81 to 83, and the like.

In addition, each of the switches 81 to 83c, &i east tsnus Φuv, Φ6. When Φ is positive, 'i'@tc is present, and when it is negative, it is switched to 'm2'. The operation will be explained with reference to FIGS. 2 and 3.

Each of the effective magnetic flux ff [components (Φuv, ΦVWeΦwu) as shown in Fig. *ΦvW+Φ'VW
eΦwu→Φ'wu).

Incidentally, if the input signal is a three-phase balanced input, this phase advance circuit 71 may be a simple addition/subtraction circuit. It can be configured as follows. Φ'uV FΦ'VWs obtained in this way
Φ'wu is the speed electromotive force "11/#"VW
It has the same phase as eEwu (if N, Euv is the same velocity electromotive force as uv). On the other hand, the margin angle setting voltage ■γ obtained by dividing the output of the magnetic flux absolute value calculator 74 and the overlap angle calculation voltage ■ obtained by the U calculator 73 from the current command value (or detected value) and the magnetic flux absolute value. are added to create a control advance angle command voltage Vβ. Next, the polarity of the control advance angle command voltage Vβ is switched by the switch 31''83 according to the positive or negative sign of the input magnetic flux waveform of each phase. The rectangular wave β command voltage (±Vβ) obtained in this way is Φ'LIT tΦ'vw t, respectively, as shown in Fig. 3 (b).
By comparing the magnitude with Φ'wu, voltage/angle conversion is performed, and a constant margin angle pulse (xs
o”ez16) is produced.

On the other hand, the magnetic flux Φ obtained from the voltage model (111 divider) 6
(To be exact, the absolute value of magnetic flux 1Φ1) is the magnetic flux regulator (A
Φ几) 11, where its setting value (command value)
An adjustment operation is performed so that it becomes equal to Φ*, and its output becomes the current command IF* of the field current regulator (FC) 12. At this time, the current regulator 12 has an actual field current value (detected value).
Since iF is input, the regulator 12 performs a 14m calculation such that the deviation between the output iF* of the magnetic flux regulator 11 and the actual field current value ip becomes zero, and the output is used to control the phase regulator 13. By supplying a predetermined signal to the field thyristor through the thyristor, the internal magnetic flux of the motor is controlled to be kept constant over the entire load range.

As mentioned above, the thyristor motor system that performs constant margin angle and constant magnetic flux control has the characteristics and advantages of a small electric motor, high power factor, and high efficiency. Since the current is minimized over a range, there is a problem in that current interruption during light loads is more likely to occur than in conventional systems. Furthermore, if the armature current is intermittent, the optimal adjustment point of the AC control loop will change, resulting in a decrease in control characteristics (responsiveness to setting changes and load fluctuations), and in some cases may cause problems such as hunting. It is.

[Purpose of the invention]

This invention G:1 has been made in view of the above points, and provides a control method that makes it difficult for the Zyristor motor to cause current interruption during light loads and does not impair the constant margin angle characteristics of the motor side converter. The purpose is to

[Key points of the invention]

The key points are that a separately excited inverter controlled by a voltage model is used as a converter on the motor side, and a thyristor motor is equipped with a field flux control loop that controls the internal magnetic flux of the motor to be approximately constant to compensate for armature reaction. In the control system, in order to prevent several cases where the armature current is intermittent during light loads and the control characteristics deteriorate, the magnetic flux command value of the magnetic flux control loop is forcibly kept constant when the armature current drops below the level. This problem can be avoided by making the value smaller than the value of .

[Embodiments of the invention]

Fig. 4 is a main part configuration diagram showing an embodiment of this invention, ft5s
The figure is a graph showing the relationship between armature W, current, and magnetic flux command value.

FIG. 4 shows only the magnetic flux control loop similar to the conventional example shown in FIG. 1, and is characterized in that a magnetic flux command value calculation circuit 14 is added. This magnetic flux command value calculation circuit 14 is composed of, for example, a function generator, and has the characteristics as shown in FIG. It is designed to output a value that decreases in proportion to the current IM. Note that as the armature current in this case, the output of the speed regulator (As) 1 shown in FIG. 1, that is, the armature current command value or the armature current actual value can be used. Here, the discontinuation point of the armature current when the load becomes lighter while the magnetic flux command value remains Φ* is Pl
Assuming that, if the magnetic flux* command value becomes smaller than Φ, the current interruption point will move to a lower point, such as point 22, and therefore, even if the load becomes lighter, interruption of the armature current can be avoided. I can do it. The discontinuation point P2 of the armature current can be appropriately set by adjusting the way the magnetic flux is lowered in the range up to the current value IMI, that is, by adjusting the gradient.

Further, even in this case, the constant margin angle control of the motor-side converter is not affected, so the electric rfIJJ power factor is maintained at a high power factor. Note that as the magnetic flux command value decreases, the motor's internal magnetic flux decreases, the armature reaction increases, and the internal phase difference angle J increases, but this is because constant margin angle control is originally performed at light loads. Therefore, there is no influence on the motor power factor and the commutation of the motor-side converter. In addition, there is no problem with increasing the commutation type turning angle, since this is originally a discussion in the area where the current is intermittent.
There is almost no effect on the electric motor power factor. Note that the magnetic flux command value calculation circuit 14 can also be realized using a ROM memory.

〔Effect of the invention〕

According to this invention, when the armature current is less than a predetermined value, control is performed based on intermittent armature current during light loads by simply reducing the magnetic flux command value in accordance with the decrease in the current. Since it can prevent performance deterioration, it has the advantage of enabling stable operation even under light loads.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing a conventional example of a thyristor motor control device, Fig. 2 is a block diagram showing a specific example of a constant margin angle pulse generator, and Fig. 3 is a waveform of each part to explain the operation of Fig. 2. Fig. 4 is a main part configuration diagram showing an embodiment of the present invention, and Fig. 5 is a graph explaining the relationship between armature current and magnetic flux command value. 0 Symbol explanation 1 ... speed adjustment Vessel (As几), 2...
Current regulator (ACR), 3, 13... Firing angle regulator, 4 (41, 42)... Thyristor converter, 5... Back electromotive force calculator , 6... Magnetic flux calculator (integrator, voltage model), 7... Constant margin angle pulse generator, 8... Pulse distributor, 9...
... Thyristor motor, IO ... Speed detection generator, 11 ... Magnetic flux adjustment j'a (AΦ几), 12 ... Field current w4 M1 device (li'c
几), 14...Magnetic flux command value calculation circuit, 71...
... Phase advance circuit, 72 ... Comparator, 73 ... Commutation type or 34 square wave devices, 74 ...
...Magnetic flux absolute value calculator, SEX, SB2...
Setting device, DCL...DC reactor, S1~S
3...Switch agent Patent attorney Akio Namiki Agent Patent attorney Kiyoshi Matsuzaki gEl Figure 2 Q bar i3 Figure Wi 4 Figure Haya 5 Figure

Claims (1)

[Claims] Terminal voltage of a commutatorless motor supplied by a power conversion device including at least a separately excited inverter. A control loop that calculates the TIl motive magnetic flux by integrating the back electromotive force obtained by performing a predetermined calculation from each actual value of the armature [flow] and performs constant margin angle control of the separately excited inverter based on the magnetic flux waveform. , a magnetic flux control loop that controls the electric magnetic flux a to a substantially constant value in order to compensate for armature reaction, when the armature current is above a predetermined value, A function generator is provided that outputs a substantially constant magnetic flux command value, and when the current is below a predetermined value, the magnetic flux command value is decreased and output accordingly, and the motor magnetic flux is adjusted based on the output from the function generator. A control method for a commutatorless motor, which is characterized by: