JPS5825037B2 - Armature reaction compensation method for commutatorless motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of controlling a commutatorless motor, which compensates for armature reaction equivalent to that of a commutatorless motor equipped with a compensation winding.

Among non-commutator motors, so-called self-controlled non-commutator motors use a synchronous motor as the motor, and the commutating element of the power converter is commutated by the induced voltage of the synchronous motor. It has many advantages and is widely used.

However, since the commutation capacity, that is, the output limit, is determined by the induced voltage and commutation impedance of the motor, the overload capacity is small, and therefore, it has the disadvantage of being smaller in size and weight than other motors.

Conventionally, as a method to compensate for this, a damper line shaft was installed on the field pole side to reduce the impedance during commutation, and a compensation line ring was installed on the field pole side to reduce the reverse bias voltage of the commutating element due to armature reaction. Methods of compensation have been proposed.

Among these, the latter method using a compensation wire is difficult to make the motor brushless because the compensation wire is provided on the field pole side.Furthermore, due to the requirements for a self-limiting non-commutated motor, the terminal voltage of the motor is Since the armature current has a leading phase, if a compensation wire similar to a DC machine is provided, the IKk armature reaction cannot be canceled out on the horizontal axis, and negative torque is generated by the compensation wire current to compensate. I don't have much hope for the effects of shinrin.

It is necessary to shift the axis of the compensation line wheel, but since the shift direction and angle differ depending on the forward rotation, reverse rotation, force, and regeneration modes, the compensation line wheel axis must be switched in each mode. There are certain drawbacks.

The present invention has been made with attention to the above-mentioned points, and it is possible to completely compensate armature reaction by providing a compensation wire in the motor by controlling from the outside of the motor without providing a compensation wire in the motor. It is characterized by obtaining the same effect as.

FIG. 1 is a vector diagram of a commutatorless motor.

The solid line in Figure 1 shows the case where the armature reaction is not compensated, jt< is the field magnetomotive force, Fa is the armature reaction magnetomotive force, and the armature reaction Reactance drop due to magnetomotive force Fa jxd im
occurs, and the terminal voltage of the motor becomes the sum of its vectors,
The control advance angle γ decreases from γ0 at no-load, and as shown in FIG. 2, as the armature current im increases, the commutation condition worsens.

The broken line in Fig. 1 shows the case where the armature reaction is completely compensated.
jxdic (ic is converted into armature current), which has the same magnitude as im and the opposite direction, occurs, and the motor terminal voltage becomes small, which is equal in magnitude and direction to the no-load voltage (virtual induced voltage Eo), and therefore the control advance angle Both are equal to γ0 at no load.

As shown in Figure 1, this is caused by the field magnetomotive force and the compensation magnetomotive force F.
It may be considered that a virtual induced voltage capability' is generated by the vector sum (Ff+Fe) with e, and the vector sum t with the reactance drop jxdim due to the armature reaction magnetomotive force Fa becomes the terminal voltage.

Considering this, it is completely equivalent to setting the field magnetomotive force to the same magnitude as IFf+Fel and setting the mechanical control advance angle γ0 of the current determined from the relative mechanical position of the armature and the field to γ0'.

In other words, from Fig. 1, instead of compensating the armature reaction using a compensation wire, the field current is adjusted to keep the motor terminal voltage constant, and the mechanical control lead angle γ0 is adjusted to control the motor terminal voltage. It can be seen that if the advance angle γ is controlled to be constant, compensation equivalent to the case where the armature reaction is completely compensated by the compensation coil can be achieved.

Of course, FIG. 1 is a vector diagram at a certain rotational speed, and each voltage vector in FIG. 1 is proportional to the rotational speed, so if the rotational speed changes, it is necessary to control the voltage to be proportional to the rotational speed.

This means that the amount of magnetic flux in the air gap of the electric motor is kept constant regardless of the rotational speed, and the electric motor may be provided with a magnetic flux amount detection device to control the amount of magnetic flux to be constant.

Figure 2 shows the relationship between line voltage and armature current of a commutatorless motor.

As shown in FIG. 1, as the current increases, the phase of the terminal voltage advances due to armature reaction and its magnitude decreases.

The shaded voltage in FIG. 2 is the reverse bias applied to the commutating element, and this voltage causes the element to commutate.

Therefore, if armature reaction is not compensated for,
As the load increases, the current value to be commutated increases, and the commutation reverse bias that contributes to commutation decreases, so the commutation conditions become increasingly worse, the commutation type angle suddenly becomes dog, and the control advance angle decreases. Along with the decrease in γ, the reverse bias time required for commutation of the element also decreases rapidly.

Figure 3 shows commutation type angle U and control advance angle γ with respect to torque.
This shows the relationship between

In FIG. 3, A is the case where the armature reaction is not compensated, and B is the case where the armature reaction is completely compensated.

In the case of B, as shown in Figure 1, the width of the terminal voltage and the control advance angle γ are kept constant regardless of the load, so even if the load increases, the commutation condition is only the increase in current. The only disadvantage is that the commutation limit is significantly increased compared to A.

As described above, the present invention achieves the effect of armature reaction compensation by controlling the field current so that the terminal voltage is proportional to the rotational speed or so that the amount of magnetic flux in the motor air gap is constant, and the control progresses. This is achieved by controlling the angle γ to a constant value, and one embodiment of the present invention will be described below.

FIG. 4 is a block diagram showing an embodiment according to the present invention.

In Fig. 4, 1 is a power supply, 2 is a power converter that converts the power of the power supply 1 into variable AC power, and the gx is driven by a 3ki force converter 2.
A synchronous motor, 4 is a field wire ring of the synchronous motor 3, and 5 is a field power source.

6 is a Sakai current regulator, which has a mechanism for converting the electric power of the field power source 5 and supplying an appropriately adjusted excitation current to the field wire ring 4.

7 is a rotor position detector that detects the rotational position of the rotor of the synchronous motor 3, and 8 is a speed detector that detects the rotational speed of the synchronous motor 3.

A gamma detector 9 detects the zero point of the line voltage of the synchronous motor 3.

Reference numeral 10 denotes a pulse oscillator which uses the output signal of the speed detector 8 as a control input and generates pulses with a frequency proportional to the speed.

11 is a γ controller which receives the output signals of the γ detector 9 and the pulse oscillator 10 and generates a commutation control signal;
, the pulse oscillator 10, and the γ controller 11 to control the current control advance angle γ with respect to the terminal voltage of the motor to be constant.
It constitutes a control mechanism.

Reference numeral 12 denotes a control signal switch that selects the output signal of the rotor position detector 7 and the output signal of the γ controller 11 as appropriate depending on startup and other operating conditions.

Reference numeral 13 denotes an input control section that generates a control signal for adjusting the input power of the power source 1, and thereby controls the rotational speed or current of the electric motor.

14 is a logic circuit that combines the output signals of the control signal switch 12 and the input control section 13 to generate control signals for each commutating element of the power converter 2.

15 is a terminal voltage detector that converts the terminal voltage of the synchronous motor 3 into a digital or analog signal.

16 compares the output signal of the terminal voltage detector 15 and the output signal of the speed detector 8, detects whether the terminal voltage is a set voltage proportional to the speed, and outputs a control signal according to the deviation. This is a comparator that generates.

17 is a field current regulator 6 according to the output signal of the comparator 16.
This is a control signal generator that generates control signals, and includes a terminal voltage detector 15, a speed detector 8, a comparator 16, and a control signal generator 1.
7. Together with the field current regulator 6, it constitutes a voltage control mechanism that controls the terminal voltage of the motor to a voltage proportional to the rotational speed. This is exactly the same as voltage control for a generator.

FIG. 5 is a detailed diagram of the γ controller 11, FIG. 6 is a detailed diagram of the γ detector 9,
FIG. 2 is an explanatory diagram of the operation of the γ control mechanism of the pulse oscillator 10 and the γ controller 11.

20 shown in FIG. 5 is a pulse counter, and a γ detector 9
The pulse oscillator 10 uses the output signal as a count start command.
When the preset number n of pulses is counted, one pulse is output, and the counter is reset until the next count start command is received.

21.21-1.21-2, 21-3 are inverters,
22, 22-1 to 22-6 are AND circuits, 23.23-
1.23-2.23-3 are flip-flops, and the subscripts 1° and 2.3 correspond to the U phase, ■ phase, and W phase, respectively.

The γ detector 9 in FIG. 4 detects the zero point of the line voltage of the motor as shown in FIG. 61 and generates the signal shown in FIG. The signal shown in FIG. 3, which is a combination of each phase, is output.

On the other hand, the pulse oscillator 10 shown in FIG. 4 oscillates pulses with a frequency proportional to the rotational speed so that a constant number of pulses come at a constant electrical angle corresponding to the frequency of the motor.

The number of pulses to be emitted at a constant electrical angle is determined by how many steps the control advance angle γ is controlled.

For example, when controlling the control advance angle γ in 1° increments, the oscillation frequency is set so that 60 pulses occur during an electrical angle of 60°.

The pulse counter 20 shown in FIG. 5 starts counting the output pulses of the pulse oscillator in response to the output signal of the detector shown in FIG.

Therefore, the output of the counter is as shown in FIG. 6.

The setting number n is the commutation repetition angle 600 and the setting control advance angle γS
The number of pulses is selected to correspond to the difference between (60° - γS).

For example, if the frequency of the pulse oscillator 10 is set so that 60 pulses come during an electrical angle of 60°, and γ is controlled to 45°, n=60-45=15.

Therefore, the electrical angle between pulses of the counter output signal in FIG. If γ is larger than γS, it will be smaller than 60°, so if the next commutation point is determined by the output signal of this counter, if γ is smaller than γS, the next commutation point will be If γ is larger than γS, the next commutation point will be delayed, and the control advance angle will be delayed until γ matches the set γS.

The inverter 21, AND circuit 22, and flip-flop 23 in FIG. 5 are circuits that generate a commutation control signal from this counter output signal, and as shown in FIG.
From the detector output and the counter output signal of FIG. 6, the signal shown in FIG. 6 T is generated and used as the flip-flop ON command signal. The signal shown in Figure 6 is generated from the counter output signal of Figure 6 and Figure 6, and the output signal of the flip-flop is
If the FF command signal is used, the output of the flip-flop 23 will be the commutation control signal shown in FIG. 6.

The solid line in FIG. 6 shows the case when the control advance angle γ matches the set value γS, and the broken line shows the case when γ becomes smaller than γS.
When γ is smaller than γS, the next commutation point is earlier and γ is corrected to match γS.

As described above, the present invention greatly improves the characteristics of a non-commutated motor by adding relatively simple control elements such as constant terminal voltage control and constant commutation control angle γ control to the control system of a non-commutated motor. It is much more difficult to install a compensating wire with the same characteristics as this, and it is much more difficult to install a compensating wire with the same characteristics as it is, which has the various disadvantages mentioned above and has major structural and engineering difficulties. In addition to being advantageous, the magnetomotive force for compensating the armature reaction requires the same magnitude as the armature reaction magnetomotive force when using compensation wires as shown in FIG. The field magnetomotive force is the vector sum of Fe and Ff in Figure 1.
Since the size is equivalent to , the increase due to compensation is smaller than when using compensation wires, and the cost reduction, including labor and material costs, is significant compared to installing compensation wires.

In addition, in order to extend the commutation limit, a method of simply controlling the control advance angle to a constant value, or a method of providing a series winding coil in the field has been proposed, but in the former case, the terminal voltage decreases as the load increases. As the current value relative to the torque increases, the commutation reverse bias also decreases, so the effect is not so great, and the air gap magnetic flux decreases due to armature action, so as the load increases, it is used at a looser saturation degree, which makes the use of iron less effective. rate is low.

On the other hand, the latter becomes oversaturated when the load increases, and even if the magnetomotive force of the series winding ring is increased, the terminal voltage does not increase much.
As the control advance angle γ also becomes smaller as it becomes saturated, the effect is small.

In contrast, the present invention constantly controls the terminal voltage to a voltage proportional to the rotational speed, that is, the amount of air gap magnetic flux is constant, so it is always used at a preferable saturation regardless of the load, and the iron utilization rate is increased. Since there is no need to consider the reduction in commutation effect due to supersaturation and the commutation reverse bias remains unchanged, the overload capacity is greatly increased and the size of the motor can be reduced.

[Brief explanation of drawings]

Fig. 1 is a vector diagram of a commutatorless motor, Fig. 2 is an operation explanatory diagram showing the relationship between line voltage and armature current, and Fig. 3 is a commutation type turning angle u1 control lead angle γ with respect to torque. 4 is a block diagram showing an embodiment of the present invention, FIG. 5 is a detailed diagram of the γ controller 11 in FIG. 4, and FIG.
The figure is an explanatory diagram of the operation of the γ control mechanism. 1...Power supply, 2...Power converter, 3.
・Song synchronous electric motor, 4... Field wire ring, 5...
・・・Field power supply, 6...Curved field current regulator, 7...
...Rotor position detector, 8...Speed detector, 9
...... γ detector, 10... pulse oscillator, 11... gamma controller, 12... control signal switcher, 13... - Input control unit, 14... Curved ring circuit, 15... Terminal voltage detector, 16...
... Comparator, 17 ... Control signal generator, 2
0...Pulse counter, 21-1 to 21-3.
...Inverter, 22-1 to 22-6...
-AND circuit, 23-1 to 23-3...Flip-flop.

Claims (1)

[Claims] 1. In a non-commutator motor consisting of a power source, a static power converter that converts the power from the power source into variable AC power, and a synchronous motor driven by the power converter, the A mechanism for controlling a control advance angle γ of an output current of a power converter and a mechanism for controlling a field current of the synchronous motor are provided, and the control advance angle γ is controlled to be constant, and magnetic flux is applied to the synchronous motor. A means for detecting or a means for detecting the terminal voltage and rotational speed of the synchronous motor is provided so that the amount of magnetic flux of the synchronous motor is constant or the terminal voltage of the synchronous motor is a voltage proportional to the rotational speed. A method for compensating armature reaction of a commutatorless motor, characterized in that the field current of the synchronous motor is controlled so that: