JPH02188178A - Commutatorless motor - Google Patents

Abstract

PURPOSE:To control a speed while stabilizing a load by directly adding a correcting command through the a command of armature current being the output of a speed control circuit according to the angle of rotation of said load. CONSTITUTION:A speed control circuit 8 compares a speed feedback omegar with a speed reference omegar* to output the armature current reference I1r* so that said both values are equal. On the other hand, when a load torque changes in the manner of corresponding to an angle of rotation thetar, the value I1a* with a pattern of torque-correcting current reference I1a* corresponding to thetar is outputted in a torque-correcting circuit 15. Said torque-correcting current reference I1a* is added to said I1r* and, on the basis of the resulting armature current reference I1*, a current control circuit 9 control the armature current of a synchronous machine 4. When the current reference is corrected in such manner, the variation of said load torque can be directly reflected in the armature current without going by way of said speed control circuit 8.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention relates to a non-commutator motor, and particularly to a non-commutator motor that can operate stably when the load fluctuates periodically in synchronization with the rotation angle. Regarding possible commutatorless motors.

(Prior Art) Fig. 1O shows an example of the configuration of a conventional non-commutator motor. In Fig. 1O, 1 is a rectifier that rectifies AC power into DC power, 2 is a DC reactor that smoothes DC current, and 3 is a rectifier that rectifies AC power into DC power.
is an inverter that reversely converts DC power into AC power of any frequency; 4 is a periodic machine to be controlled; 5 is a load directly connected to the synchronous machine; 6 is a speed sensor that detects the speed of the synchronous machine;
7 is the speed command of the synchronous machine, 8 is the speed control circuit, 9 is the current control circuit, 1G is the phase control circuit, 11 is the β setting circuit, 1
2 is a position sensor of the synchronous machine, 13 is a β control circuit, and 14 is a current sensor. In the circuit configured as above 0, the speed control circuit 8 has a speed reference ω, which is the output of the speed command 7, and the speed sensor 6. It compares the speed feedback ω, which is the output, and outputs the armature current reference value □ of the synchronous machine 4 so that both are equal. The current control circuit 9 receives current feedback obtained from the current reference circuit and the current sensor 14,
The phase control circuit 10 outputs a gate pulse REC to the rectifier 1 based on the phase reference PHC, so that the armature current of the synchronous machine 4 is adjusted to the rectifier 1. controlled by On the other hand, the β control circuit calculates the optimal control advance angle β from values such as the commutation margin angle γ required for the inverter 3 and the current type angle U during commutation, and calculates the optimum control advance angle β from the values of the commutation margin angle γ required for the inverter 3 and the current type angle U at the time of commutation, and adjusts the rotation of the synchronous machine 4 obtained by the position sensor. The β control circuit 13 controls the advance angle of the inverter 3 based on the child phase θ.
The inverter 3 outputs NV and supplies an armature current according to the rotational phase of the synchronous machine. Since the control technology for commutatorless motors is already well known, a detailed explanation will be omitted.

(Problems to be Solved by the Invention) The non-commutator motor configured as shown in FIG. 10 can stably vary the speed of most loads. However, in the case of a load such as a reciprocating compressor where the load torque varies greatly depending on the rotation angle of the load device, it has been difficult to perform stable variable speed control. With such a load, there is a large load torque fluctuation once or several times per rotation, and a speed fluctuation occurs in synchronization with this cycle. In variable speed control, the rotational speed varies over a wide range, so the frequencies of load torque fluctuations and speed fluctuations also vary over a wide range. Therefore, no matter how the response of the speed control system is selected, there will be a speed where the speed response and the speed fluctuation frequency are close to or coincide with each other, making it difficult to control.

In view of the above problems, an object of the present invention is to provide a commutatorless motor capable of stably controlling the speed of a load that periodically fluctuates in synchronization with the rotation angle.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention includes a position sensor that detects the rotation angle of a load, and a means for outputting an armature current correction command according to one rotation angle, By directly adding the correction command to the armature current command which is the output of the speed control circuit according to the rotation angle.

Provided is a commutatorless motor that can stably operate under fluctuating loads.

In addition, the present invention provides a commutatorless motor that has a means for speed detection in synchronization with load fluctuations, allows the detected speed to remove the influence of load fluctuations, and is capable of stable operation against fluctuating loads. I will provide a.

(Function) With this configuration, the necessary torque according to the rotation angle can be controlled without going through speed control, so the speed control response is independent of the load fluctuation frequency.

Furthermore, since the speed detection signal is independent of load fluctuations, speed control can be performed stably.

(Example) An embodiment of the present invention will be described below with reference to FIG.

As shown in FIG. 1, reference numeral 15 is a torque correction circuit for correcting the generated torque of the synchronizer. In FIG. 1, the speed control circuit 8 compares the speed reference ω and the speed feedback ω, and outputs the armature current reference xxr of the synchronous machine 4 so that the two become equal. The torque fluctuation of the - side load 5 is calculated from the rotation angle θ by the torque correction circuit 15, and a torque correction current reference Iz11 corresponding to the required torque is added to the xzr. The current control circuit 9 controls the armature current of the synchronous machine 4 based on the armature current standard obtained as a result.

The operation of the torque correction circuit 15 will be explained using FIG. 2.

In FIG. 2, the horizontal axis represents the load and the motor rotation angle θ1.
When the load torque changes corresponding to the vertical axis T is the load torque and Ixa is the torque correction current reference 0 rotation angle θ, the torque correction circuit 15 has a pattern of the torque correction current reference Ixa and Iza corresponding to 01. Output. This variation in load torque is not limited to once per revolution, but if it is an integral multiple of one revolution, it is possible to similarly create a pattern based on the torque correction current. By correcting the current reference in this manner, fluctuations in load torque can be directly reflected in the armature current without going through the speed control circuit 8.

Next, another embodiment of the present invention will be described with reference to FIG. Components that are the same as those in FIG. 1 are given the same reference numerals and their explanations are omitted. In FIG.
This is a transmission gear inserted between the load 5 and the load 5. Since the speeds of the synchronous machine 4 and the load 5 differ due to the gear 16, the rotation angle of the synchronous machine and the rotation angle of the load are no longer the same. Since load fluctuation occurs in response to the rotation angle of the load, the 1-position sensor 12 is attached to the load and the output θ is used to perform torque correction, thereby making it possible to obtain a torque output corresponding to the load torque fluctuation.

A modification of the embodiment shown in FIG. 1 will be explained using FIG. 4. In FIG. 4, 17 is a pattern correction circuit. The torque correction current reference pattern possessed by the torque correction circuit 15 is corrected under certain conditions to obtain an optimal torque correction current reference pattern. That is, a constant speed reference ω
When the synchronous machine is operating at 1, the output I of the speed control circuit 8
The torque correction current reference pattern is corrected using the output P of the pattern correction circuit 17 so that the deviation Δω between xl' or the speed reference ω and the speed feedback ω is constant. In other words, the torque correction current reference pattern can be optimized by setting the speed fluctuation that occurs under the condition of constant speed reference ω1 to 0.

FIG. 5 shows a different embodiment of the present invention. In FIG. 5, 18 is a sample and hold circuit. Due to load fluctuations, the speed feedback ω also fluctuates in synchronization with the rotation angle θ. This does not cause speed fluctuations if the torque correction is ideally performed, but in reality, periodic fluctuations occur, and as a result, the output 11r of the speed control circuit 8 also fluctuates. This variation changes depending on the frequency of speed control response and load fluctuation, and affects the stability of speed control. In order to eliminate this periodic speed fluctuation, the output ω of the speed sensor 6 is adjusted at the timing when the rotation angle θ1 reaches a certain specific position. is sampled and held, and the result is fed back as speed feedback ω. This will be explained with reference to FIG. Fig. 6 shows the speed ω of the synchronous machine when the load torque varies as shown in the figure depending on the rotation angle θ4. also fluctuate with the same period, so a certain rotation angle or.

and the speed ω,. , and henceforth θ. This shows that periodic fluctuations can be removed by holding the period up to .

Another embodiment of the present invention is shown in FIG.
9 is a differential circuit. The speed of the synchronous machine is determined by differentiating the rotation angle θ1, which is the output of the position sensor 12, without using a speed sensor. This speed ωr.

The sample-and-hold circuit 18 removes periodic fluctuations and uses it as the speed feedback ω.

FIG. 8 shows another embodiment of the present invention, in which the torque correction circuit 15 is removed from the embodiment of FIG. In this case, since the speed feedback ω removes periodic fluctuations due to load fluctuations, the ampere current reference I□ remains constant. Therefore, the armature current of the synchronous machine 4 is also constant, and the synchronous machine outputs a constant torque. On the other hand, since the load torque fluctuates periodically, periodic fluctuations in speed cannot be suppressed. Although ωra causes periodic fluctuations, it does not affect the speed control circuit 8, so control stability is maintained. be able to.

FIG. 9 shows another embodiment of the present invention, in which the torque correction circuit 15 is removed from FIG. 7.

Although speed fluctuations cannot be suppressed as in FIG. 8, the sample-and-hold circuit 18 prevents fluctuations in speed feedback ω1 and current reference I□, thereby maintaining control stability.

(Effects of the Invention) As described above, according to the present invention, it is possible to provide a commutatorless motor that can perform stable speed control when the load torque fluctuates greatly in synchronization with the rotation angle. can.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention. FIG. 2 is an explanatory diagram of the operation of the torque correction circuit shown in FIG. 1. 3 to 5 and 7 to 9 are schematic configuration diagrams showing other embodiments of the present invention, FIG. 6 is a diagram explaining the speed sample and hold operation, and It is a schematic configuration diagram showing a control device of 4...Synchronous machine, 5...Load, 6...Speed sensor, 12...Position sensor, 15...Torque correction circuit, 16... Gear, 17...Pattern correction circuit. 18...Sample hold circuit, 19...Differential circuit. Agent Patent attorney Nori Chika Ken Yudo Daishimaru Ken Figure Figure

Claims (1)

[Claims] In a non-commutator motor, the motor is configured to include means for detecting the rotor position of a synchronous machine and to determine the phase of an armature current in accordance with the detected position angle. A commutatorless motor characterized by increasing or decreasing the amplitude of current.