JPS6348177A - Torque control type rotary motor-driven machine - Google Patents

Abstract

PURPOSE:To enable the control of high reliability to be performed, by using a counter for counting the number of pulse during one rotation of a rotary main shaft, and a timer for enabling one rotation of the rotary main shaft to be exactly measured, and by obtaining pulse-train-time system data. CONSTITUTION:One end of a rotary main shaft 4 connecting the rotor 3 of a motor element 20 directly to the rotor 8 of a compression element 21 is extended, and a toothed gear 22 is firmly fitted. On a vessel 1, a gap sensor 23 detecting the tooth train of the toothed gear 22 and generating the output of pulse signal is fixed. In the meantime, by a magnetic pole position detection circuit 37, rotor position signal is formed through the armature winding voltage of the motor element and is applied to a timer 39. By a CPU 31, an inverter 36 is controlled according to a counter 38 for counting the pulse signal of the gap sensor 23, and rotational speed signal computed based on the output signal of the timer 39 and the rotor position signal.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates generally to rotary electric machines in which load elements are driven by electric elements, and in particular to detecting and reducing rotational pulsation on the rotating side thereof, The present invention also relates to a torque-controlled rotating electric machine suitable for reducing vibrations of the entire rotating machine.

[Conventional technology]

A hermetic compressor will be described as an example of a rotating machine driven by an electric element. 7 and 8 show the conventional structure of a rotary compressor. In these figures, reference numeral 1 is a container that houses an electric element and a compression element therein. Reference numeral 2 denotes a stator fixed to the container 1, and is fixed to the inner circumference of the container 1. A rotor 3 that is fitted onto the main shaft 4 and rotates together with the main shaft 4 is disposed inside the stator 2 . The main shaft 4 is supported by a main bearing 5 and an end bearing 6. These bearings 5 and 6 are fastened to a cylinder block 7. The cylinder block 7 is fixed to the container, and a compression chamber 12 is formed within the cylinder block 7. A roller 8 eccentrically integrated with the main shaft 4 is provided in the compression chamber 12, and a vane 9 urged against the surface of the roller 8 by a spring 10 is provided. With this configuration, when the main shaft 4 rotates, refrigerant gas is sucked in from the suction accumulator 11 provided outside the container 1, is pressurized to a predetermined pressure by the compression chamber 12, and is released into the case along the direction of the arrow. It is discharged outside.

[Problem that the invention seeks to solve]

A compressor with such a structure is disclosed in Japanese Patent Application Laid-Open No. 58-187635.
As disclosed in the above publication, the gas absorption torque within the compression element fluctuates greatly during one rotation of the main shaft 4, and due to the difference between this and the electromagnetic torque of the electric element, that is, the residual torque, the main shaft 4
The rotating system includes rotating speed fluctuations, a container 1 and a vibration-proof support member 1.
．． A problem arises in that vibrations in the rotational direction are induced on the fixed side consisting of 3 and 3.

If the rotational speed fluctuation of the rotating system is detected and controlled so that it becomes zero, the residual torque mentioned above will also become zero, and as a result, rotational direction vibration, which is the cause of vibration and noise in rotating machinery, will be suppressed. can.

Here, in order to detect rotational speed fluctuations, as shown in FIGS. 1 and 2, a rotational speed detection gear 2 is attached to the rotating main shaft 4.
2 may be directly connected to detect rotation pulse signals using an external sensor 23 such as a gap sensor attached to the stationary side (container 1).

However, since the external sensor is fixedly attached to the container 1, when the container 1 vibrates in the rotational direction, the external sensor mounting position also vibrates. As a result, the pulse time series detection from the gear is affected.

FIG. 9 shows the influence on the detected rotational speed fluctuation data. In other words, when the vibration in the direction of one rotation and the rotational speed fluctuation are in opposite phases, the actual rotational speed fluctuation is W.
Like l, it is measured to be larger than the true rotational speed variation No, and when it is in the same phase, it is measured to be smaller than the actual rotation speed variation like X2.

In particular, when excessive rotational vibration is induced at the resonance point of the vibration isolation support system on the case side, the vibration angle amplitude α becomes larger than the angle between one tooth surface of the gear (minimum resolution angle θm). A possibility arises. At this time, FIGS. 10(a) and (b)
As shown in , when the rotational direction amplitude angle α of the sensor exceeds the minimum resolution angle 01, erroneous pulses are measured due to the "tooth skip" of the sensor, and not only a completely erroneous rotational speed fluctuation value is obtained, but also the number of pulses There is also a problem in that a deviation occurs when counting and obtaining one cycle, making it impossible to synchronize the torque control command with the pulsation pattern.

On the other hand, in order to perform high-precision control that can detect even higher harmonic components of the fluctuation frequency component of the rotational speed fluctuation of the rotating spindle and suppress this fluctuation component, it is necessary to increase the number of pulses or pulses as much as possible. It is desirable to increase the maximum/J% resolution angle to make it smaller. Here, FIG. 11 shows detection data when the number of pulses is changed for one period of rotational speed fluctuation. As is clear from the figure, fluctuation 1
The greater the number of pulses per cycle, the more accurate data can be obtained.

The present invention has been made in view of the nature of the above problems,
The purpose of this is to use a counter to count the number of pulses during one rotation of the rotating spindle and to accurately calculate one rotation of the spindle, in order to prevent false detection signals caused by "skipping teeth" of the external sensor caused by vibrations in the rotational direction of the fixed case of the rotating electric machine. To provide a 1-Rue controlled rotating machine that can be controlled with higher reliability and high precision by correcting this using a timer that can measure the rotational pulse train so that correct rotational pulse train data is always obtained. be.

[Means for solving problems]

As described above, the torque-controlled rotary electric machine according to the present invention has the following features:
An electric element, a load element connected to this electric element via a rotating main shaft and driven by the electric element, and the difference (residual A torque control type rotary electric machine comprising: a torque control device that controls electromagnetic torque of an electric element to make the difference torque (differential torque) O; The pulse time series data is corrected by a counter that calculates the period of one rotation by counting the number of rotations, and a timer that can accurately measure the period of one rotation of the rotating main shaft.

[Effect]

According to the present invention, even if a detection error occurs due to "tooth skipping" due to vibration in the rotational direction of the external sensor when detecting rotational speed fluctuation, the number of pulses counted by the counter and the period of one rotation of the rotating main shaft by the timer are compared. By correcting this, correct pulse train time series data can be obtained.

Therefore, there is no risk of malfunction based on erroneous detection data.

Furthermore, regardless of the magnitude of the amplitude of rotational direction vibration on the case side, the number of gear teeth or the number of encoder pulses can be increased, and torque control can be made more precise.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows an example in which the present invention is applied to a case where a rotary compressor, which is a type of rotating machine driven by an electric element (DC motor), is driven by an inverter. Here, since the compressor according to this embodiment has almost the same configuration as the conventional compressor shown in FIGS. 12 and 13, only the different parts will be explained, and the same parts will be given the same reference numerals. The explanation thereof will be omitted.

In FIG. 1, the rotor 3 of the electric element 20 and the compression element 2
One end of the rotating main shaft 4, which is directly connected to the rotor 8, is extended, and a gear 22, which is a rotation detection member, is fixed, so that the gear 22 and the main shaft 4 rotate together. A gap sensor 23 is fixed to the container 1, and a gear 2
2 is detected and a pulse signal corresponding to the rotational speed of the main shaft 4 is output.

FIG. 2 shows a series of processes for determining the rotation speed fluctuation of the rotating main shaft 4 from the pulse signal detected by the gap sensor 23.

A sinusoidal detection waveform 24 appears. This is converted into a pulse train by waveform shaping using the threshold voltage 27 as a reference, as shown in FIG. 3(C). Each pulse width Ti, T2, ......Tn of this pulse time series data is measured, and the rotational speed fluctuation Ni (28) at each time is determined from its reciprocal N + = 1 / T t , and this 1 The figure (d) shows changes in each rotation angle during rotation.

The signal from the sensor 23 is transmitted to the control circuit 2 as shown in FIG.
8, and this control circuit 28 controls the electromagnetic torque of the electric element 20. That is, the detection signal 24 obtained by the gap sensor 23 is converted into a digital signal related to rotational speed fluctuation by the waveform shaping preamplifier 29 and sent to the CPU 31 via the interface 30.

Here, the current value to be applied to the electric element 20 of the compressor necessary to reduce the rotational speed fluctuation after one rotation to O is calculated from the momentary speed fluctuation amount, and the data is stored in the RAM 32 until the time it is needed. I'll let it happen.

Next, the data written in the RAM 32 is read out by the CPU 31, sent to the control unit 34, and sent to the pace driver 35.
form the chopper signal that drives the.

At the same time, the CPU 31 controls the interface 30 so that the inverter 36 generates the required current value at each rotation angle.
A timing signal is sent to the pace driver 35 via the pace driver 35.

The inverter 36 driven by the pace driver 35 performs control by increasing/decreasing the amount of current given to the electric element so that the fluctuation in the rotational speed of the main shaft 4 becomes 0 at each rotation angle. Then, the rotational speed of the main shaft 4 is continuously controlled so that the fluctuation is always within a certain permissible value. Moreover, these series of control loops are written in the ROM 33.

Here, the magnetic pole position detection circuit 37 is
As disclosed in Publication No. 15, this is a circuit that uses a filter circuit to form a position detection signal corresponding to the rotor position from the armature winding voltage of the electric element, and is related to the timing of driving the inverter. .

In this embodiment, the rotation pulse signal 25 converted into a rectangular wave by the waveform shaping circuit 29 is counted by the counter 38 and sent to the CPU 31 via the interface 30. Then, a timer 39 creates a reference signal corresponding to one rotation of the rotating main shaft from the rotor position detection signal 26 of the magnetic pole position detection circuit 37 described above, and sends the signal to the C through the interface 30.
Sent to PU31.

Next, FIG. 4 is a flowchart showing the procedure for correcting the pulse time series data based on the signals obtained from the counter 38 and timer 39 in this manner.

First, after detecting the rotational pulse train in step 1]-〇,
Measure individual pulse intervals (step 120) and create pulse time series data 130 (step 130)
), the counter 38 counts the number of pulses. (Step 122) Here, at the same time, step 210,
At 220, a signal from timer 39 is detected and 1
An interrupt is made during rotation to capture the number of pulses counted by the counter at that time. (Step 230) Then, in step 124, the counted number of pulses n and the exact number of pulses in one rotation (number of gear teeth) n11
are compared, and if they are equal, it is assumed that there is no extra count due to the "tooth skipping" of the sensor, and step 130 directly proceeds to step 140, where the rotational speed is calculated based on this.

(Step 150) On the other hand, if the number of pulses n is greater than nI, the difference Δn=
nn umbrella is calculated in step 126, and step 128
Pulse time series data (T1゜T2...Tn
), modify the smallest one by 61 and proceed to step 140.
Move to. Then, in step 150, the rotation speed is calculated from this corrected time series data.

Next, FIG. 5 shows a procedure for correcting the detected pulse time series data to obtain true pulse time series data.

First, in step 310, after detecting the th time series data Tk, in step 320, it is compared with the minimum T umbrella of the previous time series data (Tt...Tk-1), If Tb is smaller than this, 'r*
='rk, and at the same time, the pulse number k is stored. If it is larger than this, the process moves directly to step 330, where k is compared with the number n of pulses detected during one rotation. Here, if k < n, step 3
40, set = to +1 and return to step 310 k
When = n, the process moves to step 420, and step 41
The time series data Tk for the pulse number held at 0 is (T
x...Tn), T k = T ka
t T k-x is calculated in step 430 . Then, in step 440, the pulse numbers subsequent to the pulse number are decreased by one, and in step 450, corrected true time series data (Tx+Tz...T-) is obtained.

Here, in this case, the process is performed when tooth skipping occurs only once per cycle, but if it occurs Δn times, multiple storage units in step 410 are prepared and the same procedure is performed Δn times.
Make sure it can be repeated n times.

It goes without saying that a certain amount of processing time is required to perform the series of processing routines explained above, but when controlling using data from one revolution before, as in this embodiment, pulse detection Since it can be performed in parallel with the processing of control commands, this does not pose a problem, unlike when processing in real time.

Further, the means for supplying the reference signal of one rotation to the timer may be other than the magnetic pole position detection circuit as in this embodiment.

FIG. 6 shows a second embodiment of the present invention, and is an example in which a timer gear is prepared for creating a reference signal for one rotation. Here, the number of teeth of the timer gear is sufficiently small (minimum resolution angle is large) to such an extent that vibrations in the rotational direction of the sensor and the container do not pose a problem.

Further, the reference signal does not necessarily have to correspond to one rotation of the main shaft, and the pulse time series data described above may be corrected by setting one rotation as one period as the number of teeth N of the timer gear.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, the rotating main shaft is driven by an electric element, has periodic load fluctuations of 1 to 100 mph, and detects the rotational speed fluctuations caused by this by an external sensor. , in a torque-controlled rotary electric machine that controls this as much as possible, and even if an error occurs during detection, it can be corrected, so there is no risk of malfunction due to detection error, and highly reliable control can be achieved. .

Furthermore, regardless of the magnitude of the vibration in the rotational direction of the external sensor, the number of pulses of the rotational speed variation detection gear or encoder can be increased, so that it is possible to achieve high precision control.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a compressor which is an embodiment of the present invention, FIG. 2(a), FIG. 2(b), and FIG. 2(C). Fig. 2(d) is a diagram showing a method for determining rotational speed fluctuation from a detection signal, Fig. 3 is a schematic diagram of a torque control device, Fig. 4 is a diagram showing a flow for correcting a detected rotational pulse train, and Fig. 5
The figure shows the details of the correction method, FIG. 6 shows the second embodiment of the present invention, FIGS. 7 and 8 are longitudinal cross-sectional views of a conventional closed type rotary electric machine, and FIG. 9 shows the details of the correction method. FIG. 10 is a diagram showing the influence of measurement data due to vibration in the rotational direction of the sensor, and FIG. 10 is a diagram showing the influence of pulse train due to tooth skipping of the sensor.
FIG. 11 is a diagram showing the detection accuracy of rotation speed fluctuation when the number of pulses is changed. 4...Rotating main shaft, 20...Electric element, 21...Compression element, 22...Gear, 23...Gap sensor,
28... Control circuit, 30... Interface, 31
...CPU, 36...Inverter, 37...Magnetic pole position detection circuit, 38...Counter, 39...Timer, 40...Timer gear.

Claims (1)

[Claims] 1. An electric element, a load element connected to the electric element via a rotating main shaft and driven by the electric element, an electromagnetic torque generated by the electric element, and a load generated by the load element. (absorption) torque and a torque control device that controls the electromagnetic torque of the electric element so as to make the difference (residual torque) zero, the torque control device comprising: As a means for detecting residual torque information, a gear or an encoder is connected directly to the rotational spindle to measure rotational speed fluctuations of the rotational spindle, and a gear or encoder is fixedly attached to the case side of the rotating machine.
Separately from these, it has a rotation speed fluctuation detector composed of an external sensor that detects a rotation pulse train obtained during rotation, and a counter that counts the rotation pulse train during one rotation to obtain one rotation period when detecting the rotation speed. A torque-controlled rotating electric machine characterized by having a timer that generates a reference signal that can accurately measure the period of one revolution of a rotating main shaft. 2. If the torque control device counts more pulses during one rotation or 1/N rotation obtained by the timer than the number of pulses corresponding to one rotation or 1/N rotation obtained by the counter, the torque control device compares the pulse time series data. Then, from the smallest pulse interval, remove the number counted by the counter in order to create new rotation pulse time series data, and based on this, calculate the rotation speed at each rotation angle of the rotating spindle. The torque-controlled rotary electric machine according to claim 1, characterized in that the fluctuation is calculated. 3. The torque control device serves as a timer for determining the rotation period of the rotating main shaft, and is coaxial with a gear or encoder for measuring rotational speed fluctuations directly connected to the rotating main shaft. 2. The torque-controlled rotary electric machine according to claim 1, in which a gear or an encoder with a small number of teeth or pulses can be used to the extent that vibration of an external sensor caused by vibration does not become a problem. 4. The torque control device serves as a timer for determining the rotation period of the rotating main shaft, and detects a position where a back electromotive force is generated in the electric element stator due to the passage of the magnetic poles of the electric element rotor as the rotating main shaft rotates. The torque-controlled rotary electric machine according to claim 1, wherein the rotation period can also be determined by a magnetic pole position detection circuit that detects the magnetic pole position.