JPH0254315A - Torque control type motor-driven machine - Google Patents

Abstract

PURPOSE:To reduce the exciting torque with high accuracy without performing a high-speed arithmetic process by reading a load waveform out of a torque waveform memory part in accordance with the operating state of a motor-driven machine and controlling the electromagnetic torque produced by an motor-driven element. CONSTITUTION:The operating state of a compression element 15 of a motor- driven machine which is revolved by an motor-driven element 14 is detected by the pressure pickups 20 and 21 and supplied to a microcomputer 26 via the A/D converters 29 and 30. At the same time, the rotational angle of a rotary spindle is detected via the electromagnetic pickups 18 and 19 and supplied to the microcomputer 26. Then the microcomputer 26 reads the torque waveform of the element 15 for each rotational angle corresponding to the operating state out of a ROM 31 via a CPU 28. A base driver 33 of a torque controller controls the electromagnetic torque so that the torque waveform of the element 14 is coincident with the reading torque waveform. In such a constitution, it is not required to perform a high-speed arithmetic process from the residual torque. Then the exciting torque can be reduced with high accuracy in simple constitution.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates generally to rotating machines in which load elements are driven by electric elements, and in particular to a rotary machine that reduces vibrations caused by fluctuations in load torque generated by load elements. The present invention relates to a torque-controlled rotating electric machine suitable for.

[Prior Art] A hermetic compressor will be described as an example of a rotating machine driven by an electric element. 4 and 5 show the conventional structure of a rotary compressor. In these figures, reference numeral 1 denotes a closed container that houses an electric element and a compression element therein. Reference numeral 2 denotes a stator of an electric element fixed to the container 1, and is fixed to the inner periphery of the container 1. Inside this stator 2,
A rotor (rotor) 3, which is an electric element, is fitted onto the rotating main shaft 4 and rotates together with the main shaft 4. The main shaft 4 is
It is supported by a main bearing 5 and a bearing 6. and,
These bearings 5 and 6 are fastened to a cylinder block 7. A cylinder block 7 is fixed to the container 1, and a compression chamber 12 is formed within the cylinder block 7. Disposed within this compression chamber 12 are a roller 8 eccentrically and integrally attached to the main shaft 4, and a vane 9 (FIG. 5) urged against the surface of the roller 8 by a spring 10. When the main shaft 4 rotates under such a configuration, 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 moved into the container along the direction of the arrow. 1 is discharged outside.

A compressor having the above-mentioned structure is disclosed, for example, in Japanese Patent Application Laid-Open No. 58-18
It is disclosed in Japanese Patent No. 7635.

[Problem to be solved by the invention] By the way, the gas compression torque generated by the compression element is
As shown in the figure, it fluctuates greatly during one rotation of the main shaft 4.

Due to the difference between this gas compression torque and the electromagnetic torque generated by the electric element, that is, the residual torque, rotational speed fluctuations occur in the rotating system including the main shaft 4, and the container 1 and the vibration isolating support material 1.
A problem arises in the fixed system consisting of 3 and 3 in that vibrations occur in the rotational direction.

FIG. 6 schematically shows, as an example, the causes of vibration in a rotary compressor. Rotation system of each compression element and electric element (rotor 3, roller 8. main shaft 4)
and fixed system (stator 2. cylinder block 12. container 1)
, gas compression torque To3. Electromagnetic torques T and 4 act as shown in the figure. In addition, in the figure, clockwise direction when viewed from above (motorized element side) is positive.
Anti-old clockwise rotation is considered negative.

Equations of motion for the rotating system and fixed system at this time In order to make the vibration in the rotational direction of the fixed system 0, the residual torque △T or =T
The excitation torque may be set to 0 by detecting 1.1-To and controlling the electromagnetic torque T2 so that ΔTr==0.

Conventionally used methods for detecting the residual torque ΔT1 include, for example, using equation (1), which is the equation of motion of the rotating system, and inertia torque of the rotating system and fixed system, respectively. , K is the spring constant of the compressor support spring, and φ8 is the rotation angle of the main shaft 4.

In equation (2), which is the equation of motion of a fixed system, To-T
M is a torque that is equal in magnitude and opposite in direction to the residual torque ΔT, and acts as an excitation torque for vibration in the rotational direction of the fixed system. Therefore, from the value △T r / J R
There is a way to find out.

However, in order to measure rotational acceleration, a means (for example, a rotation encoder) that generates a rotation pulse every time the main shaft 4 rotates by a certain angle is used, and the rotation speed is determined from the reciprocal of the generation period of this rotation pulse. , it is necessary to differentiate this rotation speed with respect to time. Therefore, even in the high-speed rotation range, in order to perform torque control that sufficiently follows the residual torque generated by the rotary electric 81 machine, calculations such as calculation of rotational acceleration must be performed at extremely high speed. was there.

In addition, if high-speed calculation is not possible, the interval at which the residual torque is detected must be made coarse, resulting in problems such as difficulty in accurately reducing the excitation torque (residual torque). was there.

The purpose of the present invention is to solve these problems and to calculate the excitation torque with sufficient accuracy without requiring particularly high-speed calculation processing in order to obtain the residual torque generated by the rotating electric machine. An object of the present invention is to provide a torque-controlled rotary electric machine that can reduce vibration and realize low vibration.

[Means for Solving the Problems] To achieve the above object, the present invention provides an electric element, a load element connected to the electric element via a rotating main shaft and driven by the electric element, and a load element that is driven by the electric element. A torque control type rotary electric machine is provided with a torque control device that controls the electromagnetic torque of the electric element so that the difference between the electromagnetic torque and the load torque (residual torque) generated by the load element is τ. a rotation angle detection means for detecting each rotation angle; an operation state detection means for detecting an operating state of the rotating electric machine; a torque waveform storage unit that stores a torque waveform of a load torque that is known in advance; is read from the torque waveform storage unit, and based on the read load torque waveform, the torque control device adjusts the electromagnetic torque generated by the electric element at each rotation angle of the rotating main shaft detected by the rotation angle detection means. The configuration is such that control is performed so that the waveform is equal to the load torque waveform.

[Function] With this configuration, the residual torque that should be generated by the electric element of the rotary electric machine can be immediately and accurately determined by knowing the operating state of the rotary electric machine. The excitation torque can be reduced with sufficient accuracy without requiring particularly high-speed calculation processing to obtain the residual torque generated by the machine.

[Example of implementation] 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 rotary electric machine driven by an electric element (brushless motor), is driven by an inverter. Here, since the compressor according to the present embodiment has almost the same configuration as the conventional compressor shown in FIG. 6 in FIGS. 4 and 5, only the different parts will be explained below. , the same parts are given the same reference numerals, and the explanation thereof will be omitted.

In this embodiment, as shown in FIG. 1, the rotating main shaft 4 that directly connects the rotor 3 of the electric element 14 and the rotor 8 of the compression element 15 has one end extended so that the number of teeth is n (n>1). A gear 16 and a gear 17 having one tooth are fixed, and this gear 1
6, the gear 17, and the main shaft 4 rotate together. container 1
has an electromagnetic pickup 18 and an electromagnetic pickup 19.
is fixed. The electromagnetic pickup 18 detects the tooth row of the gear 16, and the electric pickup 19 detects the tooth row of the gear 17 and outputs a pulse signal. The rotation angle of the main shaft 4 is uniquely detected by the gear 16 and the electromagnetic pickup 18, and by the gear 17 and the electromagnetic pickup 19. That is, the electric pickup 19 outputs one pulse (I) every time the main sensor 4 rotates once.
P/R) is output, and the electromagnetic pickup 18 outputs one pulse (n P / R) every time the main shaft 4 rotates by 2π/n (radians). (In the above, P is a pulse. , R means revolution), of these two types of rotation pulses, the former is used as a signal indicating the standard rotation angle of the main shaft 4, and the latter is used to further finely divide the reference angle determined by the former. If this signal is used as a signal, the instantaneous rotation angle of the main shaft 4 can be detected precisely (every 2π/n radians) and easily.

On the other hand, the operating status of the compressor is determined. The easiest way to know the operating state of the compressor is to know the suction pressure Ps and discharge pressure Pd of refrigerant gas, and the average rotational speed ω of the main shaft 4. Among these, the suction pressure Ps and the discharge pressure Pd are
They are detected by pressure sensors 20 and 21, respectively. In addition, the average rotational speed ω of the main shaft 4 can be easily determined by measuring the generation period Δt of the rotational pulse of the I P/R output from the electromagnetic pickup 19, and by performing the calculation shown in equation (3) below. It can be calculated.

ω=2π/△t (radian/S)...(3)
In addition, if it is difficult to perform the division shown in equation (3) due to limitations in the ability of the arithmetic device, calculate the average rotational speed ω corresponding to Δt in advance and store the result in the storage device. , if the average rotational speed ω corresponding to the measured Δt is read out sequentially from the storage device, the load on the arithmetic unit can be greatly reduced.

Note that the method described above is just an example of the easiest way to determine the operating status of the compressor; by adding and detecting other state variables such as the suction temperature and discharge temperature of the refrigerant gas, it is possible to It is possible to specify and detect the operating status of the machine in more detail.

FIG. 2 is a diagram showing the overall configuration of the torque-controlled rotary electric machine of this embodiment. The operating state detection means for detecting the operating state of the compressor using FIG. 2 will be described below.

That is, the signals outputted by the electromagnetic pickups 18 and 19 when they detect the gear tooth row are converted into n P / R rotation pulse signals (hereinafter referred to as n P / R signals) 24 and n P / R signal in the waveform shaping circuits 22 and 23, respectively. I P/R
rotation pulse signal (hereinafter referred to as IP/R signal) 25
The waveform is shaped into the interface 2 in the microcontroller 26.
7 to the CPL 128. CPIJ2B is
Of the above two types of rotation pulses, I P/R signal 25
The generation period Δt is measured by a timer built into the CpH 28, and the average rotational speed ω is calculated using equation (3).

On the other hand, analog signals that detect the magnitude of the suction pressure Ps and discharge pressure Pd of the refrigerant gas of the compressor, which are output from the pressure pickups 20 and 21, respectively, are converted into digital signals by the A/D converters 29 and 30. It is converted and sent to CPL 128 via interface 27.

The operating state of the compressor is detected based on the combination of the CPO 28 internal suction pressure Ps and discharge pressure Pd.

The torque waveform of the gas compression torque generated by the compression element at each rotation angle of the main shaft 4 (every 2π/n radians in the case of this embodiment) during a certain operating state is a torque waveform that is known in advance according to various operating states. ROM in the microcontroller 26
It is obtained by storing the torque waveform in a torque waveform storage section provided as 31 and reading out the torque waveform corresponding to the detected operating state from therein.

The rotation angle of the main shaft 4 is detected as described below using the two types of rotation pulses described above.

That is, the I P/R output by the electromagnetic pickup 19
The signal 25 is used as a reference for the rotation angle of the main shaft 4. (In this embodiment, this reference rotation angle is set to 0 radian.) In other words, each time the I P/R number 25 is output, it can be known that the main shaft 4 has made one revolution.

On the other hand, from the electromagnetic pickup 18, the main shaft 4 or 2π/n
Since the n P/R signal 24 is output every time the I P/R signal 25 is outputted, the rotation angle of the main shaft 4 is set as O radian, and thereafter, the n P
/R(-If an angle of 2π/n radians is added each time the -i number is output, the rotation angle of the main shaft 4 can be detected with a resolution of 2π/n radians.

Next, a method for controlling the electric torque generated by the electric element will be described.

First, the magnitude of the electromagnetic torque generated by the electric element can be controlled by changing the magnitude of the current flowing into the electric element by applying a current control signal to the pace driver 33 in the inverter 32.

Furthermore, as mentioned above, the torque waveform of the gas compression torque generated by the compression element corresponding to the operating state of the compressor is read into the CPO 28 as data for each rotation angle of the main shaft 4 (every 2π/n radians). Therefore, in order to make the residual torque zero, the magnitude of the electromagnetic torque generated by the electric element at each rotation angle of the main shaft 4 may be controlled so as to be equal to the slope of the gas compression torque.

That is, the rotation angle of the main shaft 4 is detected with the I P/R signal 25 as a reference, and the rotation angle is increased by 2π/n radians each time the n P/R signal 24 is input to the CPII 28, and the CPt 128 detects the rotation angle from the ROM 31. Using the read gas compression torque data at each rotation angle of the main shaft 4, the CPII 28 manually inputs gas compression torque data corresponding to the detected rotation angle to the pace driver 33 via the interface 27. The magnitude of the electric 611 torque generated by the electric element at each rotation angle of the main shaft 4 is controlled to be equal to the magnitude of the gas compression torque.

In addition, in the torque control described above, the rotation angle of the main shaft 4 is changed to C every time the nP/R signal 24 is input.
There is no particular need to calculate it in the Pt128.In other words, if the data of the gas compression torque at each rotation angle of the main shaft 4 is stored in order according to the magnitude of the rotation angle, the nP/R signal 24 is simply treated as a synchronization signal every 2π/n radians, and n P / R signal 24
It is only necessary to sequentially output the stored gas compression torque data to the pace driver 33 each time the data is input. As a result, the work that CPO28 has to do is to detect the operating state of the compressor and read out the torque waveform of the gas compression torque corresponding to this operating state from ROM31.
8 does not need to perform particularly high-speed arithmetic processing, and by increasing the number n of teeth of the gear 16, it becomes possible to reduce the residual torque with high accuracy.

Figure 3a shows the gas compression torque of the compression element when the compressor of this embodiment is operated under torque control;
The gas compression torque (
the electromagnetic torque of the electric element), and the residual torque (the difference between the two) (
In the same figure, the hatched part) is shown, and 3b
The figure shows an example of an I P/R signal and an n P/R signal.

[Effects of the Invention] As is clear from the above description, the present invention has the following effects.

The operating state of the rotating electric machine is detected, the load torque waveform generated by the load element according to the operating state is read from the torque waveform storage unit, and the electromagnetic torque generated by the electric element is rotated based on this load torque waveform. Since the spindle is controlled to be equal to the load torque waveform at each rotation angle, the electromagnetic torque that should not be generated by the electric element of the rotating electric machine can be determined immediately and accurately by knowing the operating status of the rotating electric machine. Therefore, the excitation torque can be reduced with sufficient accuracy without requiring particularly high-speed calculation processing to measure the residual torque generated by the rotating electric machine. Therefore, for all rotating machines that are driven by electric elements and have load torque fluctuations, a significant reduction in the excitation torque, in other words, a significant reduction in the rotational direction vibration of the entire machine, is achieved, and the resonance point It is possible to achieve low-speed operation at the following speeds or to greatly simplify the vibration isolation structure. Furthermore, the burden of calculation processing on the control system can be significantly reduced, resulting in faster response, expanding the torque control execution range to higher speeds, and achieving low vibration over a wide rotational speed range. can. As a result, it can contribute to downsizing the entire system, reducing power consumption through variable speed operation over a wide range, and improving comfort.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a compressor according to an embodiment of the present invention, FIG. 2 is a diagram showing the overall configuration of a torque control device according to an embodiment of the present invention, and FIG. A diagram showing the generated gas compression torque, electromagnetic torque, and residual torque waveforms,
Fig. 3b is a diagram showing an example of each waveform of the rotation pulse signal, Fig. 4 is a vertical cross-sectional view of a conventional hermetic compressor, Fig. 5 is a xi-xr cross-sectional view of Fig. 4, and Fig. 6 is a rotational A partial vertical sectional view for explaining the residual torque generation mechanism in a machine, and FIG. 7 is a diagram showing an example of the waveforms of gas compression torque, electromagnetic torque, and residual torque that would occur when torque control is not performed. It is. 4...Rotating main shaft 14...Electric element 5...
Compression element 16. 7... Gear 9... Electric stone n pickup 20. ...Pressure surprise 26...Microcomputer 2...Inverter Fig. 2 Fig. 3α Fig. 1 Spindle rotation angle (rαd) 2π Fig. 3b Fig. 4 b Fig. 6

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, and the difference between the electromagnetic torque generated by the electric element and the load torque generated by the load element. a torque control device for controlling electromagnetic torque of an electric element to make (residual torque) zero; and a rotation angle detection means for detecting each rotation angle of a rotating main shaft;
an operating state detection means for detecting an operating state of the rotating electric machine; and a load torque that is known in advance to be generated by the load element at each rotation angle of the rotating main shaft for each of various operating states of the rotating electric machine. a torque waveform storage section storing waveforms, the load torque waveform of the load element corresponding to the operating state of the rotating electric machine detected by the operating state detection means is read from the torque waveform storage section; Based on the load torque waveform, the torque control device controls the electromagnetic torque generated by the electric element so that it is equal to the load torque waveform at each rotation angle of the rotating main shaft detected by the rotation angle detection means. A torque-controlled rotary electric machine. 2. The rotating electric machine is an electric compressor, and the operating state detection means detects the operating state of the electric compressor based on detected values of the average rotational speed of the rotating main shaft, suction pressure, and discharge pressure of the electric compressor. 2. The torque-controlled rotary electric machine according to claim 1, wherein the torque-controlled rotary electric machine is configured to detect the torque.