JPH0279793A - Compressor driving apparatus - Google Patents

Abstract

PURPOSE:To prevent vibrations and noises by computing acceleration by correcting the detected value of position change obtained with the rotational- position detecting circuit in a compressor motor with time, and making the output of the motor approximately equal to the torque of a changing load based on said acceleration. CONSTITUTION:A commercial power source 3 is rectified 4, and a DC voltage Ed is obtained. An inverter 6 is driven with said DC voltage Ed, and AC voltages VA to VC are generated. Thus a compressor motor 7-1 is rotated. A position detecting signal 10S for a rotor is obtained in a phase detector 10 out of the voltages VA to VC by using a filter circuit. The signal 10S is inputted into a microcomputer 9. The microcomputer 9 has a CPU 9-1, a ROM 9-2, a RAM 9-3 and high speed input/output ports HSI and HSO. The data in the RAM 9-3 are operated in the CPU 9-1 using the program in the ROM 9-2, and a rotating speed is obtained. The result is outputted through a current control part 11 and a base driver 12, and the gates of transistors TR1 to TR6 are controlled. In this way, the output of the motor is made approximately equal to the torque of a changing load, and the vibration and the noises of the compressor are prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an apparatus equipped with a compressor, and particularly to a compressor drive device capable of suppressing vibrations of the compressor and rotating the compressor at low speed.

[Conventional technology]

In a conventional device of this kind, the output torque of the synchronous motor is adjusted to the load torque for each rotor position, as described in Japanese Patent Laid-Open No. 60-60286.

[Problem to be solved by the invention]

The above-mentioned prior art uses a non-commutator motor to form a position detection signal using a filter circuit for the terminal voltage of the motor, thereby creating a current pattern.

This is a method of suppressing vibration. However, the terminal of the motor (
The position detection signal obtained by the filter circuit from the pressure has a phase delay caused by the circuit constant of the filter circuit.
Sufficient consideration was not given to the fact that this could prevent the effect of vibration suppression. That is, when outputting the current pattern created by the position detection signal, the terminal voltage waveform of the motor becomes uniform, and the rotor position detection error causes an error in the current pattern, reducing the vibration suppressing effect. In addition, as the rotational speed of the electric motor decreases, the inertia torque of the rotor decreases, so the fluctuation per rotation applied to the compressor, especially in rotary type compressors where the load is large in the range of one rotation. The influence of load torque increases. The influence of the fluctuating load torque increases the rotor position detection error and impedes low-speed operation of the compressor.

Furthermore, there is no consideration given to the need for faster responsive control as the rotation speed of the compressor becomes lower. , non-commutated motors would lose synchronization, narrowing the range of rotational speeds that could be operated at low speeds.

An object of the present invention is to provide a control method that improves the vibration suppression effect of the compressor and expands the rotational speed range in which the compressor can operate at low speeds.

[Means to solve the problem]

The above purpose is to analyze the cause of the rotor position detection error included in the position detection signal created from the terminal voltage of the electric motor, which is the position detection means, using a filter circuit, and to analyze the cause of the rotor position detection error, The computer of the microcomputer calculates the residual voltage due to the accumulated charge in the filter circuit in the past, compensates for the position detection error, calculates the speed and acceleration, and calculates the output torque of the motor to the compressor. This is achieved by making the variable load torque approximately equal to the variable load torque applied per rotation.

[For production]

The electric motor outputs a torque approximately equal to the variable load torque per revolution applied to the compressor. As a result, when the output torque of the motor is large, the terminal voltage of the motor also becomes large, and the terminal voltage fluctuates during one revolution of the compressor, and the waveform of the filter circuit, which is the position detection means, also fluctuates during one revolution of the compressor. . The waveform of the filter circuit causes an error in the position detection signal, and a position error occurs between the compressor load torque and the motor output torque at each rotational position of the compressor, resulting in inhibiting the vibration suppression effect. Since the position detection error is caused by the winding impedance drop of the motor and the accumulated voltage of the filter circuit, the microcomputer calculates the position detection error and performs offset error compensation. As a result, the accurate rotational position of the rotor of the electric motor can be detected inside the microcomputer, so that the photographing suppression effect can be improved.

Additionally, as the compressor rotation speed becomes lower, the excitation torque of the compressor due to the residual torque between the fluctuating load torque of the compressor and the output torque of the electric motor increases, and the risk of tax adjustment for the electric motor increases. Since the position detection error is reduced by compensation of the detection error, it becomes possible to operate the compressor at low speed.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 6. FIG. 1 is a block diagram of a control device related to a compressor drive device, which includes an inverter device 1 and a control section 2. As shown in FIG. The inverter device 1 includes an AC power source 3, a full-wave rectifier circuit 4, a smoothing capacitor 5, and a transistor T14 as a switching element.
．． ~TR, and an inverter main circuit 6 formed by freewheeling diodes D1 to D. The inverter main circuit 6 is a 120° current type inverter, and the AC power supply 3
The positive potential side transistors TR, ~T of the DC voltage E4 obtained through the full-wave rectifier circuit 4 and the smoothing capacitor 5 from
The conduction period (electrical angle 120°) of R is controlled by chopper operation under pulse width modulation. Further, the transistor T Ra of the inverter main circuit 6
A low resistance R, is connected between the common emitter of ~'I'FL, and the smoothing capacitor 5.

7 is a compressor, for example, a commutatorless motor 7-1 whose field is a four-pole permanent magnet, and a compressor 7-1 which is its load body.
Consists of 2. The winding current flowing through the armature winding of the commutatorless motor 7-1 also flows through the low resistance (tl), and the winding current (2) can be detected as a voltage drop across this low resistance (a).

-The force control unit 2 includes a microcomputer 9, a non-commutator,
, [a magnetic pole position detection circuit 10 that detects the magnetic pole position of the rotor of the motor 7-1, a current control unit 11 that controls the armature winding current of the commutatorless motor 7-1, and transistors TR, ~'r
It is composed of a pace driver 12 for rL.

The magnetic pole position detection circuit 10 described above includes a non-commutator motor 7-1.
This circuit uses a filter circuit to form a position detection signal 103 corresponding to the rotor position from the armature winding terminal voltage (vc). Using this position detection signal 108,
The rotational speed N of the commutatorless motor 7-1 is determined using the microcomputer 9.

The microcomputer 9 is 0PU9-1, 0M
9-2, AM9-3, high speed output port (H80) 9-
4, a high-speed input port (H8I) 9-5, etc., and are connected to each other by an address bus, a data path, and a control bus (not shown). The ROM 9-2 stores various processing programs necessary to drive the commutatorless motor 7-1. On the other hand, the AM9-3 has a main memory section 9-3a for reading and writing various data necessary for executing various processing programs, and a main memory section 9-3a for reading and writing various data necessary for executing various processing programs, and a memory section 9-3a for reading and writing various data necessary for executing various processing programs, and a and a current pattern storage section 9-3b that stores current data. The high speed output port (H80) 9-4 sets the output data and output time using 0PU9-1, and when outputting data, 0PU
Data is output independently without intervening 9-1.

The high-speed input capo (H8I) 9-5 records the input data at the time of input generation and the input time without the intervention of the 0PU 9-1. This enables output.

The current control unit 11 controls the winding current 1 based on the current output data in the current pattern storage unit 9-3b of the microcomputer 9 and in accordance with the current output signal 9S1 output for each rotational position.

The pace driver 12 receives a driver drive signal 982, which is output from the microcomputer 9 in synchronization with the position detection signal 108, corresponding to the a position of the non-commutated motor 7-1.
and the chopper signal 118 output from the current control section 11.
Accordingly, transistors TR, ~ in the inverter main circuit 6
It controls the TFL.

That is, in a commutatorless motor, the winding current flowing through the armature winding corresponds to the output torque of the motor, and the winding current can be controlled for each rotational position.

FIG. 2 is a diagram showing changes in the load torque T1, the output torque TM of the motor, and the rotational speed N with respect to the rotation angle of the non-commutated motor.The output torque T1 is approximated to the pulsation pattern of the load torque T. By generating this at each rotor position, it is possible to maintain the rotational speed N at -.

Figure 3 shows the position detection signal 10i9 and the current output signal 9i9.
1 is an operation explanatory diagram showing a time relationship with 1. Example 1 cycle corresponds to 180 degrees in mechanical angle, and one revolution of the rotor is 36 degrees.
With respect to 0°, it is divided into 12 modes every 30° from mode 11'' to “12” shown in the figure.The current pattern storage section 9-3 is created for each of these modes.
After reading the 12 pieces of current data stored in b according to each mode and outputting it as a current output signal 981, the current control section 15 creates a chopper signal 118 and controls the winding current (2).

FIG. 4 is a diagram showing a position detection circuit and its output waveform. The position detection circuit 10 detects vA from the terminal voltage of the non-commutated motor 7-1 and from the resistor C1, r from the phase voltage.

The terminal voltage waveform vA' is shaped by a low-pass filter consisting of a capacitor C8 and a bypass filter consisting of a capacitor cl and a resistor r, and the waveforms v,' of the Vs and Vc phases are shaped by a similar filter. , vc′ with resistance r1, “6, r.

An operation is performed to generate the iron position detection signals 10Ia-10zc with the virtual neutral point potential V averaged by .

Here, when the motor output is adjusted to the compressor load torque, the pulse width of the chopper of the transistor in the inverter main circuit 6 changes according to the rotation angle of the rotor, so that the motor terminal voltage changes according to the rotation angle of the rotor. and change. FIG. 4(b) is a waveform showing the operation of the filter circuit when the electric motor outputs a variable load. Motor terminal voltage V
Filter output v waveform-shaped for A, V, , vc
A', ■, ', ■c' are pulsating, and the position detection signal 108 obtained by comparison with the neutral point potential V is obtained by detecting the angle of the rising and falling edges of the rectangular wave in the figure, and detecting the actual rotation. An error (represented by Δθ) occurs between the angle (vertical dotted line). This position detection error significantly impairs the effectiveness of compressor vibration suppression.

The above-mentioned positioning error is compensated for by the microcomputer 9, which is based on the following arithmetic expression.

That is, the terminal voltage V of the motor at 7 is the inductance 51 of the motor winding, and the winding resistance is 51, and the induced voltage at no load is e.
o, winding current 1. Then, V,==r is +L
9+ e @ (11, considering only the first-stage low-pass filter of the filter circuit, and its time constant as RO
far. Therefore, the waveform-shaped voltage v of the filter circuit,
' is V,' = Table 7"V, dt = 工 (r/' i@d t+Lf"10f' 5
eat) 10V@OR@6 dt
5 Here, the integral constant V is calculated as the sum of the residual voltages after discharge of the voltage V due to the charges accumulated in each capacitor in the filter in the past.

v = upper Vl e-” (
3) From the above, the detection error angle Δθ between the actual rotational position and the position obtained by the position detection circuit is expressed as
In equation (2), v,'=o (3B ('
7;' + a d t 10L Ku;jI"-11+
V”r K e sin Δθ〕+ΣVl e−”
=O(4) By solving for Δθ, the detection error angle can be obtained.

Furthermore, equation (5) is obtained by transforming equation (4).

−y/T −s + nΔθ FIG. 7 is an explanatory diagram for determining Δθ in equation (5). The left side of equation (5) is the sine wave shown in FIG. 7 that changes with Δθ. The zero crossing point of this sine wave is the exact position of the motor rotor, and the transistor T
r+~Tr, is the timing at which commutation is performed. The right-hand side is expressed as an integral of how many times the exact position is set to 1=0. The solution lθ of equation (5) is ttxo
Time 1 delayed by angle θ from 1 = 1. This indicates the angle of error between the position detection signal of the filter circuit generated in 1 and the accurate rotor position. Therefore, by performing commutation after an angle Δθ after the position detection signal of the filter circuit is input to the microcomputer, rotational pulsation of the motor can be minimized.

The calculation to find the error of the above position detection circuit is θ' in angle.
(J low angle), but if the microcomputer is equipped with a timer that records the time when the input change of the position detection signal occurs, the angle can be up to 60 degrees (J low angle). It is sufficient that the error calculation is completed within the time period (pneumothorax). In addition, in the commutation, after the position detection signal is input, a new position detection signal may be input to the microcomputer within the compensation period of Δθ, but in this case, the output for commutation of the motor is If you use a microcontroller that has the ability to change the output signal to be controlled at a specified time with minimal CPU overhead, you can output a signal for commutation at a precise position, making it easier to control the motor. Rotational pulsation can be minimized.

FIG. 5 is a control block diagram explaining the operation of this control. All operations in this control diagram are performed by the microcomputer 9. The position detection error of the position detection signal 10i9 generated by the position detection circuit 10 is time-corrected according to the current output signal 981, the phase characteristics of the position detection circuit 10, and the motor constant of the non-commutated motor 7-1. As a result, it is compensated by Δθ in the correction calculation formula (4), and a corrected position detection signal 108' is created. The drive signal 982 is the corrected position detection signal 1
It is created by converting into a phase which is the rotation angle of the electric motor based on 08'. The current pattern is calculated based on the deviation from the acceleration command 9C1 (in this control, the command value is 0 in order to set the rotational pulsation of the motor to 0) by calculating the acceleration from the corrected position detection signal 108'. It is created in a form divided into 12 modes per rotation. Here, we will explain how to calculate the acceleration p. From the temporally different rotational speeds N, , N, obtained by the corrected position detection signal 108', the acceleration α is calculated as a-(Nr Nr)/Δ1 [r pm/s
Calculated as eC).

Here, the reason for using acceleration to create the current pattern will be described. As the speed of the compressor decreases, the residual torque, which is the difference between the variable load torque per rotation of the compressor and the output torque of the first engine, becomes an excitation force of the compressor, increasing the vibration, and the excitation force increases. Gives vibration to the rotor of an electric motor. The vibration of the rotor causes an error between the position detection signal obtained from the terminal voltage of the motor and the actual position of the rotor, resulting in a tax adjustment in the worst case. This is because the control response is slow, the current pattern converges slowly, and the motor adjusts and stops before the current pattern converges. Therefore, when the rotational speed of the compressor is low, it is necessary to quickly create the current pattern, that is, to speed up the response of the control system so that the current pattern converges before the motor stops. In this control, in order to speed up the response of the control system, we use acceleration, which is a two-machine division of position, so the response of the control system becomes faster, and it is possible to create the current pattern before the motor steps out and stops. It is. This is because acceleration is a differential form of speed, so it takes less time to create a current pattern and converge it than to create the current pattern based on the speed deviation of the rotor. It's for a reason. Further, the rotation speed of the non-commutated motor is determined by the corrected position detection signal 108'
The average speed for one revolution is calculated from the above, and is maintained constant in a proportional-integral manner using this and an internal speed command 902 set inside the microcomputer 9. The current gravity signal 981 is output according to the information on the average speed per rotation and the information on the current pattern.

FIG. 8 is a flow diagram showing the processing of the microcomputer. This routine starts with a position detection signal from the position circuit. First, position detection signal generation time 1. /
is read from a timer in the microcomputer and stored in RAM, which is a storage unit. Next, the angle lθ is calculated as the position detection error based on the above calculation formula, and the error time Δ
Find the electric current from Δt=Δθ/ω. And the calculated l
The drive signal output time t is determined by adding t and the position detection signal generation time tl', and commutation is performed by switching the transistor of the main transistor circuit on and off at this time. Next, calculate velocity and acceleration. compressor 1
The number of rotations N from the time in the generation order i of the position detection circuit that occurs 12 times per rotation, is a constant 0, and the i-th and i
+ From the second time Nl = a/ (IIes +
t+). Further, the acceleration α is the velocity Nl5N1. I, time type 6, electric 1+ at that time, α= (N14.-N
1)/(ts-1*). The current pattern is determined by multiplying this acceleration α by a proportionality constant and adding it to the value of the previous '1 flow pattern. By operating the microcomputer as described above, it is possible to create a current pattern for outputting a motor output approximately equal to the variable load per revolution of the compressor.

In this way, commutatorless electric fa? -1 rotation 36
0° is divided into 12 rotational positions every 30', and corresponding to the divided positions, independent current data is provided in the readable/writable area of RAM9-3b, and the current data at each rotational position is stored. As a result of creating the acceleration at the rotational position, it is assumed that the pattern of one rotation of 360° formed by the 12 pieces of current data is approximately equal to the pulsation pattern of the compressor load torque.

FIG. 6 shows the compressor vibration effect showing the effect of this control.

The horizontal axis is the rotational speed, and the vertical axis is the vibration acceleration, and the vibration acceleration increases as the vibration of the compressor increases. From the top, the data are for the case of a constant upstream pattern, the case of a large position detection circuit, and the case of this control, and it can be seen that the vibration suppression effect increases in this order. This is because acceleration is used when creating the ED style pattern, so the position detection error superimposed on the acceleration is small.

After time-correcting the position fluctuation detection value obtained from the rotational position detection circuit of the non-commutator motor, which is the compressor motor, as described above, the speed and acceleration are calculated, and the output of the motor is adjusted by approximately 1 to the variable load torque. By making it substantially equal to , it is possible to improve the effect of suppressing vibration and noise of the compressor.

Furthermore, by using acceleration when creating the torque pattern, the response becomes faster than the conventional method using speed deviation. This is because the speed deviation is a one-time differential of the rotational position of the rotor, whereas the acceleration is a two-time differential.

Generally, when a non-commutator motor is used in a compressor, it is known that the influence of pulsating load at low speeds causes rotational pulsation, which causes the motor to step out and stop. According to this embodiment, since it is possible to suppress rotational pulsation, it is possible to expand the rotational speed range in which the compressor can be operated at low speed.

〔Effect of the invention〕

According to the present invention, after time correction is performed on the position fluctuation detection value obtained from the rotational position detection circuit of the compressor motor, acceleration is calculated, and the output of the motor is made approximately equal to the fluctuating load torque using this acceleration. &゛ゝ improves the effect of suppressing compressor vibration and noise.
□It has the effect of making you swollen. It also has the effect of preventing the compressor motor from adjusting at low speeds and expanding the operable range.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a control device according to an embodiment of the present invention;
Fig. 2 is a diagram illustrating changes in load torque, motor output torque, and rotational speed with respect to the rotation angle of the 7L motor, and Fig. 3 is a diagram illustrating the operation of the current control method with respect to one revolution of the motor.
Fig. 4 shows the position detection circuit diagram (,) and output waveform (b), Fig. 5 is a control block diagram explaining the operation of this control, and Fig. 6 shows compressor vibration suppression of this control. 1. Inverter device, 2. Control unit, 3.
- AC power supply, 4... Full-wave rectifier circuit, 5... Smoothing capacitor, 6... Inverter main circuit, 7... Compressor section, 7-1... Non-commutator motor, 7-2 ...compressor,
9... Microcomputer, 10... Position detection circuit, 11... Current control unit, 12... Pace driver.乎 l Mouth 2nd Mouth 3rd Fast Mouth 4th<Q-) (Ryodo(ya) in b times) 5th Mouth Den, *t尤+LztsL number L5 ts-1+ Mut2 N2-N+ B-1z

Claims (1)

[Scope of Claims] 1. means for changing the rotational speed of the compressor motor into multiple stages; position detecting means for detecting the rotational position of the rotor from the terminal voltage of the motor using a filter circuit; and the position detecting means A compressor control device includes a microcomputer that controls the output torque of an electric motor based on a position detection signal obtained from a position detection signal obtained from The microcomputer calculates the residual voltage due to the accumulated charge stored in the microcomputer, performs error compensation, calculates the speed and acceleration, and converts the output torque of the motor into approximately the variable load torque per rotation applied to the compressor. A compressor drive device characterized by equal parts. 2. The microcomputer according to claim 1,
A timer that records the time when the input change of the position detection signal occurs and an output signal that controls the output of the motor to the minimum opu
A compressor drive device characterized by having a function of causing an output change at a specified time with overhead.