JPH02202387A - Motor drive controller - Google Patents

Abstract

PURPOSE:To reduce the loss and to improve the efficiency of a motor by providing a motor for driving a load, a power source, a power converter, and a means for removing the pulsating component of a load. CONSTITUTION:Control power is fed from a power source 4 through a power converter 5 to a DC motor, for example, in order to drive a load such as a compressor 3. Fluctuation of rotary speed is detected through a fluctuation detector 11, for example, thus producing a feedback signal. Then pulsating component of load is eliminated through a fluctuation eliminating means, e.g. a low-pass filter 12, and a converter 5 is controlled through a controller 6 so that current supply to the motor 2 is not influenced by the pulsating component of load. By such arrangement, loss of the motor 2 can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a drive control device for an electric motor that drives a driven machine such as a compressor.

(Prior Art) Generally, a compressor provided in an air conditioner is driven by an electric motor, and the electric motor is controlled by a drive control device. For example, as shown in FIG. 18, the drive control device converts electric power supplied from a power source (a) into predetermined electric power using a power converter (b) and supplies the same to a DC motor (c), The controller (e) controls the power converter (b) based on the command value of the speed setter (d), and the DC motor (
The power supplied to the DC motor (c) is controlled so that the rotational speed of the DC motor (c) matches the command value, thereby controlling the drive of the compressor (f).

Furthermore, as disclosed in Japanese Patent Application Laid-open No. 173690/1983, while power is supplied from a power source to a synchronous motor via a rectifier circuit, a smoothing capacitor, and an inverter, the voltage at the armature winding terminals of the synchronous motor is The detected rotational speed is calculated by a microcomputer, compared with the setting value of the speed setting device, and a current command value of the rotational speed is output to the current control section.

Then, the current control section compares the winding current of the synchronous motor with the current command value and outputs a chopper signal to the drive circuit, and the drive circuit controls the inverter to adjust the rotational speed of the synchronous motor to the command value. The compressor is controlled to match.

(Problems to be Solved by the Invention) In the drive control device for the electric motor described above, when the compressor is driven, the load torque fluctuates (pulsates) during one revolution of the electric motor due to suction and compression of the compressor. If the voltage of the motor is controlled to be constant, the angular velocity of the motor will vary during one rotation due to the load torque fluctuation.

Due to this speed fluctuation, the back electromotive force of the motor changes, the motor current associated with loss changes, and the effective value of the current increases. Since the copper loss of the motor is proportional to the square of the effective value of the current, the loss increases as the load torque fluctuates (pulsation), resulting in poor motor efficiency. Furthermore, since the effective value of the current is large, there is a problem that the element capacitance of the power converter becomes large.

In particular, the drive control device disclosed in JP-A-61-173690 changes the rotational speed of the motor in accordance with load torque fluctuations, and as mentioned above, the effective value of the current of the motor is large.
There are problems in that the motor efficiency is poor and a power converter with a large element capacity is required.

The present invention has been made in view of the above points, and by controlling the supply current of the motor so as not to follow the pulsating component of the load, it is possible to improve the efficiency of the motor and reduce the element capacitance of the power converter. The purpose is to achieve this goal.

(Means for Solving the Problems) In order to achieve the above object, the means taken by the present invention are to remove the fluctuation component accompanying the load pulsation component from the feedback signal, and control the command value based on this feedback signal. A current that does not fluctuate with the pulsating component of the load is supplied to the motor.

That is, as a result of many years of research, the present inventors discovered that the basic idea of controlling the torque of the motor by controlling the supply current in electric motors, especially induction motors, did not exist, and as a result of many years of research, It has been discovered that if the supplied current is controlled to be constant so as not to follow, and the motor is driven with a constant torque, the efficiency of the motor is significantly improved.

Specifically, in the invention according to claim (1), first, a driven machine that generates a load including a basic fluctuation component and a pulsation component that fluctuates at a higher frequency than the basic fluctuation component is provided. and an electric motor that drives the driven machine, a power source that supplies power to the electric motor, a power converter that converts the electric power from the power source into predetermined electric power according to the electric motor, and supplies the electric power to the electric motor. A controller is provided that outputs a control signal to the converter based on a command value to control the power converter.

Furthermore, a fluctuation detector is provided for detecting the amount of fluctuation that changes in response to load fluctuations in the driven machine. In addition, based on the amount of variation detected by the variation detector, a feedback signal is output so as to remove a variation component accompanying the pulsation component of the load in the driven machine, so that the electric motor does not fluctuate in response to the pulsation component of the load. The configuration is such that a fluctuation removing means for controlling the command value of the controller is provided.

Further, as shown in FIG. 1, in the invention according to claim (2), first, a compressor (3) that generates a load including a basic fluctuation component and a pulsation component that fluctuates at a higher frequency than the basic fluctuation component.
is provided. A DC motor (2) that drives the compressor (3), a power source (4) that supplies power to the DC motor (2), and a power source that converts the power from the power source (4) into DC power. 1. A power converter (5) that supplies the DC motor (2), and a controller (5) that outputs a control signal to the power converter (5) based on a command value to control the power converter (5).
6) is provided. Furthermore, a fluctuation detector (11) is provided that detects the amount of fluctuation in the rotational speed of the DC motor (2), which fluctuates in response to load fluctuations in the compressor (3). In addition, based on the amount of variation detected by the variation detector (11), a feedback signal is output that removes a variation component associated with the pulsation component of the load in the compressor (3), and the armature of the DC motor (2) is The structure includes a fluctuation removing means (12) for controlling the command value of the controller (6) so that the current does not fluctuate in response to the pulsating component of the load.

Further, in the invention according to claim (3), the fluctuation detector (11) detects the armature voltage that changes with the rotation speed of the DC motor (2), and in the invention according to claim (4), the fluctuation detector (11) detects the armature voltage that changes with the rotation speed of the DC motor (2). 2) is configured to detect the rotational speed.

Further, in the invention according to claim (5), the fluctuation removing means (12) generates a voltage feedback signal obtained by removing a fluctuation component accompanying a pulsation component of the load from the detected voltage value of the fluctuation detector (11). The invention according to item (6) is configured to output a speed feedback signal obtained by removing a fluctuation component associated with a pulsation component of the load from the speed value detected by the fluctuation detector (11).

Further, in the invention according to claim (7), the controller (6) controls the output voltage of the power converter (5) so that it does not fluctuate with the pulsating component of the load by the voltage feedback signal of the fluctuation removing means (12). In the invention according to claim (8), the speed feedback signal of the fluctuation removing means (12) is configured to set a current value that does not fluctuate with the pulsation component of the load as the command value.

In addition, in the invention according to claim (9), the above claim (1)
In the invention according to claim (K), an AC motor is used as the electric motor, and in the invention according to claim (K), a brushless DC motor is used in place of the DC motor (2) in the invention according to claim (2). The configuration uses (21).

Further, in the invention according to claim 0D, first, a compressor (3) is provided that generates a load including a basic fluctuation component and a pulsation component that fluctuates at a higher frequency than the basic fluctuation component. and an AC motor (31) that drives the compressor (3);
a power source (4) that supplies power to the AC motor (31);
A power converter (52) converts the power from the power source (4) into AC power and supplies it to the AC motor (31), and the voltage and frequency applied to the AC motor (31) become command values. a controller (51) that outputs a control signal to the power converter (52) to control the power converter (52);
and is provided. Furthermore, a fluctuation detector (54) is provided that detects a DC current of the power converter (52) that fluctuates in response to load fluctuations in the compressor (3). In addition, based on the detected current value detected by the fluctuation detector (54), a feedback signal is outputted to the AC motor (31) so as to remove a fluctuation component accompanying the pulsation component of the load in the compressor (3). The structure includes a fluctuation removing means (57) for controlling the command value of the controller (51) so that the supplied current does not fluctuate in response to the pulsating component of the load.

Further, the AC motor is a synchronous motor in the invention according to claim 02), and an induction motor (31) in the invention according to claim (13).

Further, in the invention according to claim (14), in the invention according to claim (9), the controller (32) is connected to the AC motor (31).
) by controlling the torque current and excitation current of the AC motor (3).
1), the fluctuation detector (34) detects the rotational speed of the AC motor (31), and the fluctuation removing means (
35) outputs a speed feedback signal from which fluctuation components associated with load pulsation components have been removed to control the torque command value of the controller (32).

Further, in the invention according to claim (15), in the invention according to claim (9), the controller (41) is connected to the AC motor (31).
) to control the instantaneous torque of the AC motor (31), while the fluctuation detector (45) detects the rotational speed of the AC motor (31) and removes the fluctuation. The means (46) is configured to output a speed feedback signal from which fluctuation components associated with load pulsation components have been removed to control the torque command value of the controller (41).

(Function) According to the above configuration, in the present invention, control power is supplied from the power source (4) to the electric motor, for example, the DC motor (2) or the induction motor (3), via the power converter (5, etc.). The electric motor rotates and a wave machine such as a compressor (3) is driven.

The power converter (5, etc.) performs a switching operation based on a control signal from a controller (6, etc.) to drive and control the electric motor. For example, the power converter (5, etc.) controls the voltage of the DC motor (2),
Further, the induction motor (31) is subjected to f/v control, vector control, or instantaneous torque control.

On the other hand, in the above-mentioned electric motor, the load on the compressor (3) includes a basic fluctuation component due to air conditioning load, etc., and a pulsation component due to suction/compression, etc., and as a result of this load, the rotation speed etc. It fluctuates accordingly. Then, a variation detector, for example, a speed detector (11, etc.) detects the amount of variation in the rotational speed, etc., and outputs a feedback signal. after that,
A fluctuation component associated with the pulsating component of the load is removed or extracted from this feedback signal by a fluctuation removing means, such as a low-pass filter (322, etc.), and the command value of the controller (6, etc.) is controlled in response to this feedback signal. , the controller (6, etc.) controls the power converter (5, etc.) so that the O (supply current) to the motor does not fluctuate with the pulsating component of the load, and for example, controls the armature current of the DC motor (2). , the torque current, etc. of the induction motor (31) is controlled so as not to pulsate.

(Effects of the Invention) Therefore, according to the motor drive control device of the present invention, the supply current of the motor is controlled so as not to fluctuate due to the pulsating component of the load in the driven machine such as the compressor (3). In addition, since the effective value of the motor current can be reduced, motor loss can be reduced, and motor efficiency can be significantly improved compared to conventional motors.

Furthermore, since the peak value of the motor current can be suppressed, the element capacitance of the power converter can be reduced.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

(First Embodiment) As shown in FIGS. 2(a) and 2(b), (1) is a drive control device for driving and controlling a DC motor (2), which is an electric motor. A compressor (3), which is a wave machine and is provided in an air conditioner, is connected to the compressor (3), and is configured to drive and control the compressor (3) by controlling the DC motor (2).

The DC motor (2) uses a permanent magnet as a field, and is supplied with electric power from an AC power source (4) via a power converter (5). The power converter (5) converts AC power from an AC @ source (4) into a rectifier circuit (5a) and a smoothing capacitor (5).
b) is converted into direct a power and supplied to the switching transistor (5c).
It is configured to supply control power to the DC motor (2) by chopper operation based on the on/off operation of c), and the residual magnetism of the DC motor (2) when the transistor (5c) is off is transferred to the freewheel diode ( 5d
) is configured to be removed by

Further, the transistor (5C) of the power converter (5) is controlled by a control signal outputted by a controller (6), and the controller (6) has a speed setter (7), a comparator (8)
, PI regulator (9) and switching signal generation circuit (1
0). The speed setter (7) is configured to set a target speed of the DC motor (2) so that the compressor (3) is driven at a predetermined capacity, and to output a voltage setting value corresponding to the target speed. There is. The voltage setting value outputted by the speed setter (7) is compared with the voltage value of a feedback signal, which will be described later, by the comparator (8), and the
After being amplified by the I regulator (9), the signal is input to the switching signal generating circuit (10). The switching signal generation circuit (10) is a voltage controlled oscillation circuit (VCO), and outputs a chopper signal to the transistor (5C) in response to a voltage command value from the PI regulator (9), It is configured to control the on/off operation of the transistor (5c) to control the power supplied to the DC motor (2), that is, the armature current.

On the other hand, a speed detection circuit (11) such as a tacho generator is connected to the DC motor (2), and the speed detection circuit (11) is connected to the DC motor (2).
1) constitutes a fluctuation detector that detects the rotational speed of the DC motor (2) which changes in response to load fluctuations in the compressor (3) and detects the amount of fluctuation in the rotational speed. It is configured to output a feedback signal with a voltage value corresponding to the speed. Then, the speed detector (1
The feedback signal 1) is input to a pulsation removal circuit (12), which constitutes a fluctuation removal means such as a low-pass filter, and removes the pulsation component of the load in the compressor (3), i.e. It is configured to output a feedback signal from which fluctuation components associated with pulsating load have been removed to the comparator (8).

Since this pulsation removal circuit (12) is the most characteristic feature of the present invention, the rotational speed fluctuation of the DC motor (2) will be explained. First, the compressor (3) handles the basic fluctuation component load (basic fluctuation load) caused by changes in air conditioning load, etc., and the pulsating load that fluctuates at a higher frequency than the basic fluctuation load, that is, from the piston caused by suction and expansion. This causes a pulsating load. And the above DC motor (3)
The rotational speed of the compressor (3) fluctuates with the basic fluctuating load and pulsating load, and in particular, the pulsating load causes speed fluctuations that occur during one rotation of the DC motor (2), and the speed detection The circuit (11) outputs a feedback signal including fluctuation components corresponding to the basic fluctuation load and the pulsating load. Therefore, the pulsation removal circuit (12) removes the fluctuation component caused by the pulsating load, the switching signal generation circuit (10) outputs a chopper signal that does not follow the fluctuation caused by the pulsating load, and the power converter (5) The output voltage of the DC motor (2) is controlled so that the armature current of the DC motor (2) does not vary with the pulsating load.

Here, the basic principle of keeping the armature current constant, which is a feature of the present invention as described above, will be explained.

First, in general, the voltage equation for a DC motor (2) is vf: field voltage ■a: armature voltage 1f: field current 1a: armature current ω: rotational angular velocity P: differential symbol -d/di Ra: armature Resistance La: Self-inductance of the m ring. M: Mutual inductance between the field and the armature. Also,
The torque T is T −M 1f' φ Ia −(
2J, and the mechanical output Po is Po-ω・T (3). If the field is composed of a permanent magnet, the field current (1f) in each of the above equations becomes constant, and If'
-If (constant), and from equation (1), the voltage equation of the armature circuit is as shown in the following equation: Va-ω・M −1f+ (Ra+P −La) ・
Ia...m-1, and the equivalent circuit of equation (1)-1 is as shown in FIG. Generally, a block diagram of a DC motor system that receives a pulsating load (TL) is shown in FIG. Note that (J) in FIG. 4 is the moment of inertia of the rotating portion.

Next, when considering the instantaneous loss of the DC motor (2) that drives the pulsating load (TL), this instantaneous loss P 9 oss is expressed as P , Q oss as shown in the following equation.
s -Ra-Ia2-(4). Furthermore, if the block diagram of the transfer function of TL-1a is obtained from the block diagram of FIG. 4 above, it will be as shown in FIG. ), the armature current (la
) will also change.

On the other hand, in the block diagram of FIG. 4, feedback control is generally performed so that the average value of the rotational speed (ω) of the load is constant, and the control is performed as shown in the following equation.

〒L−〒 ...(5) 〒: Average torque Therefore, since the torque (T) generated by the DC motor (2) has a repetitive waveform with a period of mechanical rotation angle 2π, (2)
From the equation, the armature current (ia) also changes according to the generated torque (T), and the following equation (6) holds true during a predetermined period (0 to τ seconds), for example, a period of 2π rotation.

(1/τ), I'0rla-dt-constant -
(6) Also, the above instantaneous loss (P9.oss) is (4
) From the formula, P9oss −(1/r) J”orRa−
1a2・dt −・−(T).

Therefore, from the above equation (6), if the effective value is minimized while keeping the average value of the armature current (Ia) constant, the instantaneous loss (PNoss) will be reduced from the equation (7). Based on this principle, the present invention maintains the armature current (1a) constant so that it does not fluctuate following fluctuations in the pulsating load (TL).

Next, we will discuss the control operation of this drive control device (1) in the sixth section.
This will be explained with reference to the block diagram shown in the figure.

First, AC power is converted from AC current (4) to power converter (5).
The AC power is converted into DC power by a rectifier circuit (5a) and a smoothing capacitor (5b), and then supplied to a transistor (5C). The transistor (5b) is turned on and off by the chopper signal of the switching signal generation circuit (10), and the control power is supplied to the DC motor (2) to rotate the DC motor (2). The compressor (3) will be driven, and the compressor (3) will be driven.
), the DC motor (2) will receive a basic fluctuating load and a pulsating load.

In other words, when a voltage (Va) is applied to the armature of the DC motor (2), the armature current (la
) flows, torque (T) is generated based on equation (2),
In addition to the basic fluctuating load, the rotational angular velocity (ω) changes due to the pulsating load (TL).

On the other hand, the rotational speed (rotational angular velocity) of the DC motor (2)
is detected by a speed detection circuit (11), and a feedback signal of a voltage value corresponding to the rotation speed is output. This feedback signal includes a fluctuation component due to the basic fluctuating load and the pulsating load (TL) of the compressor (3), and this feedback signal is sent to the pulsation removal circuit (12) by the fluctuation component due to the pulsating load (TL). The components are removed and input to a comparator (8). In this comparator (8), a voltage setting value corresponding to the target speed is inputted from the speed setting device (7), and this voltage setting value is compared with the above-mentioned feedback signal. After being amplified, it is input to the switching signal generation circuit (10). The switching signal generation circuit (10) is connected to P
A chopper signal corresponding to the voltage command value of the I regulator (9) is output to the transistor (5C) to
5C) is turned on and off, and the armature current (ia) of the DC motor (2) is controlled to control the rotational speed to a command value.

In other words, the switching signal generation circuit (10) outputs a chopper signal that does not follow fluctuations caused by the pulsating load (TL), so that the armature current (la) of the DC motor (2) does not fluctuate due to the pulsating load. In other words, it does not follow load fluctuations during one rotation of the motor, for example,
The rotation speed is controlled by changing the armature current (ia) of the DC motor (2) in accordance with basic variable loads such as air conditioning load changes.

Therefore, since the armature current (1a) of the DC motor (2) does not fluctuate according to the pulsating load (L), the instantaneous loss can be reduced compared to the power type (power type), so it is possible to improve the motor efficiency. can.

Furthermore, since the armature winding of the DC motor (2) is directly connected to each element of the power converter (5), a current having the same current value as the armature current (1a) flows through each element. Therefore, the current rating (1 s) of the power converter (5) is the armature current (
ia) (peak value of 1sccta), the relationship is expressed by the following equation.

l5-K ll1a I peak -(8)
However, K>1 On the other hand, the voltage applied to each element of the power converter (5) is determined by the power supply voltage (V), and is defined by the maximum value of the voltage ti and the voltage (V), so the element capacitance ( Ps) has the relationship shown in the following equation, similar to equation (8).

Peak value of pscci3 −(9)Ps −(
K ・ial peak) Vmax-K' ・
[a l peak -(9) -1 this(9
)-1 formula, the armature current (1a) is held constant as described above to reduce the peak value, so the power converter (5)
The element capacitance of can be reduced.

FIG. 7 is a block diagram showing a modified example. In the above embodiment, instead of feeding back the voltage value corresponding to the rotational speed of the DC motor (2), the detected speed (ω) is changed to the set value (ω
'), this speed command value is amplified by the fluctuation removal means using the PI sub-control, and the current command value (i') from which fluctuation components accompanying the pulsating load have been removed is output to the current loop. ing.

In addition, as another modification, the fluctuation detector is a DC motor (2).
The armature voltage that changes with the rotational speed of the motor may be detected.

(Second Embodiment) In this embodiment, as shown in FIGS. 8 and 9, a brushless DC motor (21) is applied to the electric motor.

The brushless DC motor (21) uses a 4-pole permanent magnet as a field, and is connected to a power converter (22) by an AC power source (4).
AC power is supplied through the compressor (3), and a compressor (3) is connected thereto. The power converter (22) is connected to an AC power source (4
) is configured to convert AC power from the converter into DC power via a rectifier circuit (22a) and a smoothing condenser (22b), and to supply the DC power to an inverter (22c). and,
The inverter (22c) has six transistors (TR
1) ~(TRs) and 6 freewheeling diodes (Dl)~
(D6) is a 120 degree conduction type inverter, and the output AC voltage is the current conduction period (electrical angle 120 degree) of the positive potential side transistors (TR+) to (Tl?3) of the DC voltage (Ed). ) is controlled by chopper operation under pulse width modulation. Further, the negative potential side transistors (TR4) to (TRs
) common emitter terminal and freewheeling diodes (D4) to (D
A low resistance (R1) is connected between the common anode terminal of 6), and the armature current flowing through the armature winding of the brushless DC motor (21) also flows through the low resistance (R1). The structure is such that the armature current is detected by the voltage drop across the low resistance (R1).

Furthermore, the transistor (TR
+) to (TRs) are controlled by a control signal outputted by a controller (23), and the controller (23) is controlled by a speed setter (24) and a comparator (
25a) and PI regulator (25b) and current control circuit (25b)
8) and a transistor sequential drive circuit (29). The speed setter (24) is configured to set a target speed of the branless DC motor (21) so that the compressor (3) is driven at a predetermined capacity, and to output a set value corresponding to the one drift speed. ing. Then, the speed setting device (
The set value outputted by the PI adjuster (24) is compared with a feedback signal (described later) by the comparator (25a), and
25b) and then manually inputted to the current control circuit (28) as a current command value (i'). Further, the comparator (25a) of the arithmetic circuit (25), P
The I controller (25b> is composed of a microcomputer, and although not shown in the figure, the microcomputer includes the following:
Built-in CPU, ROM that stores program data, RAM that stores processing data, etc., and an arithmetic circuit (25)
outputs a control signal to the transistor sequential drive circuit (29).

Furthermore, as shown in FIG. 10, the current control circuit (28) includes a D/A converter (28a), an amplifier (28b),
It is composed of a current comparator (28c), a comparator (28d), and a triangular wave oscillator (28e). The D/A converter (28a) is connected to the PI controller (
The current command value (1') from the amplifier (25b) is converted into analog and output to the current comparator (28c).
8b) is configured to amplify the voltage drop across the low resistance (R1) and the armature current obtained from 1 to 1 and output it to the current comparator (28c). And the current comparator (28c)
is a comparator (28d) that compares the detected current value and the current command value.
), and the comparator (28d) outputs the triangular wave signal output from the triangular wave oscillator (28e) and the current comparator (28c).
) and outputs a chopper signal to the transistor sequential drive circuit (29).

This chopper signal causes the transistor sequential drive circuit (2
9) is the transistor (TRI) of the inverter (22c)
~(TI?6) on/off control, brushless DC
The armature current of the motor (21) is controlled.

On the other hand, an angle detection circuit (26) constituting a fluctuation detector detects the rotation angle of the armature, which is a rotor, from the armature winding voltages (VA) to (VC) of the brushless DC motor (21), and It is configured to output a signal to a speed detection circuit (25c) included in the arithmetic circuit (25).

The speed detection circuit (25c) is connected to the PI regulator (25b).
It is composed of a microcomputer and calculates the rotational speed of the brushless DC motor (21), and sends the feedback signal to a low-pass filter (25) which is a means for removing fluctuations.
d).

The low-pass filter (25d) is a feature of the present invention, and the speed detection circuit (25d) is similar to the first embodiment.
Since the feedback signal c) includes a fluctuation component due to the pulsating load of the compressor (3), the feedback signal from which the fluctuation component has been removed is output to the comparator (25a). . The PIFI moderator (25b) outputs a current command value excluding the fluctuation component caused by the pulsating load, and is configured so that the armature current of the brushless DC motor (21) does not fluctuate due to the pulsating load. ing.

Here, as in the first embodiment, a brushless DC motor (2
The basic principle of preventing the armature current from pulsating in 1) will be explained.

First of all, equations (1) to (7) of the first embodiment apply to the DC motor (2
) and cannot be directly applied to AC motors. Therefore, for two-phase AC, rotational coordinate transformation (
dq transformation), the power before and after the rotation remains unchanged.

Therefore, if the brushless DC motor (21) is considered to be a fixed cylindrical field type synchronous motor, the voltage equation and output equation will be as follows by applying the rotational coordinate transformation and using the impedance matrix of the two-phase rotating machine. However, the above (15)
In equation (02), a permanent magnet is used for the field, the field current (1r) is constant (C1f - 1f - constant), and the d-axis armature current (ld) is unrelated to the generation of torque (T). Therefore, it is assumed that it is controlled so that it becomes zero.

This fIl1 formula and 02) formula and (1 in the first embodiment)
) and (2), the armature current (1a) in the DC motor (2) and the brushless DC motor (21
) can be calculated in exactly the same way as the q-axis armature current (1q). Therefore, from the above equation (11), the instantaneous loss (PQoss) of the brushless DC motor (21) becomes P 9 oss -Ra ・1q2- (13) as shown in the following equation,
Similar to the DC motor (2) in the first embodiment, 1d-
By keeping it constant, the instantaneous loss (P9oss) is reduced. Based on this principle, a brushless DC motor (2°
1) The armature current (1d) follows the fluctuation of the pulsating load so as not to fluctuate.

Next, the control operation of this brushless DC motor (21) will be explained.

First, AC power supplied from an AC power source (4) is converted into a DC value by a rectifier circuit (22a) and a smoothing capacitor (22b), and is supplied to an inverter (22c).

Each transistor (T
l? l) to (TRI3) are turned on and off by the output signal of the transistor sequential drive circuit (29), convert the DC value back into AC value, and control power is transferred to the brushless DC motor (
21), the brushless DC motor (21) rotates, and the compressor (3) is driven.

On the other hand, the angle detection circuit (26) detects the armature winding terminal voltage (VA) to (VC) of the brushless DC motor (21).
The rotation angle of the armature is detected from the angle detection circuit (2).
The speed detection circuit (25c) calculates the rotational speed of the brushless DC motor (21) based on the angle signal of 6). The feedback signal output by the speed detection circuit (25c) includes a fluctuation component due to the basic fluctuating load and the pulsating load in the compressor (3), as in the first embodiment. The component is a low pass filter (25d
) and input to the comparator (25a).

Thereafter, in this comparator (25a), the speed setter (
The set value of 24) and the detected value of the feedback signal are compared, and a current command value (1') is output from the PI regulator (25b). This current command value (1') is the D/A
The current command value is converted into analog by the converter (28a), and this current command value is compared with the armature current detected by the voltage drop of the low resistance (R1) by the current comparator (28c).
In step d), it is compared with the triangular wave signal from the triangular wave oscillator (28e), and a chopper signal is output to the transistor sequential drive circuit (29). This chopper signal causes each transistor (TRI) to (T
R6) is turned on and off, and the brushless DC motor (
The rotational speed of 21) is controlled to a command value.

At that time, as mentioned above, since the fluctuation component due to the pulsating load is removed from the feedback signal, the brushless D
The armature current of the C motor (21) is controlled so as not to follow the pulsating load.

Therefore, the instantaneous loss (PNoss) shown in equation (13) above
is reduced, the motor efficiency can be significantly improved, and element 8 poisoning of the power converter (22) can be reduced.

(Third Embodiment) In this embodiment, as shown in FIG. 11, an induction motor (31) is applied to the motor, and a controller (32) performs vector control on the induction motor (31). It is something.

The induction motor (31) is supplied with AC power from an AC power source (4) via a power converter (33), and is connected to a compressor (4). Then, the power converter (3
3) is configured to convert AC power from the AC power supply (4) into DC power using a thyristor rectifier circuit (33a), smooth it using a reactor C33b), and supply the smoothed power to an inverter (33c). The inverter (33c) is a self-excited current inverter that converts DC power back into AC power and supplies it to the induction motor (31). )
The output AC current is controlled by the inverter (33c), and the phase of the output AC current is controlled by the inverter (33c).

On the other hand, the controller (32) performs vector control on the induction motor (31), and the principle of this vector control will be explained.

First, the relationship between the negative current vector 11 and the secondary magnetic flux vector ψ2 in the induction motor (3) is as shown below, M・i+ = fl + (L2/R2)P+j (L
2 / R2) ωs l ψ2 − (141
R2: Secondary winding resistance L2: Secondary winding self-inductance M: Mutual inductance between the primary and secondary windings ωS: Slip angular velocity P: d/dt. From this formula (14), M”llγ−(1+ (L 2/R2) circle ψ2...
05] M-116-J (L 2 /R2) (IJ
S ・ψ2 ・−06111γ: Primary current charge current vector 11 magnetic component current i+ 62 This becomes the torque component current of the primary current vector 11, and the instantaneous value current vector diagram on the γ-6 plane shown in FIG. 12 is obtained.

And the above Q4), (15), I'16) formula)
), tj[71t! The instantaneous torque (T) and secondary magnetic flux vector (ψ2) of (3]-) are as shown in the following equation, T= (M/L 2 )? 2 ・Iδ ・
・・07) ψ2 = [M/ll+ (L 2 / R
2) flit γ (18). In addition, the above sliding angular velocity (ωS) is as shown in the following formula, → −U −9 ω2 = iM/(12・ψz)it δ= (L2
/(L2/R2)ψ22)T...(15)
)12: Becomes a secondary current vector.

Therefore, the instantaneous torque (T) and the secondary magnetic flux vector (ψ2) coincide with the torque reference (T) and the secondary magnetic flux reference (ψ2).
) In order to operate the induction motor (31) so as to have the excitation component current (11
γ) and the torque component current (i + δ), and the composite angular velocity (
This means that it is sufficient to supply an alternating current having ω1−ωm+ωS).

The configuration of the controller (32) etc. will be explained based on this principle.

First, a speed detector (34) such as a tacho generator, which is a variation detector, is connected to the induction motor (31) to detect the operating angular velocity (0 m), and the speed signal of the speed detector (34) is pulsating. A low-pass filter (35
) is entered. As explained in the first and second embodiments, the speed signal of the speed detector (34) includes the speed signal of the compressor (34).
) includes fluctuation components associated with the basic fluctuation load and pulsating load. A feature of the present invention is that the low-pass filter (35) outputs a feedback signal obtained by removing the fluctuation component caused by the pulsating load from the speed signal of the speed detector (34), and specifically cuts off the frequency(
rl) is set smaller than the rotational frequency (ra) of the induction motor (31) (f + <ra).

On the other hand, the speed setter (32) included in the controller (32)
The set value of the driving angular velocity is output from a), and this set value and the detected value of the feedback signal from the low-pass filter (35) are compared by the comparator (32b), and P
It is configured so that it is amplified by an I regulator (32c) and outputted as a torque command value (T') which is a torque reference.

Furthermore, the setting value (ψ2') of the secondary magnetic flux (ψ2) is output from the secondary magnetic flux setter (32d) included in the controller (32), and this secondary magnetic flux setting value (ψ2') is In response, the excitation component calculation circuit (32e) receives the excitation component current (i + γ) based on the above formula 08), and also receives the secondary magnetic flux setting value (ψ2') and the torque command value (T'). The torque component calculation circuit (32r) calculates the torque component current (11δ) based on the above equation 07). At this time, the torque component current (11γ) has a current value that does not fluctuate due to the pulsating load because the fluctuation component accompanying the pulsating load of the compressor (3) has been removed by the above-mentioned low-pass filter (35). It has become. Furthermore, upon receiving the secondary magnetic flux set value (ψ2') and the torque command value (T'), the slip calculation circuit (32g) calculates the slip angular velocity (ωS) based on the above equation (15). It is configured.

Then, the adder (32h) calculates the primary current (11-1+7"+1+6i") from the excitation component current (11γ) and the torque component current (11δ), and the current control circuit (32
i) is this primary current (11) and 7T4. Sub-detector (32
j) and the feedback signal of the power converter (33).
) is configured to output a control signal to the Furthermore,
An adder (3210) calculates a composite angular velocity (ω1) from the sliding angular velocity (ωS) and the driving angular velocity (0 m), and the frequency is set by a frequency control circuit (3210) corresponding to this composite angular velocity (ω1).
29) outputs to the power converter (33), and the induction motor (31) is controlled so that the driving angular velocity and the secondary magnetic flux vector match the set values by the control of the power converter (33).
) is controlled.

In addition, (32m) is a logic circuit that outputs a control signal to turn on/off the output of the current control circuit (32i), and the operation switch (32n)
According to the opening and closing of the induction motor (31), when the operation is stopped, the current flowing through the induction motor (31) is throttled so that the current does not flow, and when the induction motor (31) is in operation, a current is caused to flow through the induction motor (31).

Here, as in each of the above embodiments, the induction motor (31)
The basic principle for preventing the torque component current (l l γ) from pulsating will be explained below.

First, the voltage equation of the induction motor (31) is as shown in the following equation: (20) R2: Secondary winding resistance L2: Secondary winding self-inductance 11γ: γ-axis component (torque) of the primary wire component current) 11δ
: δ-axis component of primary current (excitation component current) 12γ: γ-axis component of secondary current 12δ: δ-axis component of secondary current ωffi: Operating angular velocity ω1: Primary angular frequency ω2: Secondary angular frequency, 2 The next angular frequency (ω2) is expressed as ω2 ω1−ωl (21), and the torque (T) is expressed as T=n −M (1+
γ・12 δ−116・12δ) (22)

Further, the instantaneous loss (PUosS) of the induction motor (31) is as shown in the following equation.

If the torque is linearly controlled by vector control as in the controller (32) of this embodiment, the following relationship holds true.

Substituting this equation (24) into the above equations (22) and (23), T-(n -M2/L2)l δ・11
γ...(22)-1 PROss = (R+ +R2(M/L2) 21
1172+R1-11δ2...(23)-1
In this equation (23)-1, the excitation component current (11δ)
is controlled to be constant by the excitation component calculation circuit (32e) or the like, the instantaneous loss (P, Qoss) is reduced by controlling the torque component current (11γ) to be constant. 1 in the induction motor (31) based on this principle.
The torque component current (11γ), which is the next current, follows the pulsating load so as not to fluctuate.

Next, vector control operation of this induction motor (31) will be explained.

First, AC power supplied from an AC power source (4) is supplied to an induction motor (31) via a power converter (33). Then, the operating angular velocity (ω
l) is detected by a speed detector (34), and the feedback signal of the speed detector (34) is filtered by a low-pass filter (35) to remove a fluctuation component due to the pulsating load of the compressor (3).

Thereafter, the feedback signal from the low-pass filter (35) and the set value of the speed setter (32a) are transmitted to the comparator (
32b), and the torque component calculation circuit (32f) generates pulsations based on the torque command value (T') of the PI regulator (32c) and the secondary magnetic flux set value (ψ2') of the secondary magnetic flux setter (32d). Torque component current (i +
γ) is calculated. In addition, the secondary magnetic flux setting value (ψ2′)
Therefore, the excitation component calculation circuit (32e) calculates the excitation component current (11
δ) is calculated, and the adder (32h) calculates the primary current (
11), and the current control circuit (32i) controls the current of the power converter (33).

On the other hand, the torque command value (T') and the secondary magnetic flux setting value (ψ
2') and the slip calculation circuit (32g) calculate the slip angular velocity (ω
S), and add the driving angular velocity (ωS) to this slip angular velocity (ωS).
ωff1), the frequency control circuit (32Q) outputs a control signal to the power converter (33), and the induction motor (
31) is controlled.

Therefore, as mentioned above, the torque component current (1+γ) does not fluctuate following the pulsating load, so the instantaneous loss (PNoss) shown in equation (23)-1 is reduced, motor efficiency is improved, and the power converter The element capacitance of (33) is reduced.

FIG. 13 shows another embodiment of vector control, and instead of the previous embodiment where the excitation component current (i + 6) is constant, this embodiment is where it varies. In other words, when the excitation component current (1+δ) changes, the instantaneous loss (P9 ass) in equation (23)-1 above also changes.

At that time, the following equation holds true during the predetermined period (τ) corresponding to equation (6) in the first embodiment, and (1#) fo i + δ・i+ γ・dt−constant・
...(25) Also, from equation (23)-1, the instantaneous loss (pHoss) is
P 9 oss = (1/r) J'or[IR+
”Rz (M/L2) 211 Hγ+R+ ・I
1 δ]di...(2B). Therefore, the torque component current (11γ) and the excitation component current (1+6) are controlled so that the instantaneous loss (P9oss) shown in equation (26) is minimized.

That is, the torque component calculation circuit (32
When the torque component current (11γ) is calculated from f), the average value of this torque component current (1+γ) is calculated by the average value calculation circuit (37), and from this average value, the storage circuit (38) stores the average value. Excitation component current (11δ) corresponding to
is configured to extract and output to an adder (32h). This memory circuit (38), for example, as shown in FIG.
Torque component current (i + γ) so that s) is minimized
and the excitation component current (11δ) are stored. As a result, the induction motor (31) is controlled so that the instantaneous loss (Ploss) is minimized.

In addition, in place of the memory circuit (38), the excitation component current (11δ) that minimizes the instantaneous loss (IJloss) in equation (26) from the detected torque component current (i + γ) and excitation component current (IIδ) is used. ) may be used as an arithmetic circuit for calculating.

(Fourth embodiment) In this embodiment, as shown in Fig. 15, an induction motor (31
), the controller (41) performs instantaneous torque control. The induction motor (31) is connected to the rectifier circuit (42) of the power converter (42) from the AC power source (4) as in the previous embodiment.
a), smoothing capacitor (42b) and inverter (42
AC power is supplied via c).

Therefore, the principle of the instantaneous torque control mentioned above will be explained (
(Refer to the January 1986 issue of the Journal of the Institute of Electrical Engineers of Japan).

This instantaneous torque control simultaneously controls the instantaneous magnetic flux and instantaneous torque of the induction motor (31). First, the switching function (S) of the inverter (42c) is
a, Sb, Sc) is 1 when the positive side switch is on (S
a, Sb, Sc -1) and 0 (Sa, Sb, Sc -0) when the negative side switch is on, there are 23 switching modes of the inverter (42c) corresponding to the switching modes. Induction motor (42c
The primary voltage vector (V + ) of ) is as shown in the following equation.

(However, E + −explj (1/3) πIE z
−exp[j(2/3) πIE 3−explj
(4/3) πIE 4-explj (5/3)
π1■=DC section voltage) The primary flux linkage vector (ψ1) of the induction motor (31) is expressed as follows: l+ = V' + (S
a, Sb, Sc)t-fRl ・Complete+ ・dt+ f
+o ・= (28) t: Time R1: Primary winding resistance 11 Secondary current vector? +o: becomes the initial value of jl at t-0, and the primary flux linkage vector (?+) changes in the direction of the primary voltage vector (vl).

Therefore, by appropriately selecting and outputting the primary voltage vector (1), a nearly constant rotating magnetic field can be created. Furthermore, when considering the d-q plane, the primary voltage vector (vl) differs at each d-q plane position, so the d-q plane can be expressed as (2n-3)π/6≦α≦(2n -1 ) π/
6 (however, low 1...6), and the primary voltage is adjusted so that the primary flux linkage vector (ψ1) falls within a predetermined range (ψl l1ln < lψ <"flmax) in each region. By selecting the vector (vl), the primary flux linkage vector (ψ1) can be controlled.

On the other hand, the instantaneous torque (T) of the induction motor (31) is as shown below: * → T-1m (M ・12 ・it)...
(29) 1m: Imaginary part 11: Instantaneous value of primary current r 2 * Instantaneous value of 2nd-order current conjugate instantaneous vector M of 〒2: Mutual inductance between primary and secondary windings, and the (
The equation 29) is transformed into T-1m(f+zero'j'+)=430) using the primary flux linkage vector (f+) as shown in the following equation. Therefore, since the instantaneous torque (T) changes depending on the primary flux linkage vector (?+), it can be controlled within a predetermined range by appropriately selecting the primary voltage vector (■1).

Therefore, the deviation value between the absolute value of the primary flux linkage vector (?+) and the instantaneous torque (T) with respect to the target value is calculated, and the area of the primary flux linkage vector (?+) is determined. The induction motor (31
) can be rotated.

The configuration of the controller (41) etc. will be explained based on this principle.

First, the primary voltage and primary current of the induction motor (31) are detected by the voltage detector (43) from the output of the inverter (42c).
and a 3/2 phase converter (41a) included in the controller (41) detected by the current detector (44) and based on the primary voltage and primary current.

(41b) is the primary voltage pect/l/ (Vd+, Vq
+ ) and primary current vector (xd+ , iq +
) and calculate the primary voltage vector (V'd+, 'V'
Q + ) and primary current vector (ld+ , tq l
), the magnetic flux calculation circuit (41c) is configured to calculate the primary flux linkage vector (Fd + , fQ + ). Then, the above primary flux linkage vector (fd
1. ? q + ), the absolute value calculation circuit (41d) converts the absolute value 1ψ11 of the primary flux linkage vector (?1) into the primary flux linkage vector ('i'd + , 'jq 1
) and the primary current vector (Id+, iq 1), the torque calculation circuit (41e) calculates the instantaneous torque (T), while the primary flux linkage vector (ψd2.ψ
q+), the area determination circuit (41f) determines the direction of the primary flux linkage vector (ψ1), that is, the area on the dq plane, and outputs an area signal to the control circuit (41g), and Is the absolute value of the above primary flux linkage vector ('F+) 1? A comparator (41h) compares the absolute value l? with a predetermined range set in advance. It is configured to output a limit signal to the control circuit (41g) when +l reaches an upper limit value or a lower limit value.

On the other hand, the speed detection circuit (45), which is a variation detector, detects the rate of change of the rotating magnetic field from the primary current of the current detector (44). Although there is slippage between them, when the rotating magnetic field is at a constant speed, the rotor speed is also constant, and the speed detection circuit (45
) is input to a low-pass filter (46) which is a pulsation removing means. The low-pass filter (46) is a feature of the present invention, and the speed signal output from the speed detector (45) includes the compressor (3).
It includes a fluctuation component associated with the pulsating drive load, and is configured to remove this fluctuation component. Specifically, the cutoff frequency is set below the rotation frequency, and the speed ripple within the pulsation period is removed. It consists of

(Hereinafter, blank space) Furthermore, the speed value of the feedback signal outputted by the low-pass filter (46) is compared with the set value outputted by the speed setter (47) by a comparator (48),
), the torque command value (T') is output to the controller (41). The torque command value (T') is compared with the instantaneous torque (T) of the torque calculation circuit (41e) by a comparator (41i), and then determined by a comparator (41j) to an upper limit value of a preset range or It is configured such that it is determined whether the torque has reached the lower limit value and a limit signal is output to the control circuit (41g). The control circuit (41g) has a voltage of the primary voltage vector (■1) corresponding to the area of the primary flux linkage vector (T+) mentioned above, the magnitude of the absolute value 1ψ11, and the magnitude of the torque value (T). The pattern is stored in advance, and a predetermined primary voltage vector (¥1) is determined from the area signal of the primary flux linkage vector (?2), the limit signal, and the torque limit signal.
is configured to extract the primary voltage vector (71) and output a switching signal corresponding to the primary voltage vector (71) to the inverter (42C).

The basic principle for preventing the primary current (11) of the induction motor (31) from fluctuating due to pulsating loads was explained using formulas (22)-1 and (23)-1 in the third embodiment. This is because the principle is the same, that is, the torque is controlled linearly, so it can be applied as is.

Next, the instantaneous torque controller for this induction motor (31) will be explained.

First, the induction motor (31) is supplied with power from the AC power supply (4) via the power converter (42), while the primary voltage and primary current of the induction motor are detected by the voltage detector (43) and the current. Detected by the detector (44), the primary voltage and primary current are detected by the 3/2 phase converter (41a), (41b
), the magnetic flux calculation circuit (41c) calculates the primary flux linkage vector (ψd1, ψq1). Then, the area determination circuit (41f) sends the area signal of d+, FQ 1) to the primary flux linkage vector, and the limit signal is sent to the control circuit by the comparator (41h) via the absolute value calculation circuit (41d). (41g), and furthermore, the torque calculation circuit (41e) outputs the primary flux linkage vector (ψd1.ψq
+) and the primary current vector (Id+, iQ +) to calculate the instantaneous torque (T).

On the other hand, the rotational speed of the rotor in the induction motor (31) is detected by a speed detection circuit (45), and a feedback signal of the rotational speed is output to a low-pass filter (46). Then, the low-pass filter (46) removes a fluctuation component due to the pulsating load of the compressor (3), and the speed value from which this fluctuation component has been removed and the speed setting value are output to the comparator (4).
8), and a torque command value (T') is outputted via the Pla moderator (49). Next, this torque command value (T') and the instantaneous torque (T
) are compared by the comparator (41i), and then the comparator (41j) outputs a torque limit signal to the control circuit (41g). Thereafter, the control circuit (41g) sends a switching signal corresponding to a predetermined primary voltage vector (■1) to an inverter (42c) using the area signal and limit signal of the primary flux linkage vector (ψ1) and the torque limit signal. ) to control the induction motor (31).

At this time, since the primary current is controlled so as not to fluctuate due to the pulsating load of the compressor (3), it is possible to improve motor efficiency and reduce element capacitance in the power converter (42).

(Fifth Embodiment) In this embodiment, as shown in Fig. 16, an induction motor (31
) is applied with the so-called f'/v control method in which a controller (51) controls the primary frequency and voltage.

The induction motor (31) is connected to the rectifier circuit (52a) of the power converter (52) from the AC power source (4) as in the fourth embodiment.
, smoothing capacitor (52b) and inverter (52c)
A predetermined AC power is supplied through the inverter (5
2c) is configured to be controlled by inputting a switching signal from a controller (51).

The controller (51) includes a control circuit (51a) and a speed setter (5lb), and the control circuit (51a) includes:
Although the internal configuration is not shown, it is configured as a primary frequency control circuit. Then, the speed setting value such as voltage or frequency outputted by the speed setter (5l b) is sent to the comparator (53).
The control circuit (51a) is configured to control the inverter (52c) based on a speed command value output from the comparator (53), which is compared with a speed value of a feedback signal to be described later.

On the other hand, the power converter (52) is an inverter (52c)
A DC current on the input side of the filter is detected by a current detector (54) which is a fluctuation detector, and the DC current is input to a bandpass filter (55). The band low pass filter (55) is a feature of the present invention, and the band low pass filter (55)
is configured to detect a DC section current that includes a fluctuating component due to the pulsating load of the compressor (3), and specifically, is lower than the switching frequency of the inverter (52c),
In addition, it is configured to extract only the DC portion current having a frequency higher than the frequency of the basic fluctuation component of the load, and to output only the DC portion current having the fluctuation component associated with the pulsating load. Furthermore, the output signal of the bandpass filter (55) is PI
It is proportionally integrated by the adjuster (56), outputted as a feedback signal to the comparator (53), and transmitted to the band pass filter (55), the comparator (53), and the PI adjuster (
56) constitutes a fluctuation removing means (57), in which a feedback signal containing only the fluctuation component caused by the pulsating load is subtracted from the speed setting signal, and when the DC part current increases due to the pulsating load, the DC part It is configured to output to the controller (51) a command signal that causes the current to drop, and conversely, a command signal that causes the DC section current to rise when the DC section current falls due to a pulsating load.

Here, the basic principle for preventing the DC current from fluctuating due to the pulsating load of the compressor (3) will be explained.

First, the instantaneous loss of the induction motor (31) is as shown in equation (23) in the third embodiment, and in the I'/v control method that does not linearly control the torque, the primary current (
It is extremely difficult to determine which of the secondary currents (I2γ, 12δ) should be controlled to control the torque.

However, as shown in FIGS. 17(a) and 17(b), the pulsating load in the induction motor, that is, the torque fluctuation waveform, and the DC current fluctuation waveform in the power exchanger (52) are almost the same. It was experimentally confirmed that this is the case. The induction motor (31) used in the experiment is a squirrel cage type Sanwa induction motor with a pole count of 2P and a rated output of 2. OKW,
The rated power is 194v1 and the rated frequency is 75112.

As is clear from the above experimental results, the DC section current also fluctuates with the pulsating load, and by keeping the DC section current constant, the instantaneous loss is reduced, so the DC section current follows the pulsating load. I try to keep it from changing.

Next, the control operation of this induction motor (31) will be explained.

First, the induction motor (31) is supplied with power from the AC power source (4) via the power converter (52) as in the fourth embodiment, and the inverter (52) of the power converter (52)
c) is controlled by a switching signal from a controller (51).

On the other hand, the inverter (5) in the electric converter (52)
The DC part current on the input side of 2c) is derived by a current detector (54) and input to a bandpass filter (55). Then, the bandpass filter (55) outputs a DC current signal which removes high frequencies such as the switching frequency and low frequencies of basic fluctuation components that do not include fluctuation components associated with pulsating loads from the DC current signal, and The DC part current signal with only the fluctuation component associated with the change is detected, and the PI controller (5
After being proportionally integrated in step 6), it is compared with the speed set value of the speed setter (5lb) in a comparator (53). Then, the variation due to the pulsating load is subtracted from the speed setting value and inputted as a command value to the control circuit (51a), and when the DC current increases due to the pulsating load, the control circuit (51a) The inverter (52c) is controlled so that it descends, and vice versa, so that it rises when it descends, that is,
The rotation speed of the induction motor (31) is controlled by varying the input command value of the control circuit (51a).

As a result, the DC current does not follow the pulsating load, so
Motor efficiency is improved and element capacitance of the power converter (52) can be reduced.

In each of the above embodiments, the compressor (3) is used as the driven machine, but it may also be a pump or the like that causes load fluctuations during one revolution of the electric motor.

Further, the electric motor may be any type of electric motor such as a synchronous motor, and the control method is not limited to the embodiment. Further, the variation detector is not limited to one that detects the rotational speed of the electric motor, but may be any one that changes in response to load variations.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the present invention. 2 to 17 show embodiments of the present invention, FIGS. 2 to 7 show the first embodiment, and FIG. 2(a) is a block circuit diagram of the drive control device, and FIG. Figure (b) is a circuit diagram of a power converter, Figure 3 is an equivalent circuit diagram of a DC motor for explaining the first embodiment, and Figures 4, 5, and 6 are for explaining the first embodiment. FIG. 7 is a block diagram of a modified example. 8 to 10 show the second embodiment, FIG. 8 is a block circuit diagram of the drive control device, FIG. 9 is a block circuit diagram of the arithmetic circuit, and FIG. 10 is a block circuit diagram of the current control circuit. be. 11 to 14 show the third embodiment, FIG. 11 is a block circuit diagram of the drive control device, FIG. 12 is a current vector diagram on the γ-9 plane, and FIG. 13 is the main part of a modified example. FIG. 14 is a characteristic diagram of the excitation component current versus the torque component current. FIG. 15 is a block circuit diagram of a drive control device showing a fourth embodiment. 16 and 17 show the fifth embodiment, FIG. 16 is a block circuit diagram of the drive control device, FIG. 17(a) is a torque waveform diagram of the induction motor, and FIG. 17(b) is a power conversion diagram. FIG. 3 is a DC part current waveform diagram of the device. FIG. 18 is a block circuit diagram showing a conventional drive control device. (1)... Drive control device, (2)... DC motor,
(3)...Compressor, (4)...Power supply, (5),
(22) (33), (42), (52)...
Power converter, (5a)...Switching transistor, (6). (23), (32), (41), (51)...
・Controller, (11) (34), (45)... Speed detector, (12)... Pulsation removal circuit, (21)...
Brushless DC motor, (22c), (33c),
(42c) (52c)...Inverter, (26)
... Angle detection circuit, (25d), (35),
(46)...Low pass filter, (31)...Induction motor, (54)...Current detector, (59)...Fluctuation removal means. Other 2 people Figure 4 Figure 6 Figure Figure 6: Circle p fake 16 Figure interval (ms) Mark PT interval (ms) Figure 17

Claims (15)

[Claims] (1) A driven machine that generates a load that includes a basic fluctuation component and a pulsating component that fluctuates at a higher frequency than the basic fluctuation component, an electric motor that drives the driven machine, a power source that supplies power to the electric motor, and the power source. a power converter that converts the electric power from the electric motor into predetermined electric power according to the electric motor and supplies the electric power to the electric motor; and a controller that outputs a control signal to the electric power converter based on a command value to control the electric power converter. and a fluctuation detector that detects the amount of fluctuation that changes in response to the load fluctuation in the driven machine, and removes a fluctuation component accompanying a pulsation component of the load in the driven machine based on the amount of fluctuation detected by the fluctuation detector. a fluctuation removing means for outputting a feedback signal such that the command value of the controller is controlled so that the motor does not fluctuate in response to the pulsating component of the load; Device. (2) A compressor (3) that generates a load including a basic fluctuation component and a pulsation component that fluctuates at a higher frequency than the basic fluctuation component, a DC motor (2) that drives the compressor (3), and a DC motor (2) that drives the compressor (3); a power source (4) that supplies power to the motor (2); a power converter (5) that converts the power from the power source (4) into DC power and supplies the DC power to the DC motor (2); and the power converter. a controller (6) that outputs a control signal to the power converter (5) based on a command value to control the power converter (5); and a DC motor that changes in response to load fluctuations in the compressor (3). (2) a fluctuation detector (11) for detecting the amount of fluctuation regarding the rotational speed; and a fluctuation component associated with the pulsation component of the load in the compressor (3) based on the amount of fluctuation detected by the fluctuation detector (11). The removed feedback signal is output to the above DC motor (
2) fluctuation removing means (12) for controlling the command value of the controller (6) so that the armature current does not fluctuate in response to the pulsating component of the load; Drive control device. (3) The electric motor drive control device according to claim (2), wherein the fluctuation detector (11) detects an armature voltage that changes with the rotational speed of the DC motor (2). (4) The electric motor drive control device according to claim (2), wherein the fluctuation detector (11) detects the rotational speed of the DC motor (2). (5) The fluctuation removing means (12) outputs a voltage feedback signal obtained by removing a fluctuation component associated with a pulsating component of the load from the detected voltage value of the fluctuation detector (11). ) The pulsation control device for the electric motor described in ). (6) The fluctuation removing means (12) outputs a speed feedback signal obtained by removing a fluctuation component accompanying a load pulsation component from the speed value detected by the fluctuation detector (11). ) The drive control device for the electric motor described in ). (7) The controller (6) controls the output voltage of the power converter (5) so that it does not fluctuate due to the pulsating component of the load using the voltage feedback signal of the fluctuation removing means (12). The drive control device for an electric motor according to claim (2) or (5). (8) The controller (6) is characterized in that the command value is a current value that does not vary with the pulsating component of the load based on the speed feedback signal of the fluctuation removing means (12). ) The drive control device for the electric motor described in ). (9) a compressor that generates a load that includes a basic fluctuation component and a pulsation component that fluctuates at a higher frequency than the basic fluctuation component; an AC motor that drives the compressor; a power source that supplies power to the AC motor; a power converter that converts power from the power source into AC power and supplies the AC power to the AC motor; a controller that outputs a control signal to the power converter based on a command value to control the power converter; A fluctuation detector detects the fluctuation amount of the AC motor that fluctuates in response to the load fluctuation in the compressor, and removes a fluctuation component accompanying the load pulsation component in the compressor based on the fluctuation amount detected by the fluctuation detector. a fluctuation removing means for outputting a feedback signal and controlling a command value of the controller so that the AC motor does not fluctuate in response to a pulsating component of the load; Device. (10) A compressor (3) that generates a load including a basic fluctuation component and a pulsation component that fluctuates at a higher frequency than the basic fluctuation component, and a brushless DC motor (21) that drives the compressor (3).
), a power source (4) that supplies power to the brushless DC motor (21), and a power converter ( 22
), and a brushless DC motor (21) to the power converter (22).
a controller (23) that outputs a control signal to control the power converter (22) so that the armature current of the compressor (3) becomes a command value; A fluctuation detector (26) that detects the rotational speed of the DC motor (21); and a fluctuation component associated with the pulsation component of the load in the compressor (3) is removed based on the rotational speed detected by the fluctuation detector (26). fluctuation removing means (25d) for controlling the command value of the controller (23) so that the armature current of the brushless DC motor (21) does not fluctuate in response to the pulsating component of the load by outputting a speed feedback signal; A drive control device for an electric motor, comprising: (11) A compressor (3) that generates a load including a basic fluctuation component and a pulsation component that fluctuates at a higher frequency than the basic fluctuation component; an AC motor (31) that drives the compressor (3); and the AC motor (31) that drives the compressor (3). a power supply (4) that supplies power to the motor (31); a power converter (52) that converts the power from the power supply (4) into AC power and supplies it to the AC motor (31); and the AC motor A controller (5) that controls the power converter (52) by outputting a control signal to the power converter (52) so that the voltage and frequency applied to the power converter (31) become the command values.
1), a fluctuation detector (54) that detects the DC section current of the power converter (52) that fluctuates in response to load fluctuations in the compressor (3), and a fluctuation detector (54) that detects Based on the detected current value, a feedback signal is outputted to remove a fluctuation component accompanying the load pulsation component in the compressor (3), so that the supply current of the AC motor (31) fluctuates in response to the load pulsation component. A drive control device for an electric motor, comprising: a fluctuation removing means (57) for controlling the command value of the controller (51) so that the command value does not change. (12) The electric motor drive control device according to claim (11), wherein the AC motor (31) is a synchronous motor. (13) The electric motor drive control device according to claim (11), wherein the AC motor (31) is an induction motor. (14) The controller (32) controls the torque current and excitation current of the AC motor (31) to perform vector control of the AC motor (31), while the fluctuation detector (34) controls the rotation of the AC motor (31). The present invention is characterized in that the speed is detected, and the fluctuation removing means (35) outputs a speed feedback signal from which fluctuation components associated with load pulsation components are removed, thereby controlling the torque command value of the controller (32). A drive control device for an electric motor according to claim (9). (15) The controller (41) controls the primary chain AC magnetic flux vector and instantaneous torque of the AC motor (31) to control the instantaneous torque of the AC motor (31), while the fluctuation detector (45) The rotational speed of the motor (31) is detected, and the fluctuation removing means (46) outputs a speed feedback signal from which fluctuation components associated with load pulsation components are removed to control the torque command value of the controller (41). The drive control device for an electric motor according to claim 9, characterized in that: