JP2006078095A - Refrigerator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refrigerator capable of suppressing vibration and noise by a reciprocating compressor while saving energy. <P>SOLUTION: This refrigerator comprises a limiter limiting, in a torque control for extracting a torque pulsating component from an axial error in a vector control method and carrying a torque current component canceling the extracted torque pulsating component, the torque current component canceling the pulsating component. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a refrigerator provided with a motor control device for a compressor.

  FIG. 9 is a longitudinal sectional view showing a general configuration of a reciprocating compressor. An electric motor 27 comprising a stator 27a and a rotor 27b is provided in the hermetic container 26, and a rotary shaft 28 that engages with the rotor 27b and performs a rotary motion, and the rotary motion of the rotary shaft 28 is converted into a reciprocating motion. And an eccentric portion 28b for conversion, and has a compression mechanism portion that compresses the refrigerant supplied into the cylinder 30 disposed on the bearing body 29 by the reciprocating motion of the piston 31.

  In such a reciprocating compressor, an internal vibration isolation structure is generally used. That is, with the support spring 32 that supports the structure composed of the electric motor 27 and the compression mechanism section, the loop pipe 33 that guides the gas discharged from the compression mechanism section, etc., due to torque fluctuations that occur according to the load A method of damping the vibration of the structure and controlling the vibration or noise is used.

  As a method of suppressing such vibration of the compressor, there is one described in Patent Document 1. In this example, torque control is used in a reciprocating compressor to give the motor a torque that approximately matches the load torque generated according to the load of the refrigerator and the rotational speed of the compressor. Patent Document 2 discloses a torque control device that detects torque flowing in an electric motor and obtains an excitation current component (d-axis current) and a torque current component (q-axis current) to perform torque control.

JP2003-4352

JP2003-339197

  As described above, the vibration of the internal structure of the compressor is damped by the support spring 32 or the loop pipe 33, etc., but these have only a certain damping characteristic regardless of load fluctuations and rotation speed changes. Therefore, if the load fluctuation increases to some extent, the vibration damping characteristics are insufficient, and the possibility of occurrence of abnormal vibration or noise increases. As a result, diversification of additional functions of the product or a wide range of rotation speed variable control that can sufficiently follow the load that fluctuates according to changes in the use environment can be hindered.

  For example, when the load temperature in the cabinet changes due to the ambient temperature around the refrigerator, the amount of food stored, and other additional functions, the rotation speed of the compressor is changed by inverter control, as shown in FIG. Furthermore, normally, high speed operation is performed in a high load region, and low speed operation is performed in a low load region. At this time, as shown in FIG. 11, the pressure applied to the compressor changes according to the load, so that the compression load resulting from the gas compression load is often increased under the condition of operating at high speed. In FIG. 11, the rotation angle of 0 ° indicates the top dead center where the piston reaches the innermost part of the cylinder, and 180 ° indicates the bottom dead center. The same applies hereinafter.

  Further, in the case of the reciprocating compressor, since the piston 31 is installed in the eccentric portion 28b of the rotating shaft 28, these generate an inertial force around the rotation center 28a. This inertial force changes according to the number of revolutions as shown in FIG. As shown in FIG. 13, the sum of the torque caused by the gas compression load and the inertial force becomes the load torque of the compressor, and the difference between this load torque and the motor output torque is expressed as the torque fluctuation per rotation of the rotary shaft 28. Then, this torque fluctuation becomes a vibration source or noise source of the compressor. Of these, the inertia torque acts in the reverse direction near the peak of the gas compression torque, and plays a role of reducing the peak load. For this reason, since the magnitude of the inertia torque becomes small at low speed, when the pressure load is constant, the difference between the load torque and the motor output torque is widened more than at high speed, and it is predicted that the vibration will also increase.

  On the other hand, in recent years, the refrigerant sealed in the refrigeration cycle of a refrigerator has been switched from a fluorocarbon refrigerant to a hydrocarbon refrigerant. When a flammable refrigerant such as isobutane is used as the refrigerant, it is necessary to increase the pushing amount of the reciprocating compressor in order to obtain a cooling capacity equivalent to that of the chlorofluorocarbon refrigerant. Therefore, the piston diameter itself is also increased. If this amount of pushing is increased by about 70% and a cooling capacity equivalent to that of conventional chlorofluorocarbon refrigerant is ensured, the piston diameter will increase by about 30%, and the piston weight will increase accordingly. For this reason, the gas compression torque increases, and the vibration of the compressor itself increases. This vibration is particularly great during low-speed operation, which not only becomes an obstacle to the stable operation of the compressor, but also causes noise.

  Under such circumstances, as a vibration suppression means of the compressor, torque control has been proposed in which the motor torque is made to follow the load torque to prevent speed fluctuation. As shown in Patent Document 1, by giving the motor a torque that substantially matches the load torque generated according to the load of the refrigerator and the rotation speed of the compressor, the torque fluctuation can be greatly reduced as shown in FIG. However, in the conventional reciprocating compressor built in the refrigerator, the current flowing in the motor is adjusted in the conventional torque pulsation suppression control, and the motor torque is adjusted. Although it can be suppressed, vibrations other than the direction of piston movement were not considered. Therefore, vibrations other than in the direction of piston movement cannot be suppressed. In addition, vibrations other than in the direction of piston movement increase due to the motor current increased to reduce the vibration in the direction of the piston. The vibration reduction effect in the entire area cannot be obtained.

  In addition, since the motor torque is made to follow the load torque, the effective value of the motor current increases, and the compressor single input power increases in the entire area. This increase in input power becomes more noticeable as the rotational speed is lower, which hinders power saving by lowering the rotational speed. Furthermore, lowering the minimum rotation speed of the compressor operation is very effective for power saving, but in the situation where the vibration becomes large during low speed operation as described above, In some cases, the loss of power also increases, and on the contrary, it may be a cause of hindering power saving.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a refrigerator including a compressor motor control device that reduces vibration noise and achieves power saving.

  In order to achieve the above object, the refrigerator of the present invention has an electric motor that drives a compressor having a fluctuating load during one rotation, an inverter that outputs a pulse train for driving the electric motor, and an input to the inverter. A torque generator that controls the output of the inverter based on a DC generation circuit that generates a DC voltage, a torque fluctuation component during one rotation of the rotor of the electric motor, and a rotation speed command of the electric motor. And a limiter function for limiting the fluctuation torque suppression command value calculated based on the limiter function. By having the limiter function in this way, there is an effect of suppressing the vibration of the compressor, and noise and power saving can be achieved as the whole refrigerator.

  In addition, a torque fluctuation output unit that calculates and outputs the torque fluctuation of the electric motor from the shaft error during one rotation of the rotor of the electric motor is output, and the torque fluctuation component is output.

  The limiter value limited by the limiter unit is 100% when the variable torque suppression command value corresponding to the torque fluctuation component value is set to 100%, and 0% when the variable torque suppression command value is zero. It differs depending on the rotational speed command of the electric motor.

  The torque fluctuation output unit may calculate and output a torque fluctuation component from a difference between an actual position of the compressor rotor and a driving position estimated by a microcomputer.

  The control unit calculates a torque current component that cancels the torque variation component to obtain a current command value, and the current command value is limited by the limiter unit to obtain a variation torque suppression current command value. To do.

  Further, the limiter value is set to a smaller value when the rotational speed of the rotational speed command of the motor is high than when the rotational speed is low.

  The limiter value is set so as to minimize the peak value of the motor current or the inverter current.

  The compressor is a reciprocating compressor, and the limiter value is set to 20 to 30% when the rotation speed of the compressor is 1000 to 1500 rpm, and the compressor is a reciprocating compressor. This is a compressor of the type, and is characterized in that the limiter value is set to zero at a predetermined rotational speed or more of the compressor. With this configuration, it is possible to suppress vibration noise and reduce power consumption in the compressor and the refrigerator even in a wide rotation range from low speed to high speed.

  Further, in a refrigerator provided with an electric motor for driving a compressor, an inverter for controlling the rotation speed of the electric motor, and a converter for inputting a current and supplying a DC voltage to the inverter, the present invention provides an internal temperature and a set temperature. The rotation speed of the electric motor is detected by a first control mode in which control is performed by the pulse width modulation function of the inverter and the torque pulsation detection means of the compressor motor so as to approach the speed command generated based on It is controlled by the second control mode for performing control to suppress the pulsating component.

  Further, the compressor constitutes a refrigeration cycle using a non-fluorocarbon refrigerant.

  In this way, when performing torque control that provides a suppression command value that cancels the torque fluctuation component, by providing a limiter that limits the value that cancels this fluctuation component, vibration can be reduced and power saving can be achieved. It contributes and achieves the above object of the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, the refrigerator provided with the motor control apparatus of the compressor which reduces vibration noise and implement | achieves power saving can be provided.

  FIG. 1 is a diagram illustrating a control mode of the refrigerator of the present embodiment. The refrigerator 100 according to the present embodiment includes a refrigeration room 110 that is a storage room in a refrigeration temperature zone and a freezing room that is a storage room in a refrigeration temperature zone. In addition, a refrigeration cycle is provided to bring each of these chambers to a desired temperature, and the operation of the compressor 6 constituting the refrigeration cycle is controlled by the control device 200. The control device 200 mainly receives two types of input signals and controls the operation of the compressor 6. As the types of input signals, there are firstly those for keeping the temperature in each room at a predetermined temperature, and secondly, they are inputted by an external input device in order to realize the temperature required by the user. There is something.

  An example of the first input signal is an input signal from the temperature sensor 210. For example, in a situation where the compressor 6 is not operating or operating at a low speed, when the temperature in the refrigerator compartment 110 rises to a predetermined high temperature, the control device 200 detects the temperature sensor 210. Based on the signal from, the compressor 6 is operated or controlled to operate at a higher rotational speed. Further, when the compressor 6 is in operation and the temperature in the refrigerator compartment 110 decreases and reaches a predetermined low temperature, the operation of the compressor 6 is stopped based on a signal from the temperature sensor 210, or at a low rotational speed. Control to drive.

  In the present embodiment, the temperature of the refrigerator compartment 110 has been described, but the same control can be performed even when the freezer compartment is maintained at a predetermined temperature. As an example of the second input signal, there is an input signal when the user turns on the quick freezing switch 120. When the quick freezing switch 120 is turned on, the control device 200 receives the quick freezing command signal and controls the operation of the compressor 6 based on the signal.

  Regardless of the input signal, the control device 200 receives the signal and controls the rotational speed of the compressor 6 and ON / OFF of the operation.

  The control device 200 is roughly divided into a main control device that controls the overall operation of the refrigerator 100 and a compressor control device that controls the operation of the compressor 6, as shown in the figure. Thus, by using two microcomputers of the main control microcomputer and the compressor control microcomputer that performs inverter control of the compressor as the sub-control, each microcomputer ROM capacity is reduced, and the refrigerator control program and efficiency are reduced. In parallel, development of inverter control programs for compressors that are required to be improved is carried out to increase development efficiency, thereby shortening the development period and reducing costs.

  Further, since the compressor control microcomputer can be shifted to a standby mode with low power consumption while the compressor is stopped, the power consumption of the entire control device can be reduced. These may be arranged on the same substrate. The main control device includes a main control microcomputer, receives the above-described input signal, and transmits an operation command to the compressor control device. The compressor control device includes a compressor control microcomputer, and controls the operation of the compressor 6 by transmitting a drive signal to an inverter circuit driver based on an operation command from the main control device.

  Further, the compressor control device transmits the operation status such as ON / OFF of the compressor and the rotation speed to the main control device. Thus, the main control circuit transmits the operation command based on the current operation state of the compressor and the above-described input signal.

Hereinafter, details of the control device 200 will be described with reference to the drawings.
FIG. 2 is a diagram showing a system configuration of an embodiment of the AC motor control device according to the present invention. The motor operation control is a motor current sensorless / position sensorless 180-degree energization vector control method, and the torque control unit 11 is provided in the vector control method control unit.

  The control device of the present embodiment includes a control unit 2 that gives a rotational speed command to the electric motor. The controller 2 is configured by a controller that calculates an AC applied voltage of the electric motor, converts it into a pulse width modulated wave signal (PWM signal), and outputs the pulse width modulated wave signal (PWM signal). An inverter 3 that receives a PWM signal output from the control unit 2 and outputs a pulse train for driving the PM motor 5, a DC power supply 4 that supplies power to the inverter 3, a PM motor 5 to be controlled, The compressor 6 serving as a load for the PM motor 5 and the current detector 7 for detecting the current I0 supplied from the DC power source to the inverter are provided, and the rotational speed of the compressor 6 is controlled with these configurations. Yes.

  The control unit 2 includes a current reproducer 8 that detects the current I0 and reproduces the three-phase AC currents Iu, Iv, and Iw flowing through the PM motor 5 by calculation inside the controller. It is also possible to directly detect the three-phase alternating current flowing through the PM motor 5. That is, it is only necessary to provide a configuration for outputting a current flowing through the PM motor to the dq coordinate converter 9 described later. For example, when a three-phase alternating current flowing through the PM motor 5 is directly detected, A detector may be arranged to detect them. However, if the current detector 7 is configured to detect the current supplied to the inverter 3 as in this embodiment, the protection resistor of the circuit can be used as the current reproducer 8, and all the phases are used. The circuit configuration can be simplified as compared with the case where the detector is separately provided.

  The current reproduced by the current reproducer 8 is sent to the dq coordinate converter 9. This coordinate converter 9 converts the reproduced three-phase alternating current into components Idc and Iqc on the d-axis and q-axis by the phase angle θdc (position of the magnetic flux of the PM motor assumed inside the controller). And coordinate transformation. The d-axis and the q-axis indicate a rotating coordinate system in which the direction in which the magnetic flux easily passes is the d-axis and the q-axis whose phase is 90 ° [electrical angle] advanced with respect to the d-axis.

  Further, a filter 10 is provided, and commands Iq * and Id * are given to the current component on the q-axis and the current component on the d-axis, and the voltage command calculator 12 has these Id *, Iq *, and electrical Based on the angular frequency command ω1 *, the voltage commands Vdc * and Vqc * are calculated. The dq inverse converter 13 converts the voltage commands Vdc *, Vqc * into three-phase AC voltage commands vu *, vv *, vw *, and the PWM pulse generator 14 is based on the three-phase AC voltage command, A pulse width modulation signal (PWM signal) for switching the inverter 3 is generated.

  In addition, an axis error estimator 15 for estimating and calculating an angle (axis error) Δθdc corresponding to an error between the magnet magnetic flux position θd of the PM motor 5 and the position θdc assumed in the controller 2 is provided. The shaft error Δθdc is output to the torque control unit 11 described later. Furthermore, an adder / subtractor 16 that performs addition and subtraction, a zero generator 17, a proportional compensator 18 that compensates the electrical angular frequency command ω1 * to control Δθdc to zero, and the number P of PM motor poles Based on the conversion gain 19 for converting the rotational speed command ωr * to the electrical angular frequency command ω1 * of the motor, the integrator 20 for integrating the electrical angular frequency and calculating the magnet magnetic flux position θdc, and the estimated axis error Δθdc. A ΔTm estimator 21 for estimating and calculating ΔTm, which is a periodic disturbance torque component, and a periodic torque disturbance compensator ATR22 for correcting the q-axis current command Iq * based on the estimated value of ΔTm. Become.

  The DC power supply 4 includes a converter circuit that converts AC to DC, and includes an AC power supply 23, a diode bridge 24, and a smoothing capacitor 25.

  The torque control unit 11 includes a torque fluctuation output unit. That is, a ΔTm estimator 21 that estimates the torque fluctuation component ΔTm from the axis error Δθdc output from the axis error calculator 15 is provided. As will be described later, the torque fluctuation component is calculated from the axis error Δθdc and is estimated. Torque fluctuation component ΔTm is output. The pulsating torque suppression current command IqSIN for making the output torque fluctuation component ΔTm zero is output from the periodic torque disturbance compensator ATR22. That is, the torque control unit 11 according to the present embodiment includes a ΔTm estimator 21 and a periodic torque disturbance compensator ATR22.

  The ΔTm estimator 21 estimates the torque fluctuation component ΔTm from the axis error Δθdc. In vector control, the rotor position of the electric motor is continuously estimated by a microcomputer. The axis error Δθdc is the difference between the “position where the rotor actually passes through the stator (actual position)” and the “position estimated by the microcomputer”. In vector control, operation control is performed so that this axis error becomes zero. During constant speed rotation, the load on the rotor is stable and the actual position matches the estimated position. At this time, the value of the axis error is zero.

  Since the rotation of the rotor is delayed due to inertial force during acceleration, the estimated position is advanced. At this time, the axis error takes a positive value. On the other hand, at the time of deceleration, the rotor advances on the contrary, so the estimated position is delayed and the axis error takes a negative value.

  In torque control, the torque fluctuation component ΔTm is estimated using this shaft error Δθdc. When the shaft error Δθdc during one rotation of the rotor is zero, the torque fluctuation component ΔTm is zero. This is because the vector control performs operation control so that the shaft error Δθdc becomes zero. When the load torque TL and the motor output torque Tm are equal, the shaft error Δθdc during one rotation of the rotor becomes zero.

  When the load is heavy (when the load torque TL exceeds the motor output torque Tm), the estimated position is advanced because the rotation of the rotor is delayed. At this time, the axis error Δθdc takes a positive value. On the other hand, when the load is light (when the load torque TL is less than the motor output torque Tm), the estimated position of the delay axis error Δθdc takes a negative value because the rotor advances.

  That is, the torque fluctuation component ΔTm can be estimated by observing the shaft error Δθdc during one rotation of the rotor. The torque fluctuation component ΔTm is calculated by adding the rotational speed and inertia (inertia) of the rotor to the change in the shaft error Δθdc during one rotation of the rotor.

  The periodic torque disturbance compensator ATR22 receives ΔTm output from the ΔTm estimator 21 which is a torque fluctuation output unit, and performs a Fourier expansion with a mechanical angle primary frequency, thereby extracting a pulsating torque synchronized with the rotor rotation, In this configuration, the torque current command value is calculated so that the pulsation torque is zero using integral control. The configuration of the periodic torque disturbance compensator ATR22 is shown in FIG.

  The Fourier transform unit 33 simulates the Fourier series expansion by performing a coordinate transformation operation in the α-dq coordinate converter 33a, and decomposes the torque pulsation component ΔTm into a mechanical angle primary frequency sin component and a cos component, and the basics. The magnitude of the wave component is obtained. Here, the α coordinate is a two-axis fixed coordinate system in which the α axis is defined on the basis of the three U phases, and the axis whose phase is electrically advanced by 90 ° [electrical angle] is defined as the β axis. The filter 33b removes a non-periodic torque fluctuation component.

  The integral control unit 34 performs integral control so that the magnitude of the fundamental wave component of ΔTm obtained by the Fourier transform unit 33 is zero, and calculates pulsation torque suppression current commands IqSINd * and IqSINq * that suppress the pulsation torque to zero. ing. The limiter unit 35 is provided with a limiter 35a that limits the pulsation torque suppression current commands IqSINd * and IqSINq * calculated by the integration control unit 34. The limiter value can be varied depending on the rotational speed, and thereby the amount of suppression of the torque fluctuation component ΔTm is adjusted.

  The limiter value is a value when the pulsation torque suppression current command IqSIN for setting the torque fluctuation component ΔTm to zero is 100%. The Fourier inverse transform unit 36 calculates the pulsation torque suppression current command IqSIN using the dq-α coordinate converter 36a. The pulsating torque current command IqSIN may be calculated and output each time by the torque control unit 11, but in the case where the pressure condition for gas compression is determined by linking to the ambient temperature to some extent like a refrigerator, An output pattern may be set in advance, and an optimum pattern may be selected according to changes in conditions. Further, when the fluctuation pattern of the load torque for each rotation does not change greatly, the pulsating torque suppression current command IqSIN may be output for each cycle.

  Next, the vibration of the compressor chamber by the limit value for torque control and the compressor single input power will be described. The limiter value is 100% when the pulsation torque suppression current command value corresponding to the value of the torque fluctuation component ΔTm is set as described above, and the limiter value 50% is ΔTm / 2 when the torque pulsation component is ΔTm. Is given as a current command value. As described above, when torque control is performed, the problem that the vibration suppression effect is reduced during low-speed rotation (especially 1500 rotations or less in this embodiment), and on the contrary, vibration is increased. In order to solve this problem, we propose a method for changing the limiter value according to the rotational speed.

  FIG. 4 shows the relationship between the limiter value and the reciprocating compressor vibration value, and FIG. 5 shows the relationship between the limiter value and the motor input power. The vibration value is a squared average of accelerations in the x-axis and z-axis directions when the piston moving direction is the x-axis, the rotor axis direction is the y-axis, and the vertical direction of the xy plane is the z-axis.

  As shown in FIG. 4, the vibration value varies depending on the limiter value. When the limiter value is 100%, that is, the vibration value of the normal torque control that does not limit the amount of suppression for the torque pulsation component ΔTm, the vibration value tends to be smaller when the limit is applied. . On the other hand, compared to the case where the torque control is not performed with the limiter value set to zero, the vibration value tends to be smaller when the torque control is suppressed, and in the case of 1500 revolutions or less, the limiter value is 20 to It was found that a minimum value was observed at about 30%.

  In addition, as shown in FIG. 5, the motor input power also varies depending on the limiter value, and the motor input power also has a minimum value when the limiter value is 20-30%. When the limiter value exceeds 40%, the motor input power is It turned out to be increasing.

  The figure also shows that the optimum limiter value that minimizes the vibration value and motor input power varies between 20 and 30% depending on the rotational speed. Therefore, the limiter value is more variable depending on the rotational speed. It is effective. Therefore, an optimum limiter value is set according to the number of rotations, and the limiter value is variably controlled. That is, the limiter unit 35 performs variable control of the limiter value based on the rotational speed of the compressor by outputting the pulsation torque suppression current command IqSIN using the optimum limiter value.

  FIG. 6 sets the optimum limiter value for the rotational speed in consideration of the above circumstances. The limit value at 1000 rpm is set to 30%, the limit value at 1500 rpm is set to 20%, the limit value at 1700 rpm is set to 0%, and the setting point is linearly varied. The limiter unit varies the limiter value based on the set value. With this setting, torque control is activated only in the low speed range of 1700 rpm or less.

  Normal torque control that does not limit the amount of suppression of the torque fluctuation component ΔTm, the vibration value of torque control that limits the pulsating torque suppression current command by varying the optimum limiter value according to the rotation speed according to the present invention, and the motor input A comparative diagram of power is shown in FIG. 7 and FIG. These are all compared in the example shown in FIG. As shown in these figures, the motor input power and the vibration value are reduced as compared with the case of the normal torque control, which is effective for both power saving and noise reduction. In particular, when the vibration value rotates but is small, its reduction effect increases, and can greatly contribute to the reduction in the speed of the compressor.

  By using the present invention, it becomes possible to provide a product such as an inverter-controlled reciprocating compressor and a refrigerator using the inverter that is low in vibration and noise even in a low speed region, and further, fatigue of piping due to vibration of a product using a flammable refrigerant. Deterioration can be reduced and high safety can be secured.

  In addition, even when the weight of the compression mechanism is increased by using a combustible refrigerant, the compressor can be rotated at a low speed, contributing to power saving in a wide rotation range from low speed to high speed. Can be.

  In the embodiments described above, various numerical values are shown and described. However, these numerical values are examples, and other numerical values may be used as long as they match the control concept.

The figure which shows the control form of a refrigerator. The figure which shows the system | strain structure of an AC motor control apparatus. The block diagram which shows the system | strain structure of the period torque disturbance compensator ATR. The figure which shows the relationship between a limiter value and the vibration value of a reciprocating compressor. The figure which shows the relationship between a limiter value and motor input electric power. The figure which shows an example of the relationship between a limiter value and compressor rotation speed. The figure which shows a motor input electric power characteristic. The figure which shows a compressor vibration value. The figure which shows an example of the longitudinal cross-sectional view of a reciprocating compressor. The figure which shows an example of the relationship between the chamber internal load temperature of an inverter control refrigerator, and compressor rotation speed. The figure which shows the relationship between the internal load and gas compression load. The figure which shows the relationship between compressor rotation speed and piston inertia force. The figure which shows an example of the relationship between the compressor load torque and motor torque in a prior art. The figure which shows an example of the relationship between compressor load torque and motor torque.

Explanation of symbols

2 ... Control unit, 3 ... Inverter, 4 ... DC power supply, 5 ... PM motor, 6 ... Compressor, 7 ... Current detector, 8 ... Current reproduction device, 9 ... dq coordinate converter, 10 ... Filter, 11 ... Torque Control unit, 12 ... Voltage command calculator, 13 ... dq inverse converter, 14 ... PWM pulse generator, 15 ... Axis error estimator, 16 ... Adder / Subtractor, 17 ... Zero generator, 18 ... Proportional compensator, 19 ... Conversion gain, 20 ... integrator, 21 ... ΔTm estimator, 22 ... periodic torque disturbance compensator ATR, 33 ... Fourier transform unit, 33a ... α-dq coordinate converter, 33b ... filter, 34 ... integration control unit, 34a ... I control, 35 ... limiter unit, 35a ... limiter, 36 ... Fourier inverse transform unit, 36a ... dq-α coordinate converter.

Claims (10)

  An electric motor that drives a compressor that fluctuates in a load during one rotation; an inverter that outputs a pulse train for driving the electric motor; a DC generation circuit that generates a DC voltage input to the inverter; Torque control is performed to control the output of the inverter based on the torque fluctuation component during one rotation of the rotor and the rotation speed command of the electric motor, and the fluctuation torque suppression command value calculated based on the torque fluctuation component is limited. A refrigerator having a limiter function.   The refrigerator according to claim 1, further comprising a torque fluctuation output unit that calculates and outputs torque fluctuation of the electric motor from an axis error during one rotation of the rotor of the electric motor, and outputs the torque fluctuation component.   The limiter value limited by the limiter unit is 100% when the variable torque suppression command value corresponding to the torque fluctuation component value is set, and 0% when the variable torque suppression command value is zero. The refrigerator according to claim 1, wherein the refrigerator is different depending on a rotational speed command.   The control unit calculates a torque current component that cancels the torque fluctuation component to obtain a current command value, and the current command value is limited by the limiter unit to obtain a fluctuation torque suppression current command value. Item 4. The refrigerator according to any one of Items 1 to 3.   5. The refrigerator according to claim 2, wherein the limiter value is set to a smaller value when the rotation speed of the rotation speed command of the electric motor is high than when the rotation speed is low.   The refrigerator according to any one of claims 2 to 5, wherein the limiter value is set so as to minimize a peak value of a motor current or an inverter current.   The refrigerator according to any one of claims 2 to 6, wherein the compressor is a reciprocating compressor, and the limiter value is set to 20 to 30% when the rotation speed of the compressor is 1000 to 1500 rotations.   The refrigerator according to any one of claims 2 to 7, wherein the compressor is a reciprocating compressor, and the limiter value is set to zero at a predetermined rotation speed or more of the compressor.   In a refrigerator provided with an electric motor for driving a compressor, an inverter for controlling the rotational speed of the electric motor, and a converter for inputting a current and supplying a DC voltage to the inverter, it is generated based on the internal temperature and the set temperature. The pulsation component detected by the torque pulsation detecting means of the compressor motor and the first control mode in which the rotational speed of the motor is controlled by the pulse width modulation function of the inverter so as to approach the speed command The refrigerator controlled by the second control mode for performing control. The refrigerator according to any one of claims 1 to 9, wherein the compressor constitutes a refrigeration cycle using a non-fluorocarbon refrigerant.

Images