JP2018109859A - Control device, power conversion equipment, motor driving device and refrigerator using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide control means which are able suppress not only periodic fluctuations and current distortions of controlled objects caused by periodic disturbances, but also interference phenomena when command signals are suddenly changed.SOLUTION: A control device comprises a controller to have command signals inputted from outside and to output controlling signals, objects to be controlled based on the controlling signals and detecting means to detect the output of the controlled objects and to output detection signals and the controller comprises a PI controller or a PID controller that is inputted the deviation between the detection signal and the controlling signal and outputs the control input for the controlled object based on the deviation, a lowpass filter that is inputted the controlling signal and buffers sudden changes of the controlling signal, S controller that is inputted the deviation between the detected signal and the output of the lowpass filter and outputs a signal contained in the deviation, having the prescribed frequency and inverse phase and an adder that adds the output of the PI controller or PID controller to the output of the S controller and outputs the result of the addition as the controlling signal finally.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a control device, a power conversion device, a motor drive device, and a refrigeration apparatus using the same, and particularly in a power conversion device and a motor drive device having a converter and an inverter circuit, The present invention relates to a technique for reducing current distortion caused by periodic disturbance such as nonlinear characteristics.

  The output (voltage, current, position, speed, angle, flow rate, etc.) of the control target is compared with a predetermined command, the deviation value is calculated, and the proportional integral controller (PI controller) or proportional integral derivative controller ( 2. Description of the Related Art Control devices that use a PID controller) to adjust an operation amount to be controlled so that there is no deviation between an output and a command are widely used.

  As a specific example of such a control device, there is a power conversion device such as a converter or an inverter circuit that converts a DC voltage into an AC voltage. Power converters are widely applied in uninterruptible power supplies, grid-connected power converters, and AC motor drive devices.

  When a periodic disturbance is applied to the controlled object, the influence of the periodic disturbance appears in the output. It is difficult to suppress the influence of such a periodic disturbance only with the PI controller or the PID controller.

  For example, the inverter circuit used in the power converter is generally of a voltage type, and the output voltage is adjusted to control the output current. Therefore, if there is a distortion component (periodic disturbance) in the AC voltage (system voltage or motor induced voltage) on the power source side or load side, distortion of the same component occurs in the AC current. Furthermore, distortion is likely to occur near the peak of the alternating current due to the influence of the magnetic saturation (nonlinear) characteristics of the reactor and the motor. Also, the inverter circuit itself has non-linear characteristics such as a dead time correction error and a voltage drop of the semiconductor power element, which causes current distortion. When distortion of the output current of the inverter circuit occurs, there are problems such as an increase in reactor loss, pulsation of motor torque, and an increase in power harmonics.

  By detecting distortion (periodic disturbance) of the AC voltage on the load side and adopting appropriate control, current distortion due to AC voltage distortion can be improved, but high-accuracy voltage detection means is required. This increases costs. In general, it is difficult to detect the induced voltage during motor driving.

  As a background art in this technical field, there is a power conversion control device disclosed in Patent Document 1. This discloses a technique for improving the dead time correction accuracy of an inverter circuit and reducing current distortion.

Japanese Patent No. 5049707

  In the power conversion control device described in Patent Document 1, a highly accurate dead time correction can be realized by using a dedicated voltage detection circuit and a specific semiconductor integrated circuit (microcomputer) function. Circuits are essential, leading to increased manufacturing costs.

  Further, in Patent Document 1, since the configuration is such that the output voltage is detected and the control correction amount is adjusted, a control delay occurs. In particular, it is considered that suppression of current distortion generated in the output of the control target when the command signal for controlling the power converter changes suddenly is insufficient.

  Therefore, the present invention provides a control device, a power conversion device, a motor drive device, and a refrigeration apparatus using the same that can suppress current distortion without using an additional circuit and can suppress an interference phenomenon when a command signal suddenly changes. There is.

  In order to solve the above problems, a control device of the present invention includes a controller that receives a command signal from the outside and outputs a control signal, a control object that is controlled based on the control signal, and an output of the control object And a detection device that outputs a detection signal, wherein the controller receives a deviation between the control signal and the detection signal, and determines an operation amount of the control object based on the deviation. An output PI controller or PID controller, the control signal is input, a low-pass filter that alleviates the sudden change, an output of the low-pass filter and a deviation of the detection signal are input, and a specific frequency included in the deviation A control comprising: an S controller that outputs a signal in reverse phase; and an adder that adds the output of the PI controller or the PID controller and the output of the S controller and outputs the result as the control signal Location.

  Moreover, the power converter of the invention includes an AC power source and an inverter circuit that is connected between a DC load or a DC power source and converts power, and a current detection that detects an AC current of the AC power source and outputs an AC current detection signal. Means, a predetermined current command and the alternating current detection signal are inputted, a voltage controller for generating a command voltage of the inverter circuit based on them, a predetermined current command and the alternating current detection signal are inputted, and And a correction unit that generates a correction signal for correcting the command voltage based on the low-pass filter that receives the current command and relaxes sudden change thereof, and the low-pass filter. And an S controller for generating the correction signal by inputting a deviation between the output of the AC current detection signal and the alternating current detection signal, and making a signal of a specific frequency included in the deviation an opposite phase It was the thing.

  Furthermore, the motor driving device of the present invention includes an AC power supply, a rectifier circuit that rectifies AC power that is connected to the motor and that is output from the AC power supply, a smoothing capacitor that smoothes the power output from the rectifier circuit, and the smoothing circuit. An inverter circuit that converts a DC voltage output from a capacitor into an AC voltage; current detection means that detects an AC current output from the inverter circuit and outputs an AC current detection signal; and a controller that controls the inverter circuit; The controller is supplied with a current command calculated from a motor torque command or a motor rotation speed command and the AC current detection signal, and generates a command voltage for the inverter circuit based on them. Voltage controller, and the current command and the AC current detection signal are input, and a correction signal for correcting the command voltage is generated based on the input And a correction unit that receives the current command and receives a deviation of the low-pass filter that relaxes the sudden change, and an output of the low-pass filter and the AC current detection signal, and is included in the deviation. And an S controller that generates the correction signal by setting the specific frequency signal to be in reverse phase.

  According to the present invention, it is possible to provide a control device, a power conversion device, a motor drive device, and a refrigeration apparatus using the same that can suppress the influence of periodic disturbances and suppress an interference phenomenon when a command signal suddenly changes. it can.

1 is an overall configuration diagram of a control device according to Embodiment 1. FIG. FIG. 3 is an internal configuration diagram of a controller of the control device according to the first embodiment. FIG. 3 is a diagram illustrating gain characteristics and phase characteristics of the S controller according to the first embodiment. FIG. 3 is an internal configuration diagram of a controller of the control device according to the first embodiment. FIG. 5 is a waveform diagram for explaining suppression of periodic disturbances by the control device according to the first embodiment. The wave form diagram which shows the interference phenomenon of a control apparatus. FIG. 6 is a waveform diagram for explaining suppression of an interference phenomenon by the control device according to the first embodiment. The block diagram of the power converter device of Example 2. FIG. FIG. 6 is a block diagram of a control function of the power conversion device according to the second embodiment. The functional block diagram of the voltage controller of the power converter device of Example 2. FIG. The functional block diagram of the harmonic suppressor of the power converter device of Example 2. FIG. FIG. 6 is a configuration diagram of a motor drive device according to a third embodiment. FIG. 6 is a block diagram of a control function of a motor drive device according to a third embodiment. 4 shows a control shaft and a motor rotation shaft of the motor drive device according to the third embodiment. FIG. 10 is a functional block diagram of a speed & phase estimator of the motor drive device according to the third embodiment. The block diagram of the refrigeration equipment of Example 4.

  Embodiments of the present invention will be described below with reference to the drawings.

  A control apparatus according to a first embodiment of the present invention will be described with reference to FIGS. In addition, if the control apparatus of a present Example controls the output (voltage, electric current, a position, speed, an angle, flow volume, etc.) of a control object based on the command from the outside, a specific control object will be It is not limited.

  FIG. 1 is an overall configuration diagram of a control device 100 according to the present embodiment. As shown here, the control device 100 is configured to include a controller 1 and detection means 3 that detects the output of the controlled object 2. Here, it is assumed that a periodic disturbance is applied to the controlled object 2. The detection means 3 is a sensor that converts various physical quantities into signals, such as a voltage sensor, a current sensor, a position sensor, and a temperature sensor. The controller 1 receives the detection signal 8 detected by the detection means 3 and the command signal 11 from the external host device, and outputs a control amount for controlling the controlled object 2 so as to suppress the influence of the periodic disturbance. .

  FIG. 2 is an internal configuration diagram of the controller 1. The controller 1 mainly includes a proportional-integral controller (hereinafter referred to as “PI controller 4”), a sine wave transfer function controller (hereinafter referred to as “S controller 5”), and a low-pass filter (hereinafter referred to as “LPF 6”). Provided). The input of the PI controller 4 is a deviation between the command signal 11 and the detection signal 8. The input of the S controller 5 is a deviation between the output after the command signal 11 is processed by the LPF 6 and the detection signal 8. The output of the PI controller 4 and the output of the S controller 5 are added together and output from the controller 1 as a controlled variable.

The PI controller 4, although not shown in FIG. 2, by using the integrator of the proportional gain K _p amplifier and integral gain K _i of, calculates the input signals, respectively, by summing the outputs of the output of the amplifier integrator Output. In addition to the PI controller 4, any one of a proportional integral derivative (PID) controller, a proportional (P) controller, and an integral (I) controller is used in accordance with the characteristics of the controlled object 2 and the control target. May be.

  The S controller 5 is a means for suppressing the influence of the periodic disturbance applied to the controlled object 2, and uses a transfer function as shown in Equation 1.

Here, s: Laplace operator, ω ₀ : center frequency, K ₁ , K ₂ , K ₃ : control gain.

The transfer function of Equation 1 has three gains (K ₁ , K ₂ , K ₃ ). By adjusting these gains, it is possible to adjust the gain size, bandwidth, and phase characteristics corresponding to a specific center frequency (ω ₀ ).

In FIG. 3, the gain characteristic 7a and the phase characteristic 7b of the S controller 5 are shown. As can be seen from this, the S controller 5 is characterized by having a large gain at a specific center frequency (ω ₀ ). In other words, only the component of the center frequency (ω ₀ ) set in the transfer function of Equation 1 appears at the output of the S controller 5. In particular, in the vicinity of the center frequency (ω ₀ ), as shown in the lower graph of FIG. 3, the phase of the phase characteristic 7b changes suddenly from 90 ° to −90 °, so that the output of the S controller 5 changes to the phase of the input signal. Some features do not depend.

  Further, when a plurality of frequency components are present in the periodic disturbance applied to the controlled object 2, as shown in FIG. 4, a plurality of S controllers 5 (5a, 5b,...) Corresponding to the respective frequencies are used. By providing in parallel, periodic disturbance of each frequency component can be suppressed.

  The LPF 6 is provided to suppress an interference phenomenon that occurs between the PI controller 4 and the S controller 5 when the command signal 11 changes suddenly, and may be a simple primary low-pass filter. The cutoff frequency of the LPF 6 may be set to the same level as the response frequency of the PI controller 4. The suppression of the interference phenomenon will be described later with reference to FIG.

  First, the effect of suppressing the periodic disturbance by the S controller 5 will be described with reference to FIG. At the beginning of the time axis (0.2 s to 0.3 s of the time axis), no periodic disturbance was applied to the controlled object 2 as in the middle graph, so the detection means 3 detected as in the upper graph. The detection signal 8 follows the value “1” of the command signal 11, but when a periodic disturbance waveform 9 having a fixed frequency (= 50 Hz) is applied to the control target 2 after 0.3 s of the time axis, the detection signal 8 A periodic disturbance component with a fixed frequency appeared in. Therefore, as shown in the lower graph, the S controller 5 is operated after 0.4 s of the time axis, and the S controller output waveform 10 having the opposite phase to the periodic disturbance waveform 9 extracted according to the transfer function of Expression 1. , And using this to control the control object 2, the periodic disturbance component of the detection signal 8 is suppressed as shown after 0.4 s in the upper graph.

  Next, the effect of suppressing the interference phenomenon by the LPF 6 will be described while comparing FIG. 7 relating to the controller 1 of the present embodiment having the LPF 6 and FIG. 6 relating to the controller omitting the LPF.

  6 shows that when the command signal 11 input from the controller 1 of FIG. 2 to the controller without the LPF 6 changes suddenly, an interference phenomenon occurs between the outputs of the PI controller 4 and the S controller 5, and the detection signal It is a wave form diagram explaining the phenomenon 8 is disturbed.

  In FIG. 6, the periodic disturbance is applied to the controlled object 2, but the periodic disturbance component is removed from the detection signal 8 by the action described in FIG. 5. However, when the command signal 11 suddenly changes from “1” to “2” or suddenly changes from “2” to “1” (0.6s and 0.8s on the time axis) as shown in the upper graph. As shown in the middle graph, a large instantaneous change appears in the S controller input waveform 12 that is the deviation between the command signal 11 and the detection signal 8, and the S controller that processed the S controller input waveform 12 as shown in the lower graph. A large instantaneous change also appears in the output waveform 10. As a result, as shown in the upper graph, a ringing phenomenon (interference phenomenon) appears in the detection signal 8 immediately after the sudden change of the command signal 11. The cause of the large instantaneous change appearing in the S controller input waveform 12 is the control delay of the PI controller 4.

  On the other hand, in FIG. 7, when the command signal 11 input to the controller 1 of FIG. 2 having the LPF 6 changes suddenly, the interference phenomenon between the outputs of the PI controller 4 and the S controller 5 is suppressed and detected. It is a wave form diagram explaining the effect by which disorder of signal 8 was controlled. Even when the command signal 11 changes suddenly (0.6 s and 0.8 s on the time axis) as shown in the upper graph, the S generated using the command signal 11 processed by the LPF 6 as shown in the middle graph. Since there is no large change in the controller input waveform 12, no significant change appears in the S controller output waveform 10 as in the lower graph. As a result, when the controller 1 of the present embodiment is used, as shown in the upper graph, the ringing phenomenon (interference phenomenon) at the time of sudden change of the command signal 11 is almost eliminated while removing the periodic disturbance from the detection signal 8. Can be removed.

  As described above, according to the control apparatus 100 of the present embodiment, the control amount corresponding to the frequency component of the periodic disturbance is output using the S controller 5 included in the controller 1, so that The influence of the applied periodic disturbance can be suppressed, and by processing the command signal 11 using the LPF 6, it is possible to suppress the interference phenomenon that appears in the output of the control target when the command signal 11 changes suddenly.

  Next, the power converter of Example 2 of this invention is demonstrated using FIGS. 8-11.

  FIG. 8 is an overall configuration diagram of the power conversion apparatus 101 according to the third embodiment. As shown here, the power conversion device 101 includes a noise filter 22 connected in series to an AC power source 21, a reactor 23, an inverter circuit 24 composed of semiconductor switching elements, and a positive / negative polarity on the DC side of the inverter circuit 24. A smoothing capacitor 25 connected in between, a voltage detection circuit 26 for detecting an AC voltage, a voltage dividing resistor (voltage detection circuit) 27 for detecting a DC voltage, and PWM (Pulse width modulation) control of the inverter circuit 24 are performed. The controller 28 includes a current detection circuit 29 that detects an alternating current. The AC side of the power converter 101 is connected to an AC power source 21 and the DC side is connected to a DC load or a DC power source (hereinafter referred to as “DC load / DC power source 20”).

  Next, the operation mode of the inverter circuit 24 will be described. The operation mode of the inverter circuit 24 includes a rectification mode (AC / DC conversion mode) for receiving AC power from the AC power source 21 and supplying DC power to the DC load / DC power source 20, and a DC load / DC power source 20. There is a regeneration mode (DC / AC conversion mode) in which DC power is inversely converted and AC power is output to the AC power source 21. Switching between the two operation modes is realized by a control signal from the controller 28. Examples of the DC power source used for the DC load / DC power source 20 include a photovoltaic power generation facility and a storage battery.

  In the inverter circuit 24, a three-phase bridge circuit is configured by six semiconductor switching elements (in this embodiment, an IGBT (Insulated Gate Bipolar Transistor)) and a diode connected in antiparallel to each semiconductor switching element. This three-phase bridge circuit corresponds to a three-phase AC power supply 21. The diodes connected in antiparallel to each semiconductor switching element are commutation diodes when the respective semiconductor switching elements are off, and are well-known diodes, and thus detailed description thereof is omitted.

  The smoothing capacitor 25 is an element for suppressing a DC voltage ripple and a surge voltage on the DC side of the inverter circuit 24.

  As the controller 28, an arithmetic processing unit such as a microcomputer or a DSP (Digital Signal Processor) is used. A sampling hold circuit and an A / D (Analog / Digital) conversion unit incorporated in the controller 28 convert the input detection signals of each voltage and current into digital signals.

  Next, the control configuration of the controller 28 will be described using the functional block diagram of FIG. The controller 28 calculates a voltage command of the inverter circuit 24 by the arithmetic processing unit executing a predetermined program, and performs PWM control for switching (ON / OFF) control of each semiconductor switching element of the inverter circuit 24. Operates to generate a signal.

  More specifically, as shown in FIG. 9, the controller 28 includes a power supply phase calculator 31, a voltage controller 32, a 3-phase / 2-axis converter 33, a 2-axis / 3-phase converter 34, a harmonic, A wave suppressor 35 and a PWM controller 36 are provided.

The power supply phase calculator 31 receives the AC voltage detection signal detected by the voltage detection circuit 26, calculates the power supply voltage phase (θ _s ), and calculates the 3-phase / 2-axis converter 33 and 2-axis / 3-phase converter. 34 respectively.

The three-phase / two-axis converter 33 includes two-phase AC current detection signals (I _u , I _v ) detected by the current detection circuit 29 and the power supply voltage calculated by the power supply phase calculator 31. Using the phase (θ _s ), the d-axis current I _d and the q-axis current I _q are calculated based on the following formulas 2 and 3. Equation 2 represents an arithmetic expression for 3-phase / 2-axis conversion, and Expression 3 represents an arithmetic expression for conversion from the fixed coordinate system to the rotating coordinate system.

The voltage controller 32 includes a d-axis current command value I _d ^* and a q-axis current command value I _q ^* , a d-axis current detection value I _d and a q-axis current detection value obtained by the three-phase / 2-axis converter 33. so as to eliminate the error of the I _q, by using a PI controller 4 calculates a d-axis voltage command value V _d and q-axis voltage command value V _q.

FIG. 10 shows an example of the internal configuration of the voltage controller 32. As shown here, in the voltage controller 32, the current error is processed by the PI controller 4 to generate a voltage command. The control in order to improve the responsiveness and stability, feedforward wad term _{(2π × f s × L ×} I d *, 2π × f s × L × I q *, E s) to each of the voltage command Add (subtract). Here, f _s is the power frequency, L is the inductance value of the reactor 23, the E _s is the effective value of the AC power supply voltage.

  However, in the control configuration shown in FIG. 10, in order to maintain the stability of the control system, a PI controller 4 having a response frequency of about several tens Hz is used, and a disturbance component having a high frequency of several hundred Hz is used. On the other hand, the suppression effect is insufficient. For example, in the case of a three-phase power supply, main power supply voltage distortions are a fifth order component (frequency is 250 Hz (50 Hz power supply) / 300 Hz (60 Hz power supply)) and a seventh order component (frequency is 350 Hz (50 Hz power supply) / 420 Hz (60 Hz power supply). Therefore, only the voltage controller 32 shown in FIG. 10 is difficult to suppress the fifth-order and seventh-order current distortion. Therefore, in the controller 28 of the present embodiment, a harmonic suppressor 35 shown in FIG. 9 is added in order to suppress high-order harmonic components of the alternating current.

The detailed configuration of the harmonic suppressor 35 will be described with reference to FIG. The harmonic suppressor 35 is for suppressing the AC component of the specific frequency of the d-axis current detection value I _d and the q-axis current detection value I _q , and mainly includes the LPF 6 and the plurality of S controllers 5 (5a 5b, ...). These S controllers 5 have the same configuration as that described in the first embodiment. Further, the center frequency of each S controller 5 is set based on the higher-order component (distortion) of the alternating current signal detected by the current detection circuit 29.

As described in FIG. 7 of the first embodiment, also in FIG. 11, in order to suppress the interference phenomenon between the PI controller 4 and the S controller 5 when the current command values (I _d ^* and I _q ^* ) change suddenly. The current command values (I _d ^* and I _q ^* ) are processed using the LPF 6. For this reason, the difference between the output of the LPF 6 and the current detection values (I _d and I _q ) is input to each S controller 5. In the output of each S controller 5, only the component of the center frequency (ω ₀ ) set in the transfer function of each S controller 5 appears in an antiphase due to the gain characteristic 7a shown in FIG. Therefore, the output (harmonic) of the harmonic suppressor 35 that is in the opposite phase to the periodic disturbance is added to the output of the voltage controller 32 including the phase of the periodic disturbance (d-axis voltage command value V _d , q-axis voltage command value V _q ). By adding the components V _dh and V _qh ) as correction signals, the harmonic components of the current can be canceled.

In the three-phase AC system, the fifth and seventh components of the power supply frequency are the main components of the AC current distortion, so the d-axis current detection value I _d and q-axis current detection converted by the three-phase / two-axis converter 33 are used. A sixth-order component appears in the value _Iq . Therefore, if the harmonic wave suppressor 35 is provided with the S controller 5 having a frequency (ω ₀ = 2π × f _s × 6) corresponding to the sixth order of the power supply frequency, the sixth-order component of the alternating current is passed. The fifth and seventh order components can be suppressed.

To enhance the effect of improving the current distortion further, 11 th and against 13-order frequency components, as well as S control of the power supply frequency of 12 then the corresponding frequency _{(ω 0 = 2π × f s} × 12) A vessel 5 may be added. As described above, when a plurality of higher-order components exist in the alternating current signal detected by the current detection circuit 29, each periodic disturbance can be removed by using a plurality of S controllers 5 together. Further, with respect to the current distortion caused by the DC voltage ripple of the DC load / DC power supply 20, the current distortion can be similarly improved by adding the S controller 5 corresponding to the frequency of the DC voltage ripple. .

The 2-axis / 3-phase converter 34 in FIG. 9 is the sum of the d-axis and q-axis voltage command values obtained by the voltage controller 32 and the harmonic suppressor 35 (that is, the d-axis voltage command value V _d ^{* And} q-axis voltage command value V _q ^* ) and the power supply voltage phase (θ _s ) obtained by the power supply phase calculator 31, and the voltage command reverse conversion based on the following equations 4 and 5 The three-phase voltage command values (V _u ^* , V _v ^* , V _w ^* ) are calculated and output to the PWM controller 36. Equation 4 represents an arithmetic expression for conversion from the rotating coordinate system to the fixed coordinate system. Equation 5 represents an arithmetic expression for 2-axis / 3-phase conversion.

The PWM controller 36 includes a three-phase voltage command value (V _u ^* , V _v ^* , V _w ^* ) from the 2-axis / 3-phase converter 34, a DC voltage signal E _dc , and a triangular wave or sawtooth wave carrier. A PWM control signal is generated based on the wave, each semiconductor switching element of the inverter circuit 24 is switched, and the output voltage of the inverter circuit 24 is controlled.

  As described above, in this embodiment, a control means that uses a transfer function having a large gain with respect to a specified frequency component is added to the current control system of the inverter circuit, so that a specific high-order component is detected. By correcting the command voltage, it is possible to provide a power converter that can suppress current distortion while eliminating the need for an additional circuit, and by processing the current command using the LPF, the PI controller and the S The interference phenomenon between the controllers can be suppressed and the response characteristics of the power conversion device can be maintained.

  Next, a motor drive device according to a third embodiment of the present invention will be described with reference to FIGS.

  FIG. 12 is a diagram illustrating an overall configuration of the motor driving apparatus 102 according to the present embodiment. As shown here, an AC power supply 41 and a motor 45 are connected to the motor drive device 102, and mainly a rectifier circuit 42, a smoothing capacitor 43, an inverter circuit 44, a controller 46, a current detection circuit 47, a DC voltage detection circuit. 48 is provided. The rectifier circuit 42 is connected to the AC power supply 41 and converts the AC voltage from the AC power supply 41 into a DC voltage. The smoothing capacitor 43 is connected to the DC output terminal of the rectifier circuit 42 and smoothes the DC voltage that is the output of the rectifier circuit 42. The inverter circuit 44 turns on and off semiconductor switching elements such as IGBTs and power MOSs according to the PWM signal input from the controller 46, converts the DC voltage output from the smoothing capacitor 43 into an AC voltage, and outputs the AC voltage. The number of rotations of the motor 45 is controlled. When power is supplied from a DC power source such as a storage battery instead of the AC power source 41, the rectifier circuit 42 may be omitted and the output of the DC power source may be directly input to the inverter circuit 44.

  The current detection circuit 47 detects a direct current (bus current) of the inverter circuit 44 by a shunt resistor provided between the smoothing capacitor 43 and the inverter circuit 44. The DC voltage detection circuit 48 detects the DC voltage across the smoothing capacitor 43. The controller 46 generates a PWM signal for controlling the inverter circuit 44 based on the output of each detection circuit. The controller 46 uses a semiconductor arithmetic element such as a microcomputer or a DSP (digital signal processor).

FIG. 13 is a functional block diagram of a controller 46 for calculating a voltage command signal applied to the motor 45 and generating a PWM control signal for controlling the inverter circuit 44. Each function is realized by a CPU (computer) and a calculation program. Is done. As shown here, the controller 46 calculates voltage command signals (V _u ^* , V _v ^* , V _w ^* ) to be applied to the motor 45 by dq vector control, and outputs a PWM control signal for the inverter circuit 44. As shown in FIG. 13, a speed controller 50, a d-axis current command generator 51, a voltage controller 52, a 2-axis / 3-phase converter 53, and a speed & phase estimation, as shown in FIG. , A three-phase / two-axis converter 55, a current reproduction calculator 56, a harmonic suppressor 57, and a PWM controller 58.

Among these, the current reproduction computing unit 56 includes the bus current signal I _sh output from the current detection circuit 47 and the three-phase voltage command values V _u ^* , V _v ^* , V output from the 2-axis / 3-phase converter 53. _{Using w} ^* , the output currents I _u , I _v and I _w of the inverter circuit 44 are reproduced. In FIG. 13, a method of reproducing the three-phase current from the bus current signal I _sh is adopted for cost reduction. However, the AC that is the output of the inverter circuit 44 using current detection means such as a current sensor is used. The current may be detected. In this case, the three-phase current detected by the current detection means may be input to the three-phase / two-axis converter 55.

FIG. 14 is a diagram illustrating a control shaft and a motor rotation shaft of the motor driving apparatus 102 according to the present embodiment. In the figure, the dc-qc axis is the estimated axis of the control system, the dq axis is the motor rotation axis, and the axis error between the dq axis and the dc-qc axis is defined as Δθ _c . At this time, the three-phase / 2-axis converter 55 outputs the three-phase output currents I _u , I _v , I _w reproduced by the current reproduction calculator 56 and the phase information θ estimated by the speed & phase estimator 54. _{Using dc} , the dc-axis current detection value I _dc and the qc-axis current detection value I _qc are calculated based on Equations 6 and 7.

The speed controller 50 outputs a q-axis current command value I _q ^* according to the deviation between the speed command value ω ^* from the outside and the estimated motor rotation speed value ω ₁ . The d-axis current command generator 51 outputs a d-axis current command value I _d ^* that minimizes the motor current.

In the voltage controller 52, the d-axis current command value I _d ^* , the q-axis current command value I _q ^* , the dc-axis current detection value I _dc , the qc-axis current detection value I _qc, and the speed command value ω _{1 described above.} ^* , And the dc axis voltage command value V _dc and qc axis voltage command value used for controlling the motor 45 by using previously registered motor constants such as the winding resistance r and the dq axis inductances Ld and Lq. _Vqc is calculated. Since the voltage control in the voltage controller 52 is well known, detailed description thereof is omitted.

  Next, a speed & phase estimation method for realizing motor position sensorless control will be described in detail.

FIG. 15 is a detailed functional block diagram of the speed & phase estimator 54 of FIG. The speed & phase estimator 54 estimates the rotor position and the rotational speed by a motor rotor position sensorless control method. Specifically, the speed & phase estimator 54 specifically includes a motor axis (dq axis) and a control system axis ( axis error calculator 61 for calculating an axis error Δθ _c with respect to the dc−qc axis), a speed estimator 62 for estimating the motor rotation speed estimated value ω ₁ , and a phase calculator for calculating phase information θ _dc of the control system. 63, and the axis error Δθ _c is held at the command value “0”.

The axis error calculator 61 includes the dc-axis voltage command value V _dc , the qc-axis command voltage value V _qc , the dc-axis current value I _dc , the qc-axis current value I _qc , the motor constant 64, and a motor described later. The axis error Δθ _c is calculated from the estimated rotational speed value ω ₁ using the following equation (8).

The speed estimator 62 processes the shaft error Δθ _c output from the shaft error calculator 61 using a so-called PI controller 4 and outputs a motor rotation speed estimated value ω ₁ . Here, the PI controller 4 performs PLL (Phase-Locked Loop) control so as to eliminate the axis error Δθ _c estimated by the axis error calculator 61. Further, the phase calculator 63 integrates the estimated value ω ₁ of the motor rotation speed to calculate and output the phase information θ _dc of the control system.

By using the speed & phase estimator 54 described above, the motor rotational speed estimated value ω ₁ and the phase information θ _dc can be obtained, so that the rotor position sensor of the motor 45 can be omitted, and the entire system can be omitted. Cost reduction is possible. Of course, a rotor position sensor such as an encoder may be employed to always detect the rotor speed and position information.

Further, the harmonic suppressor 57 of FIG. 13 is for suppressing the harmonic component of the motor current. The harmonic suppressor 57 is configured to incorporate the S controller 5 and the LPF 6 in the same manner as the harmonic suppressor 35 shown in FIG. 11 of the second embodiment, and a detailed description thereof is omitted, but a dc-axis current detection is performed. This is for suppressing the AC component of the specific frequency of the value I _dc and the qc-axis current detection value I _qc , and is configured by arranging a plurality of S controllers 5 in parallel. The center frequency of the S controller 5 adjusts according to the motor speed and the inverter frequency f ₁ and the characteristics of the inverter. For example, in the case of a three-phase AC motor, the fifth-order and seventh-order components of the inverter frequency are the main components of the motor current distortion. Therefore, the detected dc-axis current values I _dc and qc converted by the three-phase / 2-axis converter 55 are used. A sixth-order component of the inverter frequency appears in the shaft current detection value I _qc . Therefore, if the harmonic suppressor 57 is provided with the S controller 5 having a frequency (ω ₀ = 2π × f ₁ × 6) corresponding to the sixth order of the inverter frequency, the fifth and seventh order components of the motor current are obtained. Can be suppressed. Of course, in order to further improve the current distortion improvement effect, the S controller 5 may be added to the 11th-order or higher frequency components. Further, when it is desired to suppress the current distortion component caused by the DC voltage ripple of the smoothing capacitor 43, an S controller 5 corresponding to the frequency of the DC voltage ripple may be added.

Then, as shown in FIG. 13, the voltage command values (V _dc , V _qc ) that are the outputs of the voltage controller 52 are corrected by the correction amounts (V _dh , V _qh ) that are the outputs of the harmonic suppressor 57. Thus, the motor voltage command (V _dc ^* , V _qc ^* ) can be calculated.

Here, since the outputs (V _dh , V _qh ) of the harmonic suppressor 57 are mainly harmonic (AC) components, the AC components of the outputs (V _dc and V _qc ) of the voltage controller 52 are reduced. As a result, the ripple of the axis error Δθ _c calculated by Expression 8 is reduced, and the stability of the motor control system can be improved. That is, the stability of the motor control system can be improved by performing an axis error calculation on the output of the voltage controller 52 before adding the output of the harmonic suppressor 57 and the output of the voltage controller 52.

Using this motor voltage command (V _dc ^* , V _qc ^* ) and the phase information θ _dc from the speed & phase estimator 54, a three-phase command voltage (V _u ^* , V _v ^* , V _w ^* ).

Finally, the PWM controller 58 includes a three-phase command voltage (V _u ^* , V _v ^* , V _w ^* ) from the 2-axis / 3-phase converter 53 and a DC voltage signal E _dc from the DC voltage detection circuit 48. The PWM controller 58 calculates the modulation factor and creates a PWM signal for the inverter circuit 44. The semiconductor switching element of the inverter circuit 44 is turned on / off according to the PWM signal, and outputs a pulsed voltage (amplitude value is a DC voltage, and a width is changed by the PWM signal) from the output terminal of each phase.

  As described above, according to this embodiment, a transfer function having a large gain with respect to a specified frequency component and a control unit that uses an LPF are added to the current control system of the inverter circuit, so that a specific high frequency is obtained. Correcting the command voltage for the next component suppresses current distortion while eliminating the need for an additional circuit, and uses the command signal after LPF processing for control, so that it appears in the motor output when the command signal changes suddenly. It is possible to provide a motor drive device that suppresses the interference phenomenon between the PI controller and the S controller.

  In this embodiment, a refrigeration apparatus will be described.

  FIG. 16: shows the block diagram of refrigeration equipment, such as an air conditioner and a refrigerator, in Example 4 of the present invention. The refrigeration equipment 200 is a device that harmonizes the air temperature, and is configured by connecting an indoor unit 200A and an outdoor unit 200B by a refrigerant pipe 206. Here, the outdoor unit 200B includes a heat exchanger 202 that performs heat exchange between the refrigerant and air, a fan 204 that blows air to the heat exchanger 202, and a compressor 205 that compresses and circulates the refrigerant.

  The compressor 205 has a compressor motor 208 having a permanent magnet synchronous motor therein, and the compressor is driven by driving the compressor motor 208 by the motor driving device 207. The motor driving device 207 converts the AC voltage of the AC power source into a DC voltage and provides it to the motor driving inverter to drive the motor.

  Although the compressor 205 does not have a detailed illustrated structure, a rotary compressor, a scroll compressor, or the like is adopted, and a compression mechanism unit is provided therein. The compression mechanism unit is driven by a compressor motor 208. If the compression mechanism unit is a scroll compressor, it is composed of a fixed scroll and a turning scroll, and the turning scroll makes a turning motion with respect to the fixed scroll, thereby forming a compression chamber between the scrolls.

  By using the motor drive device 102 of the third embodiment as the motor drive device 207, distortion of the motor current can be suppressed and high control performance can be ensured. In addition, since the motor current distortion is suppressed, more stable driving can be performed, so that the vibration and noise of the product can be reduced as the refrigeration equipment.

  Although the embodiments have been described above, the present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment.

100: control device,
101: Power conversion device,
102: Motor drive device,
1: controller,
2: Control target
3: Detection means,
4: PI controller,
5: S controller,
6: LPF (low pass filter),
7a: S controller gain characteristics,
7b: S controller phase characteristics,
8: Detection signal,
9: Periodic disturbance waveform,
10: S controller output waveform,
11: Command signal,
12: S controller input waveform,
20: DC load / DC power supply,
21: AC power supply,
22: Noise filter,
23: Reactor,
24: Inverter circuit,
25: Smoothing capacitor,
26: voltage detection circuit,
27: Voltage dividing resistance,
28: Controller
29: current detection circuit,
31: Power phase calculator
32: Voltage controller,
33: 3-phase / 2-axis converter,
34: 2-axis / 3-phase converter,
35: harmonic suppressor,
36: PWM controller,
37: Multiplier
38: d-axis harmonic suppressor,
39: q-axis harmonic suppressor,
41: AC power supply,
42: rectifier circuit,
43: smoothing capacitor,
44: Inverter circuit,
45: Motor,
46: Controller
47: current detection circuit,
48: DC voltage detection circuit,
50: Speed controller,
51: d-axis current command generator,
52: Voltage controller,
53: 2-axis / 3-phase converter,
54: Speed & phase estimator,
55: 3-phase / 2-axis converter,
56: Current reproduction calculator,
57: Harmonic suppressor,
58: PWM controller,
61: Axis error calculator,
62: Speed estimator,
63: Phase calculator
64: Motor constant,
200: Refrigeration equipment,
200A: indoor unit,
200B: outdoor unit,
201, 202: heat exchanger,
203, 204: Fan,
205: Compressor,
206: refrigerant piping,
207: motor drive device,
208: Motor for compressor

Claims (17)

A controller that receives a command signal from the outside and outputs a control signal;
A controlled object controlled based on the control signal;
Detecting means for detecting an output of the controlled object and outputting a detection signal;
A control device comprising:
The controller is
A PI controller or a PID controller that receives a deviation between the control signal and the detection signal and outputs an operation amount of the control object based on the deviation;
A low-pass filter that receives the control signal and relaxes the sudden change;
An S controller for inputting a deviation between the output of the low-pass filter and the detection signal, and outputting a signal of a specific frequency included in the deviation in an opposite phase;
An adder that adds the output of the PI controller or the PID controller and the output of the S controller and outputs the result as the control signal;
A control device comprising: The control device according to claim 1,
The S controller uses a transfer function represented by the following equation.

Here, s: Laplace operator, ω ₀ : center frequency, K ₁ , K ₂ , K ₃ : control gain The control device according to claim 1,
The cut-off frequency of the low-pass filter is set similarly to the response frequency of the PI controller or PID controller. The control device according to claim 2,
The control apparatus is characterized in that the center frequency ω ₀ set in the S controller is set based on a higher-order component included in the detection signal. The control device according to claim 1 or 2,
When a plurality of higher-order components exist in the detection signal, a control device using a plurality of S controllers corresponding to each frequency in combination. The AC power supply and the DC load or DC power supply are connected.
An inverter circuit for converting power;
Current detection means for detecting an alternating current of the alternating current power supply and outputting an alternating current detection signal;
A voltage controller that receives a predetermined current command and the alternating current detection signal and generates a command voltage of the inverter circuit based on the current command;
A correction unit that receives a predetermined current command and the alternating current detection signal and generates a correction signal for correcting the command voltage based on the predetermined current command,
A power conversion device comprising:
The correction unit is
A low-pass filter that receives the current command and relaxes the sudden change;
An S controller that receives a deviation between the output of the low-pass filter and the AC current detection signal, and generates a correction signal by making a signal of a specific frequency included in the deviation into an opposite phase. Power conversion device. The power conversion device according to claim 6, wherein
The S controller uses a transfer function represented by the following equation.

Here, s: Laplace operator, ω ₀ : center frequency, K ₁ , K ₂ , K ₃ : control gain The power conversion device according to claim 6, wherein
The cutoff frequency of the low-pass filter is set similarly to the response frequency of the voltage controller. The power conversion device according to claim 7,
The center frequency ω ₀ set in the S controller is set based on a higher-order component of the alternating current detection signal. The power conversion device according to claim 6 or 7,
When a plurality of higher order components exist in the alternating current detection signal, a plurality of S controllers corresponding to each frequency are used in combination. AC power supply and motor are connected,
A rectifier circuit for rectifying AC power output from the AC power source;
A smoothing capacitor for smoothing the power output from the rectifier circuit;
An inverter circuit for converting a DC voltage output from the smoothing capacitor into an AC voltage;
Current detection means for detecting an alternating current output by the inverter circuit and outputting an alternating current detection signal;
A controller for controlling the inverter circuit;
A motor drive device comprising:
The controller is
A voltage controller that receives a current command calculated from a motor torque command or a motor rotation speed command and the alternating current detection signal and generates a command voltage of the inverter circuit based on the current command;
A correction unit that receives the current command and the alternating current detection signal and generates a correction signal for correcting the command voltage based on the current command and the alternating current detection signal;
The correction unit is
A low-pass filter that receives the current command and relaxes the sudden change;
An S controller that receives a deviation between the output of the low-pass filter and the AC current detection signal, and generates a correction signal by making a signal of a specific frequency included in the deviation into an opposite phase. Motor drive device. The motor drive device according to claim 11, wherein
The S controller uses a transfer function represented by the following equation.

Here, s: Laplace operator, ω ₀ : center frequency, K ₁ , K ₂ , K ₃ : control gain The motor drive device according to claim 11, wherein
The motor driving device characterized in that the cutoff frequency of the low-pass filter is set in the same manner as the response frequency of the voltage controller. The motor drive device according to claim 11 or 12,
The motor drive apparatus according to claim 1, wherein the center frequency ω ₀ set in the S controller is set based on a higher-order component of the alternating current detection signal. The motor drive device according to claim 11 or 12,
When a plurality of higher order components exist in the alternating current detection signal, a plurality of S controllers corresponding to each frequency are used in combination. The motor drive device according to any one of claims 11 to 14,
A motor drive device that performs an axis error calculation using a command voltage output from the voltage controller before correcting the command voltage. Refrigeration equipment having a compressor,
The compressor has a built-in motor,
A refrigeration apparatus that drives a motor built in the compressor using the motor driving device according to any one of claims 11 to 16.

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