JP4742590B2 - Inverter controller for motor drive - Google Patents

Description

  The present invention relates to a motor drive inverter control device using a small capacity reactor and a small capacity capacitor.

  As a general motor drive inverter control device used in a general-purpose inverter or the like, a motor drive inverter control device as shown in FIG. 11 is well known.

  In FIG. 11, the main circuit is composed of a DC power supply device 113, an inverter 3, and a motor 4. The DC power supply device 113 is used for the AC power supply 1, the rectifier circuit 2, and the DC voltage source of the inverter 3. Are composed of a smoothing capacitor 112 for storing electrical energy and a power factor improving reactor 111 of the AC power source 1.

  On the other hand, in the control circuit, a motor voltage creating means 14 for creating a voltage command value for the motor 4 based on the speed command for the motor 4 and a PWM signal for the inverter 3 based on the voltage command value created from the motor voltage creating means 14. It is comprised from the PWM control means 18 which produces | generates.

  Here, when the AC power supply 1 is 220 V (AC power supply frequency 50 Hz), the input of the inverter 3 is 1.5 kW, and the smoothing capacitor 112 is 1500 μF, the harmonics of the AC power supply current when the power factor improving reactor 111 is 5 mH and 20 mH. FIG. 12 shows the relationship between the wave component and the order with respect to the AC power supply frequency. FIG. 12 is shown together with the IEC (International Electrotechnical Commission) standard. When the power factor improving reactor 111 is 5 mH, the third harmonic component greatly exceeds that of the IEC standard. In the case of, it is understood that the IEC standard is cleared in the harmonic components up to the 40th order.

  For this reason, it is necessary to take measures such as further increasing the inductance value of the power factor improving reactor 111 in order to clear the IEC standard even when the load is high, increasing the size and weight of the inverter device, and further increasing the cost. There was an inconvenience of inviting.

  Therefore, for example, Patent Document 1 as shown in FIG. 13 describes a DC power supply device that suppresses an increase in inductance value of the power factor improving reactor 111 and achieves a reduction in power harmonic components and an increase in power factor. DC power supply devices have been proposed.

  In FIG. 13, the AC power supply voltage of the AC power supply 1 is applied to the AC input terminal of the full-wave rectifier circuit formed by bridge-connecting the diodes D1 to D4, and the output is charged to the intermediate capacitor C via the reactor Lin. The electric charge of the intermediate capacitor C is discharged to the smoothing capacitor CD, and a DC voltage is supplied to the load resistor RL. In this case, the transistor Q1 is connected to the positive and negative DC current path connecting the load side of the reactor Lin and the intermediate capacitor C, and the transistor Q1 is driven by the base drive circuit G1.

  The circuit further includes pulse generation circuits I1 and I2 for applying a pulse voltage to the base drive circuit G1, and a dummy resistor Rdm. The pulse generation circuits I1 and I2 are circuits for detecting a zero cross point of the AC power supply voltage, respectively. From the detection of the zero cross point, the pulse current circuit is configured to flow a pulse current through the dummy resistor Rdm until the instantaneous value of the AC power supply voltage becomes equal to the voltage across the intermediate capacitor C.

Here, the pulse generation circuit I1 generates a pulse voltage in the first half of the half cycle of the AC power supply voltage, and the pulse generation I2 generates a pulse voltage in the second half of the half cycle of the AC power supply voltage.

  When the transistor Q1 is turned on and a current is forced to flow through the reactor Lin, a backflow prevention diode D5 is connected so that the charge of the intermediate capacitor C is not discharged through the transistor Q1, and further, the intermediate capacitor C A backflow prevention diode D6 and a reactor Ldc for enhancing the smoothing effect are connected in series to a path for discharging the electric charge of the current to the smoothing capacitor CD.

With the above configuration, the transistor Q1 is turned on in part or all of the phase interval in which the instantaneous value of the AC power supply voltage does not exceed the voltage across the intermediate capacitor C. Component reduction and higher power factor can be achieved.
JP-A-9-266684 Inverter Drive Handbook Editorial Committee, “Inverter Drive Handbook”, published by Nikkan Kogyo Shimbun, first edition in 1995

  However, the above-described conventional configuration still has the smoothing capacitor CD having a large capacity and the reactor Lin (described in the simulation result at 1500 μF and 6.2 mH in Patent Document 1), and further the intermediate capacitor. C, transistor Q1, base drive circuit G1, pulse generation circuits I1 and I2, dummy resistor Rdm, backflow prevention diodes D5 and D6, and a reactor Ldc that enhances the smoothing effect, thereby increasing the size of the device and the number of parts. There has been a problem of incurring a cost increase accompanying the increase.

  The present invention solves such a conventional problem, and by using a small-capacitance capacitor and a small-capacity reactor, a motor capable of suppressing a harmonic component of an AC power supply current in a small size, light weight, and low cost. An object is to provide a drive inverter control device.

In order to solve the above problems, an inverter control apparatus for driving a motor according to the present invention comprises a rectifier circuit comprising an AC power supply as an input and comprising a diode bridge and a small capacity reactor connected to the AC input side or DC output side of the diode bridge. When an inverter for converting the DC power into AC power, and small capacitance of the capacitor provided between the DC bus of the inverter is constituted by the motors, the resonance frequency of the small-capacity capacitor and the small capacity reactor Each of the inverter and the motor phase current detecting means for determining the combination of the small capacity reactor and the small capacity capacitor so as to be larger than 40 times the AC power supply frequency and detecting the phase current value of the motor. PWM control means for generating a PWM signal for controlling the operation of the switching element, and the speed command value of the motor Motor voltage command generating means for generating the voltage command value of the motor, target input current generating means for generating a target value of the input current flowing from the AC power supply, and duty of the PWM signal generated by the PWM control means. Input current estimation means for deriving an input current value flowing from the AC power source based on the motor phase current obtained from the motor phase current detection means, and a target value of the input current created by the target input current creation means, Input current error calculation means for calculating an error from the input current value derived by the input current estimation means, and in order to eliminate the input current error calculated by the input current error calculation means (number of motor phases) × ( It calculates the input current error eliminated component is a pulsating component of the frequency represented by the number of poles) × (rpm), the voltage command value obtained from the motor voltage command preparing means It is obtained and an input current error eliminating voltage generating means calculated for.

With the above configuration, a small, lightweight, and low cost motor drive inverter control device can be realized by using a small-capacity reactor and a small-capacitor, and the inverter DC voltage varies greatly, making it difficult or impossible to drive the motor. Even in this case, it becomes possible to maintain the motor drive by making the voltage applied to the motor substantially constant by the PN voltage correction means, and further suppress the harmonic component of the AC power supply current. There is an effect that the reliability can be improved.

  ADVANTAGE OF THE INVENTION According to this invention, the inverter control apparatus for motor drive which can suppress the harmonic component of alternating current power supply current by small size, a light weight, and low cost can be provided by using a small capacity | capacitance capacitor and a small capacity | capacitance reactor.

A first invention includes an AC power supply as an input, a rectifier circuit including a diode bridge, a small-capacity reactor connected to an AC input side or a DC output side of the diode bridge, an inverter for converting DC power into AC power, a small capacity of a capacitor provided between the DC bus of the inverter is constituted by the motors, the resonance frequency of the small-capacity reactor and the small capacitance capacitor becomes greater than 40 times the AC power source frequency As described above, the combination of the small-capacity reactor and the small-capacitance capacitor is determined, and the motor phase current detecting means for detecting the phase current value of the motor and the PWM signal for controlling the operation of each switching element of the inverter are generated. Based on the PWM control means and the speed command value of the motor, a motor voltage indicator that creates the voltage command value of the motor. Creating means; target input current creating means for creating a target value of the input current flowing from the AC power supply; duty of the PWM signal generated by the PWM control means; and motor phase current obtained from the motor phase current detecting means An input current estimating means for deriving an input current value flowing from the AC power source based on the input current, a target value of the input current created by the target input current creating means, and an input current value derived by the input current estimating means An input current error calculation means for calculating an error, and a frequency represented by (number of motor phases) × (number of poles) × (number of rotations) in order to eliminate the input current error calculated by the input current error calculation means calculates the input current error eliminated component is pulsating component, and a input current error eliminating voltage generating means for adding the voltage command value obtained from the motor voltage command preparing means motor A dynamic inverter control device.

  With the above configuration, a small, lightweight, and low cost motor drive inverter control device can be realized by using a small-capacity reactor and a small-capacitor, and the inverter DC voltage varies greatly, making it difficult or impossible to drive the motor. Even in this case, it becomes possible to maintain the motor drive by making the voltage applied to the motor substantially constant by the PN voltage correction means, and further suppress the harmonic component of the AC power supply current. There is an effect that the reliability can be improved.

According to a second aspect of the present invention, there is provided a rectifier circuit comprising an AC power supply as an input, a diode bridge, a small-capacity reactor connected to an AC input side or a DC output side of the diode bridge, an inverter for converting DC power into AC power, a small capacity of a capacitor provided between the DC bus of the inverter is constituted by the motors, the resonance frequency of the small-capacity reactor and the small capacitance capacitor becomes greater than 40 times the AC power source frequency Determining a combination of the small-capacity reactor and the small-capacitance capacitor, detecting a DC voltage value of the inverter, a PN voltage detection means, a motor phase current detection means detecting the motor phase current value, PWM control means for generating a PWM signal for controlling the operation of each switching element of the inverter, and a speed command for the motor Based on the motor voltage command generating means for generating the voltage command value of the motor, and a comparison between the preset DC voltage reference value of the inverter and the DC voltage detected value of the inverter obtained from the PN voltage detecting means A PN voltage correction means for deriving a PN voltage correction coefficient; a voltage command value obtained by multiplying a voltage command value obtained from the motor voltage command creation means by a PN voltage correction coefficient that is an output value of the PN voltage correction means; Motor voltage command correction means for performing correction, target input current creation means for creating a target value of input current flowing from the AC power supply, duty of the PWM signal generated by the PWM control means, and motor phase current detection means An input current estimating means for deriving an input current value flowing from the AC power source based on the obtained motor phase current; Input current error calculation means for calculating an error between the target value of the input current created by the input current creation means and the input current value derived by the input current estimation means, and the input calculated by the input current error calculation means In order to eliminate the current error , an input current error canceling component which is a pulsation component of the frequency represented by (number of phases of motor) × (number of poles) × (number of rotations) is calculated and obtained from the motor voltage command correcting means. Motor drive inverter control device with input current error elimination voltage creation means to be added to the voltage command correction value. Small, lightweight, and low cost motor drive inverter control by using a small capacitor and small capacity reactor So that the voltage applied to the motor is almost constant even when the inverter DC voltage fluctuates significantly and it becomes difficult or impossible to drive the motor. Inverter is operated, it is possible to maintain the driving of the motor can be further suppressed harmonic components of the AC power source current.

  The third aspect of the invention is characterized in that, in particular, in the motor drive inverter control apparatus of the first or second aspect of the invention, PI control is used for calculation of the input current error elimination component in the input current error elimination voltage generating means. Therefore, even if a noise component is included in the input current value derived by the input current estimating means, it is possible to flow an input current that is stable and has no residual deviation with respect to the target value.

  According to a fourth aspect of the invention, in the motor control inverter control apparatus of the third aspect of the invention, in the PI control used for the calculation of the input current error elimination component in the input current error elimination voltage creating means, the proportional gain and integral gain At least one of the gains can be changed, and the oscillation of the input current can be prevented even when the motor type, the rotational speed, the load status, or the like changes.

In the first to fourth inventions, the combination of the small-capacity reactor and the small-capacitance capacitor is determined so that the resonance frequency of the small-capacity reactor and the small-capacitance capacitor is larger than 40 times the AC power supply frequency. The harmonic component of the AC power supply current can be suppressed and the IEC standard can be cleared.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 shows a system configuration diagram of a motor drive inverter control apparatus showing a first embodiment of the present invention.

  In FIG. 1, the main circuit includes an AC power source 1, a diode bridge 2 for converting AC power into DC power, a small capacity reactor 11 of 2 mH or less, a small capacity capacitor 12 of 0.4 μF or more and 100 μF or less, and DC power. Is converted to AC power, and a motor 4 is driven by the AC power converted by the inverter 3.

On the other hand, in the control circuit, the motor voltage generating means 14 for generating the voltage command value of the motor 4 based on the speed command ω * of the motor 4, the PN voltage detecting means 15 for detecting the DC voltage value of the inverter 3, and the motor Motor phase current detection means 13 for detecting a phase current value, and a PN voltage correction coefficient obtained by dividing a preset DC voltage reference value of the inverter 3 by a DC voltage detection value of the inverter 3 obtained from the PN voltage detection means 15 When the DC voltage detection value is 0 or less, the PN voltage correction means 16 for setting the maximum value of the PN voltage correction coefficient set in advance to the PN voltage correction coefficient and the motor voltage command preparation means 14 are used. A motor voltage command correction means 17 for correcting the voltage command value by multiplying the voltage command value to be outputted by a PN voltage correction coefficient which is an output value of the PN voltage correction means 16; An input current error calculation unit 21 for calculating an error between a target value of the input current generated by the target input current generation unit 22 and an input current value derived by the input current estimation unit 20; From the input current error cancellation voltage creating means 19 that calculates the input current error cancellation component that eliminates the input current error and adds it to the voltage command correction value obtained from the motor voltage command correction means, and the input current error cancellation voltage generation means 19 The PWM control means 18 generates a PWM signal of the inverter 3 so that the generated input current error elimination voltage is applied to the motor 4.

  Hereinafter, a specific method will be described.

The motor voltage command creating means 14 creates voltage command value values v _u *, v _v *, v _W * by the calculation represented by (Equation 1).

(1)
Here, Vm is a motor voltage value, and θ ₁ is derived by time-integrating the speed command ω * as expressed by (Equation 2).

(2)
FIG. 2 is a diagram showing a first embodiment of the PN voltage correction means 16 according to the present invention. In the PN voltage correction means 16, the preset DC voltage reference value _{Vpn0 of} the inverter 3 and the PN voltage detection means. 15 is used to derive the PN voltage correction coefficient kpn as shown in (Equation 3).

(3)
Here, since a small-capacitance capacitor is used in the present invention, the DC voltage detection value vpn may be 0, so it is necessary to set a minute term δ ₀ for preventing 0%. Instead of the small term δ ₀ in (Equation 3), when the detected DC voltage value vpn is 0 or less, the maximum value of the preset PN voltage correction coefficient is set as the PN voltage correction coefficient kpn, so Prevention can be achieved. That is, the PN voltage correction coefficient kpn may be derived as in (Equation 4).

(4)
Here, k _pn-max is a preset maximum value of the PN voltage correction coefficient. Further, the motor voltage command correction means 17 uses the voltage command values v _u *, v _v *, v _W * and the PN voltage correction coefficient kpn, as shown in (Equation 5), and the motor voltage command correction values v _{uhl *} , v _{vhl. *} , V _{Whl *} is derived.

(5)
As described above, by using a small capacity reactor and a small capacity capacitor, it is possible to realize a motor drive inverter control apparatus that is small, light, and low in cost, and the inverter DC voltage fluctuates greatly, making it difficult or impossible to drive the motor. Even in this case, the inverter can be operated so that the voltage applied to the motor is substantially constant, and the motor can be maintained.

  FIG. 3 shows the first operation result of the motor drive inverter control device of the present invention. Since the capacitor 12 of the present invention uses a capacitor with a very small capacity, the inverter DC voltage is equal to the AC power supply frequency fs (= It can be seen that there is a large pulsation at a frequency twice that of 50 Hz. As for the AC power supply current, since the capacitor 12 has a small capacity and the charge / discharge time is extremely short, there is almost no current quiescent period and a high power factor is realized.

  FIG. 4 shows a second operation result of the inverter control apparatus for driving a motor according to the present invention, and shows a waveform when a 6-pole three-phase motor is driven at 40 Hz when the AC power supply frequency is 50 Hz. Here, when the AC power supply current is observed in more detail, it can be seen that a pulsation having a period T larger than the carrier component of the inverter appears.

  The frequency of this pulsation is 720 Hz, and is obtained by the product of the number of phases, poles, and revolutions of the motor, that is, 3 (phases) × 6 (poles) × 40 (Hz). 5 will be described with reference to FIG. The inverter 3 is PWM-controlled, but if the motor current flows almost sinusoidally by the PWM control, the motor current in the inverter bus is synchronized with the switching operation, and the motor current is pulsed in a waveform like the solid line in FIG. Appear in

When a three-phase motor is driven by, for example, a two-phase modulation system, there are six switching patterns in one electrical angle cycle as shown in FIG. 6, and the motor phase current that appears on the inverter bus for each switching pattern. Will be switched.

  In FIG. 5, the switching timing of the switching pattern is indicated by an arrow. At each timing, the phase of the motor current flowing through the inverter bus changes, and the amount of current (sum of two motor currents: broken line in FIG. 5). ) Also decreases. This decrease in the amount of current occurs every time the switching pattern is switched, so that one cycle of the electrical angle occurs twice as many times as the number of motor phases and occurs six times in the case of a three-phase motor. Further, since the mechanical angle makes one revolution with a period of ½ the number of motor poles, in the case of a six-pole motor, it makes one revolution with three electrical angles. In other words, this decrease in the amount of current during one mechanical angle cycle occurs (number of motor phases × 2) × (number of poles / 2) times, and the expression is simplified as the pulsation of the current waveform (number of motor phases) × The frequency is represented by (number of poles) × (number of rotations).

  In the inverter control apparatus for driving a motor according to the present invention, an extremely small capacity reactor and capacitor are used, so that the above-described current pulsation is likely to appear in the AC power supply current.

  Next, consider the harmonic regulation of AC power supply current.

  The harmonic current indicates a current having a frequency component that is an integral multiple of the sinusoidal waveform of the AC power supply. In electronic equipment, a regulation value is provided for the harmonic current. If the pulsation of the AC power supply current described so far has a frequency that is an integral multiple of the sine wave waveform of the AC power supply, the regulation value may not be satisfied. Therefore, an input current error calculating means 21 is provided to derive an error between the target value of the input current created by the target input current creating means 22 and the input current value derived by the input current estimating means 20 to eliminate the input current error. The voltage creating means 19 adds the input current error elimination component that eliminates this input current error to the voltage command correction value obtained from the motor voltage command correcting means, thereby canceling the pulsation that appeared in the AC power supply current.

  FIG. 7 shows a third operation result of the motor drive inverter control apparatus of the present invention. Regarding the waveform, the upper side shows the AC power supply current and the lower side shows the input current value derived by the input current estimating means 20. It can be seen that the input current value derived by the input current estimating means 20 can roughly reproduce the AC power supply current that is actually flowing. The operation of the input current estimating means 20 for reproducing the AC power supply current will be described in detail below.

  FIG. 6 shows six switching patterns existing in one cycle of the electrical angle when the three-phase motor is driven by, for example, the two-phase modulation method. Of these, the inverter 3 for one cycle of the carrier in the pattern 1 is shown. Consider the current flowing through the bus.

  In the pattern 1, the switching state of the inverter 3 is divided into three cases shown in FIG. 8, and at the first timing, all the upper arm elements of the inverter 3 are in the off state and only the lower arm element is in the on state. In this case, the current flows between the inverter 3 and the motor 4 and does not flow to the bus.

  In the second timing, only the W-phase element among the upper arm elements of the inverter 3 is turned on. At this time, a W-phase current flows through the bus. In the third timing, the U-phase and W-phase elements among the upper arm elements of the inverter 3 are turned on. At this time, a V-phase current flows through the bus.

In the input current estimation means 20, first, from the duty information of the PWM signal generated by the PWM control means 18, from the motor phase current detection means 13 to the bus of the inverter 3 at the second timing and the third timing described above, respectively. Information on current values that will flow (in the case of pattern 1, W-phase current and V-phase current) is acquired.

  Next, the time ratio with respect to one carrier period of each of the second timing and the third timing described above is calculated from the duty information of the PWM signal generated by the PWM control means 18, and flows to the bus at the second timing. The result of adding the product of the current value and the time ratio of the second timing to the product of the current value that will flow to the bus at the third timing and the time ratio of the third timing is the inverter in one carrier. The value of the current flowing through the bus No. 3

  In the motor drive inverter control apparatus according to the present invention, an extremely small capacity reactor and capacitor are used. Therefore, the current value flowing through the bus in one carrier obtained by the above calculation almost flows directly from the AC power supply. It can be replaced as a current value.

  Subsequently, the input current error calculation means 21 subtracts the target value of the input current created by the target input current creation means 22 from the input current value derived by the input current estimation means 20 described above to obtain the input current error. The result is output to the cancellation voltage creating means 19. The input current error cancellation voltage creating means 19 obtains an input current error cancellation component by inverting the polarity of the input current error calculated by the input current error calculation means 21 and further multiplying it by a predetermined coefficient to correct the motor voltage command. By adding to the voltage command correction value obtained from the means, the harmonic component represented by (number of motor phases) × (number of poles) × (number of rotations) of the AC power supply current is suppressed.

  FIG. 9 shows the fourth operation result of the motor drive inverter control apparatus of the present invention. Regarding the waveform, the upper side shows the AC power supply current and the lower side shows the input current error elimination component obtained by the input current error elimination voltage creating means 19. In the pulsation of the AC power supply current, the input current error cancellation component is calculated to be small when the value is large, and the input current error cancellation component is large when the input current value is small. The harmonic component of the power supply current waveform can be suppressed.

  The input current error canceling voltage creating means 19 calculates an input current error canceling component that eliminates the input current error calculated by the input current error calculating means 21 to obtain a voltage command value obtained from the motor voltage command creating means 14. A system configuration as shown in FIG.

  In the motor drive inverter control apparatus, PI control may be used for the calculation of the input current error elimination component in the input current error elimination voltage creating means 19.

  By adding an integral calculation to the calculation of the input current error canceling component, even if a noise component is included in the input current value derived by the input current estimating means 20, a stable input with no residual deviation from the target value is obtained. It becomes possible to pass an electric current.

  Further, in the PI control used for the calculation of the input current error canceling component in the input current error canceling voltage creating means 19, the gain can be changed in at least one of the proportional gain and the integral gain. It is possible to adapt to changes in the type, rotation speed, load status, etc., and to always allow an appropriate input current to flow while preventing oscillation.

  Here, a specific method for determining the specifications of the small-capacity capacitor and the small-capacity reactor will be described below.

In the motor drive inverter control device of the present invention, the resonance frequency f _LC (LC resonance frequency) of the small capacitor and the small reactor is changed to AC in order to suppress the harmonic component of the AC power supply current and clear the IEC standard. The combination of the small capacitor and the small reactor is determined so as to be larger than 40 times the power supply frequency fs.

Here, when the capacitance of the small-capacitance capacitor is C [F] and the inductance value of the small-capacity reactor is L [H], the LC resonance frequency f _LC is expressed as (Equation 6).

(6)
That is, the combination of the small capacitor and the small reactor is determined so as to satisfy f _LC > 40 fs. (Because the IEC standard specifies the 40th harmonic in the harmonic component of the AC power supply current)
As described above, by determining the combination of the small-capacitance capacitor and the small-capacity reactor, the harmonic component of the AC power supply current can be suppressed and the IEC standard can be cleared.
The present invention described in the first embodiment and the second embodiment can be applied to a motor driving inverter control device that drives a motor using an inverter circuit. For example, an air conditioner equipped with an inverter circuit, a refrigerator, an electric washing machine, an electric dryer, an electric vacuum cleaner, a blower, a heat pump water heater and the like. For any product, by reducing the size and weight of the motor drive inverter device, the degree of freedom in product design is improved, and an inexpensive product can be provided.

  As described above, the motor drive inverter control device according to the present invention can realize a small, light and low cost motor drive inverter control device by using a small-capacity reactor and a small-capacitance capacitor, and the inverter DC voltage is greatly increased. Even if it becomes difficult or impossible to drive the motor due to fluctuations, it is possible to maintain the motor driving by making the voltage applied to the motor substantially constant by the PN voltage correction means, and further, the AC power supply current Since harmonic components can be suppressed and system reliability can be improved, the servo drive is not limited to cases where a speed sensor such as a pulse generator cannot be used, such as a compressor drive motor in an air conditioner. The present invention can also be applied to a case where a speed sensor can be provided as in the above.

The system block diagram of the inverter control apparatus for motor drive which shows the 1st Embodiment of this invention The figure which shows the derivation method of the PN voltage correction coefficient The figure which shows the 1st operation result The figure which shows the 2nd operation result Figure showing the inverter bus current Diagram showing the switching pattern of the inverter The figure which shows the 3rd operation result (A) Diagram showing current flowing between the inverter and motor (b) Circuit diagram showing current status at first timing in FIG. 7 (a) (c) Circuit at second timing in FIG. 7 (a) Circuit diagram showing current status (d) Circuit diagram showing current status at the third timing in FIG. 7 (a) The figure which shows the 4th operation result Another system configuration diagram of the motor drive inverter control device System configuration diagram of a general motor drive inverter control device The diagram which showed the relationship between the harmonic component of alternating current power supply current in the motor drive inverter apparatus of FIG. 11, and the order with respect to alternating current power supply frequency Circuit diagram of a DC power supply that can reduce harmonic components and increase the power factor while suppressing the increase in size of conventional devices

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 AC power supply 2 Rectifier circuit 3 Inverter 4 Motor 11 Small capacity reactor 12 Small capacity capacitor 13 Motor phase current detection means 14 Motor voltage command preparation means 15 PN voltage detection means 16 PN voltage correction means 17 Motor voltage command correction means 18 PWM control means 19 Input current error elimination voltage creation means 20 Input current estimation means 21 Input current error calculation means 22 Target input current creation means

Claims (4)

A rectifier circuit comprising an AC power supply as input and a diode bridge, a small-capacity reactor connected to the AC input side or DC output side of the diode bridge, an inverter for converting DC power into AC power, and a DC bus of the inverter and a small capacitor which is provided between, is composed of a motors,
The combination of the small-capacity reactor and the small-capacitance capacitor is determined so that the resonance frequency of the small-capacity reactor and the small-capacitance capacitor is larger than 40 times the AC power supply frequency, and the phase current value of the motor is determined. Motor phase current detecting means for detecting, PWM control means for generating a PWM signal for controlling the operation of each switching element of the inverter, and a motor voltage for creating a voltage command value for the motor based on the speed command value for the motor Command generation means, target input current generation means for generating a target value of the input current flowing from the AC power supply, duty of the PWM signal generated by the PWM control means and motor phase current obtained from the motor phase current detection means Input current estimating means for deriving an input current value flowing from the AC power source based on the target input, and the target input An input current error calculating means for calculating an error between a target value of the input current generated by the current generating means and an input current value derived by the input current estimating means; and the input current calculated by the input current error calculating means In order to eliminate the error, the voltage obtained from the motor voltage command generating means is calculated by calculating the input current error canceling component which is a pulsation component of the frequency represented by (number of phases of motor) × (number of poles) × (number of rotations). An inverter control device for driving a motor, comprising: an input current error elimination voltage creating means for adding to a command value. A rectifier circuit comprising an AC power supply as input and a diode bridge, a small-capacity reactor connected to the AC input side or DC output side of the diode bridge, an inverter for converting DC power into AC power, and a DC bus of the inverter and small capacitor provided between, is composed of a motors, the resonance frequency of the small-capacity reactor and the small capacity capacitor, to be greater than 40 times the AC power source frequency, the small volume A combination of a reactor and the small-capacitance capacitor is determined, PN voltage detection means for detecting a DC voltage value of the inverter, motor phase current detection means for detecting a phase current value of the motor, and each switching element of the inverter PWM control means for generating a PWM signal for controlling the operation, and based on the speed command value of the motor, PN voltage correction coefficient based on a comparison between a preset DC voltage reference value of the inverter and a DC voltage detection value of the inverter obtained from the PN voltage detection means; PN voltage correction means for deriving the voltage, and a motor for correcting the voltage command value by multiplying the voltage command value obtained from the motor voltage command creation means by a PN voltage correction coefficient which is an output value of the PN voltage correction means Voltage command correction means; target input current creation means for creating a target value of input current flowing from the AC power supply; duty of the PWM signal generated by the PWM control means; and motor phase obtained from the motor phase current detection means Input current estimation means for deriving an input current value flowing from the AC power source based on the current, and the target input current creation An input current error calculation means for calculating an error between a target value of the input current generated in the stage and an input current value derived by the input current estimation means; and an input current error calculated by the input current error calculation means. In order to eliminate the voltage command correction obtained from the motor voltage command correction means by calculating the input current error cancellation component which is a pulsation component of the frequency represented by (number of motor phases) x (number of poles) x (rotation speed) An inverter control device for driving a motor, comprising an input current error elimination voltage creating means for adding to a value. 3. The motor drive inverter control device according to claim 1, wherein PI control is used for calculation of the input current error elimination component in the input current error elimination voltage creating means. 4. The motor according to claim 3, wherein the PI control used for calculating the input current error canceling component in the input current error canceling voltage generating unit is configured to change the gain in at least one of a proportional gain and an integral gain. Drive inverter control device.

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