JP2955716B2 - AC motor control method and device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a method and an apparatus for controlling an AC motor, and in particular, converts the output power of a converter into AC power by an inverter, and uses the AC power to control the AC motor. The present invention relates to a method and a device for controlling an AC motor suitable for driving.

[Conventional technology]

As a device for controlling an AC motor using a converter and an inverter, for example, a device described in Japanese Patent Application Laid-Open No. 61-109491 is known. In this type of conventional device, a value obtained by adding a current on the inverter input side to a current command that compensates for a deviation between a DC voltage command for a converter output voltage and a detected value of the converter output is used as an input current command on the converter output side. A method of controlling the converter so that the current on the converter output side matches this command is adopted. According to this method, when the load torque of the motor increases sharply, the current on the inverter input side also increases, so this current is detected and the current is supplied to the smoothing capacitor on the converter output side by controlling the converter. In addition, voltage fluctuation of the smoothing capacitor can be reduced.

[Problems to be solved by the invention]

However, in the prior art, no consideration is given to the fact that the current on the inverter input side contains a large amount of ripple components, and if the current on the converter output side contains low-order or high-order ripple components, A low-order or high-order ripple component also occurs in the current on the converter input side.
That is, when an AC motor is driven by an inverter, a powering current flowing from the smoothing capacitor to the motor side during power running of the motor and a regenerative current flowing from the motor to the smoothing capacitor side during regeneration during the power running of the motor are almost every switching cycle. Flows as positive and negative currents, and ripples occur on the input side of the inverter. To completely remove the ripple component, it is possible to provide a filter having a time constant longer than the switching period on the input side of the inverter, but the responsiveness is reduced. For example, when the switching frequency is as low as 500 Hz (2 ms) such as in a large-capacity inverter, it is considered that the filter time constant needs to be about 5 ms. Therefore, when such a filter is inserted on the input side of the inverter, the responsiveness of the current control of the converter becomes slow, the DC voltage fluctuation becomes large, and the torque fluctuation of the electric motor also occurs.

An object of the present invention is to provide a motor with a sudden change in load.
It is an object of the present invention to provide a control method of an AC motor capable of flowing a current for suppressing a change in the output voltage of the converter into the converter, and a device therefor. It is still another object of the present invention to provide a method and an apparatus for controlling an AC motor that does not require a current detector on the inverter input side.

[Means for solving the problem]

In order to achieve the above object, the present invention provides, as a first method, a method of converting the output power of a converter into AC power by an inverter, and driving the AC motor with the AC power. Detect a DC voltage on the input side, calculate an inverter input average current in an integral multiple of a half cycle of the carrier of the inverter according to the detected current, calculate an inverter input power from the calculated average current and the detected DC voltage, To divide the calculated power by the AC voltage on the converter input side to generate a power supply current value, and to suppress these deviations to zero from the detected DC voltage on the inverter input side and the output voltage command indicating the target output voltage of the converter. A power supply current command value is generated, the power supply current command value is corrected with the power supply current value, and the power supply current command value is corrected based on the corrected power supply current command value. Is obtained by employing the method of controlling the AC motor giving pulse signal to the converter current of the converter input side performs control to follow the corrected power current command value.

As a second method, the output power of the converter is converted into AC power by an inverter, and when the AC power is used to drive the AC motor, an AC current on the inverter output side and a DC voltage on the inverter input side are detected. An inverter input average current in an integral multiple of a half cycle of the carrier of the inverter is calculated from the current and the duty ratio of the pulse signal applied to the switching element of the inverter, and the inverter input power is calculated from the calculated average current and the detection voltage. Calculated power is divided by the AC voltage on the converter input side to generate a power supply current value, and these deviations are reduced to zero from the detected DC voltage on the inverter input side and the output voltage command indicating the target output voltage of the converter. A power supply current command value for suppressing the power supply current is corrected, and the power supply current command value is corrected with the power supply current value. It is obtained by employing the control method of an AC motor that performs control to follow the current of giving pulse signal based on the flow command value to the converter the converter input side to the corrected power current command value.

As a third method, the output power of the converter is converted into AC power by an inverter, converted into AC power, and when the AC motor is driven by the AC power, an AC current on the inverter output side and a DC voltage on the inverter input side are used. From the detected current and the duty ratio of the pulse signal applied to the switching element of the inverter to calculate an inverter input average current in an integral multiple of a half cycle of the carrier of the inverter. An inverter input power is calculated from the voltage and a power command value for suppressing these deviations to zero is generated from a detected voltage on the inverter input side and an output voltage command indicating a target output voltage of the converter. Is corrected by the inverter input power, and the corrected power command value is divided by the AC voltage on the converter input side to obtain the power supply Generating a command value, in which the converter input side of the current by applying a pulse signal based on the power source current command value to the converter employing a control method of an AC motor that performs control to follow the source current command value.

As a fourth method, the output power of the converter is converted into AC power by an inverter, and when the AC motor is driven by the AC power, an AC current on the inverter output side and a DC voltage on the inverter input side are detected. And the duty ratio of the pulse signal applied to the switching element of the inverter, and calculates the inverter input average current in the coefficient multiple of the half cycle of the carrier of the inverter. The output voltage command indicating the calculated average current and the target output voltage of the converter And the inverter input power is calculated from this, the calculated power is divided by the AC voltage on the converter input side to generate a power supply current value, and these deviations are suppressed to zero from the detected voltage on the inverter input side and the voltage command value. A power supply current command value for correcting the power supply current value, and correcting the command value with the power supply current value, based on the corrected power supply current command value. And in which the pulse signal is given to the converter of current of the converter input side is adopted a control method of an AC motor that performs control to follow the corrected power current command value.

As a fifth method, when the output power of the converter is converted into AC power by a plurality of inverters and a plurality of AC motors are driven by each AC power, an AC current at each inverter output side and a DC voltage at the inverter input side are detected. Then, an inverter input average current in an integer multiple of a half cycle of the carrier of the inverter is calculated according to each detection current, and when controlling the converter based on the calculated average current and the detection voltage, the first to fourth inverters are used. One of the methods is applied.

As a first device, a converter that converts AC power into DC power, an inverter that converts output power of the converter into AC power and drives an AC motor, and generates a pulse signal according to a frequency command for the AC motor. Inverter control means for providing a signal to the inverter to control the output voltage of the inverter; current detection means for detecting an AC current at the inverter output side; a detection output of the current detection means and a DC voltage value at the inverter input side or a target of the converter. A power calculating means for calculating an inverter input average power in an integral multiple of a half cycle of a carrier of the inverter based on an output voltage command value indicating an output voltage, and dividing the calculated power of the power calculating means by an AC voltage on the converter input side. A power supply current value calculating means for calculating a power supply current value and a DC voltage on an inverter input side are detected. Power supply current command value generation means for generating a power supply current command value for suppressing a deviation between a detection output of the voltage detection means and a DC voltage command indicating a target output voltage of the converter to zero; Amplitude command generation means for generating an amplitude command for specifying the amplitude of the power supply current from the current command value and the power supply current value; power supply phase detection means for detecting the phase of the power supply current on the converter input side; and power supply phase detection means A current command generating means for generating a current command from the detected output and the amplitude command; an input current detecting means for detecting an input current of the converter; and a means for reducing a deviation between a detected output of the input current detecting means and the current command to zero. According to the present invention, there is provided a control device for an AC motor including converter control means for controlling a converter by supplying a pulse signal to the converter.

As a second device, a converter for converting AC power to DC power, an inverter for converting the output power of the converter to AC power to drive the AC motor, and generating a pulse signal according to a frequency command for the AC motor, An inverter control means for supplying a signal to the inverter to control an output voltage of the inverter; a current detection means for detecting an AC current on the inverter output side; a voltage detection means for detecting a DC voltage on the inverter input side; Average current calculation means for calculating an inverter input average current in an integral multiple of a half cycle of the carrier of the inverter according to the detection output, and power for calculating an inverter input average power from the calculation current of the average current calculation means and the detection output of the voltage detection means. Calculating means and the calculated power of the power calculating means by the AC voltage on the inverter input side. And a power supply for generating a power supply current command value for suppressing a deviation between an output of the voltage detection means and an output voltage command indicating a target output voltage of the converter to zero. Current command value generation means, amplitude command generation means for generating an amplitude command for specifying the amplitude of the power supply current from the power supply current command value and the power supply current value, and a power supply for detecting the phase of the AC power supply on the converter input side Phase detection means, current command generation means for generating a current command from the detection output of the power supply phase detection means and the amplitude command, input current detection means for detecting the input current of the converter, detection output of the input current detection means and current command And a converter control means for controlling the converter by giving a pulse signal to the converter to suppress the deviation from zero to zero. A.

As a third device, a converter for converting AC power to DC power, an inverter for converting output power of the converter to AC power to drive the AC motor, and generating a pulse signal in accordance with a frequency command for the AC motor; An inverter control means for supplying a signal to the inverter to control an output voltage of the inverter; a current detection means for detecting an AC current on the inverter output side; a voltage detection means for detecting a DC voltage on the inverter input side; An average current calculating means for calculating an inverter input average current in an integral multiple of a half cycle of the carrier of the inverter based on the detected output; and an inverter input average power from the calculated current of the average current calculating means and the detection output of the voltage detecting means. Power calculation means for calculating, a detection output of the voltage detection means and a target output of the converter Power command value generating means for generating a power command value for suppressing the deviation from the output voltage command indicating the pressure to zero, and a power command value correcting means for correcting the power command value with the calculated power of the power calculating means. An amplitude command generating means for generating a power supply current amplitude command by dividing the corrected power command value by a converter input side AC voltage; a power supply phase detecting means for detecting a phase of the converter input side AC power supply; Current command generation means for generating a current command from the detection output of the phase detection means and the amplitude command; input current detection means for detecting the input current of the converter; and a deviation between the detection output of the input current detection means and the current command to zero. A control device for an AC motor, comprising: a converter control means for controlling the converter by supplying a pulse signal for suppression to the converter.

As a fourth device, a converter for converting AC power to DC power, an inverter for converting the output power of the converter to AC power to drive the AC motor, and a pulse signal is generated according to a frequency command for the AC motor. An inverter control means for supplying a signal to the inverter to control an output voltage of the inverter; a current detection means for detecting an AC current on the inverter output side; a voltage detection means for detecting a DC voltage on the inverter input side; Average current calculating means for calculating an inverter input average current in an integral multiple of a half cycle of the carrier of the inverter according to the detected output, and a converter input average power from the calculated current of the average current calculating means and a DC voltage command indicating a target output voltage of the converter Power calculating means for calculating the power, and converting the power calculated by the power calculating means into a Power supply current value calculation means for calculating a power supply current value by dividing by an input side AC voltage; and a power supply current command value for suppressing a deviation between the DC voltage command and a detection output of the voltage detection means to zero. Power supply current command value generation means, an amplitude command generation means for correcting the power supply current command value with the power supply current value to generate a power supply current amplitude command, and a power supply phase for detecting a phase of an AC power supply on the converter input side. Detecting means, a current command generating means for generating a current command from a detection output of the power phase detecting means and the amplitude command, an input current detecting means for detecting an input current of the converter, a detection output of the input current detecting means and a current command. And a converter control means for controlling the converter by supplying a pulse signal to the converter to suppress the deviation of the motor to zero.

As a fifth device, a converter for converting AC power to DC power, a plurality of inverters for converting the output power of the converter to AC power to drive a plurality of AC motors, and a pulse signal according to a frequency command for each AC motor. And a plurality of inverter control means for supplying the pulse signal to each inverter to control the output voltage of each inverter, a plurality of current detection means for detecting an AC current on the output side of each inverter, and a plurality of current detection means. Average current calculating means for calculating an inverter input average current in an integral multiple of a half cycle of the carrier of the inverter in accordance with the sum of the detection outputs, and a converter based on the calculated current of the average current calculating means and the amount of electricity on the inverter input side. As the control means, an AC having any one of the first to sixth devices is used. It is obtained by constituting the motive control device.

As a sixth device including any one of the second to fifth devices, the average current calculating means may be configured to determine whether the duty ratio of the pulse signal applied to the inverter is an integral multiple of the carrier half period of the inverter. The present invention constitutes a control device for an AC motor that integrates the detected current of the current detecting means for each phase and calculates an inverter input average current from the sum of the integrated values.

[Action]

The instantaneous input current of the inverter is equal to the sum of the motor currents during the period when the inverter positive arm for each phase is on. For this reason, the inverter input current becomes a positive / negative ripple current close to the amplitude of the motor current, and needs to be smoothed by a filter. Therefore, in the present invention, in order to detect a current equivalent to the instantaneous inverter input current, an AC current on the inverter output side is detected, and a current equivalent to the inverter input average current is detected from the detected current. . That is, as the inverter input average current, for example, the duty ratio (the ratio Ton / Tc between the on-time Ton of the inverter positive arm and the carrier period Tc) of the pulse signal applied to the inverter during the carrier period Tc and the AC voltage at the inverter output side The current is multiplied for each phase, and the sum of the multiplied values is obtained. That is, the average current during the carrier cycle is calculated,
The inverter input power is calculated from the calculated average current, and the converter is controlled based on the calculated power. For this reason, a power supply current value that is not affected by the ripple component can be generated. If an AC current is supplied to the converter in accordance with the power supply current value, even if the load of the motor fluctuates rapidly, the fluctuation can be followed. As a result, necessary AC power can be supplied to the converter, and fluctuations in the output voltage of the converter can be suppressed.

〔Example〕

 Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

In FIG. 1, AC power is supplied from an AC power supply 1 to a converter 3 via a reactor 2, and the AC power is converted into DC power in the converter 3 and supplied to a smoothing capacitor 4 and an inverter 6. The inverter 6 converts the DC power from the converter 3 into three-phase AC power and supplies it to the AC motor 5. The converter 3 is controlled by a PWM signal from a current controller 17, and the inverter 6 is controlled by a PWM signal from an inverter controller 7.

When controlling the converter 3, the voltage compensator 8 generates a power supply current command ΔIq * corresponding to the deviation between the detection output of the voltage detector 25 for detecting the voltage across the smoothing capacitor 4 and the DC voltage command V _DC *. and a the command and the power supply current value Iq _L is added by the adder 13, generates an amplitude command Iq * of the power source current through the limiter 14, and the command and supply phase is detected by the detector 16 phase theta _R A three-phase AC current command i * is generated by a current command generation circuit 15 based on the current, and a PW for controlling a deviation between the three-phase AC current command and the detection current i of the current detector 17 to zero is controlled.
An M signal is generated by the current controller 18, and the PWM signal controls the converter 3. That is, the PWM is set so that the three-phase AC current command i * matches the actual current i.
The converter 3 is controlled according to the signal. When calculating the three-phase AC power supply i, the three-phase AC power supply i is calculated according to the following equations (1) to (3) based on the phase θ _{R of the} R phase and the amplitude command Iq *.

I _R * = Iq * · sin θ _R …… (1) I _S * = Iq * · sin (θ _R −2 / 3π) …… (2) I _T * = − (i _S * + I _S *) (3) On the other hand, the inverter 6 is controlled by the PWM signal from the inverter controller 7 in accordance with the primary frequency command f1 *, and the power supply current value Iq _L is determined by the detection currents i _U and i _{V of the} current detector 10 and the inverter Based on the conduction ratio δ (δ _U , δ _V , δ _W ) which is the output of the controller 7, the calculation is performed by the arithmetic unit 9, the multiplier 11 and the gain 12 which are constituted by a microcomputer. .

As shown in FIG. 2, the inverter controller 7 includes an integrator 19, a _KH / f1 * pattern generator 20, a modulated wave command generator 2,
1, a triangular wave generator 22, a comparator 23, and a conduction ratio calculator 24. When the frequency command f1 * is input to the integrator 19 and the pattern generator 20, a command for the amplitude ratio of the modulated wave M * corresponding to the magnitude of the primary voltage is issued from the pattern generator 20.
K _H is output, and the integrator 19 outputs a phase command θ * obtained by integrating the command f1 *. When these commands are input to the modulated wave command generator 21, modulated wave commands for each phase are output in accordance with the following equations (4) to (6).

M _U * = K _H · sin θ * ... (4) M _V * = K _H · sin (θ * −2 / 3π) …… (5) M _W * = K _H · sin (θ * −4 / 3π) Here, K _H indicates a ratio of the amplitude of the modulated wave to the amplitude of the triangular wave. When the modulated wave M * shown in the equations (4) to (6) is output from the modulated wave command generator 21, the comparator 23 outputs a triangular wave signal (1-2 KHz) from the triangular wave generator 22 and a carrier of the triangular wave. The comparison is performed every cycle Tc, and the comparator 23 outputs a PWM signal. On the other hand, when the modulated wave M * is input to the duty ratio calculator 24, the duty ratio is calculated according to the following equations (7) to (9).

Here, the conduction ratio δ represents the ratio of the pulse signal of each phase and the ON time during the carrier cycle Tc, and is usually 0
It is a value in the range of ≦ δ ≦ 1.

The conduction ratio δ calculated by the arithmetic unit 24 is input to the arithmetic unit 9, and the arithmetic unit 9 calculates the inverter input average current according to the following equation (10) together with the current detected by the current detector 10. Is calculated.

If the current of each phase of the pulse signal applied to the inverter 6 is multiplied by the AC current of each phase on the inverter output side according to the equation (10), and the current is obtained from the sum of the multiplied values, this current is obtained by the inverter It becomes a current equivalent to the input average current. That is, it is considered that the input current of the electric motor 5 hardly changes during the carrier cycle Tc, and the average input current of the inverter 6 is determined from the equation (10).

Here, the conduction ratio δ is generally expressed by the following equations (11) to (1).
Equation (3) is given. In the case of sine wave PWM modulation, equation (7)
Equation (9) will be used.

Thus, the inverter input average current is the carrier cycle
It becomes a current obtained by averaging the inverter input current during Tc, and can be used as a DC current with little ripple. In the present embodiment, the conduction ratio for each carrier cycle is calculated by equation (10). Can be detected in the same manner by calculating from the conduction ratio of an integral multiple of the carrier half cycle Tc / 2.

The (0,0,0) and (1,1,1) sections of the three-phase PWM signal are generally called a zero voltage vector section, and no inverter input current flows in this section. Therefore, it can be similarly detected by obtaining from the conduction ratio in a section excluding the zero voltage vector section.

Inverter input average current calculated by operation unit 9 In calculator 11, it is multiplied by the detected voltage V _DC voltage detector 25 for detecting an input voltage of the inverter 6, the inverter average input power P _L is adapted to be calculated. This calculated voltage
P _L is divided by the power supply voltage 3Ve of the AC power supply 1 with a gain of 12, and is converted into a power supply current value Iq _L.
By controlling the converter 3 on the basis of the power source current value Iq _L, the inverter average input current Is detected instantaneously with a small ripple component, so that even if the load of the inverter 6 changes suddenly, the power supply current can be supplied to the inverter 3 in accordance with the change in the load, and the DC voltage of the converter 3 can be increased. Fluctuation and motor 5
Can be suppressed. Also calculated power
Since P _L has a small ripple component, the value of the power supply current value Iq _L is also substantially constant, and the power supply current amplitude command Iq * can be maintained substantially constant, and the power factor is 1 and the low-order harmonic component is small. A sinusoidal power supply current can be obtained.

Next, as shown in FIG. 3, the adder 13 and the limiter
Insert a gain of 12 between 14 and the output of multiplier 11 to adder
13 to use the voltage compensator 8 as a power command value generating means. That is, the voltage compensator 8 compares the DC voltage command value V _DC with the DC voltage command V _DC * to generate a power command value ΔPq for suppressing the deviation to zero, and adds the power command value ΔPq to the adder Then, the adder 13 outputs the added power command value Pq. And this power command value
Pq is divided by a power supply voltage having a gain of 12, and the obtained value is generated as a power supply current amplitude command Iq * via a limiter.

In this embodiment, the same effects as in the above embodiment can be obtained.

Next, as shown in FIG. 4, a multiplier 26 is used in place of the gain 12, and the inverter input average current And multiplies the DC voltage command V _DC *, to obtain the same effect as the embodiment by calculating the power supply current value Iq _L by dividing the AC voltage of the AC power source 1 to the electric power obtained by multiplying be able to. In this case, when DC voltage command V _DC * = input voltage V _{DC of} inverter 6, approximate load compensation can be performed.

Next, an embodiment in which a plurality of inverters are connected in parallel to one converter will be described with reference to FIG.

Smoothing capacitors 4A to 4N and inverters 6A to 6N are respectively connected in parallel to the output side of converter 3, and AC motors 5A to 5N are connected to the output side of each inverter. And the current detector is on the output side of each inverter 6A ~ 6N
10A to 10N are provided, and each inverter is provided with inverter controllers 7A to 7N and arithmetic units 9A and 9N.
The outputs of the operation units 9A to 9N are input to the adder 27.

In the present embodiment, in the calculation units 9A to 9N, the inverter input average current of each inverter 6A to 6N , And these calculated values are added by the adder 27 to obtain the inverter input average current of the entire inverter. And the output current of adder 27 The input to the multiplier 11, and to seek input power P _L of the entire inverter.

Also in the present embodiment, as in the previous embodiment, even if the torque of each of the AC motors 5A to 5N fluctuates, the power supply current corresponding to the torque fluctuation is immediately input to the converter 3, so that the Torque fluctuation can be suppressed, and a sinusoidal power supply current can flow to converter 3.

In each of the above embodiments, since the average input current of the inverter 6 can be obtained without detecting the input current of the inverter 6, a current detector for detecting the current on the input side of the inverter 6 becomes unnecessary, which contributes to cost reduction. can do. Further, in the embodiment of the present invention, the current control part has been described in the AC current control system in which the power supply current is controlled by an AC amount. The same effect can be obtained by the method.

In addition, the inverter input average current detection method described in the present invention can instantaneously detect an inverter input current with a DC amount, and thus can be applied not only to converter control but also to various motor control detectors. For example, this detector can also be used for suppressing vibration of an induction motor at a light load.

〔The invention's effect〕

As described above, according to the present invention, a current equivalent to the inverter input average current is obtained from the inverter output current, and the converter is controlled based on this current value. On the other hand, a power supply current corresponding to the load fluctuation can be immediately passed through the converter,
It is possible to reduce the fluctuation of the output voltage of the converter and the fluctuation of the torque of the electric motor. Also, since the inverter input power is calculated based on the inverter input average current,
The power supply current value due to the fluctuation of the load becomes a constant DC amount, and a sinusoidal power supply current with a power factor of 1 and a small low-order harmonic component can flow through the converter. Further, a current detector on the inverter input side is not required.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is a block diagram of an inverter controller, FIG. 3 is a block diagram showing a second embodiment of the present invention, and FIG. FIG. 5 is a configuration diagram showing a third embodiment, and FIG. 5 is a configuration diagram showing a fourth embodiment of the present invention. 1 ... AC power supply, 3 ... Converter, 6 ... Inverter, 7 ... Inverter controller, 9 ... Calculation unit, 10 ... Current detector, 11 ... Multiplier, 12 ... Gain, 13 ... Adder, 14… Limiter, 15… Current command generation circuit, 16… Power supply phase detector, 17… Current detector, 18… Current controller, 21… Modulated wave command generator, 24… Conductivity calculator, 25… Voltage detector, 26… Multiplier, 27… Adder.

Continuation of front page (56) References JP-A-60-66691 (JP, A) JP-A-63-124797 (JP, A) JP-A-63-148883 (JP, A) (58) Fields investigated (Int) .Cl. ⁶ , DB name) H02P 5/408-5/412 H02P 7/628-7/632 H02P 21/00

Claims (11)

(57) [Claims] An inverter converts the output power of the converter into AC power, and when the AC power is used to drive an AC motor, an AC current on the inverter output side and a DC voltage on the inverter input side are detected. An inverter input average current in an integral multiple of a half cycle of the carrier of the inverter is calculated, an inverter input power is calculated from the calculated average current and the detected DC voltage, and the calculated power is divided by an AC voltage on the converter input side. A power supply current value is generated, and a power supply current command value for suppressing these deviations to zero is generated from the detected DC voltage on the inverter input side and an output voltage command indicating the target output voltage of the converter. The value is corrected by the power supply current value, and a pulse signal based on the corrected power supply current command value is provided to the converter to input the converter. Control method for an AC motor that performs control to follow the side of current to the corrected power current command value. 2. An inverter converts the output power of the converter into AC power and, when driving the AC motor by the AC power, detects an AC current on the inverter output side and a DC voltage on the inverter input side. An inverter input average current in an integral multiple of a half cycle of the carrier of the inverter is calculated from the pulse signal applied to the switching element of the inverter and the duty ratio, and the inverter input power is calculated from the calculated average current and the detection voltage. Then, the calculated power is divided by the AC voltage on the converter input side to generate a power supply current value, and these deviations are suppressed to zero from the detected DC voltage on the inverter input side and the output voltage command indicating the target output voltage of the converter. Power supply current command value for
The power supply current command value is corrected by the power supply current value, and a pulse signal based on the corrected power supply current command value is supplied to the converter so that the current on the converter input side follows the corrected power supply current command value. How to control the AC motor. 3. An inverter converts the output power of the converter into AC power, and exchanges the AC power with the AC power. When the AC power is used to drive the AC motor, the AC current on the inverter output side and the DC voltage on the inverter input side are converted. And calculating an inverter input average current in an integral multiple of a half cycle of a carrier of the inverter from the detected current and a duty ratio of a pulse signal applied to a switching element of the inverter, and calculating the calculated average current and the detection voltage. And the inverter input power is calculated from the detected voltage on the inverter input side and the output voltage command indicating the target output voltage of the converter to generate a power command value for suppressing these deviations to zero. The power input current is corrected by the inverter input power, and the corrected power command value is divided by the AC voltage on the converter input side. It generates a control method of the AC motor a converter input side of the current by applying a pulse signal based on the power source current command value to the converter performs control to follow the source current command value. 4. An inverter converts the output power of the converter into AC power and, when driving the AC motor with the AC power, detects an AC current on the inverter output side and a DC voltage on the inverter input side. An inverter input average current in an integral multiple of a half cycle of the carrier of the inverter is calculated from a duty ratio of a pulse signal applied to a switching element of the inverter, and the calculated average current and an output voltage command indicating a target output voltage of the converter are calculated. To calculate the inverter input power, divide the calculated power by the AC voltage on the converter input side to generate a power supply current value, and suppress these deviations to zero from the detected voltage on the inverter input side and the voltage command value. Power supply current command value, and corrects the command value with the power supply current value. The power supply current command value is corrected based on the corrected power supply current command value. Control method for an AC electric motor for performing control by applying a scan signal to the converter to follow the current of the converter input side to the corrected power current command value. 5. The converter according to claim 1, wherein said plurality of inverters convert the output power of said converter into AC power, and when each AC power drives a plurality of AC motors, an AC current at each inverter output side and a DC voltage at the inverter input side are detected. Calculating an inverter input average current in an integral multiple of a half cycle of the carrier of the inverter according to each detection current, and controlling the converter based on the calculated average current and the detection voltage, Or a control method for an AC motor to which the control method according to 4 is applied. 6. A converter for converting AC power to DC power, an inverter for converting output power of the converter to AC power to drive an AC motor, and generating a pulse signal in accordance with a frequency command for the AC motor. To the inverter to control the output voltage of the inverter, current detection means for detecting the AC current on the inverter output side, the detection output of the current detection means and the DC voltage value on the inverter input side or the target output of the converter. A power calculating means for calculating an inverter input average power in an integral multiple of a half cycle of a carrier of the inverter based on an output voltage command value indicating a voltage; and a power supply which divides the calculated power of the power calculating means by an AC voltage on the converter input side. A power supply current calculation means for calculating a current value, and a power supply current detection means for detecting a DC voltage on the inverter input side. Detection means; power supply current command value generation means for generating a power supply current command value for suppressing a deviation between a detection output of the voltage detection means and a DC voltage command indicating a target output voltage of the converter to zero; Amplitude command generation means for generating an amplitude command for specifying the amplitude of the power supply current from the value and the power supply current value; power supply phase detection means for detecting the phase of the power supply current on the converter input side; Current command generating means for generating a current command from an output and an amplitude command; input current detecting means for detecting an input current of a converter; and a pulse signal for reducing a deviation between a detected output of the input current detecting means and the current command to zero. A control device for an AC motor, comprising a converter control means for controlling the converter by giving the power to the converter. 7. A converter for converting AC power into DC power, an inverter for converting output power of the converter into AC power to drive an AC motor, and generating a pulse signal in accordance with a frequency command for the AC motor. To the inverter to control the output voltage of the inverter, current detection means for detecting an AC current on the inverter output side, voltage detection means for detecting a DC voltage on the inverter input side, and detection of the current detection means Average current calculating means for calculating an inverter input average current in an integral multiple of a half cycle of the carrier of the inverter according to the output, and power calculation for calculating an inverter input average power from the calculated current of the average current calculating means and the detection output of the voltage detecting means. And the power calculated by the power calculation means by the AC voltage on the input side of the inverter. Power supply current value calculation means for generating a power supply current value; and a power supply current command value for generating a power supply current command value for suppressing a deviation between an output of the voltage detection means and an output voltage command indicating a target output voltage of the converter to zero. Generating means, an amplitude command generating means for generating an amplitude command for specifying an amplitude of a power supply current from the power supply current command value and the power supply current value, and a power supply phase detecting means for detecting a phase of an AC power supply on the converter input side Current command generating means for generating a current command from a detection output of the power supply phase detecting means and the amplitude command,
Input current detection means for detecting the input current of the converter,
A control device for an AC motor, comprising: converter control means for controlling a converter by supplying a pulse signal for suppressing a deviation between a detection output of an input current detection means and a current command to zero to the converter. 8. A converter for converting AC power into DC power, an inverter for converting output power of the converter into AC power to drive an AC motor, and a pulse signal generated according to a frequency command for the AC motor. To the inverter to control the output voltage of the inverter, current detection means for detecting an AC current on the inverter output side, voltage detection means for detecting a DC voltage on the inverter input side, and detection of the current detection means Average current calculating means for calculating an inverter input average current in an integral multiple of a half cycle of the carrier of the inverter based on the output, and calculating an inverter input average power from a calculated current of the average current calculating means and a detection output of the voltage detecting means. Power calculating means, and the detected output of the voltage detecting means and the target output voltage of the converter. Power command value generating means for generating a power command value for suppressing the deviation from the output voltage command to zero, power command value correcting means for correcting the power command value with the calculated power of the power calculating means, Amplitude command generating means for generating the power supply current amplitude command by dividing the obtained power command value by the converter input side AC voltage, power supply phase detection means for detecting the phase of the converter input side AC power supply, and power supply phase detection Current command generation means for generating a current command from the detection output of the means and the amplitude command; input current detection means for detecting an input current of the converter; and a deviation between a detection output of the input current detection means and the current command is reduced to zero. Control device for controlling a converter by supplying a pulse signal to the converter for controlling the converter. 9. A converter for converting AC power to DC power, an inverter for converting output power of the converter to AC power to drive an AC motor, and a pulse signal generated according to a frequency command for the AC motor. To the inverter to control the output voltage of the inverter, current detection means for detecting an AC current on the inverter output side, voltage detection means for detecting a DC voltage on the inverter input side, and detection of the current detection means Average current calculating means for calculating an inverter input average current in an integral multiple of a half cycle of the carrier of the inverter according to the output; and an inverter input average power based on the calculated current of the average current calculating means and a DC voltage command indicating a target output voltage of the converter. Power calculating means for calculating, and the power calculated by the power calculating means A power supply current value calculating means for calculating a power supply current value by dividing by a side AC voltage; and a power supply current command value for suppressing a deviation between the DC voltage command and a detection output of the voltage detecting means to zero. Power supply current command value generation means, amplitude command generation means for correcting the power supply current command value with the power supply current value to generate a power supply current amplitude command, and power supply phase detection for detecting the phase of the AC power supply on the converter input side Means, a current command generation means for generating a current command from a detection output of the power supply phase detection means and the amplitude command, an input current detection means for detecting an input current of the converter, and a detection output of the input current detection means and a current command. A control device for an AC motor, comprising: converter control means for controlling a converter by supplying a pulse signal for suppressing the deviation to zero to the converter. 10. A converter for converting AC power to DC power, a plurality of inverters for converting output power of the converter to AC power and driving a plurality of AC motors, respectively.
A plurality of inverter control means for generating a pulse signal in accordance with a frequency command for each AC motor and supplying the pulse signal to each inverter to control an output voltage of each inverter, and a plurality of currents for detecting an AC current at each inverter output side Detection means, and average current calculation means for calculating an inverter input average current in an integral multiple of a half cycle of the carrier of the inverter in accordance with the sum of detection outputs of the respective current detection means. 10. The AC motor control device according to claim 6, 7, 8, or 9, as means for controlling the converter based on the amount of electricity on the side. 11. An average current calculating means for each phase integrates a duty ratio of a pulse signal applied to an inverter and a detection current of a current detecting means in an integral multiple of a half cycle of a carrier of the inverter. 11. The AC motor control device according to claim 7, wherein the inverter input average current is calculated from the sum of the values.