JPH04121059A - Power converter - Google Patents

Abstract

PURPOSE:To increase the power factor of a power source greatly and to downsize and lighten a device, by controlling the output current of a 3-phase rectifier circuit so as to be a direct current of constant amplitude, even when a single 3-phase rectifier circuit and a single booster chopper circuit are used. CONSTITUTION:When the output power of a motor 10 is constant, if the DC voltage Vdc of a capacitor 3 is controlled so as to be constant, the average value Idc of the input current of an inverter 9 becomes an approximately constant direct current, the output current Ix of a rectifier circuit 2 becomes a direct current too, and the power factor of the power source becomes comparatively large. Next when the load of the motor 10 increases suddenly, a capacitor current (ic) flows to discharge, so the DC voltage Vdc decreases. As a result, the gate-on period of a switching power element 5 becomes longer, energy stored in a DC reactor 4 is transferred to a smoothing capacitor 3 through a block diode 6, the DC voltage Vdc rises and becomes approximately equal to the same value as a voltage command V'dc.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a power conversion device, and particularly to a power conversion device suitable for driving a load according to the output power of a converter that converts three-phase AC power into DC power. Regarding.

[Conventional technology]

Conventionally, when a three-phase full-wave rectification converter is used as the DC power source for a voltage-type inverter, a pulsed power supply current flows through the converter.

In addition to causing trouble to the power system, the power factor of the power source is 0.6~
It is small at 0.7. Therefore, as a method for improving the power factor of a power supply, for example, as discussed in the 1990 National Conference of the Institute of Electrical Engineers of Japan 479 (pp. 5-27 to 5-28), a method equivalent to a voltage-type PWM inverter has been proposed. It has been proposed to provide a device on the converter side and perform PWM control on the converter so that a sinusoidal power supply current flows with a power factor of 1. According to this method, power regeneration can be performed and the three-phase power supply current can be controlled in a sinusoidal manner with a power factor of approximately 1, but there is a problem in that the price of the converter device is extremely high.

On the other hand, a power factor correcting converter is used to improve the power factor of a power supply, as described in Japanese Patent Application Laid-Open No. 19887-1987, which uses three three-phase rectifier circuits and a smoothing capacitor. Three step-up chopper circuits are installed between the
A device in which a sinusoidal power supply current flows with a power factor of 1 has been proposed.

[Problem to be solved by the invention]

The above conventional technology allows a sinusoidal power supply current to flow and limits the three-phase power supply current to a sinusoidal waveform with a power factor of approximately 1, but on the other hand,
Means for detecting the power supply voltage and phase detection means for the power supply voltage are required, and in the case of three-phase power reception, three sets of single-phase rectifier circuits and step-up choppers must be provided. For this reason, it has been difficult to apply it to a general-purpose power converter that requires a low-cost product because the main circuit and control circuit are complicated.

An object of the present invention is to provide a power conversion device that can increase the power factor of a power source using a single three-phase rectifier circuit and a single boost chopper circuit.

[Means to solve the problem]

In order to achieve the above object, the present invention provides, as a first device, a three-phase rectifier circuit that rectifies a three-phase AC voltage, a step-up chopper circuit that boosts the output voltage of the three-phase rectifier circuit by chopping, and a step-up chopper. A smoothing element that smoothes the output signal of the circuit, a voltage detector that detects the output voltage of the smoothing element, and a voltage detector that suppresses the deviation between the voltage command for the output voltage of the boost chopper circuit and the detected output of the voltage detector to zero. A DC current command generation circuit that generates a DC current command, a DC current detector that detects the output current of the three-phase rectifier circuit, and a DC current detector that suppresses the deviation between the DC current command and the detection power of the DC current detector to zero. The boost chopper circuit has a pulse signal generation circuit that generates a pulse signal, and the step-up chopper circuit includes a reactor that accumulates the output charge of the rectifier circuit, and charges and discharges the charge accumulated in the reactor according to the pulse width of the pulse signal. This is a power converter including a switching element to be controlled.

The second device includes a three-phase rectifier circuit that rectifies a three-phase AC voltage, a boost chopper circuit that boosts the output voltage of the three-phase rectifier circuit by chopping, a smoothing element that smoothes the output signal of the boost chopper circuit, and a smoothing element that smoothes the output signal of the boost chopper circuit. A voltage detector detects the output voltage of the element, an inverter converts the output power of the smoothing element into AC power and drives the AC motor, and generates a pulse signal according to the frequency command for the AC motor and sends this pulse signal to the inverter. an AC current detector that detects the output current of the inverter; and an AC current detector that detects an output current of the inverter based on the detection output of the AC current detector, and an input of the inverter in an interval that is an integer multiple of the carrier half period of the inverter based on the detection output of the AC current detector. an average current calculation means for calculating an average current; a power calculation means for calculating the average input power of the inverter from the calculated current of the average current calculation means and the detection output of the voltage detector; An inverter input current command generation means for generating an inverter input current command by dividing by voltage, and a direct current command for suppressing the deviation between the voltage command for the output voltage of the boost chopper circuit and the detection output of the voltage detector to zero. A final DC current command generation circuit that generates a final DC current command according to the deviation between the DC current command and the inverter input current command, and a DC current that detects the output current of the three-phase rectifier circuit. The step-up chopper circuit includes a detector, and a pulse signal generation circuit that generates a pulse signal for suppressing the deviation between the final DC current command and the detection output of the DC current detector to zero, and the boost chopper circuit has an output of the rectifier circuit. This power conversion device includes a reactor that stores charge and a switching element that controls charging and discharging of the charge stored in the reactor in accordance with the pulse width of a pulse signal.

The third device includes a three-phase rectifier circuit that rectifies three-phase AC voltage, a boost chopper circuit that boosts the output voltage of the three-phase rectifier circuit by chopping, a smoothing element that smoothes the output signal of the boost chopper circuit, and a smoothing element that smoothes the output signal of the boost chopper circuit. A voltage detector detects the output voltage of the element, an inverter converts the output power of the smoothing element into AC power and drives the AC motor, and generates a pulse signal according to the frequency command for the AC motor and sends this pulse signal to the inverter. an AC current detector that detects the output current of the inverter; and an AC current detector that detects an output current of the inverter based on the detection output of the AC current detector, and an input of the inverter in an interval that is an integer multiple of the carrier half period of the inverter based on the detection output of the AC current detector. an average current calculation means for calculating an average current; a power calculation means for calculating an input average power of the inverter from the calculated current of the average current calculation means and a detection output of the voltage detector; and a voltage command and voltage for the output voltage of the smoothing element. A power command generation circuit that generates a power command to suppress the deviation from the detection output of the detector to zero, a power command correction circuit that corrects the power command with the power calculated by the power calculation means, and an output of the power command correction circuit. A DC current command circuit that generates a DC current command by dividing power by a three-phase AC voltage, and a pulse signal that generates a pulse signal to suppress the deviation between the DC current command and the detection output of the DC current detector to zero. The step-up chopper circuit includes a reactor that accumulates the output charge of the rectifier circuit, and a switching element that controls charging and discharging of the charge accumulated in the reactor according to the pulse width of the pulse signal. This is a configuration of a power converter device that is configured by:

The fourth device includes a three-phase rectifier circuit that rectifies a three-phase AC voltage, a boost chopper circuit that boosts the output voltage of the three-phase rectifier circuit by chopping, and a smoothing element that smoothes the output signal of the boost chopper circuit.

A voltage detector detects the output voltage of the smoothing element, an inverter converts the output power of the smoothing element into AC power and drives the AC motor, and generates a pulse signal according to a frequency command for the AC motor, and converts the pulse signal to the inverter. an inverter control means for controlling the output voltage of the inverter according to the output voltage of the inverter; an alternating current detector for detecting the output current of the inverter; an input power calculation means for calculating the input power of the input power calculation means; an inverter input current command generation means for generating an inverter input current command by dividing the calculated power of the input power calculation means by a three-phase AC voltage; A DC current command generation circuit that generates a DC current command to suppress the deviation between the voltage command and the detection output of the voltage detector to zero, and a final DC current command corresponding to the deviation between the DC current command and the inverter input current command. A generation circuit, a DC current detector that detects the output current of the three-phase rectifier circuit, and a pulse signal generator that generates a pulse signal to suppress the deviation between the final DC current command and the detection output of the DC current detector to zero. The step-up chopper circuit includes a reactor that accumulates the output charge of the rectifier circuit, and a switching element that controls charging and discharging of the charge accumulated in the reactor in accordance with the pulse width of the pulse signal. This is a configuration of a power converter device that is configured by:

The fifth device includes a three-phase rectifier circuit that rectifies a three-phase AC voltage, a boost chopper circuit that boosts the output voltage of the three-phase rectifier circuit by chopping, a smoothing element that smoothes the output signal of the boost chopper circuit, and a smoothing element that smoothes the output signal of the boost chopper circuit. A voltage detector detects the output voltage of the element, an inverter converts the output power of the smoothing element into AC power and activates the AC motor, and generates a pulse signal according to the frequency command for the AC motor, and converts the pulse signal to the inverter. an inverter control means for controlling the output voltage of the inverter according to the output voltage of the inverter; an alternating current detector for detecting the output current of the inverter; an input power calculation means for calculating the input power of the boost chopper circuit; a power command generation circuit for generating the power command for suppressing the deviation between the voltage command for the output voltage of the boost chopper circuit and the voltage detector to zero; a power command correction circuit that corrects the power calculated by the input power calculation means; a DC current command generation circuit that generates a DC current command by dividing the output power of the power command correction circuit by a three-phase AC voltage;
It has a pulse signal generation circuit that generates a pulse signal for suppressing the deviation between the DC current command and the detection output of the DC current detector to zero.

The step-up chopper circuit includes a reactor that accumulates the output charge of the rectifier circuit, and a switching element that controls charging and discharging of the charge accumulated in the reactor according to the pulse width of the pulse signal. This is a configuration of a conversion device.

The sixth device includes a three-phase rectifier circuit that rectifies a three-phase AC voltage, a step-up chopper circuit that boosts the output voltage of the three-phase rectifier circuit by chopping, and a plurality of smoothing elements that smooth the output signal of the step-up chopper circuit. , a voltage detector that detects the output voltage of the smoothing element, a plurality of inverters that convert the output power of the smoothing element into AC power and drive each of the multiple AC motors, and generates a pulse signal according to the frequency command for each AC motor. It has a plurality of inverter control means that applies this pulse signal to each inverter to control the output voltage of the inverter, and a plurality of alternating current detectors that detect the output current of each inverter. The power conversion device includes any one of the first to fifth devices for controlling the boost chopper circuit based on the detection output and a voltage command for the output voltage of the boost chopper circuit.

A seventh device including any one of the first to sixth devices
As the device, a power conversion device is constructed in which a filter is provided on the input side of a three-phase rectifier circuit to remove ripple current accompanying switching of a switching element for a boost chopper.

[Effect]

When the output voltage of the smoothing element is in a steady state, the input power of the smoothing element is constant. Therefore, if the output voltage of the boost chopper circuit is controlled so that the output voltage of the smoothing element is constant, the DC current command to the rectifier circuit also becomes a command of a substantially constant DC amount.

Therefore, if the conduction rate of the switching element of the boost chopper circuit is controlled so that the actual current follows this current command, the output current of the rectifier circuit becomes a substantially constant direct current. As a result, the instantaneous phase voltage of the three-phase power supply is around 12
Current flows through each phase in the 0° section. That is, a 120° square wave power supply current flows, and the power supply power factor becomes approximately 0.96.

Similarly, in a steady state where the load on the motor is constant, the input power to the inverter is constant. At this time, if the boost chopper circuit is controlled so that the output voltage of the smoothing element is constant, the output power command to the rectifier circuit also becomes a nearly constant DC amount command. Therefore, if the conduction rate of the boost chopper is controlled so that the actual current follows this DC current command,
The output current of the rectifier circuit is a substantially constant direct current. As a result.

Current flows in each phase in the 120° section where the instantaneous phase voltage of the three-phase power supply is around the maximum and minimum. That is, a 120° square wave power supply current flows, and the power factor of the power supply can be significantly improved to approximately 0.96.

In addition, since the inverter output current is detected and the DC current command is corrected based on this detected current, it is possible to suppress fluctuations in the output voltage of the smoothing element even if the motor load changes suddenly. This makes it possible to reduce torque fluctuations of the electric motor.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

In FIG. 1, the power converter includes a three-phase aftereffect rectifier circuit 2.
It is equipped with a step-up chopper circuit 7 and a smoothing capacitor 3, and is connected to the input side of the three-phase full-wave rectifier circuit 2 or the three-phase AC power supply 1, and the capacitor 3 is connected to the induction motor 1 via the voltage type inverter 9.
Connected to 0.

The boost chopper circuit 7 includes a DC reactor 4, a switching power element 5, and a block diode 6. The output charge of the rectifier circuit 2 is accumulated in the DC reactor 4, and the charge and discharge of the electric charge accumulated in the reactor 4 is transferred to the switching power element. 5 to output a boosted DC signal to the capacitor 3 via the block diode 6. In order to control the switching of the switching power element 5, a voltage detector 1 is used.
1. Subtractor 13. DC voltage control circuit 14, DC current detector 15. A subtracter 16 and a current rectifier circuit 17 are provided, and the output of the current control circuit 17 is connected to the switching power element 5.

Further, an inverter control device 8 is provided for converting the input voltage of the inverter 9 into an alternating current voltage of variable frequency to control the induction motor 10 at variable speed.

The subtracter 13 outputs a signal corresponding to the deviation between the voltage command Vdc for the output voltage of the boost chopper circuit 7 and the detected output of the voltage detector 11 to the DC voltage control circuit 14. The DC voltage control circuit 14 includes a proportional-integral element and a limiter circuit, and is configured to generate Ix DC current commands for suppressing the signal from the subtracter 13 to zero. That is, the subtracter 13 and the DC voltage control circuit 14 are configured as a DC current command generation circuit. This DC current command Ix tree is input to a subtracter 16, and the subtracter 16 outputs a signal according to the deviation between the DC current command Ix tree and the detection output Ix of the current detector 15. The current control circuit 17 is configured to generate a pulse signal for suppressing the signal from the subtracter 16 to zero. That is, the subtracter 16 and the current control circuit 17 are configured as a pulse signal generation circuit. This pulse signal is then input to the base of the switching power element 5.

Next, the operation will be explained. First, when the output power of the electric motor 10 is constant, the input power PL of the inverter 9 is also constant. Therefore, when the DC voltage Vdc of the capacitor 3 is controlled to be constant, the average value Idc of the input current of the inverter 9 also becomes a substantially constant DC current. Here, if the loss of the boost chopper circuit 7 is ignored because it is relatively small, it is necessary to supply the load power equivalent to the power PL from the power supply 1, for example, PL=2
In the case of 700W, the average value VRC of the output voltage of the rectifier 2 is 1.35×200V2270V in the case of 20OV power reception. Further, the output current Ix of the rectifier circuit 2 becomes an average current from PL/VRC to IOA. In this way, when the load is constant, if the DC voltage is controlled to be almost constant, the output current command Ix tree of the rectifier circuit 2 will also be a nearly constant DC amount, and the detected current Ix of the current detector 15 will follow Ix. Therefore, the output current Ix of the rectifier circuit 2 also flows as a direct current.

That is, as shown in FIG. 2, when the output current Ix of the rectifier circuit 2 is made to flow as a direct current with a constant amplitude IXO, the output current Ixo of the rectifier circuit 2 between the maximum and minimum two phases of the power supply 1 flows, the three-phase power supply current IR+ ls+
A 12o square wave current with an amplitude of 1xo will flow through IT.

When a 12° square wave current flows as the power supply current, the power supply power factor cos ψ is expressed by the following equation (1).

■□ is the instantaneous power supply voltage and ■□=J-E-51no. Further, ■ is the effective value of the 120° square wave power supply current including harmonic current, and 11 is the instantaneous fundamental wave power supply current. Next, the effective value of the harmonic component of the 120° square wave current is given by equation (2).

Here, n is an odd number, and if the effective power in equation (1) is P, it is given by the following equation.

Next, the apparent power S is given by equation (4).

=0.81 ・E-TXO・・・・・・・・・(4) As a result, the power source power factor cosψ is P/S, so cosψ−0
,96. The reason why the power source power factor is relatively large in this manner is that in the case of a 1206 square wave current, no third harmonic current occurs.

Next, when the load on the motor 10 suddenly increases, the input current idc of the inverter 9 increases, and the capacitor current ic is discharged, so the current ic becomes negative and the DC voltage Vdc decreases.

As a result, the number of direct current command Ix trees increases, and the gate-on period of the switching power element 5 becomes longer.

As a result, the detected value Ix of the current detector 15 increases, so that the energy stored in the DC reactor 4 increases. This energy is transferred to the smoothing capacitor 3 via the block diode 6 during the gate-off period of the switching power element 5.

As a result, the DC voltage Vdc rises, and the feedback system operates so that this voltage substantially matches the voltage command Vdc*, so that the average value Idi of the diode current and the average value Idc of the input current of the inverter 9 match. Further, when the load decreases, the operation opposite to the above-mentioned operation is performed, the DC current command IX decreases, the gate-on period of the switching power element 5 becomes shorter, and the average value Idi of the diode current decreases.
decreases. Therefore, even if the load on the motor changes suddenly, the output voltage and output current of the chopper circuit 7 can be maintained in a constant state.

As described above, according to this embodiment, a single rectifier circuit 2 and a boost chopper circuit 7 are provided, and by controlling the output current of the rectifier circuit 2 so that a direct current flows, a square wave current of 1200 1ljX1, the power factor of the power source can be significantly improved to 0.96 even with a simple circuit configuration.

As a result, when the power source power is constant, the power source current can be reduced.

In addition, by controlling the output current of the rectifier port $2 to be a direct current, there is no need to detect the power supply voltage or the power supply voltage phase, and even in the case of three-phase power reception, a single rectifier circuit 2 and a single A power converter can be configured by simply providing the step-up chopper circuit 7, and a small and inexpensive power converter can be configured. Furthermore, since the current 1dl flowing from the boost chopper circuit 7 to the capacitor 3 has a constant amplitude and contains almost no ripple current, the allowable ripple current of the smoothing capacitor 3 can be reduced. As a result, the capacitance of the smoothing capacitor 3 can be reduced.

Next, another embodiment of the present invention is shown in FIG.

This embodiment differs from the one shown in FIG. 1 in that it greatly suppresses fluctuations in the DC voltage of the capacitor 3 and improves the power factor even when the load on the motor 10 changes suddenly. However, the AC current detector 18 that detects the output current of the inverter 9 and the AC current detector 18
an inverter input current calculator 19 as an average current calculation means for calculating the average input current of the inverter 9 in an integral multiple period of the carrier half period of the inverter 9 based on the detected current of the inverter 9; and a calculated current and voltage detector of the calculator 19. A power calculator 20 as a power calculation means calculates the input average power of the inverter 9 from the output of the power calculator 11, and the inverter input current command Iz is obtained by dividing the output power of the power calculator 20 by the three-phase AC voltage of the AC power supply 1. An inverter input current command generator 21 is provided as an inverter input current command generating means, and an adder 22 is provided between the DC voltage control circuit 14 and the subtracter 16 to add the outputs of the inverter input current generator 21. The information is input to the device 22.

The average value Idc of the inverter input current is obtained from the following equation (5).

1 d c = −(iu−Tu+ 1v−Tv+iw
-Tw) ---(5) where Tc is the carrier period of the inverter and T u.

Tv and Tw are the pulse widths of each phase PWM signal in the Tc interval.

Further, iu, iv, and it are instantaneous motor current detection values detected by the current detector 18. Note that the gain of 1 is a constant of 1/VRC, ignoring the loss of the boost chopper circuit 7, and in the case of 200V power reception, the average value of the output voltage of the rectifier circuit 2 VRC is 270VRC is 270■, so K
1=1/270.

Therefore, if the input power PL of the inverter 9, which is the load of the capacitor 3, is instantaneously detected every carrier period Tc, and the average value Idc of the input current of the inverter 9 is determined from equation (5), Ix DC current commands = IL.

As a result, the output ΔIx tree of the DC current control circuit 14 becomes almost zero, and only the IL detection error is corrected. For this reason, even if the load on the motor 10 suddenly changes, the DC current It, is quickly detected and the DC current command Ix tree is changed, which reduces the delay in the operation of the DC voltage control circuit 14. unaffected. As a result, a power supply current corresponding to the load flows instantaneously, and fluctuations in the DC voltage Vdc even due to load disturbances can be significantly reduced. Furthermore, since the output current Ix of the rectifier circuit 2 is a direct current, 120
° A square wave power supply current flows, and the power factor of the power supply can be greatly improved to 0.96.

Next, a third embodiment of the present invention is shown in FIG.

In this embodiment, an arithmetic unit 19 and a power calculator 20 shown in FIG.
Instead, an inverter output power calculator 23 is used as a human power calculation means to calculate the detection output of the current detector 18, the primary voltage command v1 of the inverter 9, the primary voltage vector phase θV□, and the input power of the inverter 9. The other components are the same as those shown in FIG. 3. That is, in this embodiment, the loss of the inverter 9 is omitted, and the input power of the inverter 9, which becomes the load of the capacitor 3, is approximately detected.

Here, when calculating the output power of the inverter 9,
In the case of the sine wave modulation PWM method, the amplitude of the modulated wave (sine wave) corresponds to the magnitude v1 of the primary voltage, and the phase of the modulated wave is θ.
It becomes VL. Therefore, the effective portion of the motor current in the direction of the primary voltage vector is calculated using the following equation (6).

π 1 Therefore, the inverter input power Pt is determined from equation (7), and as in the embodiment of FIG. 3, DC voltage fluctuations due to load disturbance are significantly reduced.

Pt, ”=PxNv=K a ・V d c−V, Hon・I q ---(7) Here, Kα is a constant and α・Vdc−V1* is the magnitude of the actual inverter output voltage. , increases in proportion to Vdc.

Next, as a modification of FIG.
As shown in the figure.

In this embodiment, the constant generator 21 is connected to the adder 21 and the subtracter 16.
The DC voltage control circuit 14 is used as a power command generation circuit that generates a power command to suppress the deviation between the voltage command and the output of the voltage detector 11 to zero, and the adder 22 is used as a power command correction circuit. The constant generator 21 is used as a DC current command generation circuit, and the other configuration is the same as that shown in FIG. In this embodiment as well, effects similar to those in FIG. 3 can be obtained.

Further, a fifth embodiment of the present invention is shown in FIG. 6 as a modification of FIG. 4.

In this embodiment, the constant generator 2 is similar to the one shown in FIG.
1 is provided between the adder 22 and the subtracter 16, the DC voltage control circuit 14 is used as a power command generation circuit, and the adder 22
is used as the power command correction circuit, and the constant generator 21 is used as the DC current command generation circuit.Other configurations are the same as the one shown in FIG. Obtainable.

In each of the above embodiments, when the switching frequency fc of the boost chopper circuit 7 is very large, such as 10OkHz, the output current Ix of the rectifier circuit 2 becomes almost direct current, but the frequency fc
However, when the frequency becomes small, for example, 10kHz, the power element 5
Ripple current occurs due to switching. As a result,
A power supply current in which a switching frequency fc ripple current is superimposed on a 120' square wave current flows, and harmonics such as radio noise may become a problem. In case 2, as shown in Figs. 7 and 8, the AC power supply 1 and the rectifier circuit 2
A resonant filter 24 that resonates at the switching frequency fc and absorbs ripple current between the switching frequency fc and the switching frequency fc.
By absorbing only the C-pipe filter 25 or by providing a C-pipe filter 25, it is possible to remove the ripple current accompanying the switching of the power element 5, to allow a 120° square wave current to flow through the AC power supply 1, and to It is possible to prevent harmonic current disturbances such as noise from occurring. Note that the value of LC of the filter 24 is set so that LC=1/2π·fc.

Further, as shown in FIG. 9, a plurality of smoothing capacitors 38 to 3n and a plurality of inverters 98 to 9n are provided on the output side of the boost chopper circuit 7, and a plurality of induction motors 10a-10n are provided at the output of each inverter. In the system as well,
Each of the embodiments described above can be applied.

〔Effect of the invention〕

As explained above, according to the present invention, even if a single three-phase rectifier circuit and a single step-up chopper circuit are used, the output current of the three-phase rectifier circuit is controlled to be a DC current with a constant amplitude. The power factor of the power source can be greatly improved, and the device can be made smaller and lighter. Furthermore, since the inverter's output current is instantaneously detected and the rectifier circuit's output current is corrected according to this detected value, fluctuations in the inverter's input voltage can be sufficiently suppressed even if the motor load fluctuates rapidly. can.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram showing a first embodiment of the present invention, Fig. 2 is a waveform diagram for explaining the operation of the device shown in Fig. 1, and Fig. 3 is a configuration diagram showing a second embodiment of the invention. 4 is a block diagram showing a third embodiment of the present invention, FIG. 5 is a block diagram showing a fourth embodiment of the present invention, FIG. 6 is a block diagram showing a fifth embodiment of the present invention, FIG. 7 is a block diagram showing a sixth embodiment of the present invention, FIG. 8 is a block diagram showing a seventh embodiment of the present invention, and FIG. 9 is a block diagram showing an eighth embodiment of the present invention. 1... AC power supply, 2... Three-phase aftereffect rectifier circuit, 3... Smoothing capacitor, 4... DC reactor, 5... Switching power element, 6... Block diode, 7 - Step-up chopper circuit, 8... Inverter control device, 9... Inverter, 10... Induction motor. 1...Voltage detector, 13...Subtractor, 4...DC voltage control circuit, 5...DC current detector. 6... Subtractor, 17... Current control circuit, 8
... AC current detector, 9. Inverter input current calculator, O... Power calculator, 21... Constant generator, 2.
...Adder. 3...Inverter output current calculator. Agent Tatsu Unuma 30th AC 1r Genno; Reactor switch link ° Pafu Awako 70...Tsukutaisu-F Step-up drying 3 brim circuit voltage type in-Tawashima 1 Denryokurizuri! Hama voltage system ftp hand λ 't; FL Suikogu 1r Futaneri fJpchi L2 Figure Figure Figure Figure Figure Figure Figure Figure

Claims (1)

[Claims] 1. A three-phase rectifier circuit that rectifies a three-phase AC voltage, a boost chopper circuit that boosts the output voltage of the three-phase rectifier circuit by chopping, and a smoothing element that smoothes the output signal of the boost chopper circuit. , a voltage detector that detects the output voltage of the smoothing element, and a DC current command generator that generates a DC current command to suppress the deviation between the voltage command for the output voltage of the boost chopper circuit and the detected output of the voltage detector to zero. a DC current detector that detects the output current of the three-phase rectifier circuit; and a pulse signal generation circuit that generates a pulse signal to suppress the deviation between the DC current command and the detection power of the DC current detector to zero. The step-up chopper circuit includes a reactor that accumulates the output charge of the rectifier circuit, and a switching element that controls charging and discharging of the charge accumulated in the reactor according to the pulse width of the pulse signal. power conversion equipment. 2. A three-phase rectifier circuit that rectifies three-phase AC voltage, a boost chopper circuit that boosts the output voltage of the three-phase rectifier circuit by chopping, a smoothing element that smoothes the output signal of the boost chopper circuit, and an output voltage of the smoothing element. A voltage detector detects the output power of the smoothing element, an inverter converts the output power of the smoothing element into AC power and drives the AC motor, and generates a pulse signal according to the frequency command for the AC motor, and supplies this pulse signal to the inverter to drive the inverter. An inverter control means for controlling the output voltage, an alternating current detector for detecting the output current of the inverter, and an average input current of the inverter in an interval that is an integral multiple of the carrier half cycle of the inverter based on the detection output of the alternating current detector. average current calculation means for calculating the average input power of the inverter from the calculated current of the average current calculation means and the detection output of the voltage detector; an inverter input current command generating means that generates an inverter input current command using the inverter input current command; and a DC current that generates a DC current command for suppressing the deviation between the voltage command for the output voltage of the boost chopper circuit and the detected output of the voltage detector to zero. a command generation circuit; a final DC current command generation circuit that generates a final DC current command according to the deviation between the DC current command and the inverter input current command; a DC current detector that detects the output current of the three-phase rectifier circuit; and a pulse signal generation circuit that generates a pulse signal for suppressing the deviation between the final DC current command and the detection output of the DC current detector to zero, and the boost chopper circuit accumulates the output charge of the rectifier circuit. A power conversion device that includes a reactor and a switching element that controls charging and discharging of charges accumulated in the reactor according to the pulse width of a pulse signal. 3. A three-phase rectifier circuit that rectifies three-phase AC voltage, a boost chopper circuit that boosts the output voltage of the three-phase rectifier circuit by chopping, a smoothing element that smoothes the output signal of the boost chopper circuit, and an output voltage of the smoothing element. A voltage detector detects the output power of the smoothing element, an inverter converts the output power of the smoothing element into AC power and drives the AC motor, and generates a pulse signal according to the frequency command for the AC motor, and supplies this pulse signal to the inverter to drive the inverter. An inverter control means for controlling the output voltage, an alternating current detector for detecting the output current of the inverter, and an average input current of the inverter in an interval that is an integral multiple of the carrier half cycle of the inverter based on the detection output of the alternating current detector. an average current calculation means for calculating the average input power of the inverter from the calculated current of the average current calculation means and a detection output of the voltage detector; and a voltage command for the output voltage of the smoothing element and detection of the voltage detector. A power command generation circuit that generates a power command to suppress the deviation from the output to zero, a power command correction circuit that corrects the power command with the power calculated by the power calculation means, and a three-phase power command correction circuit that adjusts the output power of the power command correction circuit A DC current command circuit that generates a DC current command by dividing by an AC voltage, and a pulse signal generation circuit that generates a pulse signal to suppress the deviation between the DC current command and the detection output of a DC current detector to zero. The step-up chopper circuit includes a reactor that accumulates the output charge of the rectifier circuit, and a switching element that controls charging and discharging of the charge accumulated in the reactor according to the pulse width of the pulse signal. power conversion equipment. 4. A three-phase rectifier circuit that rectifies three-phase AC voltage, a boost chopper circuit that boosts the output voltage of the three-phase rectifier circuit by chopping, a smoothing element that smoothes the output signal of the boost chopper circuit, and an output voltage of the smoothing element. A voltage detector detects the output power of the smoothing element, an inverter converts the output power of the smoothing element into AC power and drives the AC motor, and generates a pulse signal according to the frequency command for the AC motor, and supplies this pulse signal to the inverter to drive the inverter. An inverter control means that controls the output voltage, an alternating current detector that detects the output current of the inverter, and an input power of the inverter is calculated according to the detected output of the alternating current detector, the primary voltage command of the inverter, and the primary voltage vector phase. Inverter input current command generating means generates an inverter input current command by dividing the power calculated by the input power calculating means by a three-phase AC voltage, and voltage command and voltage detection for the output voltage of the boost chopper circuit. a DC current command generation circuit that generates a DC current command to suppress the deviation from the detected output of the inverter to zero; a final DC current command generation circuit that responds to the deviation between the DC current command and the inverter input current command; It has a DC current detector that detects the output current of the phase rectifier circuit, and a pulse signal generation circuit that generates a pulse signal to suppress the deviation between the final DC current command and the detection output of the DC current detector to zero. ,
The step-up chopper circuit is a power converter that includes a reactor that accumulates the output charge of the rectifier circuit, and a switching element that controls charging and discharging of the charge accumulated in the reactor according to the pulse width of the pulse signal. Device. 5. A three-phase rectifier circuit that rectifies three-phase AC voltage, a boost chopper circuit that boosts the output voltage of the three-phase rectifier circuit by chopping, a smoothing element that smoothes the output signal of the boost chopper circuit, and an output voltage of the smoothing element. A voltage detector detects the output power of the smoothing element, an inverter converts the output power of the smoothing element into AC power and drives the AC motor, and generates a pulse signal according to the frequency command for the AC motor, and supplies this pulse signal to the inverter to drive the inverter. An inverter control means that controls the output voltage, an alternating current detector that detects the output current of the inverter, and an input power of the inverter is calculated according to the detected output of the alternating current detector, the primary voltage command of the inverter, and the primary voltage vector phase. a power command generation circuit that generates a power command for suppressing the deviation between the voltage command for the output voltage of the boost chopper circuit and the voltage detector to zero; A power command correction circuit that corrects the calculated power; a DC current command generation circuit that generates a DC current command by dividing the output power of the power command correction circuit by a three-phase AC voltage; and detection of the DC current command and DC current detector. The step-up chopper circuit includes a pulse signal generation circuit that generates a pulse signal to suppress the deviation from the output to zero, and the boost chopper circuit includes a reactor that accumulates the output charge of the rectifier circuit, and a A power conversion device configured to include a switching element that controls charging and discharging according to the pulse width of a pulse signal. 6. A three-phase rectifier circuit that rectifies three-phase AC voltage, a step-up chopper circuit that boosts the output voltage of the three-phase rectifier circuit by chopping, a plurality of smoothing elements that smooth the output signal of the step-up chopper circuit, and a plurality of smoothing elements that smooth the output signal of the step-up chopper circuit. a voltage detector that detects the output voltage; a plurality of inverters that convert the output power of the smoothing element into AC power and drive each of the plurality of AC motors;
A plurality of inverter control means that generate a pulse signal according to a frequency command for each AC motor and apply this pulse signal to each inverter to control the output voltage of the inverter, and a plurality of AC current detectors that detect the output current of each inverter. The step-up chopper circuit is controlled based on the detection output of each alternating current detector and the voltage command for the output voltage of the step-up chopper circuit.
6. A power conversion device having the device described in 2, 3, 4 or 5. 7. The power conversion device according to any one of claims 1 to 6, further comprising a filter provided on the input side of the three-phase rectifier circuit to remove ripple current accompanying switching of the switching element for the boost chopper.