JP2990723B2 - Power regeneration voltage type inverter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Industrial Field of the Invention The present invention relates to a power supply regenerative voltage type inverter, and in particular, to a variable speed function of an induction machine and a control capable of continuously adjusting a power supply power factor from a lead to a delay. The present invention relates to a voltage-source inverter having a phase function and a waiting function.

B. Summary of the Invention The present invention relates to a power supply regenerative voltage inverter having a forward conversion circuit having a system harmonic suppression function, in which a system harmonic component is detected with instantaneous real power, and an instantaneous Add the imaginary power and the fundamental reactive power command to obtain the real power to the load from the DC voltage and current of the inverse conversion circuit, add it to the instantaneous real power to obtain the current command of the forward conversion circuit, A stable power supply to the inverter load can be performed while enhancing the suppression effect, and the power factor can be continuously adjusted.

C. Conventional technology Voltage-source inverters can regenerate power to the power supply by constructing a forward conversion circuit into a PWM control circuit using self-extinguishing devices (transistors and GTOs). FIG. 3 shows a circuit diagram of a power regeneration voltage type inverter. AC power supply 1
Are connected to voltage-type inverters 2 to 4, and the motors 5 to 7 are driven by the respective inverters. Each of the inverters 2 to 4 includes a forward conversion circuit 11 having a self-extinguishing device as a main circuit switch, a capacitor 12 and an inverse conversion circuit 13 as represented by the inverter 2. Power transfer through the forward conversion circuit 11
By performing PWM control so that the DC voltage of the capacitor 12 is kept constant, forward and reverse bidirectional conversion, that is, power supply regeneration is also possible. The carrier removal filter 15 removes a carrier component by PMW control. The control circuit 16 of the forward conversion circuit 11 is a capacitor
The PWM control of the forward conversion circuit 11 is performed by detecting the DC voltage Ed of 12 and the synchronization signal of the AC power supply 1.

Here, in order to make the voltage source inverter 2 have a harmonic suppression function by using the power regeneration function of the forward conversion circuit 11,
The control circuit 16 extracts a harmonic component from the load current of the power supply line of the AC power supply 1 and outputs an AC current corresponding to this component to the power supply 1.
Supply to the side.

D. Problems to be Solved by the Invention In the conventional configuration, in order to completely compensate for the harmonic current, the energy due to the AC component of the instantaneous real power of the load reciprocates between the load connected to the grid and the compensator and the capacitor. Twelve stored energy increases or decreases. Therefore, the capacitor
Attempting to control the voltage of 12 constant would reduce the harmonic suppression effect.

Conversely, if the harmonic suppression effect is enhanced, the DC voltage of the capacitor greatly fluctuates, and stable power supply from the inverter 13 to the load becomes impossible.

Further, even if the power supply current is a sine wave, the power factor varies depending on the load, and does not always become 100%.

SUMMARY OF THE INVENTION An object of the present invention is to provide a voltage type inverter capable of continuously supplying a stable power to an inverter load while enhancing a harmonic suppression effect and continuously adjusting a power factor.

E. Means and Action for Solving the Problems In order to achieve the above object, the present invention provides a forward conversion circuit that enables power regeneration by PWM control using a self-extinguishing device as a main circuit switch, and a forward conversion circuit. A power conversion regenerative voltage type inverter including a reverse conversion circuit that is supplied with DC power and supplies AC power to a load, and a control circuit that performs PWM control on the forward conversion circuit, wherein the control circuit includes an AC system of the forward conversion circuit. Calculating means for calculating the instantaneous real power and the instantaneous imaginary power from the load current and the phase voltage; means for obtaining a harmonic component from the instantaneous real power obtained by the calculating means; and calculating the instantaneous imaginary power obtained by the calculating means. A means for adjusting the power factor by adding a fundamental wave reactive power command; a means for obtaining a real power of a load from a DC voltage and a DC current of the inverting circuit; and a harmonic generation of the instantaneous real power. Means for obtaining a current command of the forward conversion circuit from a component obtained by adding a fundamental reactive power command to the instantaneous imaginary power and a component of the instantaneous imaginary power. It is used as a detection signal for harmonic suppression to obtain the wave component, and by adding the real power supplied to the load by the inverse conversion circuit to the harmonic component of the instantaneous real power, it becomes the real power control signal for the forward conversion circuit. Harmonic suppression control by instantaneous power includes the load power of the inverter circuit, and the power factor can be adjusted by the instantaneous imaginary power and fundamental reactive power obtained from the phase voltage.
Perform PWM control.

F. Embodiment An embodiment of the present invention will be described below with reference to FIGS.

FIG. 2 shows an overall configuration diagram according to an embodiment of the present invention, and the same or corresponding parts as those in FIG. 3 are denoted by the same reference numerals. In FIG. 2, 16A is a forward conversion unit control circuit, 17 is a base drive circuit, and 18 is an inverse conversion unit control circuit.

FIG. 1 is a control circuit diagram showing one embodiment of the present invention.
The three-phase / two-phase converter 21 converts the three-phase load currents I _U , I _V , I _{W of the system} into two-phase flows I _α , I _β on orthogonal α-β coordinates.

Similarly, the three-phase / two-phase conversion unit 22 outputs the system phase voltages E _U , E _V , and E _W
Into two-phase voltages E _α and E _β on the orthogonal α-β coordinates.

2-phase currents I _alpha described above, I _beta and 2-phase voltage E _alpha, and E _beta alpha-
handled as an instantaneous vector on beta coordinate axes, the instantaneous power _{E α, I α, E β} , represented by the scalar product of the I _beta. Accordingly, the instantaneous power calculator 23 obtains the instantaneous real power P and the instantaneous imaginary power q as the sum of the scalar products of the two-phase voltage and the current.

By the way, when the instantaneous real power P and the imaginary power Q are separated into a DC component and an AC component, In equation (4), (AC component) and (AC component) represent the instantaneous harmonic power, and the AC component calculation unit 24 to be subjected to harmonic compensation has a high-pass filter function using a low-pass filter and an adder. From the electric power P, respective AC components (instantaneous power of harmonics) _Ph are obtained.

In order to adjust the power factor by also compensating for the fundamental reactive power,
All instantaneous imaginary powers Q (attributable to a fundamental wave + attributable to harmonics) and instantaneous real power P are to be compensated.

Therefore, in the instantaneous imaginary power, there is no need to separate the instantaneous imaginary power, and the filter for extracting the compensation target is not required.
Therefore, in FIG. 1, only the instantaneous real power portion uses a filter.

That is, the current command unit 25 gives the reactive power command ^Ψ (DC component) of the fundamental wave component to the compensation target,
Arbitrary leading current / lagging current commands are given.

Since the instantaneous real power P due to the harmonic to be compensated and all the instantaneous imaginary powers Q have been obtained, the current command calculator 26 calculates the quadrature α from the instantaneous powers P _h , q _h and the phase voltages E _α , E _β. coordinate current I _alpha ^[psi on -β coordinates, obtains the I _beta ^[psi.

The two-phase / three-phase converter 27, two-phase instantaneous current I _alpha ^[psi, the I _beta ^[psi 3
Phase instantaneous current ^I _ca Ψ, I _cb Ψ, obtaining the compensation current command value of a three-phase instantaneous current is converted into I _cc ^[psi.

The PWM control unit 28 compares the three-phase instantaneous currents I _ca ^Ψ , I _cb ^Ψ , and I _cc ^Ψ with the compensation current detection signals I _R , I _S , and I _T, and compares the PWM waveform with a carrier by a comparator. A gate signal is obtained, and the switching of the self-extinguishing element of the forward conversion circuit 11 is controlled by the gate signal.

With the configuration described above, the harmonic component included in the system load current is supplied from the forward conversion circuit 11 to the AC power supply 1 as a current to be compensated.

Here, the actual power P _L supplied to the electric motor 5 by the inverse conversion circuit 13 is added to the instantaneous real power P _h and supplied to the current command calculation unit 26. The real power P _L is the voltage E _d and the inverse conversion circuit of a capacitor 12
Obtains a DC load by multiplying the 13 detection signals of the respective direct current I _d in is determined by the real power calculating section 29 with a first-order lag due to the filter as required. Further, the instantaneous real power P _h are added loss power Pl to compensate for the loss in the switching loss or the like of the forward transform circuit 11. This loss power Pl
It is obtained from the voltage control circuit 30 in the butt of the DC voltage command E _d ^[psi detection signal and the capacitor 12 of the capacitor voltage E _d.

According to this embodiment, the system load current calculated instantaneous real power P and instantaneous imaginary power q from with the instantaneous real power P seek harmonic instantaneous real power P _h, the instantaneous imaginary power q to the fundamental wave reactive power command ^Ψ Request imaginary power q _h by adding a. As a control signal of the instantaneous real power P of the forward conversion circuit 11 by adding the real power P _L and the conversion loss in Pl of the rectifier circuit 11 supplies to the load the inverse transform circuit 13 (5) in these real power P _h , and converted into a current command from the real power P and instantaneous imaginary power q _h, to obtain a PWM control signal by an additional 2-phase / 3-phase conversion and a current feedback control.

Therefore, in order to suppress harmonics, a harmonic component is obtained from the instantaneous real power and the imaginary power to obtain a current command to the forward conversion circuit 11,
To obtain the current command to the forward conversion circuit 11 by adding the actual power of the load of the inverse conversion circuit 13 to this current command, it is necessary to supply a stable power to the load of the reverse conversion circuit without lowering the harmonic suppression function. Can be. Further, since the power to be supplied to the load of the inverse conversion circuit 13 is obtained from only the DC voltage and the DC current, the actual power calculation unit 29 is simplified. In addition, an inverse conversion circuit
The real power of 13 is added to the harmonic real power P _h for harmonic suppression, since the power control of the forward conversion circuit 11, the inverse transform circuit
The power supplied from 13 to the load has a power factor of 1, and is similarly controlled to a power factor of 1 during regenerative operation.

Further, the power supply current becomes a sine wave by compensating for the harmonic component, and the phase of the fundamental wave current can be controlled to a power factor of 1 by compensating for the fundamental wave reactive current.

As described above, since all instantaneous powers are to be compensated,
By adding the fundamental reactive power command (DC component) to the instantaneous imaginary power component without extracting the compensation target with the filter, any fundamental reactive current can be compensated, and as a result, continuous power factor adjustment is possible It is.

G. Effects of the Invention As described above, according to the present invention, in the PWM control of the forward conversion circuit having the power regeneration function, the harmonic component of the instantaneous power obtained from the system load current is supplied to the load from the inverse conversion circuit. Since the power is added to the instantaneous real power, it is possible to supply power with a stable and power factor of 1 to the load of the inverter circuit while enhancing the harmonic suppression effect of the system. Further, since the actual power of the inversion circuit is obtained from the DC current and the voltage, the circuit configuration is simplified.

In addition to functioning as a variable speed device, the power supply power factor of the power system can be adjusted, so a phase-advancing capacitor for power factor adjustment, a phase control reactor, etc. become unnecessary, simplifying the circuit configuration and reducing the load. Even when the vehicle is not operating, the power supply power factor can be continuously adjusted by operating only the forward conversion unit, thereby improving the performance and improving the reliability.

[Brief description of the drawings]

FIG. 1 is a control circuit diagram showing an embodiment of the present invention, FIG. 2 is an overall configuration diagram of a power regenerative voltage type inverter according to an embodiment of the present invention, and FIG. 3 is a circuit diagram of a conventional power regenerative voltage type inverter. It is. 11: forward conversion circuit, 13: reverse conversion circuit, 23: instantaneous power calculation unit, 24: AC component calculation unit, 25: current command unit, 26 ...
... Current command calculator, 29 ... Real power calculator, 30 ... Voltage control circuit.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H02M 7/42-7/98

Claims (1)

(57) [Claims] 1. A forward conversion circuit that enables power regeneration by PWM control using a self-extinguishing device as a main circuit switch;
In a power supply regenerative voltage type inverter including a reverse conversion circuit supplied with DC power from the forward conversion circuit and supplying AC power to a load, and a control circuit for performing PWM control on the forward conversion circuit, the control circuit includes a forward conversion circuit Calculating means for obtaining an instantaneous real power and an imaginary imaginary power from the load current and the phase voltage of the AC system; means for obtaining a harmonic component from the instantaneous real power obtained by the calculating means; A means for adjusting the power factor by adding a fundamental reactive power command to the instantaneous imaginary power; a means for obtaining the actual power of the load from the DC voltage and the DC current of the inversion circuit; Means for obtaining a current command for the forward conversion circuit from a component obtained by adding a harmonic component and a component obtained by adding a fundamental reactive power command to the instantaneous imaginary power. Over data.