JP2002354844A - Inverter equipment provided with regenerative power storing and discharging function and higher harmonic suppressing function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To save energy and reduce EMI noise. SOLUTION: A first inverter 31a is provided with a voltage step-up and step-down chopper circuit 32 using an electric double layer capacitor as power regenerating function. The chopper circuit 32 is constituted of a transistor 32a, a diode 32b, a DC reactor 32c, and the electric double layer capacitor 32d. The first inverter controls charge and discharge of the capacitor 32d by PWM output from a voltage step-up and step-down chopper control circuit 33. An inverter 41 for suppressing higher harmonic has a function for driving a motor 42 which is a driving object of the inverter itself, and a function for suppressing the higher harmonic which a first inverter 31a-an N-th in inverter 31N generate. The inverter 41 is constituted of a power source regenerating type inverter device having a PWM forward converter 11, and performs suppression of power source higher harmonic generated by the first inverter part 31a, and power factor adjustment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter device in which a plurality of motors are driven by a plurality of inverter units, respectively, in which one inverter unit suppresses harmonics generated in another inverter unit together with a motor driving function. A regenerative power storage / discharge function that has a harmonic suppression function, and the other inverter section has a forward converter composed of a diode rectifier, stores regenerative power during power regeneration, and releases the stored power during driving. And an inverter device having a harmonic suppression function.

[0002]

2. Description of the Related Art FIG. 2 is a diagram showing a main circuit configuration of a voltage source inverter device widely used at present.
Is a forward converter composed of a diode rectifier, 22 is an electrolytic capacitor, 23 is an inverse converter, 24 is a resistor circuit for regenerative power discharge including a resistor R and a transistor TR1, 25 is a motor, and 26 is a power supply. The inverter device configured as shown in FIG. 2 is mainly used for a low-cost type such as a general-purpose inverter, and means for consuming regenerative power by a resistor R is used.

FIG. 3 is a circuit configuration diagram of a power regenerating inverter device having a PWM forward converter. This inverter device controls a sine wave current having the same phase as a power supply voltage by a PWM forward converter to obtain higher harmonics. It has suppression, high power factor control and power regeneration functions.

In FIG. 3, a power regeneration type inverter unit 1 is shown.
0 includes a forward conversion unit 11, an electrolytic capacitor 12, and an inverse conversion unit 13, and exchanges power with a power supply 26 through an EMI filter 27 and an AC reactor 14.
1 is to keep the DC voltage of the capacitor 12 constant.
By performing PWM control, forward and reverse bidirectional conversion, that is, power regeneration is also enabled.

The EMI filter 27 is for removing high-order noise, and the low-order filter 15 is for removing carrier frequency noise by PWM control. The control circuit 16 of the forward converter 11 detects the DC voltage across the capacitor 12 and the synchronization signal of the power supply 26, and
The PWM control of the forward conversion unit 11 is performed through. Reference numeral 18 denotes a control circuit of the inverse conversion unit 13. The output of the control circuit 18 is supplied to the inverse conversion unit 13 via the drive circuit 19, and performs PWM control of the inverse conversion unit 13. In addition, 28 is a transformer and 29 is a current transformer CT.

[0006]

In the inverter device shown in FIG. 2, since the forward converter 21 is formed of a diode rectifier, the power supply input current contains a large amount of harmonic components, There is a bad problem. In addition, there is a problem that efficiency is deteriorated because a means for consuming the regenerative power by the resistor R is employed.

Next, in the inverter device 10 shown in FIG.
Although it has a power regeneration function by the PWM forward converter 11,
Since the forward converter 11 performs the PWM control, EMI noise on the power supply side due to switching of the main circuit element poses a problem. For this reason, means for inserting an EMI filter 27 for removing high-order noise and a low-order filter 15 for removing carrier frequency noise corresponding to the input capacitance are provided on the input side of the inverter device 10. Therefore, the whole inverter device becomes expensive.

To solve this problem, if an inverter device that drives a plurality of motors by a plurality of inverter units is applied to the inverter device shown in FIG. 2, there is a problem that the efficiency and power factor of the entire inverter device are reduced. .

Further, when applied to the inverter device 10 shown in FIG. 3, there arises a problem that EMI noise is generated and the device becomes expensive.

[0010] The present invention has been made in view of the above circumstances, and is configured to store regenerative power in an electric double layer capacitor during power regeneration and release the stored power during driving, thereby saving energy and saving. It is an object of the present invention to provide an inverter device having a regenerative power storage / release function for reducing EMI noise and a harmonic suppression function.

[0011]

In order to achieve the above object, the present invention provides a first invention, which comprises a diode rectifier and converts a AC power into a DC power. A first inverse converter supplied with DC power from the first forward converter and supplying AC power to the load, a first control circuit for PWM-controlling the first inverse converter, A step-up / step-down chopper circuit that stores regenerative power in the electric double-layer capacitor during power regeneration and controls release of the stored power of the electric double-layer capacitor when driving the load, and controls the step-up / step-down chopper circuit to generate regenerative electric power. It consists of multiple inverters with a step-up / step-down chopper control circuit that stores and discharges stored power, and a self-extinguishing element, which can regenerate power by PWM control and convert AC power to DC power. A second forward converter, a second inverter that receives the DC power from the second converter and supplies AC power to the load, and a second control circuit that performs PWM control on the second inverter. And a control signal generator for controlling the second forward converter in order to suppress harmonic components generated by the plurality of inverters. .

According to a second invention, a step-up / step-down chopper control circuit comprises:
AVR that adds the DC voltage command value and the DC voltage detection values at both ends of the electrolytic capacitor connected to the output side of the first forward conversion unit, and calculates the added output to be the DC voltage command value.
A control unit, and an ACR control unit for controlling the output of the AVR control unit as a current command value, adding the current command value to the current value flowing through the electric double layer capacitor, and controlling the added output to be the current command value. And a PWM operation unit that performs a PWM operation on the current obtained by the ACR control unit and controls the switching element of the step-up / step-down chopper circuit.

According to a third aspect of the present invention, the control signal generator includes a plurality of inverters (first inverter 31a to Nth inverter 3).
An instantaneous power calculation unit for obtaining instantaneous real power and instantaneous imaginary power from a load current and a phase voltage of an AC system (1N input current), and an AC component calculation unit for obtaining a harmonic component from the instantaneous power obtained by the calculation unit Means for adding a fundamental reactive power command to the instantaneous imaginary power obtained by the instantaneous power calculation unit to adjust the power factor; and obtaining the actual power of the load from the DC voltage and DC current of the second inversion unit. Means for calculating a current command for the second forward converter from a component obtained by adding the real power to a harmonic component of the instantaneous real power and a component obtained by adding a fundamental reactive power command to the instantaneous imaginary power. Unit, and converts the current command obtained by the operation unit into a two-phase / 3-phase current command, compares it with the actual current of the second forward conversion unit,
And a PWM control circuit for obtaining an M signal.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram showing an embodiment of the present invention. The same parts as those in FIGS. 2 and 3 are denoted by the same reference numerals.

In FIG. 1, first inverter units 31a to 31a
The N-th inverter unit 31N includes a step-up / step-down chopper circuit (hereinafter, referred to as a chopper unit) 32 using an electric double layer capacitor as a power regeneration function. The chopper section 32 includes a transistor 32a, a diode 32b, a DC reactor 32c, and an electric double layer capacitor 32d. The chopper section 32 charges and charges the electric double layer capacitor 32d by a PWM output from a step-up / step-down chopper control circuit 33. Control discharge.

The step-up / step-down chopper control circuit 33 includes an adder 33a for adding the DC voltage command value Edl * and the detected DC voltage value Edl at both ends of the electrolytic capacitor 22, and an adder 33a.
AVR that calculates so that the output of a becomes the DC voltage command value
A control unit 33b, and added by the AVR controller 33b current detection value I _B output was detected by current transformer 32e provided in the chopper unit 32 as a current command value I _B * adder 33c, an adder 33c An ACR control unit 33d that controls the output of the ACR to become a current command value, and a PWM operation unit 33e that performs a PWM operation on the current obtained by the ACR control unit 33d and controls a switching element such as an IGBT of the chopper unit 32. It is composed of

Reference numeral 34 denotes an inverter control circuit for controlling the inverse converter 23, and reference numeral 35a denotes a first inverter 31.
a is a first motor controlled by a.

In the first inverter unit 31a configured as described above, the electric double layer capacitor 3 of the chopper unit 32
By 2d, in the regenerative power mode of the first motor 35a,
The regenerative electric power is stored in the electric double layer capacitor 32d by the step-down chopper operation, and the electric power stored in the electric double layer capacitor 32d is released by the step-up chopper operation in the drive mode of the first motor 35a. A similar power regeneration function is provided.

The step-up / step-down control circuit 33 of the first inverter section 31a to the N-th inverter section 31N configured as described above.
Is an electric double layer capacitor 32d having a power regeneration function
To control the step-up / step-down chopper section 32 using. here,
AVR control unit 33b so that it becomes DC voltage command value Edl *.
And a current control loop is provided as a minor loop. Therefore, when the motor is driven, the electric power is supplied from the electric double layer capacitor 32d. When the stored electric power of the electric double layer capacitor 32d is insufficient, the shortage is supplied from the forward conversion unit 21.

In the first inverter section 31a, a rectifier circuit of a capacitor input type using a diode rectifier is employed as the forward converter 21 in order to reduce EMI noise. This causes an increase in current harmonics on the input power supply side of one inverter unit 31a and an adverse effect of a decrease in power factor. In order to eliminate this adverse effect, a harmonic suppression inverter device 41 described later was employed.

The harmonic suppression inverter device 41 has a function of driving a motor 42 to be driven by the inverter itself, and a first inverter unit 31a to an N-th inverter unit 31N.
And a function of suppressing harmonic components generated by Therefore, the harmonic suppression inverter unit 41
Is composed of a power regeneration type inverter device having a PWM forward conversion unit 11 controlled by a control signal generation unit 51 having an active filter described later, and a first inverter unit 31a
The power supply harmonics generated in the Nth inverter unit 31N are suppressed and the power factor is adjusted.

The capacity of the forward converter of the harmonic suppression inverter 41 is determined by the drive capacity of the load motor 42 in charge of the inverter and the first inverter 31a to the Nth inverter 31.
Compensation capacity for harmonics generated by N (first inverter unit 3
1a to about 5 to 10% of the total capacity of the N-th inverter unit 31N).

As described above, the harmonic suppression inverter unit 4
Since only 1 is constituted by the power regeneration type inverter device having the PWM forward converter 11, the EMI noise given to the power supply side can be reduced in the whole inverter device. Also, EMI
When implementing noise countermeasures, it is sufficient to take measures only for the harmonic wave suppression inverter section 41. Therefore, when viewed as a whole of the inverter device, a small-capacity EMI filter for high-order noise countermeasures and a small-capacity low-frequency filter for removing carrier frequency noise are used. What is necessary is to insert the next filter in the harmonic suppression inverter unit 41. Thus, the entire inverter device can be manufactured at low cost.

Next, the control signal generator 51 having an active filter will be described. Reference numeral 52 denotes a three-phase / two-phase conversion unit. The conversion unit 52 includes a three-phase input current I _{LR of} a drive power supply for the first inverter unit 31a to the N-th inverter unit 31N.
I _LS and I _LT are input, and this current is converted into two-phase currents Iα and Iβ on the orthogonal α and β coordinates according to equation (1).

[0025]

(Equation 1)

[0026] 53 power supply voltage E _R detected by the power detection transformer 28, E _S, a three-phase / two-phase converter section E _T is input, the power supply voltage E _R in the conversion unit 53, E _S, E _T Can be expressed by two-phase voltages Eα and Eβ on orthogonal α and β coordinates according to equation (2).
Convert to

[0027]

(Equation 2)

The two-phase currents Iα and Iβ and the two-phase voltage E
α and Eβ can be treated as instantaneous vectors on orthogonal α and β coordinates, and the instantaneous power is represented by a scalar product of Eα and Iα and Eβ and Iβ. Accordingly, the two-phase current and voltage are input to the instantaneous power calculation unit 54, and the calculation unit 54 calculates the instantaneous real power P and the instantaneous imaginary power Q as the sum of the scalar product of the two-phase voltage and current by the following equation (3). Can be

[0029]

[Equation 3]

When the instantaneous real power P and the instantaneous imaginary power Q are separated into a DC component (corresponding to a fundamental wave component) and an AC component (corresponding to a harmonic component), the following expression (4) can be obtained. Can be. In the equation (4), the AC component represents the instantaneous power of the harmonic, and is the component to be compensated for the harmonic.

[0031]

(Equation 4)

An AC component calculation unit 55 has a high-pass filter function using a low-pass filter (LPF) and an adder. The AC component calculation unit 55 converts the instantaneous real power P to the harmonic instantaneous real power Ph (the four types of AC components). P). In order to also compensate for the fundamental reactive power, all instantaneous imaginary powers Q (the sum of the fundamental imaginary power and the harmonic imaginary power) are subjected to harmonic compensation. Therefore, in the instantaneous imaginary power, there is no need to separate the DC component Q and the AC component Q in the equation (4), and a filter for extracting a compensation target is not required. Therefore, in FIG. 1, only the instantaneous real power portion uses a filter.

Further, in the current command section 56, if the reactive power command of the fundamental wave component (DC component Q * indicated by a broken line in the current command section 56) is added to the instantaneous imaginary power Q as a compensation target,
Arbitrary leading current and delay current commands can be given.
This enables power factor "1" control.

As described above, the instantaneous harmonic real power Ph and the total instantaneous imaginary power Qh caused by the harmonic to be compensated have been obtained. From the Ph, the imaginary power Qh and the two-phase voltages Eα and Eβ, two-phase current commands Iα * and Iβ * on the orthogonal α and β coordinates are obtained.

[0035]

(Equation 5)

Next, as shown in the equation (6), the two-phase / 3-phase converter 58 converts the current into three-phase instantaneous current commands I _CR *, I _CS *, and I _CT *. The result is compared with I _CR , I _CS , and I _CT, and the comparison result is input to the PWM control circuit 59.
The PWM control circuit 59 outputs a PWM drive signal of the forward converter 11 from the drive circuit 60 based on the input comparison result. By controlling the switching of the self-extinguishing element (such as an IGBT element) of the forward converter 11 by the drive signal output from the drive circuit 60, the harmonic currents of the plurality of inverters (first inverter 31a to Nth inverter 31N) are controlled. Compensate for components.

[0037]

(Equation 6)

Here, the instantaneous real power Ph is converted to the inverse
Add the actual power P _L supplied to the motor 42 and supply it to the current command calculator 57. The real power P _L is capacitor 1
The DC load is calculated by multiplying the DC current Edh by the DC voltage Edh at both ends of the filter 2 and, if necessary, a filter (LP
F) is obtained by the actual power calculation unit 61 with the first-order lag according to F).

Further, the instantaneous real power Ph is added the loss power P _R to compensate for the loss in the switching loss or the like of the rectifier unit 11. The loss power P _R is the DC voltage command E
dh * and the DC voltage detection value Edh are determined by the voltage control circuit 62.

Reference numeral 63 denotes an inverter control circuit for controlling the inverse converter 13.

[0041]

As described above, according to the present invention,
As the power regeneration function of the first inverter unit to the Nth inverter unit, a step-up / step-down chopper unit using an electric double layer capacitor is adopted. In the regenerative power mode of the motor, the regenerative power is stored in the electric double layer capacitor, In the drive mode, by discharging the stored power, it is possible to provide a regenerative function similar to that of the power regenerating inverter.

According to the present invention, as a measure against EMI noise, the forward converters of the first inverter section to the Nth inverter section adopt a capacitor input type rectifier circuit using a diode rectifier, and the input by this is used. As a countermeasure against the increase of the harmonic current on the power supply side and the decrease in the power factor, the forward conversion unit of the harmonic suppression inverter unit is constituted by a PWM forward conversion unit.
The harmonic suppression function and the power factor adjustment function on the input power supply side of the inverter section to the Nth inverter section are added to the harmonic suppression inverter section, so that the PW having a small capacity when viewed from the entire inverter device.
Harmonics can be suppressed by the M-forward converter. Therefore, EMI noise given to the power supply side as the inverter device can be reduced.

In order to implement EMI noise countermeasures, it is only necessary to take measures against the harmonic suppression inverter only. Therefore, a small-capacity EMI filter for high-order noise countermeasures and a small-capacity low-order filter for removing carrier frequency noise are used. What is necessary is just to insert a filter. As a result, the size of the entire system can be reduced, which is more economically advantageous than the conventional power regeneration type inverter device.

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram showing an embodiment of the present invention.

FIG. 2 is a main circuit configuration diagram of a voltage source inverter device.

FIG. 3 is a circuit configuration diagram of a power regeneration type inverter device having a PWM forward converter.

[Explanation of symbols]

 11 PWM forward converter 12, 22 electrolytic capacitor 13, 23 inverse converter 21 forward converter 31a to 31N first inverter unit to Nth inverter unit 32 step-up / step-down chopper circuit 32d electricity Double layer capacitor 33 ... Step-up / step-down chopper control circuit 35a, 42 ... Motor 41 ... Harmonic suppression inverter device 51 ... Control signal generator having an active filter

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H02M 7/48 H02M 7/48 Y // H02P 7/67 H02P 7/67 EF term (Reference) 5H006 AA01 AA02 BB01 BB05 CA01 CB01 CB08 DC02 DC05 5H007 AA01 AA08 BB01 BB06 CA01 CB02 CB05 CC07 CC12 DC02 DC05 EA02 5H572 BB01 BB05 DD01 FF05 HA08 HB09 HC07 LL22 LL24

Claims (3)

[Claims] 1. A first forward converter configured by a diode rectifier for converting AC power into DC power, and a first inverter supplied with DC power from the first forward converter and supplying AC power to a load. A converter, a first control circuit for PWM-controlling the first inverter, and a regenerative power stored in the electric double layer capacitor during power regeneration from the first inverter, and an electric double layer capacitor for driving the load. A plurality of buck-boost chopper circuits for controlling the release of stored power, and a buck-boost chopper control circuit for controlling the buck-boost chopper circuit to store regenerative power in an electric double layer capacitor or to release stored power And a second forward converter for converting power from AC power to DC power, which can be regenerated by PWM control and supplied with DC power from the second forward converter. To A second inverse transform unit for supplying a flow power, the second inverse transformation unit PW
A second control circuit that performs M control; and a harmonic suppression inverter unit that includes a control signal generation unit that controls the second forward conversion unit to suppress harmonic components generated by the plurality of inverter units. An inverter device having a regenerative power storage / release function and a harmonic suppression function. 2. A step-up / step-down chopper control circuit adds a DC voltage command value and a DC voltage detection value at both ends of an electrolytic capacitor connected to an output side of a first forward conversion unit, and the added output is a DC voltage command value. An AVR control unit that calculates to be a value;
The output of the AVR control unit is used as a current command value, the current command value is added to the current value flowing through the electric double layer capacitor, and control is performed so that the added output becomes the current command value.
The current obtained by this CR control unit and this ACR control unit is PWM
2. A PWM arithmetic unit for calculating and controlling a switching element of a step-up / step-down chopper circuit.
An inverter device having the regenerative power storage / release function and the harmonic suppression function described above. 3. The control signal generator includes: an instantaneous power calculator that calculates instantaneous real power and instantaneous imaginary power from a load current and a phase voltage of an AC system of a plurality of inverters; and an instantaneous power calculated by the calculator. An AC component calculating unit for obtaining a harmonic component from the signal; a unit for adjusting a power factor by adding a fundamental reactive power command to the instantaneous imaginary power obtained by the instantaneous power calculating unit; Means for obtaining the real power of the load from the DC current and a component obtained by adding the real power to a harmonic component of the instantaneous real power and a component obtained by adding a fundamental reactive power command to the instantaneous imaginary power. A current command calculation unit for obtaining a current command of the conversion unit; and a current command obtained by the calculation unit is converted into a two-phase / 3-phase current command, and is compared with the actual current of the second forward conversion unit. PWM to obtain the PWM signal of the forward converter
The inverter device having a regenerative power storage / release function and a harmonic suppression function according to claim 1, comprising a control circuit.