KR0163702B1 - Pwm converter and its controlling method - Google Patents

Abstract

A power supply for outputting a three-phase AC power supply to provide a pulse width modulation converter device and a control method thereof to improve the response speed and reduce the number of switching using the space vector voltage modulation scheme; Power conversion means for converting AC power into DC power by applying a three-phase AC power; First current sensing means for sensing a current output from a power supply; Second current sensing means for sensing a direct current output from the power converting means; A transformer for outputting a signal corresponding to an input voltage of a power source; Input current detection means for detecting a current of the input power source using a signal input through the first current detection means; Input current coordinate converting means for calculating a reactive current and an effective current by using the current of the input power source detected by the input current detecting means; Input voltage detection means for detecting an input voltage of a power supply using a detection signal output from the transformer; Input voltage coordinate converting means for calculating an invalid voltage and an effective voltage using an input voltage of a power source output from said input voltage detecting means; Output current detection means for detecting a DC current output through the power conversion means by using the detection signal output from the second current detection means; Output voltage detection means for detecting an output voltage output from the power conversion means; Output voltage and power factor control means for calculating an orthogonal voltage set value and an in-phase component set value using each input / output current / voltage input from the input current / voltage coordinate converting means and output current / voltage detecting means; And a spatial voltage vector current control means for reading the input quadrature voltage set value and the in-phase component set value, calculating a control time for controlling each switching element of the power conversion means, and outputting a control signal to each switching element by the calculated time. It consists of

Description

Pulse width modulation converter device and control method thereof

1 is a block diagram of a pulse width modulation converter device according to an embodiment of the present invention,

2 is an operation flowchart of an output voltage and power factor control apparatus according to an embodiment of the present invention,

3 is an operation flowchart of the space voltage vector current control apparatus according to the embodiment of the present invention.

The present invention relates to a pulse width modulation (PWM) converter device and a control method thereof, and more specifically, to accurately convert the phase by axial conversion of the input voltage, to compensate for the current control and output power to achieve a fast response speed A pulse width modulation converter device and a control method thereof.

According to the applied three-phase AC power, the switching element such as a transistor or an Insulated Gate Bipolar Transistor (IGBT), a power conversion device composed of three pairs of diodes, and the phase of the applied three-phase power source are sensed to compensate for the phase. The pulse width modulated converter device including the device and a control device for driving the switching element for a predetermined time can pulse-control the drive signal of the switching element, and convert the applied AC power into a DC voltage.

Apparatus or method for controlling the operation of the pulse width modulation converter device as described above is disclosed in Korean Patent Application Publication No. 93-1018 (Application Date: May 15, 1990 AD) PWM converter device or Patent Application Publication No. Control method of PWM converter device of No. 93-1047 (Application date: April 18, 1990) and Pulse width of Patent Application No. 93-4262 (Application date: March 16, 1992) Disclosed is a control method and apparatus for a modulation (PWM) converter.

However, the above-described conventional patent applications detect each phase of an AC power source applied for control and use it without a separate conversion operation, thereby causing a problem that affects normal operation by an error occurring during phase detection.

Therefore, in order to prevent an error occurring when detecting the phase of each applied AC power as described above, many safety devices or signal conversion devices are required, which causes a problem of complicated hardware configuration and reduced operation reliability.

In addition, since the control time of the switching element is delayed, the control speed is slow, the response speed is reduced, and a lot of ripple components are generated in the converted DC voltage, which causes a problem of using many smoothing capacitors.

Therefore, an object of the present invention is to solve the above-mentioned conventional problems, and by converting the input AC power applied for control to detect each phase of the input power and to detect the correct phase and each input / output current / voltage The present invention provides a pulse width modulation converter device and a method of controlling the same, which output a control signal using a space vector voltage modulation method to improve a response speed and reduce a switching frequency.

As a means for achieving the above object, the configuration of the present invention,

A power supply for outputting three-phase AC power;

Power conversion means for applying a three-phase AC power output from the power supply and converting the AC power applied by the switching operation of the switching element into a DC power supply and outputting the connected load;

First current sensing means connected to the power source and sensing currents of the R phase and the S phase output from the power source;

Second current sensing means for sensing a direct current converted by the operation of the power converting means;

A transformer connected to a supply terminal of each phase of the power source and outputting a signal corresponding to input voltages of the R phase and the S phase of the power source;

Input current detection means for detecting currents of the R phase and the S phase of the input power by using the signal input through the first current sensing means;

Input current coordinate converting means for calculating a reactive current and an effective current by using the current of the input power source detected by the input current detecting means;

Input voltage detection means for detecting input voltages of the R and S phases of the power supply using the detection signal output from the transformer;

Input voltage coordinate converting means for calculating an invalid voltage and an effective voltage using an input voltage of a power source output from said input voltage detecting means;

Output current detection means for detecting a DC current output through the power conversion means by using the detection signal output from the second current detection means;

Output voltage detection means for detecting an output voltage output from the power conversion means;

Output voltage and power factor control means for calculating an orthogonal voltage set value and an in-phase component set value using each input / output current / voltage input from the input current / voltage coordinate converting means and output current / voltage detecting means;

Connected with the output voltage and power factor control means, the input orthogonal voltage setting value and the in-phase component setting value are read to calculate a control time for controlling each switching element of the power conversion means, and a control signal to each switching element by the calculated time. It comprises a space voltage vector current control means for outputting.

Another configuration of the present invention for achieving the above object,

A method for converting an applied three-phase alternating current power source into a direct current voltage using a power conversion means,

Detecting a voltage and a current of an input AC power source and converting the same into an in-phase component and a quadrature component;

Detecting a voltage and a current of the DC power output through the power conversion means;

Calculating an orthogonal voltage set value and an in-phase component set value using an in-phase component and an orthogonal component with respect to the voltage and current of the input power and a voltage and current of the output power;

And calculating the control signal of the power conversion means by using the spatial voltage vector pulse width modulation method using the calculated quadrature voltage set value and the in-phase component set value.

Hereinafter, the most preferred embodiments will be described in detail with reference to the accompanying drawings.

1 is a block diagram of a pulse width modulation converter device according to an embodiment of the present invention,

2 is an operation flowchart of an output voltage and power factor control apparatus according to an embodiment of the present invention,

3 is an operation flowchart of the space voltage vector current control apparatus according to the embodiment of the present invention.

Looking at the configuration of the present invention with reference to FIG.

An AC power source 1 for outputting an AC power source of R, S, and T phases;

A reactor (2) connected to supply terminals of respective phases (R, S, T) of the AC power source (1); A power converter 3 to which an AC power source 1 is applied through a reactor 2 corresponding to each of the phases R, S, and T;

A smoothing capacitor 4 for smoothing the DC voltage converted by the operation of the power converter 3;

A current detector (5) for detecting a direct current converted by the operation of the power converter (3);

A load 6 connected to both terminals of the power converter 3;

A transformer 7 connected to supply terminals of R, S, and T phases of the AC power supply 12 and outputting a signal corresponding to the power supply voltage of the AC power supply 1;

A current transformer 8 connected to the reactor 2 and outputting a signal corresponding to an input current corresponding to an R phase and an S phase output from the AC power source 1;

An input current detector (9) for detecting currents corresponding to the R and S phases of the AC power supply (1) by using the signal input through the current transformer (8);

An input current coordinate converting unit (10) for calculating an active current that is an in-phase component and an reactive current that is an orthogonal component using input currents corresponding to the R and S phases detected by the first current detector (9);

An input voltage detector (11) for detecting an input voltage of the AC power source (1) using the detection signal output from the transformer (7);

An input voltage coordinate converting unit 12 calculating an orthogonal component and an in-phase component using the input voltage of the AC power source 1 output from the first voltage detecting unit 11;

An output current detector (13) for detecting a direct current generated by the power converter (3) using the detection signal output from the current detector (5);

An output voltage detector 14 connected to both ends of the smoothing capacitor 5 to detect an output voltage output from the power converter 3;

An output voltage and power factor controller 15 for calculating an orthogonal voltage set value and an in-phase component set value using signals input from the input current / voltage coordinate converting units 10 and 12 and the output current / voltage detectors 13 and 14; ;

The space voltage vector current controller 16 is connected to the output voltage and power factor controller 15 and outputs a driving signal of the switching element of the power converter 3.

The operation of the present invention made as described above is as follows.

When the AC power corresponding to the R, S, and T phases is output with the respective phase differences from the AC power source 1, the power is converted through the reactor 2 connected to the output terminals of the respective phases R, S, and T. It is applied to the part (3).

And since the current transformer 8 is attached to the output terminal of the reactor 2 to which R phase and S phase are applied, the current transformer 8 outputs the electric signal corresponding to the alternating current of R phase and S phase.

Therefore, since the electric signal corresponding to the alternating current output through the current transformer 8 is input to the input current detection unit 9, the alternating current (Ir, Is) corresponding to the R phase and the S phase of the AC power source 1 is obtained. Detect.

Since the three-phase AC power output from the AC power source 1 is input to the input voltage detector 11 through the transformer 7, the input voltage detector 11 corresponds to the R phase and the S phase of the AC power source 1. The voltages Ers and Est are detected.

Accordingly, according to the operations of the input current detector 9 and the input voltage detector 11, the currents Ir and Is and the voltages Ers and Est corresponding to the R phase and the S phase input to the power converter 3 are reduced. When detected, the invalid components Id and Ed and the in-phase components Iq and Eq are calculated by the operation of the input current / voltage coordinate conversion units 10 and 12.

Therefore, in order to calculate the quadrature component Id which is the reactive current and the in-phase component Iq which is the effective current with respect to the input current Ir and Is, the following matrix (1) is used.

(Where Ir: input current of R phase

Is: input current of S phase

It is input current of T phase.)

In addition, the orthogonal component Ed and the in-phase component Eq use a determinant such as the following (2) using the detected voltages Ers and Est of the input voltage detector 11.

(Here Ers: input voltage of R phase,

Est: input voltage of S phase,

Etr: Input voltage of T phase.)

Accordingly, as described above, the input current / voltage coordinate converting units 10 and 12 use currents Ir and Is and voltages Ers and Est corresponding to the R and S phases output through the AC power source 1. Each invalid component and effective component can be computed using the determinant shown in Formula (1) and Formula (2).

When the power converter 3 operates and is converted into a DC voltage, a signal corresponding to the DC current converted by the current detector 5 connected to the power converter 3 is output to the output current detector 13. do.

Accordingly, the DC current Idc output from the power converter 3 is detected by the operation of the output current detector 13.

The output voltage detector 14 detects a voltage applied to both ends of the smoothing capacitor 4 that smoothes the output voltage of the power converter 3, and outputs a DC voltage Vdc output from the power converter 3. Detect.

Therefore, by using the signals output from the input current / voltage coordinate converters 10 and 12 and the output current / voltage detectors 13 and 14, the output voltage and the power factor controller 15 use the quadrature component voltage set value Vd *. And the in-phase component voltage setpoint Vq *.

The operation of the output voltage and power factor controller 15 first reads the signals output from the input current / voltage coordinate converting units 10 and 12 (S11), as shown in FIG. It converts to the orthogonal component which is an invalid part (S12).

The phase corresponding to each phase (R, S, T) is calculated using each transformed in-phase component and the orthogonal component (S13), and the synchronization is performed at the stop coordinates using the calculated each phase (R, S, T). Convert to coordinates (S14).

Therefore, after the coordinate transformation is performed as described above, the output voltage and power factor controller 15 reads the signal output from the output voltage / current detectors 13 and 14 (S15), and the in-phase and quadrature current set values Iq * and Id *. ), The in-phase or quadrature current value is calculated (S16), and the in-phase / orthogonal component voltage set values (Vq *, Vd *) are calculated (S17).

Then, the state of coordinates converted for calculation is converted from synchronous coordinates to stationary coordinates (S18), and then the set values (Iq *, Id *, Vq *, Vd *) of each calculated in-phase or quadrature current value and voltage value are calculated. Output to the space voltage vector current control unit 16 (S19).

When the quadrature component voltage set value Vd * and the in-phase component set value Vq * are generated and input to the space voltage vector current controller 16 using the above method, the operation of the space voltage vector current controller 16 is performed. Operation is performed in accordance with the control method shown in FIG. 3 to generate a control signal for controlling the gate terminal of each switching element of the power converter 3.

Accordingly, the operation of the space voltage vector current control unit 16 will be described with reference to FIG. 3.

First, an orthogonal voltage set value Vd * and an in-phase component set value Vq * output from the output voltage and power factor controller 15 may be read (S21), and the read value may implement a spatial voltage vector control operation. Axis transformation to three phases so as to (S22).

Therefore, the switching time of the switching element of the power converter 3 is calculated according to the space voltage vector control operation using the axis-converted values of the three phases R, S, and T (S23), and the power converter 3 The maximum switching time and the minimum switching time are respectively calculated (S24), so that the switching elements of the stable operation can be performed, thereby limiting the setting range of the switching time.

Therefore, only the switching time of the active component is calculated from the switching time calculated in the step S23 (S25), the driving time of each switching element of the power converter 3 is calculated (S26), and then the pulse corresponding to the set time. The signal is output to the gate terminal of each switching element of the power converter 3 (S27).

Therefore, the switching signal output from the space voltage vector current control unit 16 is input to the gate terminal of each corresponding switching element through a driving device of a switching element of a separate power converter 3, not shown, to drive the switching element. Control input power factor and output voltage.

As described above, when controlling the operation of a power converter such as a converter or an inverter using pulse width modulation, the phase conversion for each phase is performed by converting an input voltage output from an AC power source into an active component and an invalid component. The state can be determined accurately.

In addition, since the gate driving signal of the switching device of the power converter is output by using the space voltage vector modulation method, the response speed may be improved and the switching frequency of the switching device may be reduced.

Claims (7)

A power supply for outputting three-phase AC power; Power conversion means to which the three-phase AC power is applied and converts the AC power applied by the switching operation of the switching element into a DC power and outputs it to a load; First current sensing means for sensing and outputting currents of the R and S phases output from the power source; Second current sensing means for detecting a direct current converted by the operation of the power converting means; A transformer connected to a supply terminal of each phase of the power source and outputting a signal corresponding to input voltages of the R and S phases of the power source; Input current detection means for detecting currents of the R phase and the S phase of the input power by using the signal input through the first current sensing means; Input current coordinate converting means for calculating a reactive current and an effective current by using the current of the input power source detected by the input current detecting means; Input voltage detection means for detecting input voltages of the R and S phases of the power supply using the detection signal output from the transformer; Input voltage coordinate converting means for calculating an invalid voltage and an effective voltage using an input voltage of a power source output from said input voltage detecting means; Output current detection means for detecting a DC current output through the power conversion means by using the detection signal output from the second current detection means; Output voltage detection means for detecting an output voltage output from the power conversion means; Converts the input current / voltage input from the input current / voltage conversion means into in-phase and quadrature components, calculates each phase, converts the stop coordinates into synchronous coordinates, and converts the converted synchronous coordinates and the output current / voltage coordinate conversion means. An output voltage and backflow control means for calculating current / voltage set values of the orthogonal component and the in-phase component using the output current / voltage inputted from and converting the synchronous coordinates into the stop coordinates; Connected with the output voltage and power factor control means, the input orthogonal voltage setting value and the in-phase component setting value are read to calculate a control time for controlling each switching element of the power conversion means, and a control signal to each switching element by the calculated time. Pulse width modulation converter device comprising a space voltage vector current control means for outputting a. The apparatus of claim 1, wherein the input current coordinate conversion unit calculates an orthogonal component (Id) and an in-phase component (Iq) of the input current by using the following equation. (Here, Ir: R phase input current. Is: S phase input current, It: T phase input current.) The pulse width modulation converter device according to claim 1, wherein the input voltage coordinate converting means calculates an orthogonal component (Ed) and an in-phase component (Eq) of the input voltage by using the following equation. (Here, Ers: R phase input current, Est: S phase input current, Etr: T phase input current.) The switching circuit according to claim 1, wherein the space voltage vector current control means performs an axis conversion between the R phase, the S phase, and the T phase using an orthogonal voltage set value and an in-phase component set value, and then requires switching for operation of the switching element of the power conversion means. The effective switching time is calculated by calculating the time and the maximum / minimum switching time, and the switching time of each switching element of the power conversion means is calculated using the calculated effective switching time, and then the switching time of each switching element of the power conversion means is A pulse width modulation converter device for outputting a control signal. CLAIMS 1. A method for converting an applied three-phase AC power source into a DC voltage using a power conversion means, the method comprising: detecting a voltage and a current of an input AC power source and changing the same into an in-phase component and an orthogonal component; Detecting a voltage and a current of the DC power output through the power conversion means; Calculating an orthogonal voltage set value and an in-phase component set value using an in-phase component and an orthogonal component with respect to the voltage and current of the input power and a voltage and current of the output power; And outputting a control signal of the power conversion means in accordance with the spatial voltage vector pulse width modulation method using the calculated quadrature voltage set value and the in-phase component set value. The method for calculating the quadrature voltage set value and the in-phase component set value according to claim 6, wherein the input current / voltage input from the input current / voltage coordinate converting means is converted into the in-phase component and the quadrature component, and each phase is calculated to calculate the stop coordinates. Converting to synchronous coordinates; And calculating the current / voltage set values of the quadrature component and in-phase component using the converted synchronous coordinates and the output current / voltage input from the output current / voltage coordinate converting means, and converting the synchronous coordinates to the stationary coordinates. Pulse width modulation converter control method, characterized in that. 6. The method of claim 5, wherein the method for calculating the control signal of the power conversion means comprises the steps of: axially converting into three phases using an orthogonal voltage set value and an in phase component set value; Calculating the effective switching time by calculating the switching time and the maximum / minimum switching time required for the operation of the switching element of the power conversion means; Calculating a switching time of each switching element of the power conversion means by using the calculated effective switching time, and outputting a control signal to each switching element of the power conversion means for a set time, the pulse width comprising: Modulation converter control method.