KR101250454B1 - Switching fuction generator and generating method for control voltage of vienna rectifier using carrier comparison pwm - Google Patents

Abstract

PURPOSE: A switching function generator and a switching function generation method for voltage control of a Vienna rectifier applying a triangle wave comparison PWM technique are provided to simply generate a switching function of a Vienna rectifier by applying a triangle comparison PWM technique using two carrier signals. CONSTITUTION: A normalization member(140) generates a terminal voltage command. The terminal voltage command is normalized by dividing the terminal voltage command outputted from a terminal voltage command calculation unit with voltage corresponding to current link voltage. A carrier wave application unit(150) generates carrier wave. A triangle wave comparator(160) applies the normalized terminal voltage command outputted in the normalization member and the carrier wave applied in the carrier wave application unit in the triangle comparison PWM technique. The triangle wave comparator generates a switching signal for controlling a power semiconductor switch.

Description

Switching fuction generator and generating method for control voltage of vienna rectifier using carrier comparison PWM}

The present invention relates to a switching function generator and a switching function generating method for voltage control of a Vienna rectifier using a triangular wave comparison PWM scheme. More specifically, a switching function generator and a switching function for voltage control of a Vienna rectifier using a triangular wave comparison PWM method using two carriers or a triangular wave comparison PWM method using a single carrier to easily control the voltage of a three-level Vienna rectifier. It relates to a generation method.

The conventional two-level three-phase pulse width modulation (PWM) rectifier is used to reduce input current harmonics of three-phase power supplies. It has been used a lot.

Insulated Gate Bipolar Transistors (IGBTs) having high breakdown voltages are generally used as switching elements of the conventional two-level three-phase PWM rectifiers. When the high breakdown voltage IGBTs 14 require fast switching, High switching losses limit the efficiency.

In order to overcome this disadvantage, the application of the three-level three-phase rectifier has begun to be examined, and the typical circuit thereof is the Vienna rectifier (10). Figure 1 shows a circuit diagram of a three-level Vienna rectifier 10 to be controlled according to an embodiment of the present invention. As shown in FIG. 1, the Vienna rectifier 10 includes a three-phase voltage applying unit 11 for applying an alternating voltage of three phases, three inductors 12 provided at each of three phase input terminals, and two at the output stage. It is provided between the DC connection capacitor 13 and the inductor 12 and the DC connection capacitor 13 to convert a three-phase AC voltage into a DC by including a power semiconductor switch for three-phase pulse width modulation (PWM) power control. Done.

Since the output terminal voltage of the three-level Vienna rectifier 10 shown in FIG. 1 has three states of 0.5 Vdc, 0, and -0.5 Vdc, the switching is compared with the power semiconductor device used in the conventional two-level PWM rectifier. Since the breakdown voltage of the device can be reduced to about half, a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) can be used instead of the IGBT 14. Accordingly, the switching loss of the power semiconductor device can be significantly reduced, and the material cost can be lowered.

In the three-level Vienna rectifier 10 shown in FIG. 1, S _abc (S _a , S _b , S _c ) is a power consisting of a MOSFET and a diode to enable quadrant operation for voltage and current applied to a switch. Switching function indicating the switching state of the MOSFET inside the semiconductor module. In addition, it means a general rectifying diode of D ₁ to D ₆ 3 shown in FIG. The switching function representing the switching state of the MOSFET included in the above four quadrant power switching elements may be defined as Equation 1 below.

[Equation 1]

That is, when the switching function S _abc is 1, the switch is controlled to the ON state, and when the switching function S _abc is 0, the switch is controlled to the OFF state. As shown in FIG. 1, when the MOSFET switch, which is a power semiconductor, is turned on, each of the phase output terminal voltages V _{( abc ) 0} becomes 0 V, and the power rectifier 10 operates in the Vienna rectifier 10. When the switch is OFF, the output terminal voltage (V _{( abc ) 0} ) has a value of V _dc / 2 or -V _dc / 2 depending on the direction of the current. Equation 2 below shows the output terminal voltage V _{( abc ) 0} of the Vienna rectifier 10 according to the switching function Sabc.

&Quot; (2) "

As shown in Equation 2, when the MOSFET switch, which is a power semiconductor, is turned on (Sabc = 1), each phase output terminal voltage V _{( abc ) 0} becomes 0 V, and the power semiconductor switch is turned off ( In the OFF state (Sabc = 0), when the input current is a positive value, the output terminal voltage V _{(abc) 0} becomes -V _dc / 2, and the input current is negative. It can be seen that the output terminal voltage V _{( abc) 0} has a value of V _dc / 2.

Meanwhile, a method using a space voltage vector is applied as a voltage control method of the conventional Vienna rectifier 10. Figure 2 shows a spatial voltage vector diagram for controlling a conventional three-level Vienna rectifier.

In the spatial voltage vector diagram shown in FIG. 2, voltage vectors I, II, III, IV, V, and VI are respectively applied to the energized state of the three-phase diode determined by the three-phase input voltage with the MOSFET turned off. According to the space voltage vector.

In the gray area of the voltage vector diagram shown in FIG. Represents a vector. If all four high limit switches are off, the output terminal voltage has V1. If all four high limit switches are on, the output terminal voltage has V4.

In addition, the output terminal voltage has a value of V2 and V6 when one of the four upper limit switches is turned on, and the output terminal voltage has a value of V3 and V5 when the two four upper limit switches are turned on. In addition, the middle vector in the gray region can be created by turning on only the quadrant switch on a or both quadrant switches on b and c.

With this combination of voltage vectors, a total of 25 valid vectors can be used to create the desired voltage vector. As shown in Fig. 2, the Vienna rectifier, which is a three-level rectifier, is difficult to select a switching vector by a combination of input voltage and four upper limit switches, and the calculation time of each selected vector is complicated. There is a problem that is very difficult to determine.

Hereinafter, a method of using a spatial voltage vector and a method using a triangular wave comparison PWM method will be briefly described as a configuration of a conventional two-level rectifier and a method for controlling the conventional two-level rectifier.

3 shows a circuit diagram of a conventional two-level PWM rectifier 1. 4 shows a spatial voltage vector diagram for controlling the two-level PWM rectifier 1 shown in FIG. 3. As shown in FIG. 3, it is understood that the spatial voltage vector diagram for voltage control of the two-level PWM rectifier 1 is not complicated compared to the spatial voltage vector diagram for controlling the Vienna rectifier 10 shown in FIG. 2. Can be. Therefore, in the case of the two-level PWM rectifier 1, the voltage can be usefully controlled by using the spatial voltage vector diagram.

In addition, FIG. 5 illustrates a configuration diagram of a switching function generator 20 for voltage control of a two-level PWM rectifier using a conventional triangular wave comparison PWM scheme. The triangular wave comparison PWM results in the same voltage control effect as the spatial voltage vector shown in FIG. The configuration of the switching function generator using the triangular wave comparison PWM method and the triangular wave comparison PWM method will be described in detail below.

As mentioned above, when the spatial voltage vector method is used to control the conventional Vienna rectifier 10, the selection of the effective voltage vector for generating the spatial voltage vector is complicated, and the application time of the effective voltage vector and the zero voltage vector is calculated. Because of this complexity, the actual implementation is difficult.

Therefore, to control the three-level Vienna rectifier 10, a voltage control method and a device of the Vienna rectifier, which are simpler and more feasible by applying a conventional triangular wave comparison PWM method without employing the spatial voltage vector method, are provided. Was required.

The present invention has been made to solve the above problems, in one embodiment of the present invention is a scheme for simply controlling the Vienna rectifier, a triangular wave comparison PWM scheme using two carriers used in the existing three-level rectifier In this paper, a switching function generator and a switching function generation method for voltage control of a Vienna rectifier using a triangular wave comparison PWM method applicable to a Vienna rectifier are provided.

In addition, according to another embodiment of the present invention to provide a carrier comparison PWM method of the Vienna rectifier using a single carrier. The single carrier comparison PWM method according to another embodiment of the present invention provides a switching function generator and generation method for voltage control of a Vienna rectifier, which is easy to implement because of using a single carrier.

Other objects, specific advantages and novel features of the present invention will become more apparent from the following detailed description and preferred embodiments in conjunction with the accompanying drawings.

An object of the present invention, the three-phase voltage applying unit for applying the three-phase AC voltage, the inductor provided in each of the three-phase input terminal, the DC connection capacitor provided in the output terminal and the inductor and DC connection capacitor is provided between the three-phase pulse width modulation (PWM) In a Vienna rectifier having a power semiconductor switch for power control and converting three-phase AC voltage into direct current, a switching function generator for generating a switching signal for controlling the power semiconductor switch, wherein the voltage of each phase A phase voltage command generator for generating a given phase voltage command to modulate the pulse width; A neutral point voltage generator for generating a neutral point voltage; A terminal voltage command calculator configured to generate a terminal voltage command by adding the phase voltage command generated by the phase voltage command generator and the neutral point voltage generated by the neutral point voltage generator; Normalization means for generating a normalized terminal voltage command by dividing the terminal voltage command output from the terminal voltage command calculation unit by a voltage corresponding to a DC link voltage; A carrier applying unit generating a carrier; And a triangular wave comparator for generating a switching signal for controlling the power semiconductor switch by applying a triangular wave comparison PWM method to the normalized terminal voltage command output from the normalization means and the carrier wave applied from the carrier applying unit. It can be achieved as a switching function generator for voltage control of a Vienna rectifier with a triangular wave comparison PWM scheme.

The switching function for controlling the power semiconductor switch is defined by Equation 1 below, and the output terminal voltage of the Vienna rectifier 10 according to the switching function may be defined by Equation 2 below.

[Equation 1]

&Quot; (3) "

In Equation 1, S _abc is a switching function, in Equation 3, V _{( abc ) 0} is an output terminal voltage, i _abc is an input current, and if the input current is a positive value, Sign (i _abc ) is +1. If the input current is negative, Sign (i _abc ) is -1.

The carrier applying unit may generate a high carrier present in a range of 0 or more and a low carrier present in a range of less than 0 to apply the triangular wave comparator.

The triangular wave comparator may be configured to generate a switching function by comparing the normalized terminal voltage command and the high carrier or by comparing the normalized terminal voltage command and the low carrier.

When the normalized terminal voltage command is a positive value, the triangular wave comparator compares the normalized terminal voltage command with the high carrier to control the switching function to 1 when the normalized terminal voltage command is smaller than the high carrier, and the normalized terminal voltage command If the normalized terminal voltage command is greater than the low carrier, the switching function is controlled to 0 when the normalized terminal voltage command is greater than the low carrier. The control function may be controlled to 1, and the switching function may be controlled to 0 when the normalized terminal voltage command is smaller than the low carrier.

The carrier applying unit may generate a single carrier existing only in a range of 0 or more and apply the generated single carrier to the triangular wave comparator.

It is provided between the triangular wave comparator and the normalizing means, further comprising an absolute value generating unit for receiving the normalized terminal voltage command output from the normalizing means for outputting a modulated terminal voltage command that is an absolute value of the normalized terminal voltage command to the triangular wave comparator It can be characterized.

The triangular wave comparator may generate a switching function by comparing a single carrier received from the carrier applying unit with a modulation terminal voltage command applied from the absolute value generating unit.

The triangular wave comparator compares the modulation terminal voltage command with a single carrier to control the switching function to 1 when the modulation terminal voltage command is smaller than the single carrier and to control the switching function to 0 when the modulation terminal voltage command is larger than the single carrier. You can do

In another category, an object of the present invention is to provide a three-phase voltage applying unit for applying an alternating voltage of three phases, an inductor provided at each of the three phase input terminals, a DC connection capacitor provided at the output terminal, and an inductor and a DC connection capacitor. In a Vienna rectifier having a power semiconductor switch for phase pulse width modulation (PWM) power control and converting three-phase AC voltage into direct current, a switching function generating method for generating a switching signal for controlling the power semiconductor switch. Generating a given phase voltage command to pulse width modulate the voltage of each phase in the phase voltage command generator and generating a neutral point voltage in the neutral voltage generator; Generating a terminal voltage command by adding a phase voltage command generated by the phase voltage command generator and a neutral point voltage generated by the neutral point voltage generator; Generating a normalized terminal voltage command by dividing the terminal voltage command output from the terminal voltage command calculating unit by a voltage corresponding to a DC link voltage; And generating, by a triangular wave comparator, a switching signal for controlling the power semiconductor switch by applying a triangular wave comparison PWM scheme to the normalized terminal voltage command output from the normalization means and the carrier wave applied from the carrier applying unit. It can be achieved by a switching function generation method for voltage control of a Vienna rectifier using a triangular wave comparison PWM method.

The generating of the switching signal may include generating a high carrier in a range of 0 or more and a low carrier in a range of 0 or less and applying the triangular comparator; And generating a switching function by comparing the normalized terminal voltage command with the high carrier or comparing the normalized terminal voltage command with the low carrier.

The step of generating the switching signal may include: when the normalized terminal voltage command is a positive value, the triangle wave comparator compares the normalized terminal voltage command with a high carrier to control the switching function to 1 when the normalized terminal voltage command is smaller than the high carrier. If the normalized terminal voltage command is higher than the high carrier, the switching function is controlled to 0. If the normalized terminal voltage command is negative, the normalized terminal voltage command is low by comparing the normalized terminal voltage command to the low carrier. The switching function may be controlled to 1 when the carrier is larger than the carrier, and the switching function may be controlled to 0 when the normalized terminal voltage command is smaller than the low carrier.

After the step of generating the normalized terminal voltage command, the absolute value generator provided between the triangular wave comparator and the normalization means receives the normalized terminal voltage command outputted from the normalization means, thereby modulating the terminal voltage command which is an absolute value of the normalized terminal voltage command. It may be characterized in that it further comprises the step of outputting to a triangular wave comparator.

The generating of the switching signal may include: generating and applying to the triangular comparator a single carrier existing only in a range of 0 or more; And generating, by the triangular wave comparator, a switching function by comparing a single carrier received from the carrier applying unit with a modulation terminal voltage command applied from the absolute value generating unit.

In the generating of the switching function, the triangular wave comparator compares the modulation terminal voltage command with a single carrier to control the switching function to 1 when the modulation terminal voltage command is smaller than a single carrier, and to switch when the modulation terminal voltage command is larger than a single carrier. It can be characterized by controlling the function to zero.

Therefore, according to one embodiment of the present invention as described, it has the effect that it is easier and simple to control the voltage of the Vienna rectifier by applying a triangular wave comparison PWM scheme. In the conventional PWM method using the space voltage vector, the calculation of the effective voltage vector applying time and the zero voltage vector applying time for generating the space vector is complicated and difficult to implement, but according to an embodiment of the present invention, two carriers The triangular wave comparison PWM method using a carrier wave signal can be applied to generate the switching function of the Vienna rectifier more simply.

In addition, since the two carrier comparison PWM method requires a plurality of carriers, the actual implementation is difficult, and according to another embodiment of the present invention, a single carrier comparison PWM method of a Vienna rectifier is proposed to implement a triangular wave comparison PWM method more simply. Will have the effect.

Although the present invention has been described in connection with the above-mentioned preferred embodiments, it will be appreciated by those skilled in the art that various other modifications and variations can be made without departing from the spirit and scope of the invention, All fall within the scope of the appended claims.

1 is a circuit diagram of a three-level Vienna rectifier to be controlled according to an embodiment of the present invention;
2 is a spatial voltage vector diagram for controlling a conventional three-level Vienna rectifier;
3 is a circuit diagram of a conventional two-level PWM rectifier,
4 is a space voltage vector diagram for controlling a conventional two-level PWM rectifier.
5 is a configuration diagram of a switching function generator for voltage control of a two-level PWM rectifier using a conventional triangular wave comparison PWM scheme;
6 is a configuration diagram of a switching function generator for voltage control of a Vienna rectifier using two carriers according to the first embodiment of the present invention;
7 is a graph showing two carriers, a normalized phase voltage command and a normalized terminal voltage command according to the first embodiment of the present invention;
8 is a flowchart of a method of generating a switching function for voltage control of a Vienna rectifier using two carriers according to a first embodiment of the present invention;
9A is a graph showing two carriers and a normalized terminal voltage command according to the first embodiment of the present invention;
9B is an enlarged graph of FIG. 9A,
9c is a graph showing a switching function according to the first embodiment of the present invention;
10 is a block diagram of a switching function generator for voltage control of a Vienna rectifier using a single carrier according to a second embodiment of the present invention;
11 is a graph showing a single carrier, a normalized phase voltage command and a modulation terminal voltage command according to a second embodiment of the present invention;
12 is a flowchart of a method for generating a switching function for voltage control of a Vienna rectifier using a single carrier according to a second embodiment of the present invention;
13A is a graph illustrating a single carrier and a modulated terminal voltage command according to a second embodiment of the present invention;
13B is an enlarged graph of FIG. 13A,
13c is a graph illustrating a switching function according to a second embodiment of the present invention;
14A is a graph showing a normalized terminal voltage command of a Vienna rectifier according to an experimental example of the present invention;
14B is a graph showing a modulated terminal voltage command of a Vienna rectifier according to an experimental example of the present invention;
14c is a graph showing an input phase current according to an experimental example of the present invention;
14d shows a graph showing an output terminal voltage according to an experimental example of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the detailed description of known functions and configurations incorporated herein will be omitted when it may unnecessarily obscure the subject matter of the present invention.

The same reference numerals are used for portions having similar functions and functions throughout the drawings. Throughout the specification, when a part is connected to another part, this includes not only the case where it is directly connected, but also the case where it is indirectly connected with another element in between. In addition, the inclusion of an element does not exclude other elements, but may include other elements, unless specifically stated otherwise.

Hereinafter, the configuration and operation of the switching function generator 100 for voltage control of the Vienna rectifier 10 to which the triangular wave comparison PWM scheme according to the first embodiment of the present invention is applied will be described. First, Figure 1 shows a circuit diagram of a three-level Vienna rectifier 10 to be controlled according to an embodiment of the present invention. 6 illustrates a configuration diagram of a switching function generator 100 for voltage control of the Vienna rectifier 10 using two carrier waves according to the first embodiment of the present invention, and FIG. A graph showing two carriers, a normalized phase voltage command and a normalized terminal voltage command according to an embodiment is shown.

As shown in FIG. 1, since the output terminal voltage of the three-level Vienna rectifier 10 to be controlled by the present invention has three states of 0.5Vdc, 0, and -0.5Vdc, the conventional two-level PWM rectifier Compared with the power semiconductor device used, the breakdown voltage of the switching device can be lowered by half, so that it can be seen that a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) can be used instead of the IGBT 14.

In the three-level Vienna rectifier 10 shown in FIG. 1, S _abc (S _a , S _b , S _c ) is composed of a MOSFET and a diode to enable quadrant operation with respect to the voltage and current applied to the switch. Switching function indicating the switching state of the MOSFET inside the power semiconductor module. In addition, it means a general rectifying diode of D ₁ to D ₆ 3 shown in FIG.

In order to turn on and off the semiconductor switch of the three-level Vienna rectifier 10, the relationship between the switching function and the output terminal voltage may be defined by Equation 3 below.

&Quot; (3) "

In Equation 3, V _{( abc ) 0} is an output terminal voltage and S _abc is a switching function. Equation 3 is a simplification of Equation 2 mentioned above, and Sign (i) indicates the direction of the current as a function. That is, if the current is a positive value, Sign (i) is +1. If the current is a negative value, Sign (i) is -1.

As can be seen from Equation 3, the switching function S _abc of the four upper limit switch for the Vienna rectifier 10 becomes 1 when the output terminal voltage V _{( abc ) 0} becomes 0V. It is necessary to make the switching function generator (100). On the other hand, when the switching function S _abc of the four quadrant switch is zero, that is, when the four quadrant switch is off, one of the two diodes connected to the positive or negative pole is turned on, depending on the direction of the phase current, and the positive phase current the output terminal voltage _{(V (abc) 0)} in has a value of 0.5Vdc, the phase current of the negative output voltage _{(V (abc) 0)} is -0.5Vdc. Therefore, in order for the output terminal voltage to have a desired average voltage, a problem arises in that the four upper limit switch must be selected and turned on in consideration of the voltage vector when the four upper limit switch is turned off.

On the other hand, since the input power factor target value of the Vienna rectifier 10 is 1, the current command and the voltage command always become in phase. If it is assumed that the direction of the phase current of the Vienna rectifier 10 is in phase with the voltage command, Equation 3 may be expressed as Equation 4 below.

&Quot; (4) "

As can be seen in Equation 4, when the switching function S _abc is 0, since the output terminal voltage V _{( abc ) 0} is determined according to whether the terminal voltage command is positive or negative, the switching function generator 100 ) Can be designed. That is, if the terminal voltage command is positive and the switching function S _abc is 0, the output terminal voltage V _{( abc ) 0} is 0.5 V _dc , the terminal voltage command is negative and the switching function S _abc is If it is 0, the output terminal voltage (V _{( abc ) 0} ) is -0.5V _dc . If the switching function S _abc is 1, the output terminal voltage V _{( abc) 0} becomes ₀ V regardless of whether the terminal voltage command V _{( abc ) 0} is positive or negative.

As shown in FIG. 6, the switching function generator 100 according to the first embodiment of the present invention includes a phase voltage command generation unit 110, a neutral point voltage generation unit 120, a terminal voltage command operation unit 130, and a carrier application. It can be seen that the unit 150 and the triangular wave comparator 160 and the like. The phase voltage command generator 110 generates the given phase voltage commands V _{an _ ref} , V _{bn _ ref} , and V _{cn _ ref} to pulse width modulate the voltage of each phase. The neutral voltage generator 120 generates the neutral voltage _{Vno _ ref} .

In addition, the terminal voltage command calculator 130 generates the phase voltage commands V _{an _ ref} , V _{bn _ ref} , V _{cn _ ref} generated from the phase voltage command generator 110 and the neutral voltage generator 120. _Generated terminal voltage commands (V _{ao _ ref} , V _{bo _ ref} , V _{co _ ref} ) by summing the neutral point voltages V _{no_ref} .

The normalization means 140 divides the terminal voltage commands _{Va a _ ref} , V _{bo _ ref} , V _{co _ ref} ) output from the terminal voltage command calculation unit 130 into voltages corresponding to the DC link voltages to normalize the terminals. The voltage command d _a , d _b , d _c is generated and applied to the triangular comparator 160.

In addition, the carrier applying unit 150 according to the first embodiment generates two carriers, namely, a high carrier having a range of 0 or more and a low carrier having a range of less than 0, respectively, to generate two carriers. The triangular wave comparator 160 is applied.

The triangular wave comparator 160 compares the normalized terminal voltage command d _abc with two carrier signals, and when the normalized terminal voltage command d _abc is greater than zero, the triangle wave comparator 160 is located above zero in the graph shown in FIG. 7. When the normalized terminal voltage command d _abc is less than zero, a logical multiplication (AND) operation is required to compare with the low carrier signal located below zero.

That is, if the normalized terminal voltage command (d _abc ) is greater than 0 and greater than the high carrier signal, the switching function is set to 0 so that the output terminal voltage is 0.5 V _dc . The switching function should be 1 whenever possible. If the normalized terminal voltage command (d _abc ) is less than 0 and less than the low carrier signal, the switching function is zero so that the output terminal voltage is -0.5 Vdc, and the normalized terminal voltage command (d _abc ) is a low carrier signal. If it is larger, the switching function is set to 1 so that the output terminal voltage becomes 0V.

Finally, the triangular wave comparator 160 controls one phase switch after a logical OR operation on a comparison result between the high carrier and the low carrier. In FIG. 7, d _a denotes a normalized terminal voltage command and is obtained by dividing the terminal voltage command by half of the DC link voltage.

That is, the result of the comparison generates _a switching function Sa for turning on and off the bidirectional switch located on each phase. Normalized terminal voltage command (d _a) is greater when the switching function than 0 is determined by the equation (5) below, the terminal voltage command (d _a) the switching function by the equation 6 below when this is less than 0 (S _a ) is determined.

[Equation 5]

S _a = 1, d _a ≤ high carrier (carrie_Positive)

S _a = 0, d _a > high carrier (carrie_Positive), d _a ≥ 0

&Quot; (6) "

S _a = 1, d _a ≥ low carrier (carrie_Negative)

S _a = 0, d _a <low carrier (carrie_Negative), d _a <0

As shown in FIG. 7, the graph shows two carriers (high carrier (carrie_Positive), low carrier (carrie_Negative), and normalized phase voltage command V _{abc _ ref} / for the triangular wave comparison PWM scheme of the Vienna rectifier 10. the V _dc), and the normalized voltage command terminal (d _abc) exhibits can be seen. High carrier signal than when the normalized terminal voltage command (d _abc) is greater than zero, is for a normalized terminals compared to the voltage command (d _abc), a low-carrier signal is normalized terminal voltage command (d _abc) is 0, It is for comparison with the normalized terminal voltage command d _abc when small. The three-level Vienna rectifier 10 PWMs the two series switches on top if the normalized terminal voltage command (d _abc ) is greater than zero, and the top two switches when the normalized terminal voltage command (d _abc ) is greater than the high carrier. Turn on all to make the output terminal voltage 0.5V _dc .

If the normalized terminal voltage command (d _abc ) is smaller than the upper carrier, turn off the top of the two switches at the top so that the output terminal voltage becomes 0V. In this way, according to the normalized terminal voltage command (d _abc ), the method of controlling the average value according to the switching period of the terminal voltage is the same as the terminal voltage command. The triangle wave comparison PWM method is used. It can be controlled simply because it makes a switching command comparing the terminal voltage command and two carriers without calculating the application time of.

Hereinafter, a method of generating a switching function for voltage control of the Vienna rectifier 10 using the triangular wave comparison PWM scheme according to the first embodiment of the present invention will be described. First, FIG. 8 is a flowchart illustrating a method of generating a switching function for voltage control of the Vienna rectifier 10 using two carrier waves according to the first embodiment of the present invention. 9A is a graph showing two carriers and a normalized terminal voltage command according to the first embodiment of the present invention, FIG. 9B is an enlarged graph of FIG. 9A, and FIG. 9C is a first embodiment of the present invention. A graph showing a switching function according to an example is shown.

First, the phase voltage command generation unit 110 generates a given phase voltage command to pulse width modulate the voltage of each phase, and generates the neutral point voltage in the neutral point voltage generation unit 120 (S10-1). In addition, the terminal voltage command calculation unit 130 generates the terminal voltage command by adding the phase voltage command generated by the phase voltage command generation unit 110 and the neutral point voltage generated by the neutral point voltage generation unit 120 (S20-). One)

Next, the normalization unit 140 generates a normalized terminal voltage command by dividing the terminal voltage command output from the terminal voltage command calculation unit 130 by a voltage corresponding to the DC link voltage (S30-1). Then, the terminal voltage command normalized to the triangular wave comparator 160 is applied, and the carrier application unit 150 generates two carrier signals and applies them to the triangular wave comparator 160 (S40-1).

In addition, the triangular wave comparator 160 controls the power semiconductor switch by applying a triangular wave comparison PWM scheme to the normalized terminal voltage command output from the normalization means 140 and the two carrier waves applied from the carrier applying unit 150. The switching signal is generated (S50-1).

9A illustrates a graph showing two carriers and a normalized terminal voltage command according to the first embodiment of the present invention. 9B shows an enlarged graph of FIG. 9A, and FIG. 9C shows a graph showing a switching function according to the first embodiment of the present invention. As mentioned above, when the terminal voltage commands (da, db, dc) normalized by Equations 5 and 6 are greater than zero, the normalized terminal voltage commands d _a , d _b , and d _c are high. When the normalized terminal voltage command d _a , d _b , d _c is smaller than the high carrier, the switching function _Sa , S _b , S _c becomes 1 as shown in FIG. 9C. When the normalized terminal voltage command d _a is larger than the high carrier, the switching functions S _a , S _b , and S _c become zero, as shown in FIG. 9C.

Further, when the normalized terminal voltage command d _a , d _b , d _c is less than 0, the normalized terminal voltage command d _a is compared with the low carrier, and the normalized terminal voltage command d _a , d _{When b} and d _c are smaller than the low carrier, as shown in FIG. 9C, the switching functions S _a , S _b , and S _c become zero, and the normalized terminal voltage commands d _a , db, and d _c are If larger than the low-cost carrier switching function as shown in Figure _{9c (S a, S b,} S c) are presented one. Then, the power semiconductor switch of the Vienna rectifier 10 is controlled by the switching function generated in this manner (S60-1).

Hereinafter, the configuration and operation of the switching function generator 200 for voltage control of the Vienna rectifier 10 to which the triangular wave comparison PWM scheme according to the second embodiment of the present invention is applied will be described. Unlike the first embodiment, the switching function generator 200 for voltage control of the Vienna rectifier 10 to which the triangular wave comparison PWM method according to the second embodiment of the present invention further includes an absolute value generator 170. The carrier applying unit 150 uses a single carrier instead of two carriers, and the configuration of the triangular comparator 160 is simpler than that of the first embodiment.

FIG. 10 is a block diagram of a switching function generator 200 for voltage control of a Vienna rectifier 10 using a single carrier according to a second embodiment of the present invention, and FIG. 11 is a second embodiment of the present invention. Shows a single carrier, normalized phase voltage command and modulated terminal voltage command. The phase voltage command generator 110, the neutral voltage generator 120, the terminal voltage command calculator 130 and the normalization means 140 of the switching function generator 200 according to the second embodiment of the present invention The same description as the switching function generator 100 will be omitted.

The switching function generator 200 for voltage control of the Vienna rectifier 10 using a single carrier according to the second embodiment of the present invention includes an absolute value generator provided between the normalization means 140 and the triangular wave comparator 160 ( 170). The absolute value generator 170 receives the normalized terminal voltage command d _a , d _b , d _c output from the normalization means 140, and normalizes the terminal voltage command d _a , d _b , d _c . The modulated terminal voltage command (x _a , x _b , x _c ) is outputted to the triangular wave comparator 160 by taking the absolute value of.

In addition, the carrier applying unit 150 of the switching function generator 200 according to the second embodiment generates only a single carrier having a range of 0 or more and applies it to the triangular wave comparator 160 instead of generating two carriers.

Accordingly, the triangular wave comparator 160 of the switching function generator 200 according to the second embodiment includes the modulation terminal voltage command (x _a , x _b , x _c ) generated by the absolute value generator 170 and the carrier applying unit ( A single carrier generated in 150 is applied to generate a switching function (S _a , S _b , S _c ) by comparing the modulation terminal voltage command (x _a , x _b , x _c ) with a single carrier.

The switching function S _a generated by the triangular wave comparator 160 according to the second embodiment may be defined by Equation 7 below.

[Equation 7]

S _a = 1, d _a ≤ single carrier

S _a = 0, d _a single carrier

In Equation 7, the low carrier (carrie_negative) of Equation 6 is equal to the absolute value of the high carrier (carrie_positive), and Equation 6 may be defined as shown in Equation 7 if the carrier having the opposite load is used. In addition, if the modulation terminal voltage command x _a is defined as the absolute value of the normalized terminal voltage command d _a , the switching function S _a of the Vienna rectifier 10 may also be represented by Equation 8 below.

[Equation 8]

S _a = 1, x _a ≤ single carrier

S _a = 0, x _a > Single carrier

That is, as shown in FIG. 11, when the modulation terminal voltage command xa has a value equal to or less than a single carrier, the switching function S _a becomes 1, and the modulation terminal voltage command x _a is a single carrier. If a greater value to have the switching function (S _a) is to zero.

In the single carrier PWM method according to the second embodiment of the present invention, the PWM modulation of the Vienna rectifier 10 is performed by changing the voltage modulation method of the conventional two-level converter to match the triangle wave comparator 160 or the comparator 160 or the rectifier 10. Simple voltage control is possible by using.

When the normalized terminal voltage command d _a is defined as an absolute value, a modulated terminal voltage command x _a is generated, and a switching command can be generated using the generated modulated terminal voltage command x _a and a single carrier. Therefore, the S / W and H / W implementation can be very simple using a single carrier.

Hereinafter, a method of generating a switching function for voltage control of the Vienna rectifier 10 using the triangular wave comparison PWM scheme according to the second embodiment of the present invention will be described. First, FIG. 12 is a flowchart illustrating a method of generating a switching function for voltage control of a Vienna rectifier 10 using a single carrier according to a second embodiment of the present invention. 13A is a graph showing a single carrier and a modulated terminal voltage command according to the second embodiment of the present invention, FIG. 13B is an enlarged graph of FIG. 13A, and FIG. 13C is a second embodiment of the present invention. It shows a graph showing the switching function according to.

First, the phase voltage command generation unit 110 generates a given phase voltage command to pulse width modulate the voltage of each phase, and generates the neutral point voltage in the neutral point voltage generation unit 120 (S10-2). In addition, the terminal voltage command calculation unit 130 generates the terminal voltage command by adding the phase voltage command generated by the phase voltage command generation unit 110 and the neutral point voltage generated by the neutral point voltage generation unit 120 (S20-). 2)

Next, the normalization means 140 generates a normalized terminal voltage command by dividing the terminal voltage command output from the terminal voltage command calculation unit 130 by a voltage corresponding to the DC link voltage (S30-2).

The absolute value generating unit 170 receives the normalized terminal voltage command and generates a modulated terminal voltage command that is an absolute value of the normalized terminal voltage command (S40-2). Next, the modulation terminal voltage command is applied to the triangle wave comparator 160, and the carrier applying unit 150 generates one single carrier signal and applies it to the triangle wave comparator 160 (S50-2).

In addition, the triangular wave comparator 160 controls the power semiconductor switch by applying a triangular wave comparison PWM method to the modulation terminal voltage command output from the absolute value generating unit 170 and one single carrier applied by the carrier applying unit 150. To generate a switching signal for (S60-2).

13A illustrates a graph showing two carriers and a normalized terminal voltage command according to the second embodiment of the present invention. 13B illustrates an enlarged graph of FIG. 13A, and FIG. 13C illustrates a graph showing a switching function according to the first embodiment of the present invention. As mentioned above, by the equation (7) or (8), the modulated terminal voltage command (x _a , x _b , x _c ) is compared with a single carrier, and the normalized terminal voltage command (x _a , x _b , x _{When c} ) is smaller than a single carrier, as shown in FIG. 13C, the switching functions S _a , S _b , and S _c become 1, and the modulation terminal voltage command (x _a , x _b , x _c ) is smaller than that of a single carrier. If it becomes large, as shown in FIG. 13C, the switching functions _Sa , S _b , and S _c become zero.

Comparing the PWM method using two carriers, it can be seen that the PWM command is different but the switching commands are the same. Then, the power semiconductor switch of the Vienna rectifier 10 is controlled by the switching function generated in this manner (S60-1).

Hereinafter will be briefly described the experimental results according to the second embodiment of the present invention. 14A to 14D are experimental results of the Vienna rectifier 10 according to the experimental example of the present invention. The conditions for the experiment of the Vienna rectifier 10 are as follows. Input voltage condition is 120 [Vrms] of 60 [Hz]. The load for the DC output used a resistive load and the output power was 2.8 [kW]. The input inductance is 1 [mH] and the PWM control frequency is set to 20 [kHz].

FIG. 14A shows a graph showing normalized terminal voltage commands d _a , d _b , and d _c of the Vienna rectifier 10 according to an experimental example of the present invention, and FIG. 14B shows a Vienna according to an experimental example of the present invention. A graph showing the modulation terminal voltage command (x _a , x _b , x _c ) of the rectifier 10, FIG. 14C is a graph showing the input phase current (I _as , I _bs , I _cs ) according to the experimental example of the present invention, and 14D is a graph showing an output terminal voltage according to an experimental example of the present invention.

As shown in Fig. 14A, the graph shows the normalized terminal voltage commands d _a , d _b , d _c for controlling the Vienna rectifier 10, and the graph shown in Fig. 14B shows the normalized terminals of Fig. 14A. The waveform which changed the voltage command d _a , d _b , d _c into the modulation terminal voltage command x _a , x _b , x _c is shown. The graph of FIG. 14C shows the input phase currents I _as , I _bs and I _cs of the Vienna rectifier 10 operating using the proposed single carrier, and the graph of FIG. 14D shows the Vienna rectifier 10 operating using the proposed single carrier. It can be seen that the DC link output (V _dc ) of As a result of the experiment, the Vienna rectifier 10 is controlled by using the proposed single carrier, and the DC link voltage and the input current are well controlled.

1: 2 Level PWM Rectifier
10: 3 level Vienna rectifier
11: 3-phase voltage applied
12: inductor
13: DC connection capacitor
14: IGBT
20: Switching function generator for voltage control of two-level PWM rectifier using conventional triangle wave comparison PWM method
21: Conventional triangle wave comparator
100: Switching function generator for voltage control of the Vienna rectifier applying the triangular wave comparison PWM method according to the first embodiment
110: phase voltage command generation unit
120: neutral voltage generator
130: terminal voltage command operation unit
140: normalization means
150: carrier application unit
160: triangle wave comparator
170: absolute value generator
200: Switching function generator for voltage control of the Vienna rectifier applying the triangular wave comparison PWM method according to the second embodiment

Claims (14)

Three-phase voltage applying unit for applying three-phase AC voltage, an inductor provided in each of the three-phase input terminal, a DC connection capacitor provided in the output terminal and between the inductor and the DC connection capacitor to control the three-phase pulse width modulation (PWM) power In the Vienna rectifier having a power semiconductor switch for converting the three-phase AC voltage to direct current, in the switching function generator for generating a switching signal for controlling the power semiconductor switch,
A phase voltage command generator for generating a given phase voltage command to pulse width modulate the voltage of each phase; A neutral point voltage generator for generating a neutral point voltage; A terminal voltage command calculator configured to generate a terminal voltage command by adding the phase voltage command generated by the phase voltage command generator and the neutral point voltage generated by the neutral point voltage generator; Normalization means for generating a normalized terminal voltage command by dividing the terminal voltage command output from the terminal voltage command calculation unit by a voltage corresponding to a DC link voltage; A carrier applying unit generating a carrier; And a triangular wave comparator configured to generate a switching signal for controlling the power semiconductor switch by applying a triangular wave comparison PWM scheme to the normalized terminal voltage command output from the normalization means and the carrier wave applied from the carrier applying unit.
When the carrier applying unit generates a high carrier present in a range of 0 or more and a low carrier present in a range of less than 0 and applies it to the triangle wave comparator, the triangle wave comparator compares the normalized terminal voltage command with the high carrier or The switching terminal is generated by comparing the normalized terminal voltage command with the low carrier, and the triangular wave comparator compares the normalized terminal voltage command with the high carrier when the normalized terminal voltage command is positive. A switching function for turning on the power semiconductor switch when the normalized terminal voltage command is smaller than the high carrier, and switching to turn off the power semiconductor switch when the normalized terminal voltage command is larger than the high carrier. Generates function and normalizes terminal voltage When the command is negative, the normalized terminal voltage command is compared with the low carrier to generate a switching function for turning on the power semiconductor switch when the normalized terminal voltage command is larger than the low carrier. Generating a switching function for turning off the power semiconductor switch when the terminal voltage command is smaller than the low carrier;
When the carrier applying unit generates a single carrier existing only in a range of 0 or more and applies it to the triangular wave comparator, the triangular comparator and the normalization unit are provided to receive the normalized terminal voltage command output from the normalization unit. And an absolute value generator for outputting a modulated terminal voltage command that is an absolute value of the normalized terminal voltage command to the triangle wave comparator, wherein the triangle wave comparator is applied from a single carrier received from the carrier applying unit and the absolute value generator. Compare the received modulation terminal voltage command to generate the switching function, and the triangular wave comparator compares the modulation terminal voltage command and the single carrier to turn on the power semiconductor switch when the modulation terminal voltage command is smaller than the single carrier. Generate a switching function, And a switching function for turning off the power semiconductor switch when the modulation terminal voltage command is larger than the single carrier wave.
delete delete delete delete delete delete delete In the method of generating a switching function using the function generator according to claim 1,
Three-phase voltage applying unit for applying three-phase AC voltage, an inductor provided in each of the three-phase input terminal, a DC connection capacitor provided in the output terminal and between the inductor and the DC connection capacitor to control the three-phase pulse width modulation (PWM) power In the Vienna rectifier having a power semiconductor switch for converting the three-phase AC voltage to direct current, the switching function generating method for generating a switching signal for controlling the power semiconductor switch,
Generating a given phase voltage command to pulse width modulate the voltage of each phase in the phase voltage command generator and generating a neutral point voltage in the neutral voltage generator; Generating a terminal voltage command by adding a phase voltage command generated by the phase voltage command generator and a neutral point voltage generated by the neutral point voltage generator; A normalizing means dividing the terminal voltage command output from the terminal voltage command calculating unit by a voltage corresponding to a DC link voltage to generate a normalized terminal voltage command; And a triangular wave comparator generating a switching signal for controlling the power semiconductor switch by applying a triangular wave comparison PWM scheme to the normalized terminal voltage command output from the normalization means and the carrier wave applied from the carrier applying unit. ,
Generating the switching signal,
Generating a high carrier in a range of 0 or more and a low carrier in a range of 0 or less and applying it to the triangular comparator; And generating, by the triangular wave comparator, the switching terminal by comparing the normalized terminal voltage command with the high carrier or by comparing the normalized terminal voltage command with the low carrier. The triangular wave comparator compares the normalized terminal voltage command with the high carrier and turns on the power semiconductor switch when the normalized terminal voltage command is smaller than the high carrier when the normalized terminal voltage command is a positive value. Generating a switching function for generating a switching function for turning off the power semiconductor switch when the normalized terminal voltage command is greater than the high carrier, and generating the switching function for turning off the power semiconductor switch. The terminal voltage command is compared with the low carrier to A switching function for turning on the power semiconductor switch when the normalized terminal voltage command is larger than the low carrier; and a switching function for turning off the power semiconductor switch when the normalized terminal voltage command is smaller than the low carrier. Raises,
After generating the normalized terminal voltage command,
The absolute value generator provided between the triangle wave comparator and the normalization means receives the normalized terminal voltage command output from the normalization means and outputs a modulated terminal voltage command that is an absolute value of the normalized terminal voltage command to the triangle wave comparator. The method may further include generating the switching signal, wherein the carrier applying unit generates and applies a single carrier present only in a range of 0 or more to the triangular comparator; And generating, by the triangular wave comparator, the switching function by comparing a single carrier received from the carrier applying unit with a modulation terminal voltage command received from the absolute value generating unit, wherein the switching function is generated. The triangular wave comparator compares the modulated terminal voltage command with the single carrier to generate a switching function for turning on the power semiconductor switch when the modulated terminal voltage command is less than the single carrier, wherein the modulated terminal voltage command is And a switching function for turning off the power semiconductor switch when the carrier wave is larger than the carrier wave. delete delete delete delete delete

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