WO2017034276A1

WO2017034276A1 - Power converting device and method for switching control

Info

Publication number: WO2017034276A1
Application number: PCT/KR2016/009268
Authority: WO
Inventors: 김태웅; 조춘호
Original assignee: 경상대학교 산학협력단
Priority date: 2015-08-21
Filing date: 2016-08-22
Publication date: 2017-03-02

Abstract

A power converting device for switching control is disclosed. According to the present invention, a power converting device includes: an input side converter unit; an output side inverter unit; a sector discerning unit for discerning a plurality of sectors for an input current of the converter unit and an output voltage of the inverter unit; a composite vector time calculating unit for using at least one from among the input current of the converter unit, the output voltage of the inverter unit, and a modulation index (MI) to calculate a composite vector time; a sequence determining unit for determining a switching sequence of the converter unit and a switching sequence of the inverter unit for each of the plurality of discerned sectors; and a control signal generating unit for generating a control signal for conducting a switching operation of the converter unit and the inverter unit on the basis of the switching sequences of the converter unit and the inverter unit and the composite vector time, and the switching sequence of the converter unit does not include a zero vector. Accordingly, the power converting device minimizes switching commutation through simplifying the switching sequences of the input side converter and the output side inverter, so as to be able to minimize power loss that occurs during switching commutation according to a switching sequence.

Description

Power converter and method for switching control

The present invention relates to a direct type AC / AC power converter without a DC link circuit for switching control, and more particularly, to a power converter capable of zero current switching of a converter section.

In general, a power conversion device such as a two stage direct power converter system (TSDPC) consists of a direct DC link circuit of an indirect AC / AC power conversion system as a virtual DC link circuit to reduce the size and length of a large capacity system. It has an advantage for life.

In general, a three-phase power converter controls six switching elements including six bidirectional switching elements of an input side converter and an anti-parallel diode of an output side inverter, so that there are 18 semiconductor power switching elements to be controlled. The control method for controlling such a power switching element generally uses a 9-step or 11-step switching sequence.

However, when controlling the switching elements of the input-side converter and the output-side inverter through the nine-stage or eleven-stage switching sequence, there is a problem that a power loss occurs due to the switching switching of each stage.

In order to solve the above problems, an object of the present invention, furthermore, an object of the present invention is to minimize the switching switching through the simplification of the switching sequence of the input converter and the output inverter of the power converter.

Furthermore, an object of the present invention is to minimize the power loss that occurs during switching switching according to a switching sequence in an input converter and an output inverter of a power converter.

According to an aspect of the present invention, there is provided a power conversion apparatus comprising: a sector determination unit configured to determine a plurality of sectors of an input side converter unit, an output side inverter unit, an input current of the converter unit, and an output voltage of the inverter unit; A composite vector time calculating unit calculating a composite vector time using at least one of an input current of the converter unit, an output voltage of the inverter unit, and a modulation index MI, a switching sequence of the converter unit for each of the determined plurality of sectors; A sequence determination section for determining a switching sequence of the inverter section and a control signal for generating a control signal for performing a switching operation of the converter section and the inverter section based on the switching sequence of the converter section and the inverter section and the composite vector time; And a generating unit, wherein the switching sequence of the converter unit is: The not included.

And, if the power conversion device is a three-phase direct power conversion device, the converter unit includes a six-way switch as a current type converter for converting three-phase alternating current into a direct current, the inverter unit is a three-phase alternating current As a voltage converter for converting the circuit into a circuit, it may include six switches including an anti-parallel diode.

The sequence determiner may determine the switching sequence of the converter unit as a two-stage switching sequence without a zero vector, and may determine the switching sequence of the output side inverter unit as a five-stage switching sequence including a zero vector and a valid vector.

The sequence determiner may determine a switching sequence of the converter unit and the inverter unit such that the power converter has a six-stage switching sequence by combining a two-stage switching sequence of the converter unit and a five-stage switching sequence of the inverter unit. The switching sequence of step 6 may have a switching sequence of a first valid vector, a second valid vector, a first zero vector, a second zero vector, a third valid vector, and a fourth valid vector.

The sequence determining unit may determine the switching sequence of the converter unit as a two-stage switching sequence without a zero vector, and may determine the switching sequence of the inverter unit as a seven-stage switching sequence including a zero vector and a valid vector.

The sequence determiner may include a switching sequence of the input side converter unit and the output side inverter unit such that the power converter has an eight-stage switching sequence using a combination of the two-stage switching sequence of the converter unit and the seven-stage switching sequence of the inverter unit. You can decide.

The switching sequence of step 8 may include a first zero vector, a first valid vector, a second valid vector, a second zero vector, and a third based on a first predetermined condition when the determined plurality of sectors is an odd number. A zero vector, a third valid vector, a fourth valid vector, and a fourth zero vector, and when the determined plurality of sectors is an even number, the first zero vector and the second valid vector are based on a second predetermined condition. The switching sequence may include a vector, a first valid vector, a second zero vector, a third zero vector, a fourth valid vector, a third valid vector, and a fourth zero vector.

If the power converter is a three-phase / single-phase direct power converter, the converter unit includes six bidirectional switches as a current converter for converting a three-phase alternating current voltage to a direct current, and the inverter unit is configured to supply the direct current. A voltage converter for converting single phase alternating current may include four switches including an anti-parallel diode.

The sequence determining unit may determine the switching sequence of the converter unit as a two-stage switching sequence without a zero vector, and may determine the switching sequence of the inverter unit as a five-stage switching sequence including a zero vector and an effective vector.

The sequence determiner may determine a switching sequence of the converter unit and the inverter unit such that the power converter has a six-stage switching sequence by combining a two-stage switching sequence of the converter unit and a five-stage switching sequence of the inverter unit. The six-stage switching sequence may include a first switching sequence of a first zero vector, a second valid vector, a second zero vector, a third zero vector, a first valid vector, and a fourth zero vector, and a first zero vector. The first valid vector, the second zero vector, the third zero vector, the second valid vector, and the fourth zero vector may be one of a second switching sequence.

The apparatus further includes a vector time calculator configured to calculate an effective vector time and a zero vector time for calculating the synthesized vector time, wherein the vector time calculator includes an input effective vector time using an input current sector and an input current phase of the converter unit. An input vector time calculator for calculating an output effective vector time and an output zero vector time by using an input vector time calculator for calculating an output voltage sector, an output voltage phase, and the modulation index MI; The modulation index calculator may be configured to calculate the modulation index MI using an output voltage.

As described above, according to various embodiments of the present disclosure, the power conversion apparatus according to the present invention minimizes switching switching by simplifying a switching sequence of an input side converter and an output side inverter, and thus generates power in switching switching according to the switching sequence. This has the effect of minimizing losses.

1 is a block diagram of a power conversion apparatus according to an embodiment of the present invention;

2 (a) is a first circuit diagram of a three-phase direct power converter according to an embodiment of the present invention;

2 (b) is a second circuit diagram of a three-phase direct power converter with a clamp protection circuit according to an embodiment of the present invention,

3 is a circuit diagram of a three-phase / single-phase direct power converter with a clamp protection circuit according to an embodiment of the present invention;

4 is an exemplary diagram of a bidirectional switching element of an input side converter unit according to an embodiment of the present invention;

5 is an exemplary diagram illustrating a space vector of an input side converter unit and an output side inverter unit in a three-phase and three-phase / single-phase direct power converter according to an embodiment of the present invention;

6 is an exemplary diagram showing a switching sequence of a conventional power converter;

7 is an exemplary diagram illustrating a switching sequence for implementing partial zero current switching of a converter unit of a three-phase direct type power converter according to an embodiment of the present invention;

8 is an exemplary diagram illustrating a switching sequence for implementing zero current switching of a converter unit of a three-phase power converter according to an embodiment of the present invention;

9 is an exemplary diagram illustrating waveforms of a virtual DC link voltage, a current, and a gate signal in a partial zero current switching mode of a three-phase direct power converter according to an embodiment of the present invention.

10 is an exemplary diagram illustrating an enlarged waveform of a virtual DC link voltage, a current, and a gate signal in a partial zero current switching mode of a three-phase direct power converter according to an embodiment of the present invention;

11 is an exemplary diagram illustrating an enlarged waveform of a virtual DC link current and a switching gate signal of an input side converter in a partial zero current switching mode of a three-phase direct type power conversion device according to an embodiment of the present invention;

12 is an exemplary diagram illustrating waveforms of an output line voltage and an output current in a partial zero current switching mode of a three-phase direct power converter according to an embodiment of the present invention.

13 is an exemplary view showing waveforms of a virtual DC link voltage, a current, and a gate signal in a zero current switching mode of a three-phase direct power converter according to an embodiment of the present invention;

14 is an exemplary diagram illustrating an enlarged waveform of a virtual DC link voltage, a current, and a gate signal in a zero current switching mode of a three-phase direct power converter according to an embodiment of the present invention;

15 is an exemplary diagram illustrating an enlarged waveform of a virtual DC link voltage and a switching gate signal of an input side converter unit in a zero current switching mode of a three-phase direct type power converter according to an embodiment of the present invention;

16 is an exemplary diagram illustrating waveforms of an output line voltage and an output current in a zero current switching mode of a three-phase direct type power converter according to an embodiment of the present invention;

17 is an exemplary diagram illustrating a switching sequence for implementing zero current switching of a three-phase / single-phase direct power converter according to an embodiment of the present invention;

18 is an exemplary view showing waveforms of output current and output line voltage according to a simulation performed in a three-phase / single-phase direct current converter according to an embodiment of the present invention;

19 is an exemplary diagram illustrating waveforms of a DC link current and a switching signal according to a simulation performed in a three-phase / single-phase direct current converter according to an embodiment of the present invention;

20 is an exemplary view showing a ZCS operation waveform according to a simulation performed in a three-phase / single-phase direct current conversion device according to an embodiment of the present invention;

21 is an exemplary view showing a result of comparing a conventional control method and a number of partial zero current switching switching times during one cycle in a three-phase direct type power converter according to an embodiment of the present invention;

FIG. 22 is an exemplary view showing a result of comparing a conventional control method and a zero current switching switching frequency during one cycle in a three-phase direct type power converter according to an embodiment of the present invention; FIG.

23 is a flowchart of a switch control method of a power conversion apparatus according to an embodiment of the present invention.

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Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of a power conversion apparatus according to an embodiment of the present invention.

As shown in FIG. 1, the power converter is an AC / AC power converter that converts a three-phase AC input without a DC link circuit. Such a power converter may be a three-phase direct power converter or a three-phase / single-phase direct power converter, depending on the embodiment.

The three-phase direct type power converter may be a device for directly converting a three-phase AC input into a three-phase AC output without a DC link circuit. The three-phase / single-phase direct type power converter may be a device for directly converting and outputting a three-phase AC input into a single-phase AC output without a DC link circuit.

Hereinafter, a power converter consisting of a three-phase direct type power converter and a power converter consisting of a three-phase / single phase direct type power converter will be described in detail.

2 (a) is a first circuit diagram of a three-phase direct power converter according to an embodiment of the present invention, Figure 2 (b) is a three-phase direct with a clamp protection circuit according to an embodiment of the present invention It is a 2nd circuit diagram of a type power converter.

As shown in FIG. 2A, the three-phase direct power converter is an AC / AC power converter that directly converts a three-phase AC input to a three-phase AC output without a DC link circuit. The three-phase direct power converter includes an input side converter 110, an output side inverter 120, a sector discriminator 130, a sequence determiner 140, and a control signal generator 150.

The input side converter unit 110 includes six bidirectional switching elements for four quadrant operation, and the output side inverter unit 120 has a structure of a general voltage inverter. Here, the output side inverter unit 120 may be configured by, for example, two switching elements connected in series to each other to form one pole, and three poles connected in parallel to each other. At this time, in order to output the three-phase AC voltage, it is preferable that the switch elements of one pole and the neighboring pole operate complementarily.

Here, complementary means to turn on and turn off the upper switching element and the lower switching element of the adjacent pole in one pole at the same time, the upper switching element and the lower switching element in each pole alternately turn on and turn off Means that.

Meanwhile, a current direction detecting circuit is formed between the input side converter unit 110 and the output side inverter unit 120. Here, the current direction detection circuit is a circuit for identifying the regenerative section in which switching switching is changed in the regenerative section. Such a current direction detecting circuit is preferably provided in a virtual DC link circuit.

On the other hand, as shown in Figure 2 (b), the three-phase direct power conversion apparatus according to the present invention may further include a device stabilization circuit unit 170. The device stabilization circuit unit 170 protects the switching device of the power converter from surges in the input line, overvoltage generation due to switching switching, and surge due to load shutdown.

Meanwhile, the bidirectional switching device may be implemented in the following types.

3 is a circuit diagram of a three-phase / single-phase direct power conversion device with a clamp protection circuit according to an embodiment of the present invention.

As shown in FIG. 3, the three-phase / single phase direct type power converter is an AC / AC power converter that directly converts a three-phase AC input to a single-phase AC output without a DC link circuit. The three-phase / single phase direct type power converter is similar to the three-phase direct type power converter described above with the input side converter unit 110, the output side inverter unit 120, the sector discriminator 130, and the sequence determiner 140. The control signal generator 150 and the device stabilization circuit unit 170 is included.

The input side converter unit 110 includes six bidirectional switching elements for four quadrant operation, and the output side inverter unit 120 has a structure of a general single phase voltage inverter. That is, the output side inverter unit 120 may include an input side converter unit 110 including six bidirectional switching elements and four unidirectional switching elements for single phase grid connection.

The device stabilization circuit unit 170 protects the switching device of the power converter from surges in the input line, overvoltage generation due to switching switching, and surge due to load shutdown.

4 is an exemplary diagram of a bidirectional switching device of an input side converter unit according to an exemplary embodiment of the present invention.

In general, the bidirectional switching device may be implemented by using a conventional switching device (power MOSFET, IGBT, etc.).

Figure 4a is a bidirectional switching device of the first type, consisting of four diodes and one IGBT, because the bidirectional current conducts to one switch, one in each bidirectional switch compared to other types of bidirectional switching devices Only the gate driver is required. On the other hand, since there are three switches in each conduction path of the first type bidirectional switching element, the switching loss is greatest compared to other types of bidirectional switching elements, and there is a disadvantage in that the direction of the current flowing through the switch cannot be controlled.

(B) and (c) of FIG. 4 are bidirectional switching elements of a second type, and are composed of a common emitter or a common collector by combining two diodes and two IGBTs, and each of the IGBTs has a breakdown against zero voltage. Diodes for blocking are connected in anti-parallel. Since there are two switches in each conduction path, there is less switching loss than the bidirectional switching element of the first type.

Meanwhile, when each IGBT of the bidirectional switching device of FIGS. 4B and 4C can withstand the reverse voltage, as shown in FIG. 3D, the bidirectional switching device may be configured with two IGBTs. In this case, the switching loss can be minimized as compared with the other types of bidirectional switching elements.

Meanwhile, the sector discriminating unit 130 determines a plurality of sectors with respect to the input current of the input side converter unit 110 and the output voltage of the output side inverter unit 120. Specifically, the input side converter unit 110 detects the input phase from the three-phase voltage input to the input side converter unit 110 using a phase locked loop (PLL), and the output side inverter unit 120 receives the input. The output phase is detected from any given command voltage. As such, when the input phase and the output phase are detected, the sector discriminating unit 130 determines the sector for the input current from the pre-detected input phase by using the space vector for the input current, and determines the spatial vector for the output voltage. A sector for the output voltage is discriminated from the previously detected output phase.

The vector time calculator 160 calculates an effective vector time and a modulation index for calculating the synthesized vector time. The synthesized vector time calculating unit 170 calculates the synthesized vector time based on the effective vector time and the modulation index calculated by the vector time calculating unit 160. Specifically, the vector time calculator 160 for calculating at least one of an effective vector time and a modulation index for calculating a composite vector time may include an input vector time calculator 161, an output vector time calculator 163, and a modulation index calculator. A portion 165 may be included.

The input vector time calculator 161 calculates an input valid vector time by using a phase of the sector and the input current with respect to the input current of the input side converter 110. The output vector time calculating unit 163 calculates the output valid vector time using the phase of the sector and the output voltage with respect to the output voltage of the output side inverter unit 120. The modulation index calculator 165 calculates the composite vector time together with the input valid vector time calculated from the input vector time calculator 161 and the output valid vector time calculated from the output vector time calculator 163. Calculate the modulation index.

Accordingly, the composite vector time calculator 170 may determine the input valid vector time calculated from the input vector time calculator 161, the output valid vector time calculated from the output vector time calculator 163, and the modulation index calculator 165. The synthesized vector time can be calculated using the modulation index MI calculated from.

FIG. 5 is an exemplary diagram illustrating a space vector of an input side converter unit and an output side inverter unit in a three-phase and three-phase / single-phase direct type power converter according to an embodiment of the present invention.

As shown in (a) of FIG. 5, in the three-phase direct type power converter, the sector discriminator 130 may distinguish six current sectors by using a space vector for an input current. In addition, as shown in (b) of FIG. 5, the sector discriminating unit 130 may distinguish six voltage sectors by using a space vector for the output voltage. As described above, when the power converter according to the present invention is controlled through the SVPWM technique, the input converter 110 and the output inverter 120 are each composed of six current sectors and six voltage sectors. Can be distinguished.

Equation 1

The space vector of the output voltage of the output inverter 120 may be expressed by the following equation when the output inverter 120 is composed of three phases (hereinafter referred to as a three-phase output inverter). .

Equation 2

Here, Equation 2 is a formula in which the three-phase output side inverter unit 120 represents a space vector, where θ1 is a phase of the space vector with respect to the input current and θ0 is a phase of the space vector with respect to the output voltage.

On the other hand, the power conversion apparatus according to the present invention needs sector information considering the phase angle of the input current and the phase angle of the output voltage at the same time, for this purpose, the current sector of the input side converter unit 110 and the three-phase output side inverter unit 120 The input voltage converter 110 and the three-phase output inverter 120 may be controlled by dividing the voltage sector into 36 synthesized sectors. A composite sector configuration according to the current sector of the input converter unit 110 and the voltage sector of the three-phase output inverter unit 120 is shown in Table 1 below.

Table 1

Converter input current sector	Inverter output current sector	Synthetic Sector
1 to 6	One	1 to 6
1 to 6	2	7 to 12
1 to 6	3	13-18
1 to 6	4	19 to 24
1 to 6	5	25-30
1 to 6	6	31 to 36

On the other hand, when the space vector for the input current and the output voltage is calculated from the

above Equations

1 and 2, the effective vector application time for implementing the modulation scheme is determined based on the calculated space vector for the input current and the output voltage. Can be calculated. The effective vector application time for implementing the modulation technique may be expressed as Equation 3 below. That is, the input vector time calculating unit 161 and the output vector time calculating unit 163 are input effective vector time and three-phase output side inverter unit 120 with respect to the input current of the input side converter unit 110 through Equation (3). The output effective vector time for the output voltage can be calculated.

Equation 3

Here, Ti1 and Ti2 are input valid vector times, and Tv1 and Tv2 are output vector times.

As such, when the input valid vector time for the input current of the input side converter unit 110 and the output valid vector time for the output voltage of the three-phase output side inverter unit 120 are calculated, the synthesized vector time calculating unit 170 is as follows. Through Equation 4, the synthesized vector time to be used in the input side converter unit 110 and the three-phase output side inverter unit 120 of the power converter may be calculated.

Equation 4

Here, Ts is a control period, T1 to T4 is a composite vector time, T0 is a composite zero vector application time, MI is a modulation index, k is an output sector, and i is an input sector.

On the other hand, when the output side inverter unit 120 is made of a single phase (hereinafter referred to as the single-phase output side inverter unit) in the three-phase / single-phase direct type power conversion device, as shown in (c) of Figure 5, the sector discriminating unit 130 Can be divided into six current sectors using the space vector for the input current. In addition, as shown in (d) of FIG. 5, the sector discriminating unit 130 may create a virtual space vector for the output voltage and distinguish two sectors by using the virtual space vector. Here, it is preferable that the two sectors divided by the virtual space vector have a 180 degree phase difference according to the positive and negative states of the command voltage.

Therefore, the space vector with respect to the input current of the input side converter unit 110 of the three-phase / single-phase direct power converter is expressed by Equation 1, which is the same as the input converter unit 110 of the three-phase direct power converter. The space vector with respect to the output voltage of the single-phase output side inverter unit 120 may be expressed by Equation 5 below.

Equation 5

above Equations

1 and 5, the effective vector application time for implementing the modulation scheme is determined based on the calculated space vector for the input current and the output voltage. Can be calculated. The effective vector application time for implementing the modulation technique may be expressed as Equation 6 below. That is, the input vector time calculating unit 161 and the output vector time calculating unit 163 are input effective vector time and single phase output side inverter unit 120 with respect to the input current of the input side converter unit 110 through Equation 6 below. The output effective vector time for the output voltage can be calculated.

Equation 6

As such, when the input valid vector time for the input current of the input side converter unit 110 and the output valid vector time for the output voltage of the three-phase output side inverter unit 120 are calculated, the synthesized vector time calculating unit 170 is as follows. Through Equation (7), the synthesized vector time to be used for the input side converter unit 110 and the single phase output side inverter unit 120 of the power converter may be calculated.

Equation 7

In this way, when the combined vector time for the input side converter unit 110 and the three-phase or single-phase output side inverter unit 120 is calculated, the control signal generator 150 synthesizes the calculated vector time calculation unit 170. Generates a control signal for performing an operation according to the switching sequence of the input side converter unit 110 and the three-phase or single-phase output side inverter unit 120 determined by the sequence determiner 140 during the vector time and the zero vector application time. .

First, in the case of a three-phase direct type power conversion device, the sequence determiner 140 may include an input converter 110 and a three-phase inverter 120 for each of a plurality of sectors determined by the sector discriminator 130. Determine the switching sequence of. When the switching sequence for each of the input side converter unit 110 and the three-phase output side inverter unit 120 is determined by the sequence determiner 140, the control signal generator 150 generates the input side converter unit 110 and the three-phase output side. A control signal for performing the switching operation of the input side converter unit 110 and the three-phase output side inverter unit 120 is generated according to the switching sequence of the inverter unit 120 and the calculated composite vector time. Accordingly, the input side converter unit 110 and the three-phase output side inverter unit 120 may perform a switching operation according to the control signal generated through the control signal generator 150.

Meanwhile, the above-described sequence determiner 140 may determine the switching sequence of the input converter 110 and the output inverter 120 through the following embodiment.

First, an operation of determining a switching sequence of the input side converter unit 110 and the three phase output side converter unit 120 in the three-phase direct type power converter will be described.

According to an exemplary embodiment, the sequence determiner 140 determines the switching sequence of the input side converter 110 as a two-stage switching sequence without a zero vector, and determines the switching sequence of the three-phase output inverter 120 as a zero vector and a vector. It can be determined by a five-stage switching sequence including the valid vector. In this case, the sequence determiner 140 is a combination of the two-stage switching sequence of the input side converter unit 110 and the five-stage switching sequence of the three-phase output side inverter unit 120 such that the power converter has a six-stage switching sequence. The switching sequence of the input side converter unit 110 and the three-phase output side inverter unit 120 may be determined.

In this case, the six-stage switching sequence may have a switching sequence of a first valid vector, a second valid vector, a first zero vector, a second zero vector, a third valid vector, and a fourth valid vector, and a plurality of sectors. It may be made of the same pattern.

According to another exemplary embodiment, the sequence determiner 140 determines the switching sequence of the input converter 110 as a two-stage switching sequence without a zero vector, and determines the switching sequence of the three-phase output inverter 120 as a zero vector. And a seven-stage switching sequence including the valid vector. In this case, the sequence determiner 140 is a combination of the two-stage switching sequence of the input side converter unit 110 and the seven-stage switching sequence of the three-phase output side inverter unit 120 such that the power converter has an eight-stage switching sequence. The switching sequence of the input side converter unit 110 and the three-phase output side inverter unit 120 may be determined.

In this case, the sequence determination unit 140 may determine the switching sequence of eight steps based on the identification information of the plurality of sectors to which the identification information of 1 to 36 is assigned. Specifically, if the plurality of sectors determined by the sector discriminating unit 130 is odd, the sequence determining unit 140, based on the first condition, the first zero vector, the first valid vector, the second valid vector, and the second sector. An eight-stage switching sequence of the zero vector, the third zero vector, the third valid vector, the fourth valid vector, and the fourth zero vector may be determined. On the other hand, if the plurality of sectors determined by the sector discriminating unit 130 is an even number, the sequence determining unit 140 based on the second condition, the first zero vector, the second valid vector, the first valid vector, and the second zero. The eight-stage switching sequence of the vector, the third zero vector, the fourth valid vector, the third valid vector, and the fourth zero vector may be determined.

6 is an exemplary view showing a switching sequence of a conventional power converter.

In general, a power converter connected directly to an input / output without a power buffer circuit in the middle should combine input and output vector application times to simultaneously control input and output. To this end, the synthesized vector application time consists of four valid vectors and one zero vector. Therefore, the conventional power converter uses a control method of an 11-switch switching sequence or a control method of a 9-switch switching sequence.

FIG. 6A illustrates a conventional method of controlling a 11-divided switching sequence, in which a zero vector is formed in a first section, a sixth section, and an eleventh section, and a second to fifth section and a seventh to seventh section. It is a sequence in which an effective vector is formed in 10 sections. Therefore, the input side converter unit 110 and the three-phase output side inverter unit 120 perform 11 switching switching cycles according to the 11 division switching sequence. FIG. 6 (b) shows a conventional method of controlling a 9 division switching sequence, in which an effective vector is formed in the first to fourth and sixth to ninth sections, and a zero vector is formed in the fifth section. Is a sequence of. Accordingly, it can be seen that the input switching unit 110 and the three-phase output inverter 120 perform nine switching switching operations according to the nine split switching sequence, thereby reducing the number of switching switching times compared to the 11 split switching sequence control method. .

However, the conventional switching sequence controller method has a problem in that power loss occurs due to a large number of switching times compared to the present invention.

7 is an exemplary diagram illustrating a switching sequence for implementing partial zero current switching of a converter unit of a three-phase direct type power converter according to an embodiment of the present invention.

The switching sequence shown in FIG. 7 is generated by combining a two-stage switching sequence without the zero vector of the input side converter unit 110 and a five-stage switching sequence for the zero and effective vectors of the three-phase output side inverter unit 120. Phase switching sequence. The six-stage switching sequence has a sequence of a first valid vector, a second valid vector, a first zero vector, a second zero vector, a third valid vector, and a fourth valid vector.

In this case, the switching pattern of the input side converter unit 110 and the switching pattern of the three-phase output side inverter unit 120 with respect to the first sector are as shown in Tables 2 and 3 below, and the switching of the input side converter unit 110 is performed. The six-stage switching sequence according to the combination of the pattern and the switching pattern of the three-phase output side inverter unit 120 is shown in Table 4 below.

TABLE 2

	Ti1	Ti2
phase a	One	One
phase b	o	-One
phase c	-One	0

TABLE 3

	Tv1 / 2	Tv2 / 2	Tv0	Tv2 / 2	Tv1 / 2
phase a	One	One	One	One	One
phase b	0	One	One	One	0
phase c	0	0	One	0	0

Table 4

	T1	T2	T0 / 2	T0 / 2	T2	T1
input a	One	One	One	One	One	One
input b	0	0	0	-One	-One	-One
input c	-One	-One	-One	0	0	0
output a	One	One	One	One	One	One
output b	0	One	One	One	One	0
output c	0	0	One	One	0	0

When switching switching of the input side converter unit 110 occurs in the first and second zero vectors T0 / 2 shown in Table 4 above, switching is performed by performing partial zero current switching (PZCS) operation. The power loss generated during the switching can be minimized, and furthermore, the number of switching switching can be reduced as compared with the related art, thereby minimizing the power loss.

In addition, when the switching switching of the input-side converter 110 occurs in a vector section of the previous sector or the next sector consecutive to the first or fourth effective vector T1 in Table 4, partial zero current switching (Partial) By performing Zero Current Switching (PZCS) operation, power loss generated during switching of all sectors can be minimized. Furthermore, the number of switching switching of all sectors can be reduced compared to the conventional ones, thereby minimizing power loss.

8 is an exemplary view illustrating a switching sequence for implementing zero current switching of a converter unit of a three-phase power converter according to an embodiment of the present invention.

As described above, the sequence determiner 140 is a two-stage switching sequence and a three-phase output side inverter without a zero vector of the input side converter 110 based on the number of sectors determined by the sector discriminator 130. The eight-stage switching sequence may be determined by combining the seven-stage switching sequence for the zero and valid vectors of the unit 120.

Specifically, as shown in (a) of FIG. 8, when a plurality of sectors are odd, 8 according to the combination of the switching pattern <Table 2> and the switching pattern <Table 3> of the three-phase output side inverter unit 120. The step switching sequence includes a first zero vector, a first valid vector, a second valid vector, a second zero vector, a third zero vector, and a third valid vector. It has a sequence of the fourth valid vector and the fourth zero vector order.

When a plurality of sectors is odd, the eight-stage switching sequence in the first sector is shown in Table 5 below.

Table 5

	T0 / 4	T2	T1	T0 / 4	T0 / 4	T4	T3	T0 / 4
input a	One	One	One	One	One	One	One	One
input b	0	0	0	0	-One	-One	-One	-One
input c	-One	-One	-One	-One	0	0	0	0
output a	0	One	One	One	One	One	One	0
output b	0	0	One	One	One	0	0	0
output c	0	0	0	One	One	0	0	0

On the other hand, as shown in (b) of FIG. 8, when a plurality of sectors are even, the eight steps according to the combination of the switching pattern <Table 2> and the switching pattern <Table 3> of the three-phase output side inverter unit 120 The switching sequence includes a first zero vector, a second valid vector, a first valid vector, a second zero vector, a third zero vector, and a fourth valid vector. It has a sequence of the third valid vector and the fourth zero vector order.

In the case where a plurality of sectors are even, the eight-stage switching sequence in sector 7 is shown in Table 6 below.

Table 6

	T0 / 4	T2	T1	T0 / 4	T0 / 4	T4	T3	T0 / 4
input a	One	One	One	One	One	One	One	One
input b	0	0	0	0	-One	-One	-One	-One
input c	-One	-One	-One	-One	0	0	0	0
output a	0	0	One	One	One	One	0	0
output b	0	One	One	One	0	0	0	0
output c	0	0	0	One	One	0	0	0

When switching switching of the input side converter unit 110 occurs in the second and third zero vectors (T0 / 4) in Tables 5 and 6 above, a zero current switching (ZCS) operation is performed. The power loss generated during switching switching can be minimized. Meanwhile, when driving the power conversion apparatus using the partial zero current switching (PZCS) technique according to the present invention, the input side converter unit 110 and the three-phase output side inverter unit It may operate based on the hard switching switching and the partial zero current switching of 120, and the number of switching switching according to the partial zero current switching technique (PZCS) may be derived from Equation 8 below.

Equation 8

Where Nin is the number of switching cycles on the input side, Nout is the number of switching cycles on the output side, Nprd is the number of switching cycles per control cycle time, Nfout is the number of switching cycles per output frequency time, Nins is the number of switching sectors, Nout is the number of switching sectors, and Nsc Is the number of switching cycles (output cycle time) during sector switching, NZCS is the number of zero current switching (output cycle time), Tprd is the control cycle time, and Nesl is the number of switching cycles of the power converter except for zero current switching (output cycle time). Can be

Table 7 below shows a comparison relationship between the switching control times according to the conventional control method and the partial zero current switching method according to the present invention.

TABLE 7

Item		Number of switching changes
Item		Control cycle (1㎲)	Output frequency (50 Hz)
Conventional Control Method	Total number of switching changes	28	5624
Proposed Control Method	Total number of switching changes	20	3248
	Total number of switching changes except soft switching	12	2424

Table 8 below shows the relationship between the number of switching in the conventional control method according to the input commercial frequency and the output frequency and the partial zero current switching method according to the present invention.

Table 8

Output frequency	Number of switching cycles according to input commercial frequency
	50 Hz			60 Hz
	case1	case2		case1	case2
	case1	case21	case22	case1	case21	case22
10 Hz	28004	16028	12024	28004	16028	12024
20 Hz	14008	8032	6024	14008	8032	6024
30 Hz	9345	5369	4024	9345	5369	4024
40 Hz	7016	4040	3024	7016	4040	3028
50 Hz	5624	3248	2424	5620	3244	2428
60 Hz	4695	2718	2024	4691	2714	2028
70 Hz	4032	2341	1738	4028	2337	1742
80 Hz	3538	2062	1524	3532	2056	1530
90 Hz	3155	1845	1357	3147	1837	1363
100 Hz	2848	1672	1224	2840	1664	1232

Here, case1 is the number of switching switching for the conventional control method, case21 is the total switching switching for the proposed control method, and cass22 is the remaining switching switching count except for the partial zero current switching switching in the case of the proposed control method.

In addition, when driving the power converter using the zero current switching technique, all switching switching of the input side converter 110 may operate based on zero current switching, such a partial zero current switching technique (PZCS) and zero. The switching switching frequency according to the current switching technique ZCS may be derived from Equation 9 below.

Equation 9

Where Nin is the number of switching cycles on the input side, Nout is the number of switching cycles on the output side, Nprd is the number of switching cycles per control cycle time, Nfout is the number of switching cycles per output frequency time, Nins is the number of switching sectors, Nouts is the number of switching sectors, and Nsc Is the number of switching cycles (output cycle time) during sector switching, NZCS is the number of zero current switching (output cycle time), Tprd is the control cycle time, and Nesl is the number of switching cycles of the power converter except for zero current switching (output cycle time). Table 9 below shows a comparison relationship between the switching control times according to the existing control technique and the zero current switching technique according to the present invention.

Table 9

Item		Number of switching changes
Item		Control cycle (1㎲)	Output frequency (50 Hz)
Conventional Control Method	Total number of switching changes	28	5624
Proposed Control Method	Total number of switching changes	20	3248
Proposed Control Method	Total number of switching changes except soft switching	12	2400

Table 10 below shows the relationship between the number of switching in the conventional control technique according to the input commercial frequency and the output frequency and the zero current switching technique according to the present invention.

Table 10

Output frequency	Number of switching cycles according to input commercial frequency
	50 Hz			60 Hz
	case1	case2		case1	case2
	case1	case21	case22	case1	case21	case22
10 Hz	28004	20004	12000	28004	20004	12000
20 Hz	14008	10008	6000	14008	10008	6000
30 Hz	9345	6678	4000	9345	6678	4000
40 Hz	7016	5016	3000	7016	5016	3000
50 Hz	5624	4024	2400	5620	4020	2400
60 Hz	4695	3361	2000	4691	3357	2000
70 Hz	4032	2889	1714	4028	2885	1714
80 Hz	3538	2538	1500	3532	2532	1500
90 Hz	3155	2266	1333	3147	2258	1333
100 Hz	2848	2048	1200	2840	2040	1200

Here, case1 is the number of switching switching for the case of the conventional control method, case21 is the total number of switching switching for the case of the proposed control method, and cass22 is the remaining number of switching switching except for the number of zero current switching switching in the case of the proposed control method.

Simulation Analysis and Experimental Analysis

In order to verify the effectiveness of the soft switching based SVPWM control method according to the present invention, the entire circuit configuration of the current converter is shown in FIG. 2, and the simulation specification conditions are as shown in Table 11 below. Set.

Table 11

item		value
input power		3 pahse AC 50V / 50Hz
switching device	IGBT	18ea
	diode	18ea
load	resistance
		5 mH
inductance
	5 ohm
control frequency
		10 kHz

As a result of simulation using the soft switching-based spatial vector modulation method (SVPWM) control method according to the present invention using the simulation conditions of Table 11, the voltage of the virtual DC link circuit and the gate signal of the input converter 110 are Switching switching is performed in two patterns between the virtual DC link voltage and the gate signal according to before and after the idle period, and zero current switching operation is performed on three of the input side converter units 110 in which switching switching is performed in two patterns. Able to know.

FIG. 9 is an exemplary diagram illustrating waveforms of a virtual DC link voltage, a current, and a gate signal in a partial zero current switching mode of a three-phase direct power converter according to an embodiment of the present invention, and FIG. 10 is an embodiment of the present invention. FIG. 11 is an exemplary diagram illustrating an enlarged waveform of a virtual DC link voltage, a current, and a gate signal in a partial zero current switching mode of a three-phase direct type power converter according to an embodiment, and FIG. 11 is a three-phase direct type according to an embodiment of the present invention. Exemplary diagram showing an enlarged waveform of the virtual DC link current and the switching gate signal of the input side converter unit in the zero current switching mode of a power conversion device, and FIG. 12 is a part of a three-phase direct power converter according to an embodiment of the present invention. It is an exemplary figure which shows the waveform of an output line voltage and an output current in zero current switching mode.

As a result of the simulation using the switching control technique of the two-stage three-phase direct-type power converter (TSDPC) based on the partial zero current switching according to the present invention using the simulation use conditions of Table 11, as shown in FIG. It can be seen that the output waveform for the upper gate signal q1 of the a phase (R phase) of the input side converter unit 110 appears at the upper end of the virtual link voltage and current. Then, as shown in FIG. 10 from the output waveform simulated with reference to FIG. 9, the virtual link voltage and current at the top and the top gate signal q1 of the a phase (R phase) of the input side converter unit 110 are enlarged at the bottom. You can see that the output waveform appears.

In addition, as shown in FIG. 11, it can be seen from the output waveform simulated with reference to FIG. 9 that an enlarged output waveform for the switching gate signal of the input side converter unit 110 appears at the top and the virtual link current at the bottom. . In addition, as a result of simulation by the switching control technique of the two-step direct current power conversion device (TSDPC) based on partial zero current switching, as shown in FIGS. 12A and 12B, the output line voltage and the output current Notice that the waveform appears.

FIG. 13 is an exemplary view illustrating waveforms of a virtual DC link voltage, a current, and a gate signal in a zero current switching mode of a three-phase direct power converter according to an embodiment of the present invention, and FIG. 14 is an embodiment of the present invention. FIG. 15 is an exemplary diagram illustrating an enlarged waveform of a virtual DC link voltage, a current, and a gate signal in a zero current switching mode of a three-phase direct power converter according to an embodiment of the present invention. FIG. 15 is a three-phase direct power converter according to an embodiment of the present invention. FIG. 16 is an exemplary diagram illustrating an enlarged waveform of the virtual DC link voltage and the switching gate signal of the input side converter unit in the zero current switching mode of the device, and FIG. Is an exemplary diagram showing waveforms of output line voltage and output current.

As a result of the simulation using the soft switching-based Spatial Vector Modulation (SVPWM) control method according to the present invention using the simulation use conditions of Table 11, as shown in FIG. At the bottom, the output waveform of the upper gate signal q1 of the a phase (R phase) of the input side converter section 110 is shown, and the virtual DC link voltage and the gate signal q1 depending on before and after the idle period of the gate signal q1. It can be seen that switching switching (region A and region B) occurs in two patterns in between.

As shown in (a) and (b) of FIG. 14, it can be seen that an enlarged output waveform for region A and an output waveform for region B appear from the output waveform simulated with reference to FIG. 13.

In addition, as shown in FIG. 15, it can be seen from the output waveform simulated with reference to FIG. 13 that an enlarged output waveform for the switching gate signal of the input side converter unit 110 appears at the top and the virtual link current at the top. . In addition, as a result of simulation by the SVPWM control method based on zero current switching, as shown in FIGS. 16A and 16B, it can be seen that waveforms of the output line voltage and output current appear. have. It can be seen that the zero current switching operation is performed in the region A and the region B where the switching switching is performed between the virtual DC link voltage and the gate signal q1. Accordingly, the input side converter unit 110 is performed in the region A and region B. It can be seen that all of the switching switches of) perform the zero current switching operation.

Hereinafter, an operation of determining a switching sequence for implementing zero current switching of the three-phase / single-phase direct power converter according to the present invention will be described in detail.

FIG. 17 is an exemplary diagram illustrating a switching sequence for implementing zero current switching of a three-phase / single-phase direct power converter according to an embodiment of the present invention.

The switching sequence shown in FIG. 17 is a six-stage switching sequence generated by combining a two-stage switching sequence of the input side converter unit 110 and a five-stage switching sequence for the zero and effective vectors of the single-phase output side inverter unit 120.

The switching pattern of the input side converter unit 110 and the switching pattern of the single phase output side inverter unit 120 are as shown in Tables 12 and 13 below.

Table 12

	T1			T2
	phase R	phase S	phase T	phase R	phase S	phase T
sector1	One	0	-One	One	-One	0
sector2	One	-One	0	0	-One	One
sector3	0	-One	One	-One	0	One
sector4	-One	0	One	-One	One	0
sector5	-One	One	0	0	One	-One
sector6	0	One	-One	One	0	-One

Table 13

	T0 / 4		T1		T0 / 2		T2		T0 / 4
	phase A	phase B	phase A	phase B	phase A	phase B	phase A	phase B	phase A	phase B
sector1
	0	0	One	0	One	One	One	0	0	0
sector2	0	0	0	One	One	One	0	One	0	0

As shown in Tables 12 and 13, the following six switching sequences may be determined from the switching pattern of the input side converter unit 110 and the switching pattern of the single phase output side inverter unit 120.

According to an embodiment, in the case of the first sector, the six switching sequences determined from the switching pattern of the input side converter unit 110 and the switching pattern of the single phase output side inverter unit 120 may include a first zero vector, a second effective vector, and a first one. 2nd zero vector, 3rd zero vector, first valid vector, and 4th zero vector, the first switching sequence and the first zero vector, the first valid vector, the second zero vector, the third zero vector, the second valid vector, and It may be one of the second switching sequences of the fourth zero vector order.

In the case of the first switching sequence, it may be composed of a six-step switching sequence as shown in Table 14 below.

Table 14

	T0 / 4	T1	T0 / 4	T0 / 4	T2	T0 / 4
phase R	One	One	One	0	0	0
phase S	-One	-One	-One	-One	-One	-One
phase T	0	0	0	One	One	One
phase A	0	One	One	One	One	0
phase B	0	0	One	One	0	0

On the other hand, in the case of the second switching sequence, it may be made of a switching sequence of six steps as shown in Table 15 below.

Table 15

	T0 / 4	T2	T0 / 4	T0 / 4	T1	T0 / 4
phase R	One	One	One	0	0	0
phase S	-One	-One	-One	-One	-One	-One
phase T	0	0	0	One	One	One
phase A	0	One	One	One	One	0
phase B	0	0	One	One	0	0

That is, as shown in Tables 14 and 15, the single-phase output side inverter unit 120 creates a zero vector section at the time of switching switching of the input side converter unit 110 occurs. Accordingly, the power supply is cut off between the input side converter unit 110 and the single phase output side inverter unit 120 at the time when the single phase output side inverter unit 120 is controlled in the zero vector switching state. The switching operation is zero current switching, allowing bidirectional power control without current direction detection.

Hereinafter, through the simulation results to verify the effectiveness of the control method of the spatial vector modulation method (SVPWM) based on the zero current switching of the three-phase / single-phase direct power converter.

FIG. 18 is an exemplary view illustrating waveforms of output current and output line voltage according to a simulation performed in a three-phase / single-phase direct current converter according to an embodiment of the present invention, and FIG. 19 is a diagram illustrating an embodiment of the present invention. An exemplary diagram showing waveforms of a DC link current and a switching signal according to a simulation performed in a three-phase / single-phase direct current converter, and FIG. 20 is a simulation in a three-phase / single-phase direct current converter according to an embodiment of the present invention. An exemplary view showing a ZCS operation waveform according to execution.

Simulation Analysis and Experimental Analysis

In order to verify the effectiveness of the control method of the zero-current switching-based space vector modulation method (SVPWM) of the three-phase / single-phase direct type power converter according to the present invention, the entire circuit configuration of the three-phase / single-phase direct type power converter is constructed. The simulation specification conditions are set as shown in Table 16 below.

Table 16

item	simulation value
input voltage	3-phase, 220V, 50Hz
semiconductor wsitching devices	16-IGBYs with freewheeling diodes
load	100 ohm, 10 mH
output frequency
	50 Hz
switching sequence	6-step
control frequency
	10 kHz

As a result of simulating a three-phase / single-phase direct type power conversion device according to the present invention using the simulation use conditions of Table 16, the output current, output line voltage and output as shown in (a) to (c) of FIG. It can be seen that the waveform of the line voltage LPF is output. That is, the input side converter 110 of the three-phase / single-phase direct type power conversion apparatus according to the present invention, when the virtual DC link current is 0, as shown in Figure 18, it is seen that performs the switching on / off operation Can be.

In addition, as a result of simulating a three-phase / single-phase direct type power conversion device according to the present invention using the simulation use conditions shown in Table 16 above, as shown in (a) to (c) of FIG. It can be seen that the signal and the switching sequence waveform and the ZCS operation as shown in FIGS. 20A to 20C output the waveform. Through this output waveform, it can be seen that the ZCS operation is performed in the input side converter unit 110 of the three-phase / single-phase direct power converter.

As described above, the switching loss of the bidirectional switching elements of the input side converter unit 110 is minimized through the control method of the spatial vector modulation method (SVPWM) based on the zero current switching of the three-phase / single-phase direct power converter according to the present invention. In addition, switching switching of the bidirectional switching device of the input side converter unit 110 may be performed without using a conventional current direction detection circuit. Furthermore, in the three-phase / single-phase direct type power conversion apparatus according to the present invention, all switching switching of the input side converter unit 110 operates with zero current switching, thereby minimizing switching losses and increasing efficiency of the entire system.

21 is an exemplary view showing a result of comparing the conventional control method and the number of partial zero current switching switching times during one cycle in the three-phase direct power converter according to an embodiment of the present invention.

As shown in FIG. 21, when driving a three-phase direct type power converter using a partial zero current switching-based space vector modulation (TSDPC) controller method according to the present invention, the number of switching switching is a conventional control technique. It can be seen that the reduction is about 30% or more compared to the 9-stage switching switching technique. Furthermore, when using the TSD control method based on the partial zero current switching according to the present invention, the efficiency of the three-phase direct conversion device is expected to be improved, particularly in an environment with low output frequency. You can expect.

FIG. 22 is an exemplary view showing a result of comparing a conventional controller method and a zero current switching switching frequency during one cycle in a three-phase direct type power converter according to an embodiment of the present invention. FIG.

As shown in FIG. 21, when driving the three-phase direct type power converter using the zero-current switching-based space vector modulation (SVPWM) controller method proposed in the present invention, all switching of the input side converter 110 is performed. The switching is performed by a zero current switching operation, the total number of switching switching according to the control cycle, the number of switching switching of the input side converter 110, and the total number of switching switching of one cycle (50 Hz) and the switching of the input side converter 110 Since the number of switching is reduced compared to the conventional, the power loss due to the switching switching is reduced by about 40% or more compared with the conventional, and in particular, a greater effect than in an environment where the output frequency is low can be expected. Further, when using the zero current switching-based space vector modulation (SVPWM) control method according to the present invention, the configuration and control scheme of the power converter can be simplified, thereby improving the stabilization and reliability of the power converter.

Hereinafter, a switching control method of the power converter according to the present invention will be described in detail.

As shown in Fig. 23, the power converter is an AC / AC power converter that converts a three-phase AC input without a DC link circuit. Such a power converter may be a three-phase direct power converter or a three-phase / single-phase direct power converter, depending on the embodiment.

Such a power converter determines a plurality of sectors for the input current of the input side converter section and the output voltage of the output side inverter section (S2310). Thereafter, the power conversion apparatus calculates a synthesized vector time using at least one of an input current of the input side converter 110, an output voltage of the output inverter 120, and a modulation index MI (S2320). Thereafter, the power conversion apparatus determines a switching sequence of the input side converter unit 110 and a switching sequence of the output side inverter unit 120 for each of the determined plurality of sectors (S2330). Subsequently, the power conversion apparatus performs switching operations of the input side converter unit 110 and the output side inverter unit 120 based on the switching sequence of the input side converter unit 110 and the output side inverter unit 120 and the synthesis vector time. The control signal is generated and the switching operation of the input side converter unit 110 and the output side inverter unit 120 is controlled based on the generated control signal (S2340).

According to an embodiment, when the power converter is a three-phase direct power converter, the input side converter includes six bidirectional switching elements for four quadrant operation, and the output side inverter unit 120 has a structure of a general voltage inverter. Is done. Here, the output side inverter unit 120 may be configured by, for example, two switching elements connected in series to each other to form one pole, and three poles connected in parallel to each other. At this time, in order to output the three-phase AC voltage, it is preferable that the switch elements of one pole and the neighboring pole operate complementarily.

On the other hand, when the power converter is a three-phase / single-phase direct power converter, the input side converter unit 110 includes six bidirectional switching elements for four-quadrant operation, and the output side inverter unit 120 is a general single-phase voltage type The structure of the inverter is made. That is, the output side inverter unit 120 may include an input side converter unit 110 including six bidirectional switching elements and four unidirectional switching elements for single phase grid connection.

Specifically, when the power converter is a three-phase direct power converter, six current sectors are divided by using a space vector of the input current of the input side converter unit, and the output side inverter unit (hereinafter referred to as a three-phase output side inverter unit) The six voltage sectors can be distinguished using the space vector for the output voltage. Thereafter, the three-phase direct type power converter calculates the synthesized vector time based on at least one of an input current of the input side converter unit, an output current of the three-phase output side inverter unit, and a modulation index MI.

Specifically, the three-phase direct type power converter calculates the input effective vector time by using the phase of the sector and the input current with respect to the input current of the input side converter. The three-phase direct type power converter calculates an output valid vector time using the phase of the sector and the output voltage with respect to the output voltage of the three-phase output side inverter. When the input valid vector time and the output valid vector time are calculated, the three-phase direct power converter can calculate the composite vector time using the calculated input valid vector time and output valid vector time and the modulation index MI. have.

Thereafter, the three-phase direct type power converter determines the switching sequence of the input side converter unit and the switching sequence of the three-phase output side inverter unit for each of the plurality of sectors determined in step S2310. Subsequently, the three-phase direct power converter performs switching operations of the input-side converter unit and the three-phase output side inverter unit according to the switching sequence determined for each sector during the composite vector time and the composite zero vector application time. do.

According to an embodiment, the three-phase direct type power converter determines the switching sequence of the input-side converter unit as a two-stage switching sequence without zero vector, and the five-stage including the zero vector and the effective vector as the switching sequence of the three-phase output side inverter unit. Can be determined by the switching sequence. In this case, the three-phase direct power converter is a combination of a two-stage switching sequence of the input side converter section and a five-stage switching sequence of the three-phase output side inverter section so that the three-phase direct power converter has a six-stage switching sequence. And a switching sequence of the three-phase output side inverter unit.

According to another embodiment, the three-phase direct-type power conversion device determines the switching sequence of the input side converter unit as a two-stage switching sequence without zero vector, and the switching sequence of the three-phase output side inverter unit 7 including a zero vector and an effective vector. Can be determined by the step switching sequence. In this case, the three-phase direct type power conversion device is a combination of a two-stage switching sequence of the input side converter section and a seven-stage switching sequence of the three-phase output side inverter section so that the power conversion device has an eight-stage switching sequence so that the input side converter section and the output side inverter section The switching sequence can be determined.

According to an embodiment, the three-phase direct power switching device, if the determined plurality of sectors is odd, based on the first condition, the first zero vector, the first valid vector, the second valid vector, the second zero vector, and the third An eight-stage switching sequence of the zero vector, the third valid vector, the fourth valid vector, and the fourth zero vector may be determined. On the other hand, the three-phase direct-type power conversion device, if the determined plurality of sectors is even, based on the second condition, the first zero vector, the second valid vector, the first valid vector, the second zero vector, the third zero vector, An eight-stage switching sequence of the fourth valid vector, the third valid vector, and the fourth zero vector may be determined. However, the present invention is not limited thereto, and the eight-stage switching sequence may have the same pattern for each of a plurality of sectors.

As described above, the three-phase direct power converter according to the present invention is a six-stage switching generated by a combination of a two-stage switching sequence without a zero vector of the input side converter unit and a five-stage switching sequence for the zero and effective vectors of the three-phase output side inverter unit. The switching operation of the input side converter section and the three-phase output side inverter section is performed according to the eight-step switching sequence generated by the sequence or the combination of the seven-step switching sequence. Accordingly, the three-phase direct type power converter performs Partial Zero Current Switching (PZCS) operation when switching of the input side converter part occurs in a zero vector period, thereby minimizing power loss generated during switching. In addition, compared to the related art, the number of switching switching is reduced, thereby minimizing power loss.

Meanwhile, when the power converter is a three-phase / single-phase direct power converter, a virtual space vector for an output voltage may be created, and two sectors may be distinguished using the virtual space vector. Here, it is preferable that the two sectors divided by the virtual space vector have a 180 degree phase difference according to the positive and negative states of the command voltage.

That is, in the three-phase / single-phase direct type power converter, when the space vector for the input current and the output voltage is calculated from the

above Equation

1, 5, the input side is based on the calculated space vector for the input current and the output voltage. The input valid vector time for the input current of the converter section and the output valid vector time for the output voltage of the single-phase output side inverter section can be calculated.

Thereafter, the three-phase / single phase direct type power converter calculates a composite vector time to be used for the input side converter unit and the single phase output side inverter unit based on Equation 7 described above. Thereafter, the three-phase / single-phase direct type power converter determines the switching sequence of the input side converter unit and the switching sequence of the single phase output side inverter unit for each of the plurality of sectors determined in step S2310. Thereafter, the three-phase / single phase direct type power converter performs the switching operation of the input side converter unit and the single phase output side inverter unit according to the switching sequence of the input side converter unit and the single phase output side inverter unit determined for each sector.

According to an embodiment, the three-phase / single phase direct power converter has a six-stage switching sequence generated by a combination of a two-stage switching sequence of the input side converter unit and a five-stage switching sequence for the zero and effective vectors of the single-phase output side inverter unit. The switching sequence of the input side converter section and the single phase output side inverter section can be determined.

According to an embodiment, in the case of the first sector, the six-stage switching sequence determined from the switching pattern of the input side converter section and the switching pattern of the single-phase output side inverter section may include a first zero vector, a second valid vector, a second zero vector, and a third zero vector. , The first switching sequence of the first valid vector and the fourth zero vector, and the second of the first zero vector, the first valid vector, the second zero vector, the third zero vector, the second valid vector, and the fourth zero vector. It may be one of the switching sequences.

As described above, the three-phase / single-phase direct type power conversion device according to the present invention cuts off the power supply between the input side converter unit and the single phase output side inverter unit at the time when the single phase output side inverter unit is controlled in the zero vector switching state. All switching operations of 110 are zero current switched to allow bidirectional power control without current direction detection.

So far I looked at the center of the preferred embodiment for the present invention.

While the above has been shown and described with respect to preferred embodiments of the present invention, the present invention is not limited to the specific embodiments described above, it is usually in the technical field to which the invention belongs without departing from the spirit of the invention claimed in the claims. Various modifications can be made by those skilled in the art, and these modifications should not be individually understood from the technical spirit or the prospect of the present invention.

Claims

In the power converter,

An input side converter section;

An output inverter unit;

A sector discriminating unit for discriminating a plurality of sectors with respect to an input current of the converter unit and an output voltage of the inverter unit;

A synthesized vector time calculator configured to calculate a synthesized vector time by using at least one of an input current of the converter unit, an output voltage of the inverter unit, and a modulation index (MI);

A sequence determination unit that determines a switching sequence of the converter unit and a switching sequence of the inverter unit for each of the determined plurality of sectors; And

And a control signal generator configured to generate a control signal for performing a switching operation of the converter unit and the inverter unit based on a switching sequence of the converter unit and the inverter unit, and the synthesized vector time.

The switching sequence of the converter unit,

A power conversion device, characterized in that it does not contain a zero vector.
The method of claim 1,

If the power converter is a three-phase direct power converter,

The converter unit includes a six-way switch as a current converter for converting three-phase alternating current into direct current.

The switch unit may include six switches including a reverse parallel diode as a voltage converter for converting the direct current into a three-phase alternating current;

Power conversion apparatus comprising a.
The method of claim 1,

The sequence determiner,

And the switching sequence of the converter unit is determined as a two-stage switching sequence without a zero vector, and the switching sequence of the output side inverter unit is determined as a five-stage switching sequence including a zero vector and an effective vector.
The method of claim 3, wherein

The sequence determiner,

Determining a switching sequence of the converter unit and the inverter unit such that the power conversion device has a six-stage switching sequence by combining a two-stage switching sequence of the converter unit and a five-stage switching sequence of the inverter unit,

The switching sequence of the six steps,

And a switching sequence of a first valid vector, a second valid vector, a first zero vector, a second zero vector, a third valid vector, and a fourth valid vector.
The method of claim 2,

The sequence determiner,

And the switching sequence of the converter unit is determined as a two-stage switching sequence without a zero vector, and the switching sequence of the inverter unit is determined as a seven-stage switching sequence including a zero vector and an effective vector.
The method of claim 5,

The sequence determiner,

Determining the switching sequence of the input side converter unit and the output side inverter unit such that the power conversion device has an eight-stage switching sequence by a combination of the two-stage switching sequence of the converter unit and the seven-stage switching sequence of the inverter unit. Converter.
The method of claim 6,

The switching sequence of the eight steps,

If the determined plurality of sectors is an odd number, the first zero vector, the first valid vector, the second valid vector, the second zero vector, the third zero vector, the third valid vector, and the fourth are based on the preset first condition. Has a switching sequence of an effective vector and a fourth zero vector order,

If the determined plurality of sectors is an even number, the first zero vector, the second valid vector, the first valid vector, the second zero vector, the third zero vector, the fourth valid vector, and the third based on the second predetermined condition And a switching sequence of an effective vector and a fourth zero vector order.
The method of claim 1,

If the power converter is a three-phase / single-phase direct power converter,

The converter unit includes a six-way switch as a current converter for converting a three-phase AC voltage into direct current.

The switch unit may include four switches including an antiparallel diode as a voltage converter for converting the direct current into single phase alternating current;

Power conversion apparatus comprising a.
The method of claim 8,

The sequence determiner,

And the switching sequence of the converter unit is determined as a two-stage switching sequence without a zero vector, and the switching sequence of the inverter unit is determined as a five-stage switching sequence including a zero vector and an effective vector.
The method of claim 9,

The sequence determiner,

Determining a switching sequence of the converter unit and the inverter unit such that the power conversion device has a six-stage switching sequence by combining a two-stage switching sequence of the converter unit and a five-stage switching sequence of the inverter unit,

The switching sequence of the six steps,

A first switching sequence of a first zero vector, a second valid vector, a second zero vector, a third zero vector, a first valid vector, and a fourth zero vector;

And a second switching sequence in the order of the first zero vector, the first valid vector, the second zero vector, the third zero vector, the second valid vector, and the fourth zero vector.
The method of claim 1,

And a vector time calculator configured to calculate an effective vector time and a zero vector time for calculating the synthesized vector time.

The vector time calculation unit,

An input vector time calculator configured to calculate an input valid vector time using an input current sector and an input current phase of the converter unit;

An output vector time calculator configured to calculate an output valid vector time and an output zero vector time by using an output voltage sector of the inverter unit, an output voltage phase, and the modulation index MI; And

A modulation index calculator configured to calculate the modulation index MI using the output voltage of the inverter unit;

Power conversion apparatus comprising a.