JP2008043110A - Matrix converter controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain three-phase AC output which is hardly overmodulated and is little in distortion, in a matrix converter serving as a power converter that has three-phase AC power input and gets three-phase AC power of optional amplitude and frequency. <P>SOLUTION: This matrix converter controller gets three-phase AC output which is hardly overmodulated and is little in distortion by calculating and using the ratio of outputting intermediate phase voltage among three-phase power voltages, so that the difference between the maximum one and the minimum one may be minimum among output voltage commands to be compared with triangular wave carriers in the matrix converter. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a matrix converter control technique, and more particularly to distortion suppression of an output voltage.

A conventional matrix converter and its controller configuration diagram are shown in FIG. The matrix converter 2 receives a three-phase power source 1 and supplies a three-phase power source having an arbitrary amplitude and frequency to a load 3 by nine switches. The matrix converter control device 4 inputs the power supply voltage output from the power supply voltage detector 34 and the current flowing into the load 3 output from the current detector 33 and outputs a signal for controlling the nine switches of the matrix converter 2.

The power supply voltage phase detector 42 receives the power supply voltage output from the power supply voltage detector 34 and obtains and outputs the phase θd of the power supply voltage and the phase voltage amplitude Vd. The reference carrier comparison signal generator 45 inputs an arbitrary voltage command Vus, Vvs, Vws and the phase θd of the power supply voltage and the amplitude Vd of the output of the power supply voltage phase detector 42 to obtain the reference carrier comparison signals Vuc, Vvc, Vwc. Vuc = Vus · A / emax (1)
Vvc = Vvs · A / emax (2)
Vwc = Vws · A / emax (3)
It is obtained by the operation of and output. Here, A is the amplitude of the triangular wave carrier output from the carrier generator 41, and emax is the maximum (hereinafter referred to as the maximum phase) and the minimum (hereinafter referred to as the minimum phase) of the three-phase power supply voltages of the three-phase power supply 1. ) And is obtained from the phase θd and the amplitude Vd of the power supply voltage output from the power supply voltage phase detector 42, for example, as shown in FIG.

The intermediate phase current command calculator 43 inputs arbitrary voltage commands Vus, Vvs, Vws and currents Iu, Iv, Iw flowing into the load 3 output from the current detector 33, and first, Po = Vus · Iu + Vvs · Iv + Vws · Iw (4)
The output power Po to the load 3 is obtained by the following calculation. Here, it is assumed that the matrix converter 2 can apply arbitrary voltage commands Vus, Vvs, and Vws to the load 3. Then, when the three-phase power supply 1 supplies the output power Po, a current Ic to be passed through a phase that is an intermediate voltage (hereinafter referred to as an intermediate phase) among the three-phase power supply voltages of the three-phase power supply 1 is obtained and output. . For example, as shown in FIG.

The intermediate phase connection rate calculator 48 receives the intermediate phase current command calculator 43 output Ic and Iu, Iv, Iw, and connects the output phases to the intermediate phase of the power supply Ku ′, Kv ′, Kw ′. Is output. When Ix has the same sign as Ic, Kx ′ = Ic / Isum, and when it has a different sign, Kx ′ = 0. Here, x means an output phase represented by u, v, and w, and Isum is the sum of Iu, Iv, and Iw having the same sign as Ic. For example, if Ic> 0, Iu> 0, Iv <0, Iw <0, Ku ′ = Ic / Iu, Kv ′ = Kw ′ = 0. If Ic <0, Iu> 0, Iv <0, Iw <0, Ku ′ = 0, Kv ′ = Kw ′ = Ic / (Iv + Iw). Thus, when there are two output phases having the same sign as Ic, the intermediate phase connection ratios of these phases are equal.

The carrier comparison signal generator 46 inputs the output of the reference carrier comparison signal generator 45 and the output of the intermediate phase connection ratio calculator 48, and VxH = Vxc + A · Kx ′ · G (5)
VxL = VxH−A · Kx ′ (6)
To obtain and output a signal to be compared with the carrier. Here, x means an output phase represented by u, v, w, and G is G = 1−emid / emax (7)
Emid is a potential difference between an intermediate (intermediate phase) and a minimum (minimum phase) of the three-phase power supply voltages, and can be obtained from the phase θd of the power supply voltage. For example, as shown in FIG. Become.

The carrier generator 41 outputs a triangular wave carrier C having an amplitude A, and the comparator 47 outputs Fx as a result of comparing the triangular wave carrier C with the output of the carrier comparison signal generator 46. Here, x means an output phase represented by u, v, and w. Fx = 0 if C <VxL, Fx = 1 if VxL <C <VxH, Fx = 2 if VxH <C, and Fx = 0 connects the output x-phase to the maximum phase of the three-phase power supply 1 Fx = 1 means that the x phase of the output is connected to the intermediate phase of the three-phase power supply 1, and Fx = 2 connects the x phase of the output to the minimum phase of the three-phase power supply 1. Means that.

The switch controller 50 outputs a switching signal corresponding to the output of the comparator 47 and the phase θd to the matrix converter. For example, if Fu = 0, 0 <θd <60, the u phase is connected to the R phase, which is the maximum phase of the power supply, so SuR = ON and SuS = SuT = OFF.

With such a configuration, the voltage applied to the load 3 becomes the voltage commands Vus, Vvs, and Vws, the power supply current waveform can be a sine wave, for example, and the power supply power factor is also, for example, 1. Will be able to. (For example, refer nonpatent literature 1.)
Nakakojimoto, Kobayashi Hirosuke, Sato Norihiko et al .: “Proposal of PWM control method to make sine wave input / output current of matrix converter”, IEEJ Semiconductor Power Conversion Research Paper No. SPC-03-36, pages 61-66

In the conventional technique, when there are two output phases having the same sign as Ic, the intermediate phase connection ratios of these phases are equal, but there is no reason to make them equal. On the other hand, when the six signals VuH, VuL, VvH, VvL, VwH, and VwL to be compared with the carrier go out of the fluctuation width of the carrier (hereinafter expressed as an overmodulation state), the matrix converter can output the voltage as commanded. Therefore, it is desirable that the difference between the maximum and minimum of the six signals is as small as possible. For example, when Ic = 10A, Iu = 80A, and Iv = 20A, Kw = 0, Ku = Kv = 10 / (80 + 20) = 0.1, and the v-phase current is not very useful for flowing Ic. Regardless, it connects to the intermediate phase at the same time rate as the u phase, which increases VvH. If Vvc> Vuc> Vwc, the maximum of the six signals becomes VvH, so that the difference from the minimum of the six signals becomes large and there is a possibility of overmodulation. If Ic = Ku · Iu + Kv · Iv is satisfied, Ku = Kv is not necessary. For example, even if Ku = 0.12 and Kv = 0.02, there is no problem. The difference between the maximum and minimum is not increased and the risk of overmodulation is reduced.

In other words, the problem to be solved by the present invention is that when there are two output phases having the same sign as Ic, the possibility of an overmodulation state is increased by assuming that the intermediate phase connection ratio of these phases is equal. The voltage that the matrix converter can output is low.

In order to solve the above problem, a current output from the matrix converter 2 to the load 3 is detected by a main circuit configuration in which a three-phase power source 1 and a load 3 are connected by a matrix converter 2 including nine switches. A current detector 33, a power supply voltage detector 34 for detecting the voltage of the three-phase power supply 1, and a power supply voltage phase detection for inputting the output of the voltage detector 34 and obtaining and outputting the phase and magnitude of the power supply voltage In the intermediate voltage state among the three power supply voltages of the three-phase power supply 1 using the output of the power supply voltage phase detector 42, the output voltage command of each phase, and the output of the current detector 33. An intermediate phase current command calculator 43 that calculates and outputs an intermediate phase current command that is a current to be passed through an intermediate phase that is a certain phase, an output of the intermediate phase current command calculator 43, and an output of the current detector 33 Enter An intermediate phase connection ratio calculator 44 for obtaining a time ratio for connecting each output phase of the matrix converter 2 to the intermediate phase, an output of the power supply voltage phase detector 42, and an output of each phase to be output by the matrix converter 2 A reference carrier comparison signal generator 45 for inputting a voltage command and outputting a carrier comparison signal such that the output voltage of each phase of the matrix converter 2 matches the output voltage command of each phase; and generating the reference carrier comparison signal The carrier comparison signal generator 46 that outputs the output of the comparator 45 and the output of the intermediate phase connection ratio calculator 44 and outputs six carrier comparison signals, the carrier generator 41 that generates carriers, and the carrier comparison signal generation A comparator 47 for comparing the output of the comparator 46 with the output of the carrier generator 41, the output of the comparator 47 and the power supply In the matrix converter control device comprising a switch controller 50 for inputting a phase of the power supply voltage of the output of the phase detector 42 and outputting a signal for controlling the switch of the matrix converter 2, the output of the carrier comparison signal generator 46 A matrix converter control device for obtaining the output of the intermediate phase connection ratio computing unit 44 is implemented so that the difference between the maximum and minimum among the six signals is minimized.

The output voltage of the matrix converter can be increased while maintaining the power source power factor of 1 with a sine wave as the power source current waveform.

The purpose of increasing the output voltage of the matrix converter was achieved by changing the calculation method of the time ratio to be connected to the intermediate phase without reducing the performance of the power supply characteristics and without adding components.

FIG. 1 shows an embodiment. Since the main component of the present invention is the intermediate phase connection ratio calculator 44 of the present invention, the description of the same technology as in the prior art is omitted. The intermediate phase connection ratio calculator 44 of the invention receives the output currents Iu, Iv, Iw, the outputs of the reference carrier comparison signal generator 45, Vuc, Vvc, Vwc, and the output of the intermediate phase current command calculator 43, Ic. To do. An example in which the phases of the output current having the same sign as the power intermediate phase current command value Ic are u and v will be described. Assuming that the amplitude of the carrier signal C is 0 to 1 (that is, A = 1), U = (Vuc / Emax), V = (Vvc / Emax), W = (Vwc / Emax), G = (1-emid / emax) Then, the carrier comparison signal calculated in the carrier comparison signal generator 46 is calculated as shown in Equation (9) to Equation (14).
VuH = U + Ku · G (8)
VuL = U−Ku · (1-G) (9)
VvH = V + Kv · G (10)
VvL = V−Kv · (1−G) (11)
VwH = W + Kw · G (12)
VwL = W−Kw · (1-G) (13)

Here, in the intermediate phase connection rate calculator 44, the intermediate phase connection rate Kw between the power intermediate phase current command value Ic and the phase of the output current having a different sign is set to 0, so VwH = VwL = W. Further, Ku, Kv and the power supply intermediate phase current command value Ic need to satisfy the equation (14).
Ic = Ku · Iu + Kv · Iv (14)
First, Ku and Kv that minimize the difference between the maximum signal and the minimum signal of the four signals VuH, VuL, VvH, and VvL are calculated. For example, if U> V,
VuH ≧ VvH (15)
VuL ≧ VvL (16)
Therefore, if the equation (14) is substituted, Kv ≦ Iu · (U−V) / (G · (Iu + Iv)) + Ic / (Iu + Iv) (17)
Ku ≦ Iv · (U−V) / ((1−G) · (Iu + Iv)) + Ic / (Iu + Iv) (18)
And Kv ≦ Ic / Iv (19) from the equation (14).
Ku ≦ Ic / Iu (20)
The difference between the maximum signal and the minimum signal of the four signals VuH, VuL, VvH, VvL VuH−VvL = U + Ku · G−V + Kv · (1−G) (21)
In order to minimize the above, if G ≧ (1-G) · Iu / Iv, Ku ≧ 0, (19) and (17) may be satisfied. If G ≦ (1-G) · Iu / Iv, Kv ≧ 0, (20) and (18) may be satisfied.
Temporary VuH, VuL, VvH, and VvL are obtained from Ku and Kv obtained so far, and these are set as VuH ′, VuL ′, VvH ′, and VvL ′.

Next, Ku and Kv that minimize the difference between the maximum signal and the minimum signal of the three signals VuH ′, VvL ′, and W are calculated.
In the case of W> VuH ′, Ku can be increased within a range where VuH does not exceed W. Therefore, the condition is Ku ≦ (W−VuH ′) / G (22)
And the maximum value satisfying equations (18) and (20). Kv at that time is obtained from the equation (14).
In the case of W <VvL ′, Kv can be increased within a range where VvL does not fall below W. Therefore, the condition is Kv ≦ (VvL′−W) / (1-G) (23)
And the maximum value satisfying equations (17) and (19). Ku at that time is obtained from equation (14).

As described above, when the phase of the output current having the same sign as the power intermediate phase current command value Ic is u and v, and U> V, the difference between the maximum and minimum of the six carrier comparison signals is the minimum. Ku and Kv can be obtained. The same calculation is performed when U <V, when the phase of the output current having the same sign as the intermediate phase current command value Ic is v and w, and when u and w. By performing the above calculation in the intermediate phase connection ratio calculator 44 of the invention, two intermediate phases in which the difference between the maximum signal and the minimum signal of the six carrier comparison signals that are the outputs of the carrier comparison signal generator 46 is minimized. A combination of connection rates can be calculated. According to the present invention, the carrier comparison signals in the formulas (8) to (13) are easily contained in the carrier amplitude A and are less likely to be overmodulated. Therefore, the present invention is effective in improving the output possible voltage of the matrix converter. .

The present invention can obtain an output with less distortion as compared with a conventional matrix converter, and can be applied to power equipment of elevators, elevators, escalators, centrifuges, buildings, and laboratories.

FIG. 1 is a diagram showing a matrix converter control device of the present invention. FIG. 2 is a diagram showing a conventional matrix converter control device. FIG. 3 is a diagram for explaining the relationship between the input power supply voltage and the phase. FIG. 4 is a diagram for explaining the relationship between the intermediate phase current command value and the phase at a power factor of 1. FIG. 5 is a diagram for explaining the relationship between the variable G and the phase.

Explanation of symbols

1: Three-phase power supply 2: Matrix converter 3: Load 33: Current detector 34: Power supply voltage detector 4: Matrix converter control device 41: Carrier generator 42: Power supply voltage phase detector 43: Intermediate phase current command calculator 44 : Inventive intermediate phase connection rate calculator 45: Reference carrier comparison signal generator 46: Carrier comparison signal generator 47: Comparator 48: Conventional intermediate phase connection rate calculator 50: Switch controller

Claims (1)

A main circuit configuration in which a three-phase power source (1) and a load (3) are connected by a matrix converter (2) composed of nine switches, and a current for detecting a current output to the load 3 by the matrix converter (2) The detector (33), the power supply voltage detector (34) for detecting the voltage of the three-phase power supply (1), and the output of the voltage detector (34) are inputted to obtain the phase and magnitude of the power supply voltage. The three-phase power supply (42) using the output of the power supply voltage phase detector (42), the output of the power supply voltage phase detector (42), the output voltage command of each phase, and the output of the current detector (33) 1) an intermediate phase current command calculator (43) that calculates and outputs an intermediate phase current command that is a current to be passed through an intermediate phase that is a phase in an intermediate voltage state among the three power supply voltages; The output of the phase current command calculator (43) and the current detector (33) And an output of the power supply voltage phase detector (42). An intermediate phase connection ratio calculator (44) for obtaining a time ratio for connecting each output phase of the matrix converter (2) to the intermediate phase. And an output voltage command of each phase to be output by the matrix converter (2), and a carrier comparison signal such that the output voltage of each phase of the matrix converter (2) matches the output voltage command of each phase The reference carrier comparison signal generator (45) that outputs the signal, the output of the reference carrier comparison signal generator (45) and the output of the intermediate phase connection ratio calculator (44) are input, and six carrier comparison signals are output. The carrier comparison signal generator (46) for generating a carrier, the carrier generator (41) for generating a carrier, and the output of the carrier comparison signal generator (46) and the output of the carrier generator (41) are compared. And output the comparator (47), the output of the comparator (47) and the phase of the power supply voltage of the output of the power supply voltage phase detector (42), and the switch of the matrix converter (2) In a matrix converter control device comprising a switch controller (50) for outputting a control signal,
The output of the intermediate phase connection ratio calculator (44) is obtained so as to minimize the difference between the maximum signal and the minimum signal among the six signals output from the carrier comparison signal generator (46). Matrix converter control device.

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