JPH0487569A - Control method for multiple inverter device - Google Patents

Abstract

PURPOSE:To make it possible to set the resonance frequency of filters higher by stopping the operation of an inverter being out of order, when any one of a plurality of inverters is out of order, and by switching the phase difference of triangular carrier signals to be supplied to the remaining inverters from 180/n degree to 180/(n-1) degree. CONSTITUTION:When a plurality of inverters 1-3 are normal, triangular carrier signals having a phase difference of 180/n to one another are supplied to all the inverters 1-3 respectively, and the outputs of the inverters l-3 are compounded and outputted by a multiple transformer 4U. On the other hand, if any one of the inverters 1-3 is out of order by some cause, the operation of the bad-order inverter is stopped, the phase difference of the triangular carrier signals to be supplied to the remaining inverters is switched from 180/n degree to 180/(n-1) degree, and the outputs of the remaining inverters are compounded and outputted by the multiple transformer 4U. This makes it possible to set higher the resonance frequency of filters for removing the higher components of the triangular carrier signals.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to active filters, etc. that inject a compensation voltage of a predetermined frequency into a noise generation source to prevent noise components from flowing into the power system. In order to reduce the size of filters for removing frequency components of The present invention relates to a method of controlling an inverter device.

[Conventional technology]

Figure 4 (Al shows the basic circuit diagram of a three-multiplex inverter device that generates three-phase AC voltage of U phase, ■ phase, and W phase. In Figure 4 + al, 1 indicates the first three phases. The inverter is composed of a DC power source IE and three single-phase inverters IU, IV, and IW for the U phase and the W phase for the ~S4, and a diode DI-Da connected in antiparallel to the switch elements S and ~S4, respectively, and these are connected in a bridge shape, and the connection point of the switch elements S, , S, and the switch elements St, S4 Connect the connection point to DC power supply 1
E and the connection point of switch elements St and S2, respectively, and the switch element S3. Output terminals T+ and T2 are provided at the connection points of Sa, respectively.

The detailed circuit configurations of the remaining single-phase inverters IU and IW are omitted, but the single-phase inverter IU
The configuration is the same as that of single-phase inverters IU, IV,
A pulse width modulation signal, which is the comparison result between the reference voltage of each phase and the triangular wave carrier voltage, is applied to the control pole (not shown) of each switch element S, ~S4 of the IW, and thereby the single-phase inverter of each phase A three-phase AC voltage similar to the reference voltage of each phase is applied between the output terminals T+ and 72 of IU, IV, and IW. However, since this three-phase AC voltage includes frequency components of the triangular wave carrier voltage and harmonic components thereof, it is necessary to remove these frequency components with an LC filter at a subsequent stage.

2 is a second three-phase inverter, 3 is a third three-phase inverter, and their specific circuit configurations are the same as those of the first three-phase inverter 1. However, the triangular wave carrier signal for creating the pulse width modulation signal applied to each switch element of each single-phase inverter 2 and 3 is 60 degrees and 120 degrees, respectively, with respect to the triangular wave carrier signal of the first three-phase inverter 1. They differ in that they have a phase lag.

And the first. Second. Third three-phase Inno＼-Yu1゜2.
3, the phase voltages of U phase, ■ phase, and W phase are synthesized.

For example, for the U phase, a multiplex transformer 4U as shown in FIG.
Similarly, the output terminals T,,T, of the single-phase inverter (not shown) for the U phase of the second three-phase inverter 2 are connected to the primary winding n1! of the multiplex transformer 4U. The output terminals Ts and Th of the U-phase single-phase inverter (not shown) of the third three-phase inverter 3 are connected to the multiplex transformer 4U.
Primary winding n1! Connect to. This allows the secondary winding n2 of the multiplex transformer 4U to be connected to the first . Second. Single-phase inverter IU for U phase of third three-phase inverter 1, 2.3,...
The U-phase AC voltage is obtained by multiplexing the outputs of three.

The (2) phase and the W phase are the same as the U phase.

Fig. 5 is a time chart showing the pattern of creation of the U-phase pulse width modulation signal, the output of each single-phase inverter, and the pattern of multiplexed composite output. The operation will be explained for the U phase.

Note that the operation is the same for the ■ phase and the W phase.

In this multiplex inverter device, with a comparison circuit for pulse width modulation (not shown), for the first three-phase inverter 1, as shown in FIG. l 1 and its inverted signal, the triangular wave carrier signal V shown by the two-dot chain line,
are compared.

As a result of comparing the reference voltage Vl and the triangular wave carrier signal 11, a rectangular wave (pulse width modulated wave) as shown in Fig. 5 (bl) is obtained. When the switching element S of the single-phase inverter IU is turned on, the switching element Sz of the single-phase inverter IU is turned on when the level is low. As a comparison result, a rectangular wave (pulse width modulated wave) as shown in FIG. On the other hand, when the level is low, the single-phase inverter I
The switch element S3 of U is turned on. As a result of the above,
The output voltage of the single-phase inverter IU has a waveform as shown in FIG. 5(d).

Similarly, for the second three-phase inverter 2, see FIG.
As shown in al, the reference voltage V is compared with a triangular wave carrier signal VtX shown by a short broken line and a triangular wave carrier signal v0 shown by a dashed line which is an inverted signal of the triangular wave carrier signal VtX. As a result of the comparison between the reference voltage V and the triangular wave carrier signal V+Z, a rectangular wave as shown in FIG. A rectangular wave as shown in f) is obtained. These rectangular waves drive the same four switch elements as described above, and the output voltage of the U-phase single-phase inverter has a waveform as shown in FIG.

Further, regarding the third three-phase inverter 3, FIG.
As shown in J, the reference voltage vR, the triangular wave carrier signal VB shown by the long broken line, and the triangular wave carrier signal V! ff is compared. Reference voltages V, l and triangular wave carrier signal ■1. As a result of comparison, a rectangular wave as shown in Fig. 5 (hl) is obtained, and as a result of comparison between the reference voltage ■ and the triangular wave carrier signal vt3, a rectangular wave as shown in Fig. 5 (11) is obtained. These rectangular waves drive the same four switch elements as described above, and the output voltage of the U-phase single-phase inverter has a waveform as shown in FIG. 501.

Then, when the output voltages of the single-phase inverters IU, . voltage can be obtained.

With this configuration, the output voltage of the multiplex transformer 4U contains only the harmonic components of the 6th order and above as harmonic components of the triangular wave carrier signal, and the LC for removing the harmonic components of the triangular wave carrier signal is used. The resonant frequency of the filter can be set high, so the inductor and capacitor that constitute the LC filter can be made small, and the LC filter can be made smaller.

[Problem to be solved by the invention]

However, in this multiple inverter device, when one of the three-phase inverters 1, 2.3 stops operating due to a failure, for example, when the three-phase inverter 3 stops operating, the triangular wave of the normal three-phase inverters 1, 2 is Since the carrier voltage has a phase difference of 60 degrees as before the failure, the multiple inverter 4
The output voltage of U has a waveform as shown in FIG. 5(1).

If the waveform becomes non-uniform on the time axis, the lowest order of the harmonic components of the triangular wave carrier signal included in the output voltage of the multiplex transformer 4U will decrease.

In other words, in this example, the frequency of the triangular carrier signal is set to f
c, unnecessary harmonic components will be generated due to the triangular wave carrier signal in the range of 2fc<f<4fc.

In this way, when the lowest order of unnecessary harmonic components to be removed decreases, it becomes necessary to set the resonance frequency of the LC filter low to remove it, and therefore, the inductance value of the inductor or the capacitance of the capacitor must be set large. Therefore, there is a problem that the LC filter becomes larger.

Therefore, an object of the present invention is to suppress the decrease in the lowest order of the harmonic components of the triangular wave carrier signal in the multiplexed combined output voltage when the number of multiplexed signals decreases due to the stoppage of the inverter, and to eliminate the harmonic components of the triangular wave carrier signal. An object of the present invention is to provide a control method for a multiplex inverter device that can reduce the size of a filter.

[Means to solve the problem]

The method for controlling a multiplex inverter device according to the present invention includes n units (n
is an integer of 3 or more) when the inverter is normal, n
A triangular wave carrier signal having a phase difference of 180/n degrees is supplied to each inverter, and
The outputs of two inverters are combined using multiple transformers and output. On the other hand, if any one of the n inverters fails for some reason, the operation of the failed inverter is stopped and the phase difference of the triangular wave carrier signals supplied to the remaining n-1 inverters is set to 180/n degrees. From 180/(n-
1) The outputs of n-1 imparks are combined and output by multiple transformers.

[For production]

According to the configuration of this invention, not only when all n inverters are normal, but any one of the n inverters
Even when a converter fails and the operation of that inverter is stopped, the phase difference of the triangular wave carrier signal applied to the operating inverter is equalized, and the lowest harmonic component of the triangular wave carrier signal in the output voltage of the multiplex transformer is equalized. The order becomes 2(n-1), and generation of harmonic components of orders lower than that is prevented. As a result, the resonant frequency of the filter for removing harmonic components of the triangular carrier signal can be set high, and the filter can be made smaller.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram showing the configuration of a multiplex inverter device that implements a control method according to an embodiment of the present invention. This multiplex inverter device multiplexes and combines the output voltages of three inverters during normal operation, and switches to two multiplexes when one inverter fails. Note that this multiple inverter device outputs a three-phase AC voltage, and since the configurations of the U, ■, and W phases are the same, Fig. Therefore, only the circuit configuration of the U phase is illustrated, and the illustrations of the (2) and W phases are omitted.

In Figure 1, l is the first three-phase inverter, 2 is the second
3 is a third three-phase inverter, IU is a U-soma single-phase inverter in the three-phase inverter 1, and 4U is a U-soma multiplex transformer.

5 is a triangular wave carrier signal generation circuit common to each phase, which generates triangular wave carrier signals VVIZ, V with a phase difference of 60 degrees.
ll and triangular wave carrier signal v1. A triangular wave carrier signal V14 having a phase difference of 90 degrees with respect to the triangular wave carrier signal V14 is generated, and triangular wave carrier signals vz+, V2□, V2°Vt4 whose phases are exactly inverted from these are generated.

6U is a triangular wave carrier signal switching circuit which converts the triangular wave carrier signal Vll generated from the triangular wave carrier signal generation circuit 5.
+ V12-+ VI3+ v14+ vi!
l+V22+Vt3. Vta in each of the three-phase inverters 1, 2, and 3 and in each of the single-phase inverters 10, 2, and 3.・・・
・Each failure signal K S+u, K Szu, K
Based on S1u, when all three-phase inverters 1, 2.3 are normal, the triangular wave carrier signal Vll+Vl
□, V, , V□, v2□.

Vt3 is output corresponding to each three-phase inverter 1, 2.3, and when one of the three-phase inverters 1, 2, or 3 is out of order, for example, when the three-phase inverter 3 is out of order, the triangular wave carrier is output. Signals V 11 , V 14 , V z 1
.

Vta is output corresponding to three-phase inverters 1 and 2.

The specific circuit configuration will be described later (Fig. 2 (al, (bl)
reference).

7U is a pulse generation circuit, which generates the reference voltage given from the triangular wave carrier signal switching circuit 6U and the triangular wave signal vIl+ V+z+ V+i+ Via, v
Comparing Zl, vZ2V23+Vt4, each 3
Each single-phase inverter IU of phase inverters 1 and 23,...
・Switch element S.

~ Create a rectangular wave signal (pulse width modulation signal) for driving S4, amplify this rectangular wave signal, and send it to the single-phase inverter IU of the U soma of each three-phase inverter 1.2.3. Give as gate pulse.

Here, the specific circuit configuration of the triangular wave carrier signal switching circuit 6U will be described with reference to FIGS. 2(al) and (bl).

This triangular wave carrier signal switching circuit 6U is shown in FIG.
AND gates AN, , AN, and NOT circuit N shown in
T, ~NT, and switches SW, ~ shown in Figure 2 (bl)
It consists of SW.

When all three three-phase inverters 1.2.3 are normal, all three-phase inverters 1.2.3 are operated, and at this time, as shown in Table 1, the failure signals K S+u, K
Szu, K Ssu are all low, switch S
Control signals ss, -ss of W, ~SW5.

are low, high, low, high, and low, respectively.

As a result, the triangular wave carrier signals V, , V2. are used for controlling the single-phase inverter IU of the U phase of the three-phase inverter 1, and the triangular wave carrier signal V+2. Vz□ is used for controlling the single-phase inverter of the U phase of the three-phase inverter 2, and the triangular wave carrier signal v13+Vz3 is used for controlling the single-phase inverter of the U phase of the three-phase inverter 3.

In other words, the triangular wave carrier signals V+, v, .
z; vli Vzz will be provided. The time chart of each part of the multiplex inverter device at this time is the same as that shown in FIG. 5 from fat to (k+).

Next, for example, when the three-phase inverter 3 fails, the operation of the three-phase inverter 3 is stopped, and only the remaining three-phase inverter 1.2 is operated, and at this time, the failure signal KS
+u, KSz. , KS*v and switch SW +~sw
, and the triangular wave carrier signals of three-phase inverters 1 to 3 are as shown in Table 2.

That is, triangular wave carrier signals VIl+ vz+ ; VH2°V2.
A three-phase inverter will be provided.

2, the triangular wave carrier signal V, , Vt, , VH
2, the phase difference of V2° becomes equal.

FIG. 3 is a time chart showing the pattern of creation of the U-phase pulse width modulation signal and the pattern of the output of each single-phase inverter and the multiplexed composite output when the number of multiplexed signals decreases due to a failure of the three-phase inverter 3. Referring to FIG. 3, the operation of this multiplex inverter device when the number of multiplexes is reduced will be explained only for the U phase.

Note that the same operation is performed for the V phase and the W phase.

In this multiple inverter device, the first three-phase inverter 1
For reference voltage ■1, as shown in Fig. 3 1et,
, a triangular wave carrier signal ■ shown by a solid line, and its inverted signal, a triangular wave carrier signal ■t1 shown by a two-dot chain line.
are compared.

As a result of comparing the reference voltage vll and the triangular wave carrier signal V11, a rectangular wave (pulse width modulation wave) as shown in the third equivalent) is obtained, and when the rectangular wave of the third equivalent) is at a high level, When the switching element S1 of the single-phase inverter IU is turned on and is at low level, the single-phase inverter IU is turned on.
The switch element S2 of U is turned on. Also, the reference voltage Vll and the triangular wave carrier signal V! As a result of comparison with +, a rectangular wave (pulse width modulated wave) as shown in Fig. 3 (fc) is obtained, and when the rectangular wave of C1 is at a high level, the switching elements of the single-phase inverter IU Single-phase inverter IU is activated when S4 is turned on and is at low level.
The switch element S is turned on. As a result of the above, the output voltage of the single-phase inverter IU has a waveform as shown in FIG. 3 (di).The operation of this single-phase inverter IU is similar to the conventional example.

Next, regarding the second three-phase inverter 2, see Figure 3 (
As shown in a), the reference voltage V is compared with a triangular wave carrier signal V14 shown by a short broken line and a triangular wave carrier signal V14 which is an inverted signal of the triangular wave carrier signal V14 shown by a dashed line.

As a result of comparison between the reference voltage Vl and the triangular wave carrier signal V14, a rectangular wave (pulse width modulated wave) as shown in FIG. 3(e) is obtained, and when the rectangular wave in FIG. U-Soma single-phase inverter switch element SI
is driven on, and conversely, when it is at a low level, the switch element S2 of the single-phase inverter of the U phase is driven on. Also, base 1! As a result of comparing the voltage ■ wing and the triangular wave carrier signal Vz4, a rectangular wave (pulse width modulation wave) as shown in Fig. 3 (fl) is obtained, and when the rectangular wave (ff) in Fig. 3 is at a high level, The switch element S4 of the single-phase inverter of the U-soma is driven on, and conversely, when the level is low, the switch element S of the single-phase inverter of the U-soma is driven on. As a result of the above, the output voltage of the U-soma single-phase inverter has a waveform as shown in FIG. 3 (gl).

Then, when the output voltages of each single-phase inverter IU, . The harmonic components of the triangular wave carrier signal included in this waveform are 4th order or higher, and harmonic components of 3rd order or lower are not included.The reason for this is that the triangular wave carrier signal V11.Vzl added to the three-phase inverter 1.2 , VH2, Vt
This is because the phase differences of 4 are equal.

Next, for example, when the three-phase inverter 2 fails, the operation of the three-phase inverter 2 is stopped, and only the remaining three-phase inverters 1 and 3 are operated, and at this time, the failure signal KS
+u, KStu, KS3Ll and switch SW, ~
The control signals SS, ~SSS of S W s and the triangular wave carrier signals of the three-phase inverters 1 to 3 are as shown in Table 3, respectively.

Only the remaining three-phase inverter 2.3 is operated, and at this time the fault signals K S + u, K S tu, K S
control signal 5SI for su and switches SW + to SW
-3Ss and triangular wave carrier signals of three-phase inverters 1 to 3 are as shown in Table 4, respectively.

In other words, the triangular wave carrier signals V, . . . v2+;

■□ will be served.

Next, for example, when the three-phase inverter 1 fails, the operation of the three-phase inverter 1 is stopped, that is, the single-phase inverter IU of the U phase of the three-phase inverter 2.3,...
A triangular wave carrier signal Vll+Vx+; (14+Vz) having a phase difference of 90 degrees is provided to each of them.

With this configuration, the output voltage of the multiplex transformer 4U contains only the 4th order or higher harmonic components of the triangular wave carrier signal, and the three-phase inverter 1,
Although 2.3 is lower than the 6th order, which is the lowest order when everything is normal, it can be higher than the 2nd order, which is the lowest order when the three-phase inverter 3 fails in the conventional example. Therefore, the resonant frequency of the LC filter for removing harmonic components of the triangular wave carrier signal can be set to a high value. Therefore, the inductor and capacitor constituting the LC filter can be made small, and the LC filter can be made small. It is something that can be transformed into

Note that in the above embodiment, the phase difference of the triangular wave carrier signal is switched from 60 degrees to 90 degrees when the number of multiplexes is 3 during normal operation and decreases to 2 during a failure. However, the present invention can be applied to any case where the number of multiplexes during normal operation is n (n is an integer of 3 or more) and the number of multiplexes decreases to n-1 during a failure. In this case, the phase difference of the triangular wave carrier signal will be switched from 180/n degrees to 180/(n-1) degrees.

In the above embodiment, an embodiment of a multiple inverter device that generates a three-phase AC voltage has been described, but it goes without saying that the present invention can also be applied to an apparatus that generates a single-phase AC voltage.

〔Effect of the invention〕

According to the method for controlling a multiplex inverter device of the present invention, n
The phase difference of the triangular wave carrier signal applied to the operating inverter is not limited to when all the inverters in the n inverters are normal, but also when any one of the n inverters fails and the operation of that inverter is stopped. It is possible to equalize the harmonic components of the triangular wave carrier signal in the output voltage of the multiplex transformer, and the lowest order of the harmonic components of the triangular wave carrier signal can be made higher than that at the time of failure in the conventional example. The resonant frequency of the filter can be set high,
The filter can be made smaller.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a multiplex inverter device according to an embodiment of the present invention, FIG. 2 is a circuit diagram showing the specific configuration of the main parts of FIG. 1, and FIG. FIG. 4 is a time chart showing the operation of the multiple inverter; FIG. 4 is a circuit diagram showing the configuration of a conventional multiple inverter device; FIG. 5 is a time chart showing the operation of the multiple inverter shown in FIG. 1 to 3...3-phase inverter, 4U...multiple transformer,
5... Triangular wave carrier signal generation circuit, 6U... Triangular wave carrier signal switching circuit, 7U... Pulse generating circuit 4
U-Isho Heavy Transformer No. (k)

Claims (1)

[Claims] A triangular wave carrier signal having a phase difference of 180/n degrees is supplied to n voltage-type pulse width modulation inverters (n is an integer of 3 or more), and the voltage of the n voltage pulse width modulation inverters is In a control method for a multiple inverter device in which outputs of voltage type pulse width modulation inverters are combined and outputted by a multiple transformer, when any one of the n voltage type pulse width modulation inverters fails, the voltage type pulse width of the failed voltage type pulse width modulation inverter is The operation of the modulation inverter is stopped, and the phase difference of the triangular wave carrier signal supplied to the remaining n-1 voltage type pulse width modulation inverters is set to 18.
A method for controlling a multiple inverter device, characterized by switching from 0/n degrees to 180/(n-1) degrees.