JPH07298637A - Inverter - Google Patents

Abstract

PURPOSE:To compensate the transient and stationary components of anhysteresis in an inverter transformer, by generating correction signals for the deviation factors in accordance with the anhysteretic components, and taking synthetic control over these factors. CONSTITUTION:A deviation corresponding to an anhysteretic component in an inverter transformer 11 is obtained by an anhysteretic detecting unit including a subtractor 13, an amplifier 14, a DC bias generator 15, and an adder 16. A first correction circuit including a comparator 17, pulse generator 18 and an integrator 19 generates a correction signal for the stationary deviation component, and a second correction circuit (filter circuit) 20 generates a correction signal for the transient deviation component. After these correction signals are added by an adder 21, a control circuit (logic circuit) 7 generates a control signal to drive a converter circuit 10 through an amplifier 8. Since the stationary and transient anhysteretic components are compensated, the inverter transformer is operated stably and an overcurrent caused by the anhysteresis can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter device for compensating reactive power of a power system.

[0002]

2. Description of the Related Art The structure of a conventional inverter device of this type is shown in FIG. In the figure, 1 is a 3-phase AC system busbar, 2
Is a reference circuit for generating reference values (predetermined) of the system voltage, load current, etc. of the three-phase AC system bus 1, and 3 is current detection for detecting the system voltage, load current, etc. of the three-phase AC system bus 1. (CT), 4 are the reference value output by the reference circuit 2 and the system voltage of the three-phase AC system bus 1 output by the current detector 3,
The inverter circuit 1 is a current control circuit that compares the load current and the like to perform an operation to generate an output voltage reference of the inverter device.
A carrier triangular wave reference for generating a signal serving as a reference for generating a pulse for controlling 0, 6 is a comparator for comparing the output voltage reference output from the current control circuit with the reference carrier triangular wave, 7
Is a logic circuit that generates a pulse for controlling the power semiconductor element of the inverter circuit 10 based on the comparison result of the comparator 6, 8 is a pulse amplifier that amplifies the control pulse generated by the logic circuit 7 and drives the inverter circuit 10, 9 is a DC capacitor for storing a DC voltage, 10 is a GTO
An inverter circuit that is composed of a power semiconductor such as a thyristor and that converts the DC voltage stored in the DC capacitor 9 into an AC voltage. Reference numeral 11 is an inverter transformer that supplies the AC voltage converted by the inverter device 10 to the three-phase AC system bus 1. Is.

Next, the operation will be described. The inverter device of FIG. 9 operates so as to compensate for the reactive power when the reactive power is generated in the three-phase AC system bus 1 due to fluctuations in the load (not shown) or the like. That is, the current detector 3
Detects the system voltage, load current, etc. of the 3-phase AC system bus line 1,
Output to the current control circuit 4. The current control circuit 4 compares the system voltage, load current, etc. with the reference value output by the reference circuit 2 to obtain a deviation, which is the voltage to be compensated.
The amount of current is obtained and this deviation is multiplied by a predetermined current control gain to generate an output voltage reference of the inverter device.

The output voltage reference of the inverter device generated by the current control circuit 4 is output to the comparator 6. In the comparator 6, the output voltage reference of the inverter device is compared with the reference carrier triangular wave output from the carrier triangular wave reference 5 and converted into a signal serving as a reference for turning on / off the power semiconductor element of the inverter circuit 10. It The logic circuit 7 generates a predetermined pulse signal based on the output of the comparator 6.
The pulse amplifier 8 amplifies this pulse signal and then supplies it to the gate of a power semiconductor element such as a GTO thyristor of the inverter circuit 10.

The inverter circuit 10 turns on / off the output of the DC capacitor 9 based on the output of the pulse amplifier 8,
The DC voltage stored in the DC capacitor 9 is converted into a rectangular wave AC voltage approximated to the inverter output voltage reference, and the AC voltage is supplied to the three-phase AC system bus 1 via the inverter transformer 11. At this time, the output voltage of the inverter transformer 11 is 3
If the voltage is higher than the voltage of the phase AC system bus bar 1, the reactive power is compensated for, and if it is smaller, the delayed reactive power is compensated. To compensate.

[0006]

Since the conventional inverter device is constructed as described above, the inverter transformer 11 is excited by the output voltage from the inverter circuit 10 and a predetermined output is output from the three-phase AC system bus bar. Although it is supplied to one side, in the output of the inverter transformer 11, the voltage product for each half-wave on the positive polarity side and the negative polarity side of the output voltage is different,
When the balance is not balanced, or when the positive and negative polarities cannot be balanced due to a sudden change in the output voltage, the inverter transformer 11 is biased to increase the drive current of the inverter transformer 11. However, there were cases where overcurrent occurred and stable operation could not be continued. In particular, when there is a steady demagnetization, since there is no operating point at the center of the hysteresis characteristic of the iron core of the inverter transformer 11, saturation of the magnetic flux is likely to occur due to sudden demagnetization due to load fluctuations, etc., resulting in overcurrent. It had the drawback of being easy.

The present invention has been made to solve the above problems, and it is possible to compensate for the transient magnetic bias of the inverter transformer and the steady magnetic bias of the inverter transformer. is there.

[0008]

An inverter device according to a first aspect of the present invention includes an inverter circuit for converting a DC voltage into an AC voltage, an inverter transformer for receiving an output of the inverter circuit and outputting a compensation power, and the inverter. A bias magnetic detection unit for obtaining a deviation corresponding to the bias magnetic component of the transformer, and a correction signal for a stationary component of the deviation detected by the bias magnetic detection unit is generated and is output after delaying the correction signal. A first correction circuit, a second correction circuit that generates a correction signal for a transient component of the deviation detected by the bias detection unit, an output of the first correction circuit, and the second correction circuit. An adder that combines the output of the correction circuit, a control circuit that generates a control signal of the inverter circuit based on the output of the adder, and a drive circuit that drives the inverter circuit based on the output of the control circuit Those with an amplifier.

According to a second aspect of the present invention, there is provided an inverter device in which the bias detection unit detects a first current detector for detecting a primary output of the inverter transformer and a secondary output of the inverter transformer. And a subtracter for obtaining a deviation between the output of the first current detector and the output of the second current detector.

In the inverter device according to a third aspect of the present invention, the bias magnetizing detection unit detects a first voltage detector for detecting a primary side output of the inverter transformer and a secondary side output of the inverter transformer. A second voltage detector, a subtractor for obtaining a deviation between the output of the first voltage detector and the output of the second voltage detector, and a low frequency component of the deviation output by the subtractor. And a filter circuit that operates.

According to a fourth aspect of the present invention, there is provided an inverter device comprising: a magnetic flux detector for detecting the magnetic flux of an iron core of the inverter transformer; and a filter circuit for extracting a low frequency component of an output of the magnetic flux detector. It is composed of and.

An inverter device according to a fifth aspect of the present invention is an inverter circuit for converting a DC voltage into an AC voltage, an inverter transformer for receiving the output of the inverter circuit and outputting compensation power, and a biased magnetic component of the inverter transformer. And a first bias magnetic detection unit and a second bias magnetic detection unit for obtaining a deviation corresponding to the above, and a correction signal for a stationary component of the deviation detected by the first bias magnetic detection unit, and A first correction circuit that delays and outputs the correction signal; a second correction circuit that generates a correction signal for a transient component of the deviation detected by the second bias detection unit; 1
Adder for synthesizing the output of the correction circuit and the output of the second correction circuit, a control circuit for generating a control signal of the inverter circuit based on the output of the adder, and the above based on the output of the control circuit. And an amplifier that drives an inverter circuit.

According to a sixth aspect of the present invention, there is provided an inverter device comprising: a first voltage detector for detecting the primary side output of the inverter transformer; and a second side of the inverter transformer. A second voltage detector for detecting an output, and the first voltage detector
And a filter circuit for extracting the low frequency component of the deviation output from the subtracter, and the second circuit. The subtractor for calculating the deviation between the output of the second voltage detector and the output of the second voltage detector. A first current detector for detecting a primary side output of the inverter transformer, a second current detector for detecting a secondary side output of the inverter transformer, and the first bias detector. Of the current detector and the output of the second current detector.

According to a seventh aspect of the present invention, there is provided an inverter device, wherein the first magnetic bias detecting section is provided with a magnetic flux detector for detecting the magnetic flux of the iron core of the inverter transformer and a low frequency component of the output of the magnetic flux detector. And a second bias detecting section for detecting the primary side output of the inverter transformer and the secondary side output of the inverter transformer. And a subtracter for obtaining a deviation between the output of the first current detector and the output of the second current detector.

According to another aspect of the present invention, there is provided an inverter device, wherein the first correction circuit includes a comparator that outputs a signal when the deviation output from the bias magnetizing detection unit becomes larger than a predetermined value, and the comparator. It is composed of a pulse generator that outputs a pulse signal based on the output of the comparator, and an integrator that integrates the pulse signal output by the pulse generator.

[0016]

According to the first aspect of the invention, the inverter circuit converts the DC voltage into the AC voltage, the inverter transformer receives the output of the inverter circuit and outputs the compensation power, and the bias magnetizing detection unit includes the inverter transformer. Deviation corresponding to the bias magnetic component of the above, the first correction circuit generates a correction signal for a stationary component of the deviation detected by the bias magnetic detection unit, and delays and outputs the correction signal. , The second correction circuit generates a correction signal for a transient component of the deviation detected by the bias magnetic detection unit, and the adder outputs the output of the first correction circuit and the output of the second correction circuit. And the control circuit generates the control signal of the inverter circuit based on the output of the adder, and the amplifier drives the inverter circuit based on the output of the control circuit.

In a second aspect of the present invention, the first current detector of the magnetic bias detecting section detects the primary side output of the inverter transformer, and the second current detector is the inverter transformer. The secondary output is detected, and the subtractor obtains the deviation corresponding to the biased magnetic component based on the output of the first current detector and the output of the second current detector.

According to the third aspect of the invention, the first voltage detector of the magnetic bias detecting section detects the primary side output of the inverter transformer, and the second voltage detector is the inverter transformer. The secondary side output is detected, the subtractor obtains the deviation corresponding to the bias magnetic component based on the output of the first voltage detector and the output of the second voltage detector, and the filter circuit outputs the deviation. The low frequency component of the deviation is extracted.

According to a fourth aspect of the invention, the magnetic flux detector of the magnetic bias detecting section detects the magnetic flux of the iron core corresponding to the magnetic bias of the inverter transformer, and the filter circuit outputs a low frequency signal from the magnetic flux detector. Extract the ingredients.

In the invention of claim 5, the inverter circuit converts the DC voltage into the AC voltage, and the inverter transformer receives the output of the inverter circuit and outputs the compensation power.
The first bias magnetic detection unit and the second bias magnetic detection unit obtain a deviation corresponding to the bias magnetic component of the inverter transformer, and the first correction circuit detects the deviation detected by the first bias magnetic detection unit. A correction signal for a stationary component of the two components is generated, the correction signal is delayed and then output, and a second correction circuit for a transient component of the deviation detected by the second bias detection unit. A correction signal is generated, an adder combines the output of the first correction circuit and the output of the second correction circuit, and the control circuit generates the control signal of the inverter circuit based on the output of the adder. An amplifier drives the inverter circuit based on the output of the control circuit.

In a sixth aspect of the present invention, the first voltage detector of the first magnetic bias detecting section detects the primary side output of the inverter transformer, and the second voltage detector detects the inverter transformer. The secondary side output of the voltage detector, the subtractor obtains the deviation between the output of the first voltage detector and the output of the second voltage detector, and the filter circuit reduces the deviation output by the subtractor. A frequency component is extracted, the first current detector of the second bias magnetic detection unit detects the primary side output of the inverter transformer,
The second current detector detects the secondary side output of the inverter transformer, and the subtractor obtains the deviation between the output of the first current detector and the output of the second current detector.

According to a seventh aspect of the present invention, the magnetic flux detector of the first magnetic bias detector detects the magnetic flux corresponding to the magnetic bias of the iron core of the inverter transformer, and the filter circuit outputs the magnetic flux detector. Of the inverter transformer, the first current detector of the second bias detection unit detects the primary side output of the inverter transformer, and the second current detector detects the low-frequency component of the inverter transformer. The secondary output is detected, and the subtractor obtains the deviation between the output of the first current detector and the output of the second current detector.

In the eighth aspect of the present invention, the comparator of the first correction circuit outputs a signal when the deviation output from the bias magnetizing detection unit becomes larger than a predetermined value, and the pulse generator Outputs a pulse signal based on the output of the comparator, and an integrator integrates the pulse signal output by the pulse generator.

[0024]

【Example】

Example 1. An inverter device according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of the inverter device according to the first embodiment. In the figure, 1 is a 3-phase AC system busbar, 2 is a predetermined 3-phase AC system busbar 1
A reference circuit that generates reference values for system voltage, load current, etc.
3 is a system voltage of the 3-phase AC system bus 1, a current detector (CT) that detects a load current, 4 is a reference value output by the reference circuit 2 and a system voltage of the 3-phase AC system bus 1 output by CT 3,
The inverter circuit 1 is a current control circuit that compares the load current and the like to perform an operation to generate an output voltage reference of the inverter device.
A carrier triangular wave reference for generating a signal serving as a reference for generating a pulse for controlling 0, 6 is a comparator for comparing the output voltage reference of the inverter device with the reference carrier triangular wave, and 7 is based on the comparison result of the comparator 6. A logic circuit that generates a pulse that controls the power semiconductor element of the inverter circuit 10, 8 is a pulse amplifier that amplifies the control pulse that is generated by the logic circuit 7 and drives the inverter circuit 10, and 9 is a DC that stores a DC voltage. A capacitor 10 is composed of a power semiconductor such as a GTO thyristor, and an inverter circuit for converting the DC voltage stored in the DC capacitor 9 into an AC voltage. 11 is an AC voltage converted by the inverter device 10.
It is an inverter transformer that supplies the phase alternating current system bus 1.

Further, 12 is a current detector (DCCT) for measuring and outputting the secondary side current of the inverter transformer 11, 13
Is a subtracter for obtaining the difference between the output of CT3 and the output of DCCT12, 14 is an amplifier for amplifying the output of the subtractor 13, and 15
Is a DC bias generator for adjusting the offset output of the amplifier 14 during normal operation, 16 is an adder that adds the output of the amplifier 14 and the output of the DC bias generator 15, and 17 is based on the output of the adder 16. A comparator for determining whether the eccentric current exceeds a predetermined constant value,
18 is an inverter transformer 11 based on the output of the comparator 17.
When the imbalance between the positive polarity portion and the negative polarity portion of the output voltage of is larger than a predetermined reference, a pulse generator that outputs a pulse of a predetermined positive or negative constant amplitude and a constant duration, An integrator which integrates the output of the pulse generator 18 to convert it into a DC signal and delays and outputs it
20 is a filter circuit for extracting a steep and transient component of the bias magnetic component from the output of the adder 16, 21 is an integrator 19
Of the output of the filter circuit 20 and the output of the filter circuit 20,
An adder 22 adds the output of the current control circuit 4 and the output of the adder 21.

In FIG. 1, the portion surrounded by the alternate long and short dash line, that is, the direct current detector 12, the subtractor 13, the amplifier 14,
The DC bias generator 15, the adder 16, the comparator 17, the pulse generator 18, the integrator 19, the filter circuit 20, the adder 21, and the adder 22 are bias magnetic compensators. Further, the comparator 17, the pulse generator 18, and the integrator 19 are a first correction circuit for generating a correction signal of a stationary component of the bias magnetic field, and the filter circuit 20 is a transient component of the bias magnetic field. 2 is a second correction circuit for generating the correction signal of.

Next, the operation will be described. The inverter device of FIG. 1 includes a comparator 17, a pulse generator 18, and an integrator 1.
The steady bias magnetism is detected by 9 while the filter circuit 2
When 0, a transient magnetic bias is detected. For both the steady magnetic bias and the transient magnetic bias, the magnetic bias compensation is performed based on the signal added by the adder 21.

First, the operation in the case of compensating for the steady demagnetization will be described. As a premise of the operation, in the inverter device of FIG. 1, in a normal (non-biased) operating state, the deviation between the primary side current and the secondary side current of the inverter transformer 11 obtained as the output of the amplifier 14 is It has been corrected. That is, the subtractor 1 in the normal state
3. The DC bias generator 15 is adjusted so that the deviation between the primary side current and the secondary side current obtained by the amplifier 14 becomes zero at the output of the adder 16.

In this case, when a steady demagnetization occurs, an imbalance between the positive peak value and the negative peak value in the output corresponding to the current deviation of the adder 16 is generated as shown in FIG. Occurs (in the figure, it gradually demagnetizes to the negative side). This figure shows the waveform without bias correction, and since the bias magnetism accumulates and increases, it cannot be ignored even if a slight steady-state bias magnetism occurs.

Therefore, the comparator 17 detects that the imbalance between the positive peak value and the negative peak value of the output of the adder 16 becomes larger than a predetermined value due to the steady demagnetization, Then, the pulse generator 18 receives the output of the comparator 17 and generates a pulse of a predetermined constant level and a predetermined width so as to balance the positive and negative voltage-time products and correct the bias magnetization. The output of the inverter circuit 10 is controlled slowly. That is, when the pulse generator 18 sets the deviation current output from the adder 16 to Ip and the peak current which is a predetermined threshold value for determining that a steady magnetic deviation has occurred, to I ₁ , A constant pulse is generated by the following equations (1) to (3).

When Ip> I ₁ , pulse generation of level A ₁ (pulse width is T time) (1) When Ip <−I ₁ pulse generation of level −A ₁ (pulse width is T time) (2) − When I ₁ ≦ Ip ≦ I _{1 No} pulse is generated (3) However, the pulse amplitude A ₁ and the pulse width T are predetermined.

The output pulse of the pulse generator 18 is integrated in the integrator 19, delayed and converted into a constant value, and then added by the adder 21 as a steady bias magnetic correction signal.
Is output to. Here, the delay is performed for a time corresponding to several tens of cycles of the signal.

Here, the comparator 17, the pulse generator 18,
The reason why the steady correction amount of the demagnetization is obtained by the integrator 19 is as follows. In the case of a steady magnetic demagnetization caused by the imbalance of the positive and negative voltage products of the output voltage, the magnetic flux is gradually saturated over a plurality of cycles according to the hysteresis characteristic of the inverter transformer 11. In such a case, it is necessary to detect a steady sign of demagnetization (gradual change of the center of the hysteresis cycle) and correct the demagnetization before the magnetic flux is saturated. Further, at this time, if the demagnetization correction is suddenly performed, the control cannot be stabilized due to overcorrection, and thus the control needs to be delayed. Therefore, as shown in FIG. 1, a combination of the pulse generator 18 and the integrator 19 causes a slight correction when a slight bias occurs, and if an improvement is found as a result, the correction is left as it is (the correction value is kept) and the improvement is made. If is not seen, control is performed so that the correction amount is further increased (pulse is generated). As described above, even if the magnetic bias is generated once, the magnetic bias is gradually corrected by delaying the magnetic field by several seconds (several tens of cycles of the signal) and performing the stepwise control.

Next, the adder 21 adds the steady-state bias magnetic compensation signal output from the integrator 19 and the transient bias magnetic compensation signal output from the filter circuit 20 to be described later when there is a transient change, and the adder 21 22 is output. The adder 22 adds the bias magnetic compensation signal of the adder 21 and the output of the current control circuit 4 to shift the voltage reference output from the current control circuit 4 to a polarity capable of compensating for the bias ( (Fig. 4). That is, in the case of compensating for the steady magnetic deviation, the adder 2
2 is a normal voltage reference signal (FIG. 4 (a))
It is offset corresponding to the output (s ₁ ) of 9 ((b) in the same figure). The dotted line in FIG. 7B is the voltage reference signal when no correction is made.

The output voltage reference output from the adder 22 is output to the comparator 6 as in the case of the conventional example. In the comparator 6, the inverter output voltage reference is compared with the reference carrier triangular wave output from the carrier triangular wave reference 5 and converted into a signal serving as a reference for turning on / off the power semiconductor element of the inverter circuit 10. The logic circuit 7 generates a predetermined pulse signal based on the output of the comparator 6. The pulse amplifier 8 amplifies this pulse signal and then supplies it to the gate of a power semiconductor element such as a GTO thyristor of the inverter circuit 10.

The inverter circuit 10 turns on / off the output of the DC capacitor 9 based on the output of the pulse amplifier 8,
The DC voltage stored in the DC capacitor 9 is converted into a rectangular wave AC voltage approximated to the inverter output voltage reference, and the AC voltage is supplied to the three-phase AC system bus 1 via the inverter transformer 11. At this time, the output voltage of the inverter transformer 11 is 3
When the voltage is larger than the voltage of the phase AC system bus 1 and the reactive power is compensated for when the voltage is smaller than the voltage of the phase AC system bus 1, and when the voltage is smaller than the voltage of the phase AC system bus 1, the inverter device of FIG. Can be compensated,
As shown in FIG. 3, the peak value of the output of the adder 16 is -I ₁
Since the exciting current of the inverter transformer 11 is controlled so as to fall within the range from + I ₁ to + I ₁ , it is possible to compensate the steady bias magnetism.

Next, the operation of transient magnetic bias compensation will be described. When the demagnetization due to abrupt load change or the like occurs, the exciting impedance sharply decreases, so that a sudden demagnetizing current flows in the output of the DC current detector 12 as shown in FIG. Then, the device becomes an overcurrent state in an attempt to compensate for this abrupt demagnetization current, and normal operation cannot be performed. Therefore, we immediately compensate for this transient magnetic demagnetization,
It is necessary to compensate the bias before the overcurrent.

When the magnetic bias is generated due to the transient change, the filter circuit 20 detects only the sudden magnetic bias current component (transient magnetic bias current component) from the output of the adder 16. The adder 21 adds the transient magnetic bias current component output from the filter circuit 20 and the steady magnetic bias current component output from the integrator 19, and then outputs the result to the adder 22. The output of the adder 22 is, for example, as shown in FIG.
It is corrected for a part of one cycle of the signal so as to be able to compensate for the sudden demagnetization. Since the operation of the comparator 6 and below is the same as that in the case of performing steady-state bias magnetic compensation,
The description is omitted.

As described above, according to the first embodiment, the comparator 17, the pulse generator 18, and the integrator 19 gently compensate for the steady demagnetization, and the filter circuit 2 is used.
Since 0 is used to compensate for transient bias magnetization, steady bias,
It is possible to perform more effective compensation for any transient magnetic demagnetization, and it is possible to continue operation stably without overcurrent. In addition, the steady demagnetization can be gently compensated, and the operating point in the hysteresis curve can be centered, resulting in a transient demagnetization due to load fluctuation, etc. compared to the case where only transient compensation is performed. Even in this case, the saturation of the magnetic flux of the inverter transformer is unlikely to occur, and the overcurrent of the inverter device does not occur.

Example 2. In the first embodiment described above, the primary side current and the secondary side current of the inverter transformer 11 are used to obtain the deviation due to the bias magnetism, but the present invention is not limited to this, and the primary side voltage and the secondary side current of the inverter transformer 11 are used. The secondary voltage may be used. The configuration of the second embodiment is shown in FIG.

In the figure, reference numeral 23 is an inverter transformer 1.
1 is a voltage detector (PT) for detecting the primary side voltage, 24 is a voltage detector (DCPT) for detecting the secondary side voltage of the inverter transformer 11, and 25 is a low frequency component extracted from the output of the subtractor 13. It is a filter circuit that does. The three-phase AC system busbars 1, ..., And the adder 22 are the same as those shown in FIG. The operation waveforms of the respective parts are the same as those in the first embodiment.

The operation of the inverter apparatus of FIG. 5 is the same as that of the inverter apparatus of FIG. 1 except that the difference between the primary side voltage and the secondary side voltage of the inverter transformer 11 is used as the deviation. That is, PT23 finds the voltage on the side of the three-phase AC system bus 1, DCPT24 finds the voltage on the side of the inverter circuit 10, finds these deviations by the subtracter 13, and further uses the filter circuit 25 to find the low-frequency portion of the deviations. To detect. The deviation output from the filter circuit 25 is output to the amplifier 14.

In the inverter device, when the exciting voltage of the inverter transformer 11 has a direct current component (DC component),
By accumulating this DC component, the operating point on the hysteresis curve moves from the center, and steady demagnetization occurs. By the way, according to the configuration of FIG. 5, the DC component of the voltage of the inverter transformer 11 can be measured more accurately than in the case of the first embodiment, so that the symptom of steady magnetic bias can be caught earlier. By controlling the DC component so that it does not flow, it is possible to control the bias current due to the bias and the overcurrent before they flow.

As described above, according to the second embodiment, the accuracy of detecting the direct current component of the steady deviation is improved, so that the steady bias magnetic compensation is more effective than the case of the first embodiment. You can do it.

Example 3. In the second embodiment, the voltage detector is used for the voltage measurement for obtaining the deviation, but the present invention is not limited to this, and a search coil may be used. The structure of the third embodiment is shown in FIG.

In the figure, 26 is an inverter transformer 1.
The search coil is provided in the iron core in 1 and detects the magnetic flux of the iron core. The three-phase AC system busbars 1, ..., And the adder 22 are the same as those shown in FIG. The operation waveforms of the respective parts are the same as those in the first embodiment.

The operation of the inverter device of FIG. 6 is the same as that of the inverter device of FIG. 5 except that the magnetic flux of the iron core of the inverter transformer 11 detected by the search coil 26 is used as the deviation. That is, the search coil 26 outputs a voltage corresponding to the magnetic flux of the iron core of the inverter transformer 11, and the filter circuit 25 detects the low frequency component of the output of the search coil 26. The deviation output from the filter circuit 25 is output to the amplifier 14.

As described above, according to the third embodiment, the search coil 2 provided on the iron core in the inverter transformer 11 is described.
Since 6 is used, the control can be performed based on the actual magnetic flux level to improve the accuracy, and the current detector and the voltage detector required in the first and second embodiments are not required, and the device can be downsized. Can be achieved.

Example 4. In the first to third embodiments described above, the comparator 17, the pulse generator 18, the integrator 19 for correcting the steady demagnetization, and the filter circuit 20 for correcting the transient demagnetization are provided. Although a common signal is supplied to each of them, these signals may be signals by different means. The structure of the fourth embodiment is shown in FIG.

In the figure, the three-phase AC system bus bar 1, ...
The filter circuit 25 is the same as that shown in FIGS. In the operation of the inverter device of FIG. 7, in order to correct the steady demagnetization, the deviation due to PT23 and DCPT24 is input to the comparator 17 via the filter circuit 25, while the transient demagnetization is corrected. For CT3 and D
The operation is the same as that of the inverter device of FIGS. 1 and 5, except that the deviation due to the CCT 12 is input to the filter circuit 20 via the amplifier 14b (not via the filter circuit 25).

As described above, according to the fourth embodiment, the steady bias compensation is performed based on the output of the voltage detector capable of accurately detecting the DC component of the voltage, and the transient bias compensation is performed. Since it is performed based on the output of the current detector, it is possible to improve the compensation accuracy for steady-state bias magnetization while performing effective compensation even when a bias-change current with a transient change flows.

Example 5. In addition, although the fourth embodiment is a combination of the first embodiment and the second embodiment, it may be a combination of the first embodiment and the third embodiment. The structure of the fifth embodiment is shown in FIG.

In the figure, the three-phase AC system bus bar 1, ...
The filter circuit 25 is the same as that shown in FIGS. In the operation of the inverter device of FIG. 8, the magnetic flux signal from the search coil 16 is input to the comparator 17 via the filter circuit 25 in order to correct the steady magnetic bias.
On the other hand, in order to correct the transient demagnetization, CT3 and DCC
The operation is similar to that of the inverter device of FIGS. 1 and 6, except that the deviation due to T12 is input to the filter circuit 20 via the amplifier 14b (not via the filter circuit 25).

As described above, according to the fifth embodiment, the steady bias compensation is performed on the basis of the output of the search coil capable of accurately detecting the DC component of the voltage, and the transient bias compensation is performed by the current. Since it is performed based on the output of the detector, it is possible to improve the compensation accuracy for steady-state bias magnetization while performing effective compensation even when a bias-change current with a transient change flows. Further, as compared with the case of the fourth embodiment, the parts of the voltage detector are unnecessary, the number of parts can be reduced, and the device can be downsized.

[0055]

As described above, according to the first aspect of the present invention, among the deviation detected by the deviation detecting unit for obtaining the deviation corresponding to the deviation component of the inverter transformer, and the deviation detected by the deviation detecting unit. A first correction circuit for generating a correction signal for a stationary component and delaying and outputting the correction signal;
A second correction circuit for generating a correction signal for a transient component of the deviation detected by the bias magnetic detection unit;
Adder for synthesizing the output of the correction circuit and the output of the second correction circuit, a control circuit for generating a control signal of the inverter circuit based on the output of the adder, and the above based on the output of the control circuit. Since it has an amplifier that drives the inverter circuit, it can compensate for both steady and transient bias magnetism, and prevents overcurrent due to bias magnetism of the inverter transformer and stabilizes it. You can drive.

According to a second aspect of the present invention, the bias magnetic detection section includes a first current detector for detecting the primary side output of the inverter transformer and a secondary side output of the inverter transformer. Since it is composed of a second current detector for detecting the difference and a subtractor for obtaining the deviation between the output of the first current detector and the output of the second current detector, Both bias and transient bias can be compensated.

Further, according to the invention of claim 3, the bias detecting section includes a first voltage detector for detecting a primary side output of the inverter transformer, and a secondary side output of the inverter transformer. A second voltage detector for detecting the difference, a subtractor for obtaining a deviation between the output of the first voltage detector and the output of the second voltage detector, and a low-frequency component of the deviation output by the subtractor. Since it is composed of a filter circuit for extracting the steady state, it is possible to catch the symptom of steady-state bias magnetization early, and to perform steady-state bias magnetic compensation more effectively.

Further, according to the invention of claim 4, the magnetic bias detector detects the magnetic flux detector for detecting the magnetic flux of the iron core of the inverter transformer and the low frequency component of the output of the magnetic flux detector. Since it is composed of the filter circuit, the measurement accuracy of the eccentricity is improved, the eccentricity compensation can be appropriately performed, and the apparatus can be downsized.

According to the fifth aspect of the present invention, the first bias magnetic detection unit and the second bias magnetic detection unit for obtaining the deviation corresponding to the bias magnetic component of the inverter transformer, and the first bias magnetic A first correction circuit that generates a correction signal for a stationary component of the deviation detected by the detection unit and outputs the correction signal after delaying the correction signal; and a deviation detected by the second bias magnetic detection unit. A second correction circuit for generating a correction signal for the transient component, an adder for combining the output of the first correction circuit and the output of the second correction circuit, and an output of the adder. Based on the control circuit that generates a control signal for the inverter circuit based on the above, and the amplifier that drives the inverter circuit based on the output of the control circuit, the bias magnetic field for both the steady magnetic bias and the transient magnetic bias. Can compensate accurately

According to the invention of claim 6, the first
A first voltage detector for detecting the primary side output of the inverter transformer, a second voltage detector for detecting the secondary side output of the inverter transformer, and the first bias detector. And a filter circuit for extracting the low frequency component of the deviation output from the subtracter, and the second circuit. The subtractor for calculating the deviation between the output of the second voltage detector and the output of the second voltage detector. A first current detector for detecting a primary side output of the inverter transformer, a second current detector for detecting a secondary side output of the inverter transformer, and the first bias detector. Since it is composed of a subtractor that obtains a deviation between the output of the current detector and the output of the second current detector,
It is possible to accurately perform bias compensation for both steady and transient bias, and it is possible to catch signs of steady bias earlier, and steady bias compensation is more effective. Can be done

According to the invention of claim 7, the first
Of the magnetic flux detector that detects the magnetic flux of the iron core of the inverter transformer and a filter circuit that extracts the low-frequency component of the output of the magnetic flux detector,
A second current detector for detecting the primary side output of the inverter transformer, a second current detector for detecting the secondary side output of the inverter transformer, Since it is composed of a subtracter that obtains the deviation between the output of the first current detector and the output of the second current detector, compensation for eccentricity is performed for both steady eccentricity and transient eccentricity. In addition to being able to perform accurately, the measurement accuracy of the eccentricity can be improved, the eccentricity can be accurately compensated, and the device can be downsized.

According to the invention of claim 8, the first
Compensation circuit, a comparator that outputs a signal when the deviation output by the bias detection unit becomes larger than a predetermined value, and a pulse generator that outputs a pulse signal based on the output of the comparator Since it is composed of an integrator that integrates the pulse signal output from the pulse generator, it is possible to perform appropriate correction with a simple configuration.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an inverter device according to a first embodiment of the present invention.

FIG. 2 is a waveform diagram for explaining the operation of the inverter device according to the first embodiment of the present invention.

FIG. 3 is a waveform diagram for explaining the operation of the inverter device according to the first embodiment of the present invention.

FIG. 4 is an example of a voltage reference according to the first embodiment of the present invention.

FIG. 5 is a configuration diagram of an inverter device according to a second embodiment of the present invention.

FIG. 6 is a configuration diagram of an inverter device according to a third embodiment of the present invention.

FIG. 7 is a configuration diagram of an inverter device according to a fourth embodiment of the present invention.

FIG. 8 is a configuration diagram of an inverter device according to a fifth embodiment of the present invention.

FIG. 9 is a configuration diagram of a conventional inverter device.

[Explanation of symbols]

3 Current detector (CT), 11 Inverter transformer, 1
2 DC current detector (DCCT), 13 Subtractor, 14
Amplifier, 17 comparator, 18 pulse generator, 19
Integrator, 20 filter circuit, 21 adder, 22 adder, 23 voltage detector (PT), 24 direct current voltage detector (DCPT), 25 filter circuit, 26 search coil.

Claims (8)

[Claims] 1. An inverter circuit that converts a DC voltage into an AC voltage, an inverter transformer that receives the output of the inverter circuit and outputs compensation power, and a bias that determines a deviation corresponding to a biased magnetic component of the inverter transformer. A magnetic detection unit, a first correction circuit that generates a correction signal for a stationary component of the deviation detected by the bias detection unit and delays the correction signal before outputting the correction signal; and the bias detection unit A second correction circuit for generating a correction signal for a transient component of the deviation detected by the above; an adder for combining the output of the first correction circuit and the output of the second correction circuit; An inverter device comprising: a control circuit that generates a control signal for the inverter circuit based on the output of an adder; and an amplifier that drives the inverter circuit based on the output of the control circuit. 2. The bias magnetic detection unit includes a first current detector for detecting a primary side output of the inverter transformer, and a second current detector for detecting a secondary side output of the inverter transformer. 3. The inverter device according to claim 1, further comprising: a subtractor that obtains a deviation between the output of the first current detector and the output of the second current detector. 3. The bias magnetic detection unit includes a first voltage detector for detecting a primary side output of the inverter transformer, and a second voltage detector for detecting a secondary side output of the inverter transformer. And a subtractor for obtaining a deviation between the output of the first voltage detector and the output of the second voltage detector, and a filter circuit for extracting a low frequency component of the deviation output by the subtractor. The inverter device according to claim 1, wherein: 4. The magnetic bias detector comprises a magnetic flux detector for detecting a magnetic flux of an iron core of the inverter transformer, and a filter circuit for extracting a low frequency component of an output of the magnetic flux detector. The inverter device according to claim 1, which is characterized in that. 5. An inverter circuit for converting a DC voltage into an AC voltage, an inverter transformer for receiving the output of the inverter circuit and outputting a compensation power, and a deviation corresponding to a biased magnetic component of the inverter transformer. The first bias magnetic detection unit and the second bias magnetic detection unit, and after generating a correction signal for a stationary component of the deviation detected by the first bias magnetic detection unit and delaying the correction signal, A first correction circuit for outputting, a second correction circuit for generating a correction signal for a transient component of the deviation detected by the second bias detection unit, and an output of the first correction circuit An adder that combines the output of the second correction circuit, a control circuit that generates a control signal of the inverter circuit based on the output of the adder, and an amplifier that drives the inverter circuit based on the output of the control circuit. When Inverter device equipped with. 6. The first bias detection section includes a first voltage detector for detecting a primary side output of the inverter transformer,
A second voltage detector for detecting the secondary side output of the inverter transformer, a subtractor for obtaining a deviation between the output of the first voltage detector and the output of the second voltage detector, and the subtraction And a filter circuit for extracting the low-frequency component of the deviation output from the detector, and the second bias magnetizing section comprises:
A first current detector for detecting a primary side output of the inverter transformer, a second current detector for detecting a secondary side output of the inverter transformer, and an output of the first current detector The inverter device according to claim 5, comprising a subtractor for obtaining a deviation from the output of the second current detector. 7. The first bias magnetic detection unit is composed of a magnetic flux detector that detects a magnetic flux of an iron core of the inverter transformer, and a filter circuit that extracts a low frequency component of an output of the magnetic flux detector. At the same time, the second bias magnetic detection unit includes a first current detector that detects a primary output of the inverter transformer and a second current detector that detects a secondary output of the inverter transformer. 6. The inverter device according to claim 5, wherein the inverter device comprises a power supply unit and a subtracter for obtaining a deviation between the output of the first current detector and the output of the second current detector. 8. The first correction circuit includes a comparator that outputs a signal when the deviation output from the magnetic bias detection unit becomes larger than a predetermined value, and a pulse based on the output of the comparator. 8. The inverter device according to claim 1, comprising a pulse generator that outputs a signal and an integrator that integrates the pulse signal output by the pulse generator.