JP3462347B2 - Control device for variable speed generator motor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a variable speed generator / motor which excites a secondary circuit of a wire wound induction machine with an alternating current to control electric power on the primary side, and is particularly expensive and has a large DC cutoff. The present invention relates to a control device for a variable-speed generator-motor, which is capable of interrupting a ground fault current with a small and inexpensive AC breaker without using a switch.

[0002]

2. Description of the Related Art FIG. 8 is a circuit diagram showing a configuration example of a control device for a variable speed pumped storage generator motor of this type. In FIG. 8, the primary side of the wound-rotor induction machine 1 is connected to the power system 3 via the circuit breaker 2.

Further, the inverter 4 includes diodes 1D ...
6D, GTO elements 1G to 6G, and a capacitor 5 are connected as shown in the figure, and a direct current is converted into a three-phase alternating current having a variable frequency, and a secondary current is supplied to the secondary winding of the winding induction machine 1. Output.

Further, the DC power supply 6 includes diodes 7D ...
12D, GTO elements 7G to 12G, and the transformer 7 are connected as shown in the figure, and are connected to the power system 3,
DC voltage is supplied to the inverter 4.

On the other hand, the grid voltage phase detector 8 detects the grid voltage phase of the power grid 3. Further, the rotor phase detector 9 detects the rotor phase of the wound-rotor induction machine 1. Furthermore, the ground fault detector 10 detects that a ground fault has occurred in the power system 3.

Furthermore, the inverter control device 11 is
The inverter 4 is controlled based on the outputs from the system voltage phase detector 8, the rotor phase detector 9, and the ground fault detector 10,
The secondary current of the wound-rotor induction machine 1 is controlled.

A series circuit of a GTO element 13G and a discharge resistor 13 is connected between the DC power source 6 and the inverter 4 as shown in the figure. FIG. 9 is a block diagram showing a configuration example of a conventional phase control circuit.

In FIG. 9, the voltage is detected from the power system 3, and the system voltage phase detector 8 detects the system voltage phase θ _L of the power system 3. Further, the rotor phase detector 9 detects the rotor phase θ _r of the wound-rotor induction machine 1.

Further, the subtractor 22 subtracts the rotor phase θ _r Or from the system voltage phase θ _L to obtain the difference between the two,
Obtain the secondary current phase reference θ _2s . Then, this secondary current phase reference θ _2s is input to the secondary current controller 12 included in the inverter control device 11, and the secondary current controller 12 _{sets the} secondary current phase reference θ _2s to the phase difference angle based on the target power. α is added to control the phase of the secondary current of the wound-rotor induction machine 1.

Now, the angular velocity of the electric power system 3 is ω _L , the angular velocity of the primary voltage of the winding induction machine 1 is ω ₁ , the rotational angular velocity of the winding induction machine 1 is ω _r , and the secondary current of the winding induction machine 1 is If the angular velocity of is ω ₂ , the relationship of ω ₁ = ω _r + ω ₂ is established. Therefore, if ω ₂ is controlled so that ω ₂ = ω _L −ω _r , ω ₁ = ω _L and the winding induction The primary voltage of the machine 1 is synchronized with the system voltage.

[0011] Thus, even if the rotational angular velocity of the wound induction machine 1 is omega _r changes constantly by controlling the omega ₂ so that ω ₂ = ω _L -ω _r, of wound induction machine 1 Operation is possible even if the rotation speed of the rotor changes.

Due to this variable speed operation, the AFC during pumping
It becomes possible to operate, and the power generation efficiency can be improved by operating at the optimum speed. On the other hand, in order to control the electric power on the primary side of the wound-rotor induction machine 1, it is necessary to maintain the above-described relationship of angular velocities and establish the following relationship in phase.

The phase of the power system 3 voltage in the reference phase (for example, U phase) is θ _L , the rotor phase (electrical angle from the reference position) is θ _r , and the phase of the secondary current in the reference phase (for example, U phase) is When theta _2, the no-load operation, θ _L = θ ₂ + θ
The phase of θ ₂ needs to be controlled so that the relationship of _r is maintained.

That is, the secondary current phase of the wire wound induction machine 1 is controlled so that θ ₂ = θ _L −θ _r . Then, during load operation, assuming that the phase difference angle is α, θ ₂ = θ _L −
By setting θ _r + α and controlling α according to the target load amount or the target input amount, the load and the input control can be performed.

Θ ₂ during no-load operation is the secondary current phase reference θ
_{If 2s} , then θ _2s = θ _L −θ _r and θ ₂ = θ _2s + α. The secondary current phase reference θ _2s is the output voltage phase generated on the primary side when the winding type induction machine 1 is excited by the secondary current,
It is a phase value required to maintain synchronization with the system voltage phase, and the input / output power of the wound-rotor induction motor 1 can be controlled by adding the phase difference angle α with reference to this value.

By the way, in the above configuration, when a ground fault of two or more phases occurs in the power system 3, a large short-circuit current flows to the primary side of the wire wound induction machine 1. in this case,
The system protection device (not shown) detects a ground fault and opens the breaker in the path leading to the short-circuit point, thereby cutting off the short-circuit current and protecting the equipment.

FIG. 10 is a diagram showing the states of the primary and secondary currents of the winding-type induction machine 1 and the voltage of the DC power supply 6 when the system faults. In FIG. 10, (a) shows the primary current I ₁ ,
(B) shows the movement of the secondary current I ₂ , and (c) shows the movement of the DC power supply 6 voltage V _D. Further, t ₀ is a ground fault occurrence time, t _0
1 indicates the time when the circuit breaker opens.

That is, when the ground fault point is far from the winding induction machine 1, the impedance of the power transmission line causes the primary voltage drop at the end of the winding induction machine 1 at the time of occurrence of a ground fault to be small. When the junction point is close to the wire wound induction machine 1,
The voltage drop is large and almost zero.

As described above, in order to carry out the variable speed operation, it is necessary to control θ _2s = θ _L −θ _r . Therefore, θ _L is controlled by the system voltage phase detector 8 from the power system 3 to θ _r is obtained from the rotor phase detector 9.

When the ground fault point is close to the wound induction machine 1,
Since the system voltage becomes almost zero due to the ground fault, θ _L cannot be detected. Therefore, the secondary current phase reference θ _2s cannot be created and the synchronous operation cannot be performed.
Have to stop.

When the inverter 4 is stopped, the secondary winding current I _{2 of the} wound-type induction machine 1 is reduced, so that the electromotive voltage generated on the primary side is greatly reduced, and the alternating current component of the primary current I ₁ is reduced. The waveform is almost only the transient DC component.

This state is shown in FIG. Figure 10
In FIG. 10A, the dotted line is a waveform when it is assumed that the secondary current I ₂ continues to flow as shown by the dotted line in FIG. 10B. On the other hand, when a ground fault occurs, in the secondary circuit of the wound-rotor induction machine 1, an overvoltage is generated in the secondary winding due to the influence of the transient direct current component on the primary side, and a current is passed through the diodes 1D to 6D inside the inverter 2 to the capacitor 5 To the DC power supply voltage V _D.

If the secondary circuit has an overvoltage exceeding the specified value, the secondary winding of the wound induction machine 1 and the GTO element may be damaged. Therefore, in order to suppress the voltage rise within the specified value, By operating the GTO element 13G, a current is passed through the discharge resistor 13 to suppress the voltage rise.

In FIG. 10C, GS represents a control signal for the GTO element 13G. GTO element O at high signal level
When the signal level is low, the GTO element is turned off. When the DC voltage V _D exceeds a specified value, the GTO element 13G is turned on by a DC power supply voltage detector (not shown), and the discharge resistor 13
Through this, the charge of the capacitor 5 is discharged and the voltage drops.
When the DC voltage V _D drops below a specified value, the GTO element 13
G is turned off, the discharge stops and the voltage rises again,
When the specified value is exceeded again, the GTO element 13G is turned on and the operation of lowering the voltage by discharging is repeated.

[0025]

As described above, when a ground fault occurs in the power system 3, the system voltage drops, which makes phase control in variable speed control difficult.
The DC power supply 6 voltage becomes an overvoltage and the inverter 4 GTO
The inverter 4 must be stopped because the operating conditions at the time of switching the elements 1G to 6G cannot be maintained within the ratings.

Therefore, the secondary current of the wound-rotor induction machine 1 decreases, that is, the electromotive voltage of the primary-side wound-rotor induction machine 1 decreases, and the AC component of the primary-side current decreases, so that the primary current becomes zero. It will not cross. An AC circuit breaker is generally used for system fault protection, but there is a problem that the ground current cannot be cut off because the primary current does not cross zero.

Therefore, it is possible to cut off the ground fault current by using a DC breaker, but this is very expensive and large in size, which is not economical. As described above, in the conventional control device for a variable speed generator-motor, when a ground fault occurs in the power system, the inverter must be stopped, and an expensive and large DC circuit breaker must be used. There was a problem that it was impossible to cut off the junction current.

An object of the present invention is to provide a control device for a variable speed generator motor capable of interrupting a ground fault current with a small and inexpensive AC circuit breaker without using a particularly expensive and large DC circuit breaker. To provide.

[0029]

In order to achieve the above-mentioned object, control of a variable speed generator-motor for controlling a secondary current of a secondary winding of a winding type induction machine having a primary winding connected to a power system. In the apparatus according to claim 1, the system voltage phase detecting means for detecting the system voltage phase of the power system, the rotor phase detecting means for detecting the rotor phase of the wire wound induction machine, and the system voltage phase detection. Secondary current phase calculating means for determining a phase reference of a secondary current, which is a voltage in which the primary voltage of the wound induction motor is synchronized with the system voltage, based on the output of the means and the output of the rotor phase detecting means; Secondary current control means for controlling the phase of the secondary current of the wound-type induction machine based on the secondary current phase reference determined by the secondary current phase calculation means, and detection of occurrence of a ground fault in the power system Ground fault detection means, differentiating means, Of the differentiating means, the proportional integrating means for integrating the output of the proportional integrating means, the integrating means for integrating the output of the proportional integrating means, and the difference output between the output of the integrating means which is a phase feedback value and the output of the system voltage phase detecting means. When a ground fault occurs in the power system, the output of the proportional integrator is set to a value immediately before the occurrence of the ground fault when the ground fault occurs in the power system. When the ground fault occurs, the input to the secondary current phase calculation means is switched from the output of the system voltage phase detection means to the phase feedback value of the PLL control means to control the secondary current of the wire wound induction machine. I am trying to do.

Therefore, in the control device for the variable speed generator-motor of the invention according to claim 1, when the ground fault occurs in the power system, the output of the proportional-plus-integral means in the PLL control means is held at the value immediately before the occurrence of the ground fault. However, during the occurrence of a ground fault, by controlling the secondary current of the wire wound induction machine with the phase calculated by the output of the held proportional-plus-integral means, even if the system voltage drops significantly, The voltage phase and the system voltage angular velocity can be simulated, and continuous operation can be performed without stopping the inverter.

As a result, by continuously supplying the secondary current of the wire wound induction machine, the reduction of the alternating current component of the primary side ground fault current is avoided and the zero point is passed, so that the AC circuit breaker is used. It is possible to protect the system by cutting off the leakage current.

Further, in the invention corresponding to claim 2, a system voltage phase detecting means for detecting a system voltage phase of the power system, a rotor phase detecting means for detecting a rotor phase of the wire wound induction machine, and a system voltage. Secondary current phase calculation means for determining the phase reference of the secondary current, which is a voltage in which the primary voltage of the wound-rotor induction motor is synchronized with the system voltage, based on the output of the phase detection means and the output of the rotor phase detection means. , Based on the secondary current phase reference determined by the secondary current phase calculation means,
Secondary current control means for controlling the phase of the secondary current of the wound-type induction machine, ground fault detection means for detecting the occurrence of a ground fault in the power system, and system voltage angular velocity for detecting the system voltage angular velocity of the power system Detecting means, integrating means for integrating the output of the system voltage angular velocity detecting means, multiplying means for multiplying the output of the system voltage angular velocity detecting means by a constant, output of the system voltage phase detecting means, output of the integrating means and output of the multiplying means And an adding means for adding, and when a ground fault occurs in the power system, the output of the system voltage phase detecting means and the output of the system voltage angular velocity detecting means are output by the output of the ground fault detecting means before the occurrence of the ground fault. While the ground fault is occurring, the input to the secondary current phase calculating means is integrated from the output of the system voltage phase detecting means to the hold output of the system voltage phase detecting means and the hold output of the system voltage angular velocity detecting means. Value and The secondary current of the wire-wound induction machine is controlled by switching to a value obtained by adding the phase correction value obtained by multiplying the hold output of the integrated voltage angular velocity detection means by the time difference between the ground fault detection time and the time immediately before the ground fault detection. I am trying.

Therefore, in the control device for the variable speed generator-motor of the invention according to claim 2, when the ground fault occurs in the power system, the output of the system voltage angular velocity detecting means is held at the value immediately before the occurrence of the ground fault, During the occurrence of the ground fault, the hold output of the system voltage phase detection means, the integrated value of the hold output of the system voltage angular velocity detection means immediately before the occurrence of the ground fault, and the hold output of the system voltage angular velocity detection means immediately before the occurrence of the ground fault Even if the system voltage drops significantly by controlling the secondary current of the wire wound induction machine with a value that adds the phase correction value that is the time difference between the time of occurrence and the time immediately before the occurrence of the ground fault, Therefore, the system voltage phase and the system voltage angular velocity can be simulated, and continuous operation can be performed without stopping the inverter.

As a result, by continuously supplying the secondary current of the wire wound induction machine, the reduction of the alternating current component of the primary side ground fault current can be avoided and the zero point can be passed through. It is possible to protect the system by cutting off the leakage current.

On the other hand, in the invention corresponding to claim 3, in the control device for the variable speed generator-motor of the invention according to claim 1 or 2, the q-axis multiplying means for increasing the q-axis secondary current command value. And d-axis multiplying means for increasing the d-axis secondary current command value are added, and during the occurrence of the ground fault, each output of the q-axis multiplying means and the d-axis multiplying means is controlled by the output of the ground fault detecting means. The absolute value of the secondary current of the wound-rotor induction machine is increased by switching the input to the control means.

Therefore, in the control device for the variable speed generator-motor according to the third aspect of the present invention, the same effect as that of the control device for the variable speed generator-motor according to the first or second aspect of the present invention can be obtained. In addition, it is possible to increase the absolute value of the secondary current of the wound-type induction machine during the occurrence of a ground fault, and increase the alternating current component of the primary current, and to reduce the zero crossing of the primary current. It is more likely to occur, so that the AC breaker can cut off the ground fault current more reliably and protect the system.

Further, in the invention according to claim 4, in the control device for the variable speed generator-motor of the invention according to claim 1 or 2, the d-axis multiplying means for increasing the d-axis secondary current command value. When the ground fault occurs, the output of the ground fault detection unit is switched to input the output of the d-axis multiplication unit to the secondary current control unit to increase the absolute value of the secondary current of the wire wound induction machine. I am trying to let you.

Therefore, in the control device for the variable speed generator-motor of the invention according to claim 4, the same operation and effect as the control device for the variable speed generator-motor of the invention in accordance with claim 1 or 2 can be obtained. In addition to that, by increasing the d-axis component of the secondary current of the wound-rotor induction machine during the occurrence of a ground fault, the alternating current component of the primary current can be increased more effectively. It is possible to more easily generate the zero cross of the current, and thus to more surely interrupt the ground fault current by the AC breaker to protect the system.

Further, in the invention corresponding to claim 5, in the control device for the variable speed generator-motor according to claim 1 or 2, the system voltage angular velocity detecting means for detecting the system voltage angular velocity of the power system. A rotor angular velocity detecting means for detecting a rotor angular velocity of the wound induction machine; a subtracting means for subtracting an output of the system voltage angular velocity detecting means from an output of the rotor angular velocity detecting means; an output of the subtracting means; a q-axis. A sign determination means for determining whether the secondary current command value is positive or negative is added, and during the occurrence of a ground fault, the output of the subtraction means is negative and the q-axis secondary current command value is positive. When there is, or when the output of the subtraction means is positive and the q-axis secondary current command value is negative, the q-axis secondary current command value is decreased by the output of the ground fault detection means and is sent to the secondary current control means. I'm trying to switch to input .

Therefore, in the control device for the variable speed generator-motor of the invention corresponding to claim 5, the same operation and effect as the control device for the variable speed generator-motor of the invention in claim 1 or 2 can be obtained. In addition to being able to
When the axis secondary current command value is positive and the difference between the system voltage angular velocity and the rotor angular velocity is negative, the q-axis secondary current axis command value is switched to a smaller value when the ground fault occurs, and the q-axis When the secondary current command value is negative and the difference between the system voltage angular velocity and the rotor angular velocity is positive, when the ground fault occurs, the q-axis secondary current command value is switched to increase, that is, the wound-type induction machine. When the system voltage angular velocity is lower than the rotor angular velocity during power generation operation, the q-axis secondary current command value is reduced when a ground fault occurs, and when the system voltage angular velocity is higher than the rotor angular velocity during pumping operation, the ground fault occurs. By increasing the q-axis command value when a failure occurs, it is possible to suppress an increase in the DC power supply voltage due to the flow of power to the inverter in an operating state where there is a large amount of slippage, and because an overvoltage does not occur, when switching the GTO element of the inverter The operating conditions do not exceed the rating, the inverter does not have to be stopped, and the secondary current of the wire-wound induction machine can continue to flow even when a ground fault occurs. There is no decrease, and the ground fault current can be reliably cut off by the AC breaker.

Furthermore, in the invention corresponding to claim 6, in the control device for the variable speed generator-motor of the invention corresponding to claim 1 or claim 2, d-axis multiplication for increasing the d-axis secondary current command value. Means, system voltage angular velocity detection means for detecting the system voltage angular velocity of the power system, rotor angular velocity detection means for detecting the rotor angular velocity of the wound induction machine, output of the system voltage angular velocity detection means and rotor angular velocity detection means And a sign determining means for determining whether the output of the subtracting means and the q-axis secondary current command value is positive or negative are added, and during the occurrence of the ground fault, the ground The output of the d-axis multiplying means is switched to the secondary current control means by the output of the fault detecting means to increase the absolute value of the secondary current of the wire wound induction machine, and the output of the subtracting means is negative. q
When the axis secondary current command value is positive, or when the output of the subtracting means is positive and the q axis secondary current command value is negative, the q-axis secondary current command value is output by the output of the ground fault detecting means. It is arranged so that the current is reduced and input to the secondary current control means.

Therefore, in the control device for the variable speed generator-motor according to the sixth aspect of the invention, the same effect as that of the control device for the variable speed generator-motor according to the first or second aspect of the invention can be obtained. In addition to the above, it is possible to achieve the same effects as those of the control device for the variable speed generator-motor according to the invention according to claim 4 and claim 5, that is, while the ground fault is occurring, the virtual system is generated. The phase control can be continued by the voltage phase, and the rise of the DC power supply voltage due to the flow of power to the inverter can be suppressed in the operation state where the slip is large, so the inverter operation can be avoided by avoiding the inverter stop due to overvoltage protection. Since it can be continued and the d-axis secondary current command value is increased to amplify the AC component of the primary current,
The zero crossing of the ground fault current is more easily obtained, the ground fault current can be blocked by the AC breaker, and the DC break can be avoided.

As described above, it is possible to prevent the inverter from stopping when a ground fault occurs in the power system, to enable continuous operation of the inverter, to prevent the AC component of the ground fault current from decreasing due to the inverter stop, and to make the primary short-circuit current zero-cross. Therefore, the ground fault current can be interrupted by a small and inexpensive AC breaker.

[0044]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below in detail with reference to the drawings. (First Embodiment) FIG. 1 is a block diagram showing a configuration example of a phase control circuit in a control device for a variable speed generator-motor according to the present embodiment. The same parts as those in FIG. Is shown.

The main circuit configuration is the same as that of the conventional circuit shown in FIG. That is, the phase control circuit of the present embodiment includes the system voltage phase detector 81, the rotor phase detector 9, and the subtractor 22 which is the secondary current phase calculation means.
, Secondary current controller 12, ground fault detector 10, subtractor 31, differentiator 32, proportional integrator 33, and integrator 34.
And a switch 35.

Here, normally, the grid voltage phase detector 81 periodically samples the grid input voltage of the power grid 3 at high speed, calculates and outputs the grid voltage phase, and outputs a ground fault which is an external command. When the output of the detector 10 is input, the execution of the operation of the system voltage phase is stopped and the previous operation value is output and held.

The rotor phase detector 9 detects the rotor phase of the wire wound induction machine 1. Further, the subtractor 22 detects the secondary current of the primary voltage of the wound-rotor induction motor 1 based on the output of the system voltage phase detector 81 and the output of the rotor phase detector 9 so as to be a voltage synchronized with the system voltage. It determines the phase reference.

Furthermore, the secondary current controller 12 controls the phase of the secondary current of the wire wound induction machine 1 based on the phase reference of the secondary current determined by the subtractor 22. On the other hand, the ground fault detector 10 detects at high speed that a ground fault has occurred in the power system 3.

Further, the subtractor 31 obtains a difference output between the output of the integrator 34 and the output of the system voltage phase detector 81. Further, the differentiator 32 differentiates the output of the subtractor 31.

In addition, the proportional integrator 33 outputs a calculation result obtained by proportionally integrating the output of the differentiator 32 in the normal state, and calculates the proportional integral when the output of the ground fault detector 10 which is an external command is input. Is stopped and the previous calculated value is output and held.

Further, the integrator 34 integrates the output of the proportional integrator 33. Further, a PLL (Phase Iocked) is used so that the output of the integrator 34 is used as the phase feedback value and is input as the subtraction element of the subtractor 31.
Loop) controller.

Furthermore, the switch 35 receives the output of the ground fault detector 10 and inputs the input to the subtractor 22 from the output of the system voltage phase detector 81 to the integrator 3 of the PLL controller.
4 output (phase feedback value).

Next, the operation of the control device for the variable speed generator-motor according to the present embodiment having the above configuration will be described. In FIG. 1, when the power system 3 is healthy, the voltage phase θ _L from the system voltage phase detector 81 and the rotor phase θ _r from the rotor phase detector 9 are input to the subtractor 22, and the calculation result is Secondary current controller 1 as secondary current reference phase θ _2s
2 and the secondary current reference phase θ _2s is (θ _L − θ _r ).
The secondary current of the wound-rotor induction machine 1 is controlled so as to be equal to.

Therefore, even if the rotation speed of the rotor of the wound-rotor induction machine 1 changes, the operation can be synchronized.
On the other hand, the voltage phase θ _L from the system voltage phase detector 81 is input to the subtractor 31, the output thereof is passed through the differentiator 32 and further through the proportional integrator 33, and then to the integrator 34, and the output thereof is It is input to the subtractor 31 to form a negative feedback loop (this negative feedback loop is generally called a PLL).

Assuming that the output of the integrator 34, which is the feedback value, is θ _F , the output of the subtractor 31, that is, the deviation between the voltage phase θ _L and the feedback value θ _F , will be zero by the proportional integrator 33. To work. Therefore, the feedback value θ _F is the voltage phase θ
_Is equal to _L.

At this time, the output value of the proportional integrator 33 is a differential value of the voltage phase θ _L , that is, equal to the voltage angular velocity ω _L. Next, during operation in such a state, the power grid 3
When a ground fault occurs, the voltage of the power system 3 drops rapidly and the ground fault detector 10 operates.

As a result, in the system voltage phase detector 81, the phase calculation is stopped and the previous calculated value is output and held. At the same time, the output of the ground fault detector 10 is input to the proportional integrator 33 and the switch 35.

Then, the proportional integrator 33 receives the ground fault detection signal, stops the execution of the calculation, and continues to output the previous calculated value. Therefore, the calculation of the negative feedback loop is stopped, and the feedback value θ _F becomes a value obtained by integrating the previous calculated value output from the proportional integrator 33 by the integrator 34.

This feedback value θ _F is equal to the voltage phase θ _L during normal operation, but after the occurrence of the ground fault, the feedback value θ _F is output based on the held output of the proportional integrator 33. The value held by the proportional integrator 33 is the system voltage angular velocity ω _L , and after the occurrence of the ground fault, the system voltage angular velocity ω _L is integrated by the integrator 34 to substitute the system voltage phase. This system voltage angular velocity ω _L hardly changes in a short time from the occurrence of a ground fault to its removal, so even if it is the same as the angular velocity immediately before the occurrence of a ground fault, there is a problem. Absent.

In the switch 35, when the ground fault detector 10 operates, a switching operation is performed, and the input to the subtractor 22 is switched from the output of the system voltage phase detector 81 to the output of the integrator 34.

The output of the integrator 34 is a phase obtained by integrating the voltage angular velocity immediately before the occurrence of the ground fault, which continuously changes with the phase before the occurrence of the ground fault and has the same change rate. A virtual voltage phase can be created.

On the other hand, the subtractor 22 subtracts the output of the rotor phase shifter 9 from the output of the integrator 34, which is the virtual voltage phase, and outputs it to the secondary current controller 12. And
The secondary current controller 12 controls the secondary current of the wound-type induction machine 1 with this input value as a current phase reference.

FIG. 2 is a diagram showing the states of the primary current, the secondary current, and the voltage of the DC power supply 6 when a ground fault occurs in the present embodiment. 2A shows the movement of the primary current I ₁ , FIG. 2B shows the movement of the secondary current I ₂ , and FIG. 2C shows the movement of the DC power supply 6 voltage V _D. Further, SG represents a control signal of the GTO element 13G, t ₀ represents a ground fault occurrence time, and t ₁ represents an open time of the breaker 2.

That is, when a ground fault occurs in the power system 3, a ground fault current flows on the primary side and the current rapidly increases. In addition, the transient DC component included in the ground fault current causes an overvoltage in the secondary circuit of the wound-rotor induction machine 1, and the inverter 4
A current flows into the capacitor 5 through the internal diodes 1D to 6D, and the DC power supply 6 voltage V _D rises.

When the ground fault occurs, the system voltage is originally lowered and the system voltage phase cannot be detected. However, by applying the present embodiment, the system is switched to the virtual voltage phase. The secondary current control of the induction machine 1 can be continued.

Further, since the secondary current of the wound-rotor induction machine 1 can be kept flowing, the electric charge charged in the capacitor 5 is passed through the GTO elements 1G to 6G inside the inverter 4 to the secondary winding of the wound-rotor induction machine 1. It can be discharged to the line side, and the rise of the DC power supply 6 voltage V _D can be suppressed.

FIG. 2C shows how the voltage is suppressed without passing a current through the discharge resistor 13. That is, it becomes unnecessary to suppress the overvoltage by the discharge resistor 13. By suppressing this overvoltage, the GT of the inverter 4
Since the operating conditions at the time of switching the O elements 1G to 6G do not exceed the ratings, the secondary current of the wound-rotor induction machine 1 can continue to flow without stopping the operation of the inverter 4.

Therefore, since the AC component of the primary side ground fault current does not decrease and a zero cross is obtained at the breaker opening time t ₁ , as shown in FIG. It is possible to cut off.

As described above, in this embodiment, when a ground fault occurs in the power system 3, the output of the proportional integrator 33 in the PLL controller is changed by the output of the ground fault detector 10 immediately before the occurrence of the ground fault. Is held, and during the occurrence of the ground fault, the input to the subtractor 22 is switched from the output of the system voltage phase detector 81 to the output of the integrator 34 in the PLL control means (phase feedback value), and the inverter 4 is used to control the secondary current of the wire wound induction machine 1.

Therefore, even if the system voltage greatly drops, the system voltage phase and the system voltage angular velocity can be temporarily simulated, and the inverter 4 can be continuously operated without stopping.

As a result, by continuously flowing the secondary current of the wound-rotor induction machine 1, the reduction of the alternating current component of the primary side ground fault current is avoided and the zero point is passed, so that the AC circuit breaker is used. The system can be protected by cutting off the ground fault current.

As described above, the ground fault current can be cut off by a small and inexpensive AC breaker without using a particularly expensive and large DC breaker. (Second Embodiment) FIG. 3 is a block diagram showing a configuration example of a phase control circuit in a control device for a variable speed generator-motor according to the present embodiment, and the same parts as those in FIG. Is shown.

The main circuit configuration is the same as that of the conventional circuit shown in FIG. That is, the phase control circuit of the present embodiment includes the system voltage phase detector 81, the rotor phase detector 9, and the subtractor 22 which is the secondary current phase calculation means.
, The secondary current controller 12, the ground fault detector 10, the system voltage angular velocity detector 41, the switch 42, and the integrator 43.
, A multiplier 44, an adder 45, and a switch 35.

Here, normally, the system voltage phase detector 81 periodically samples the system input voltage of the power system 3 at high speed, calculates and outputs the system voltage phase, and outputs a ground fault which is an external command. When the output of the detector 10 is input, the execution of the operation of the system voltage phase is stopped and the previous operation value is output and held.

The rotor phase detector 9 detects the rotor phase of the wire wound induction machine 1. Further, the subtractor 22 detects the secondary current of the primary voltage of the wound-rotor induction motor 1 based on the output of the system voltage phase detector 81 and the output of the rotor phase detector 9 so as to be a voltage synchronized with the system voltage. It determines the phase reference.

Further, the secondary current controller 12 controls the phase of the secondary current of the wire wound induction machine 1 based on the phase reference of the secondary current determined by the subtractor 22. On the other hand, the ground fault detector 10 detects at high speed that a ground fault has occurred in the power system 3.

The system voltage angular velocity detector 41 normally calculates and outputs the system voltage angular velocity based on the voltage signal from the power system 3, and when the output of the ground fault detector 10 which is an external command is input, , The execution of the calculation of the system voltage angular velocity is stopped, and the previous calculated value is output and held.

Further, the switch 42 is the ground fault detector 1
The output of 0 switches the input to the integrator 43 from the value of zero to the output of the system voltage angular velocity detector 41.

The integrator 43 integrates the output of the system voltage angular velocity detector 41 from the switch 42. Further, the multiplier 44 includes a system voltage angular velocity detector 41.
The output of is multiplied by a constant.

On the other hand, the adder 45 adds the output of the system voltage phase detector 81, the output of the integrator 43 and the output of the multiplier 44. In addition, the switch 35 receives the input to the subtractor 22 according to the output of the ground fault detector 10.
The output of the system voltage phase detector 81 is switched to the output of the adder 45.

Next, the operation of the control device for the variable speed generator-motor of the present embodiment configured as described above will be described. In FIG. 3, when the power system 3 is healthy, the voltage phase θ _L from the system voltage phase detector 81 and the rotor phase θ _r from the rotor phase detector 9 are input to the subtractor 22, and the calculation result is two. Secondary current controller 1 as secondary current reference phase θ _2s
2 and the secondary current reference phase θ _2s is (θ _L − θ _r ).
The secondary current of the wound-rotor induction machine 1 is controlled so as to be equal to.

Therefore, even if the rotation speed of the rotor of the wound-rotor induction machine 1 changes, the operation can be synchronized.
Further, the voltage angular velocity detector 41 detects the angular velocity of the system voltage.

Further, a value of zero is input to the integrator 43 and its output is zero. Next, when a ground fault occurs in the electric power system 3 during operation in such a state, the voltage of the electric power system 5 rapidly decreases and the ground fault detector 10 operates.

As a result, in the system voltage phase detector 81, the phase calculation is stopped and the previous calculated value is output and held. At the same time, the output of the ground fault detector 10 is input to the voltage angular velocity detector 41 and the switches 35 and 42.

Then, the voltage angular velocity detector 41 receives the ground fault detection signal, stops the calculation, and continues to output the previous calculated value. At the same time, the switch 42
And the output of the voltage angular velocity detector 41 is input to the integrator 43.

On the other hand, in the multiplier 44, the output of the voltage angular velocity detector 41 is multiplied by the time difference Δt between the ground fault detection time and the time when the calculation is performed immediately before the occurrence of the ground fault, and the result is output. In the adder 45, the output of the system voltage phase detector 81, the output of the integrator 43, and the output of the multiplier 44 are added together and output to the switch 35.

In the switch 35, the switching operation is performed by the output of the ground fault detector 7, the output of the adder 45 is input to the subtractor 22 and the output of the rotor phase detector 9 is subtracted, and the secondary It is input to the current controller 12. And
The secondary current controller 12 controls the secondary current of the wound-type induction machine 1 with this input value as a current phase reference.

That is, the system voltage phase immediately before the occurrence of the ground fault and the value obtained by integrating the voltage angular velocity immediately before the occurrence of the ground fault,
A virtual voltage phase can be formed by adding a value obtained by multiplying the voltage angular velocity immediately before the occurrence of the ground fault to the time Δt required for switching.

As described above, in this embodiment, when a ground fault occurs in the power system 3, the output of the ground fault detector 10 causes the output of the system voltage phase detector 81 and the system voltage angular velocity detector. The output of 41 is held at the value immediately before the occurrence of the ground fault, and during the occurrence of the ground fault, the input to the subtractor 22 is changed from the output of the grid voltage phase detector 81 to the held output of the grid voltage phase detector 81 and the grid voltage. Switching to a value obtained by adding a value obtained by integrating the hold output of the angular velocity detector 41 and a phase correction value obtained by multiplying the hold output of the system voltage angular velocity detector 41 by the time difference Δt between the ground fault detection time and the time immediately before the ground fault detection. The inverter 4 controls the secondary current of the wound-rotor induction machine 1.

Therefore, even when the system voltage greatly drops, the system voltage phase and the system voltage angular velocity can be temporarily simulated, and the inverter 4 can be continuously operated without stopping.

As a result, the secondary current of the wound-rotor induction machine 1 is continuously flown, so that the reduction of the AC component of the primary side ground fault current is avoided and the zero point is passed, so that the AC circuit breaker is used. The system can be protected by cutting off the ground fault current.

As described above, the ground fault current can be interrupted by a small and inexpensive AC breaker without using a specially expensive and large DC breaker. (Third Embodiment) FIG. 4 is a block diagram showing a configuration example of a phase control circuit in a control device for a variable speed generator-motor according to the present embodiment. The same parts as those in FIG. 1 or FIG. Will be omitted and the description will be omitted, and only different parts will be described here.

The main circuit configuration is the same as that of the conventional circuit shown in FIG. That is, the phase control circuit of the present embodiment has a configuration in which the multipliers 55 and 56 and the switch 57 are added in the first embodiment or the third embodiment.

Here, the multiplier 55 increases the q-axis secondary current command value 53. Further, the multiplier 56 is
The d-axis secondary current command value 54 is increased. Further, the switch 57 switches the input to the secondary current controller 12 from the q-axis secondary current command value 53 to the output of the multiplier 55 by the output of the ground fault detector 10, and at the same time, outputs the d-axis secondary current. The command value 54 is switched to the output of the multiplier 56.

Next, the operation of the control device for the variable speed generator-motor of the present embodiment configured as described above will be described. The description of the operation of the same parts as those of the first embodiment or the third embodiment will be omitted, and only different parts will be described here.

In FIG. 4, when the power system 3 is sound, the q-axis secondary current command value 53 and the d-axis secondary current command value 54
Is input to the secondary current controller 12 through the switch 57. Then, the secondary current controller 12 controls the inverter 4 based on these command values so as to obtain the required secondary current.

The q-axis secondary current and the d-axis secondary current are obtained by expanding the secondary current vector on the straight axis (d axis) and the horizontal axis (q axis) of the orthogonal coordinate system. Then, when the reference point of the coordinate axis is made to coincide with the one obtained by expanding the primary side voltage vector of the wound-rotor induction machine 1 into the orthogonal coordinate system, the d-axis secondary current increases or decreases,
It is known in principle that the primary side reactive power can be controlled and the primary side active power can be controlled by increasing and decreasing the q-axis secondary current.

Next, when a ground fault occurs in the electric power system 3 during operation in such a state, the voltage of the electric power system 5 drops rapidly and the ground fault detector 10 operates. As a result, the output from the ground fault detector 10 causes the switching device 57 to perform the switching operation, and the q-axis secondary current command value 53 and the d-axis secondary current command value 54 are passed through multipliers 55 and 56, respectively. It is input to the secondary current controller 12.

In this case, if the constant K _{P of} the multiplier 55 and the constant K _Q of the multiplier 56 are set to appropriate values of 1 or more, the respective command values are amplified and the secondary current controller 12 Entered in.

Therefore, in the secondary current controller 12, during the ground fault, the inverter 4 is controlled so as to flow a larger secondary current than in the normal operation, so that the secondary current of the wound-rotor induction machine 1 is controlled. The absolute value of increases.

As described above, in the present embodiment, in the first embodiment or the third embodiment,
During the occurrence of the ground fault, the outputs of the ground fault detector 10 are switched so as to input the outputs of the multipliers 55 and 56 to the secondary current controller 12, and the absolute value of the secondary current of the wire wound induction machine 1 is changed. Is to increase.

Therefore, in addition to the same operational effect as the control device for the variable speed generator-motor according to the first or third embodiment, the AC component of the primary current is increased. Therefore, the zero cross of the primary current can be more easily generated.

As a result, the AC circuit breaker can more surely cut off the ground fault current to protect the system.
As described above, the ground fault current can be interrupted by a small and inexpensive AC circuit breaker without using a particularly expensive and large DC circuit breaker.

(Fourth Embodiment) FIG. 5 is a block diagram showing an example of the configuration of a phase control circuit in a control device for a variable speed generator-motor according to the present embodiment, and FIG. 1 or FIG. 3 and FIG. The same parts as those of the above are given the same reference numerals and the description thereof will be omitted, and only different parts will be described here.

The main circuit configuration is the same as that of the conventional circuit shown in FIG. That is, the phase control circuit of the present embodiment has a configuration in which the multiplier 56 and the switch 58 are added in the first embodiment or the third embodiment.

In other words, the multiplier 55 shown in FIG.
The switch 57 is omitted, and instead, a switch 58 is newly provided. Here, the switch 58 switches the input to the secondary current controller 12 from the d-axis secondary current command value 54 to the output of the multiplier 56 according to the output of the ground fault detector 10.

Next, the operation of the control device for the variable speed generator-motor of the present embodiment configured as described above will be described. The description of the operation of the same parts as those of the first embodiment or the third embodiment will be omitted, and only different parts will be described here.

In FIG. 5, when the electric power system 3 is healthy, the q-axis secondary current command value 53 is directly transmitted, and the d-axis secondary current command value 54 is transmitted through the switch 58 to the secondary current controller 12.
Entered in. Then, the secondary current controller 12 controls the inverter 4 based on these command values so as to obtain the required secondary current.

Next, when a ground fault occurs in the electric power system 3 during operation in such a state, the voltage of the electric power system 5 drops rapidly and the ground fault detector 10 operates. As a result, the output of the ground fault detector 10 causes the switch 58 to perform the switching operation, and the d-axis secondary current command value 54 is input to the secondary current controller 12 through the multiplier 56.

In this case, if the constant K _Q of the multiplier 56 is set to an appropriate value of 1 or more, the d-axis secondary current command value 5
4 is amplified and input to the secondary current controller 12. Therefore, in the secondary current controller 12, during the ground fault, the inverter 4 is controlled so as to flow a larger secondary current than in the normal operation, so that the absolute value of the secondary current of the wire wound induction machine 1 is increased. Will increase.

As described above, in this embodiment, in the first embodiment or the third embodiment,
During the occurrence of the ground fault, the output of the ground fault detector 10 is switched to input the output of the multiplier 56 to the secondary current controller 12, and the absolute value (d-axis) of the secondary current of the winding induction machine 1 is changed. Ingredients) are increased.

Therefore, in addition to the same operational effects as the control device for the variable speed generator-motor according to the first embodiment or the third embodiment, the AC component of the primary current can be further improved. It can be increased more effectively, and the zero cross of the primary current can be made more likely to occur.

That is, when the absolute value of the secondary current of the wound-rotor induction machine 1 is increased during the occurrence of the ground fault, both the q-axis component is increased and the d-axis component is increased. Comparing the effects of, the primary-side electromotive voltage of the wound-type induction machine 1 becomes larger when the d-axis component is increased,
The AC component of the primary current during the occurrence of the ground fault can be more effectively increased, and the zero cross of the primary current is more likely to occur.

As a result, the AC circuit breaker can more reliably cut off the ground fault current and protect the system.
As described above, the ground fault current can be interrupted by a small and inexpensive AC circuit breaker without using a particularly expensive and large DC circuit breaker.

(Fifth Embodiment) FIG. 6 is a block diagram showing a configuration example of a phase control circuit in a control device for a variable speed generator-motor according to the present embodiment.
The same parts as those of the above are given the same reference numerals and the description thereof will be omitted, and only different parts will be described here.

The main circuit configuration is the same as that of the conventional circuit shown in FIG. That is, the phase control circuit of the present embodiment is the system voltage angular velocity detector 41, the rotor angular velocity detector 51, the subtractor 52 in the first embodiment or the third embodiment, Code determiner 6
1, 62, 63, 64, AND operator 65, 66,
A logical sum calculator 67, a multiplier 68, and a switch 69 are added.

The system voltage angular velocity detector 41 calculates and outputs the system voltage angular velocity based on the voltage signal from the power system 3. In addition, the rotor angular velocity detector 5
1 detects the angular velocity of the rotor of the wound-rotor induction machine 1.

Further, the subtractor 52 subtracts the output of the system voltage angular velocity detector 41 and the output of the rotor angular velocity detector 51. On the other hand, the sign determiner 61 determines whether the output of the subtractor 52 is negative.

The sign judging unit 63 is for judging whether the output of the subtractor 52 is positive. Further, the sign determiner 62 determines whether the q-axis secondary current command value 53 is positive.

Furthermore, the sign determiner 64 determines whether the q-axis secondary current command value 53 is negative. On the other hand, the logical product calculator 65 calculates the logical product of the outputs of the sign determiner 61, the sign determiner 62, and the ground fault detector 10.

Further, the logical product operator 66 is the sign judging device 6
3, the logical product of each output of the code determination unit 64 and the ground fault detector 10 is calculated. Further, the logical sum operator 6
Reference numeral 7 is for calculating the logical sum of the outputs of the logical product calculator 65 and the logical product calculator 66.

On the other hand, the multiplier 68 increases the q-axis secondary current command value 53. Also, the switch 69
Is the output of the logical sum calculator 67, and inputs the input to the secondary current controller 12 from the q-axis secondary current command value 53 to the multiplier 6
The output is switched to eight.

Next, the operation of the control device for the variable speed generator-motor according to the present embodiment having the above configuration will be described. The description of the operation of the same parts as those of the first embodiment or the third embodiment will be omitted, and only different parts will be described here.

In FIG. 6, assuming that the slip S is S = (synchronous speed-rotor speed) / synchronous speed, when the variable speed operation is performed in the wound induction machine 1, the primary side of the wound induction machine 1 Let P1 be the output active power of P1 and P2 be the input active power from the secondary side inverter 4 to the winding-type induction machine 1, then the relationship of P2 = S · P1 is established.

Therefore, at the time of power generation, when the rotation speed is higher than the synchronous speed, the slip S becomes negative and the input active power P2 becomes negative, so that power flows from the winding induction machine 1 side to the inverter side, Increase the DC power supply 6 voltage.

When pumping water (when the motor is operating),
When the rotation speed is lower than the synchronous speed, the slip becomes positive and the output active power P1 is negative, so the input active power P
2 becomes negative, and electric power is fed from the wound-rotor induction machine 1 to the inverter 4
Flow to the side and raise the voltage of the DC power supply 6 in the same manner as described above.

In normal times, the electric power system 3 is regenerated by the converter of the DC power supply 6 to the electric power system 3 and is not overvoltage. However, when a ground fault occurs in the power system 3, the converter is stopped, so that power is not regenerated and an overvoltage is generated. Therefore, during the occurrence of the ground fault, if the q-axis secondary current command value 53 is controlled to be small, the inflow of the input active power P2 can be reduced, and the overvoltage can be suppressed.

That is, in the present embodiment, the subtractor 52
To system voltage angular velocity detector 41 and rotor angular velocity detector 51
Of the code decision unit 61,
It is output to 63 respectively.

The sign judging device 61 outputs an output signal when the sign of the difference output is negative, and the sign judging device 63
In the case, the output is output when the sign of the difference output is positive. On the other hand, the sign determiner 62 outputs an output signal when the q-axis secondary current command value 53 is positive (during power generation operation), and the sign determiner 64 determines that the q-axis secondary current command value 53 is negative. Then the output signal is issued.

In the logical product calculator 65, the logical product of the outputs of the sign judging device 61, the sign judging device 62 and the ground fault detector 7 is calculated, and the calculation result is output to the switching device 69 through the logical sum calculating device 67. To be done.

Further, the logical product calculator 66 calculates the logical product of the outputs of the sign determiner 63, the sign determiner 64 and the ground fault detector 7, and the calculation result is passed through the logical sum calculator 67 to the switch 69. Is output to.

In the switch 69, the q-axis secondary current command value 53 is normally input to the secondary current controller 12, but when the output of the logical product calculator 65 occurs, the multiplier 6
8 outputs are switched to be input to the secondary current controller 12.

In this case, if the constant K _P of the multiplier 68 is set to an appropriate value of 1 or less and 0 or more, the secondary current controller 12 receives this and the d-axis of the secondary current component is received. The inverter 4 is controlled so that the q-axis secondary current command value 53 becomes small while the secondary current command value remains unchanged.

For example, if K _P = 0, the output active power P1 = 0 and the input active power P2 also becomes 0. Therefore, the electric power does not flow from the wound-rotor induction machine 1 to the inverter 4 side, and the voltage of the DC power supply 6 is not increased.
Overvoltage is less likely to occur.

As described above, in the present embodiment, in the first embodiment or the third embodiment,
When the q-axis secondary current command value 53 is positive and the difference between the system voltage angular velocity and the rotor angular velocity is negative, q occurs when a ground fault occurs.
The axis secondary current axis command value 53 is switched to a smaller value,
When the q-axis secondary current command value 53 is negative and the difference between the system voltage angular velocity and the rotor angular velocity is positive, the q-axis secondary current command value 53 is switched to be large when a ground fault occurs, that is, If the system voltage angular velocity is smaller than the rotor angular velocity during the power generation operation of the wound-rotor induction machine 1, the q-axis secondary current command value 53 is decreased when a ground fault occurs, and the winding-type induction motor 1 operates during the pumping operation. Is larger than the rotor angular velocity, the q-axis command value is increased when a ground fault occurs.

Therefore, in addition to the same operational effect as the control device for the variable speed generator-motor according to the first embodiment or the third embodiment, the inverter in the operating state with large slip can be obtained. It is possible to suppress an increase in the voltage of the DC power supply 6 due to the flow of electric power into the inverter 4 and to prevent an overvoltage. Therefore, the operating conditions during GTO element switching do not exceed the rating, and the inverter 4 does not have to be stopped. Even when a ground fault occurs, the secondary current of the wound-rotor induction machine 1 can be continuously supplied.

As a result, the AC component of the primary current does not decrease, and the ground fault current can be reliably blocked by the AC breaker. As described above, the ground fault current can be interrupted by a small and inexpensive AC circuit breaker without using a particularly expensive and large DC circuit breaker.

(Sixth Embodiment) FIG. 7 is a block diagram showing a configuration example of a phase control circuit in a control device for a variable speed generator-motor according to the present embodiment.
The same parts as those of the above are given the same reference numerals and the description thereof will be omitted, and only different parts will be described here.

The main circuit configuration is the same as that of the conventional circuit shown in FIG. That is, the phase control circuit of the present embodiment is the system voltage angular velocity detector 41, the rotor angular velocity detector 51, the subtractor 52 in the first embodiment or the third embodiment, Code determiner 6
1, 62, 63, 64, AND operator 65, 66,
A logical sum calculator 67, a multiplier 68, and a switch 69 are added, and further a multiplier 56 and a switch 58 are added.

The system voltage angular velocity detector 41 calculates and outputs the system voltage angular velocity based on the voltage signal from the power system 3. In addition, the rotor angular velocity detector 5
1 detects the angular velocity of the rotor of the wound-rotor induction machine 1.

Further, the subtractor 52 subtracts the output of the system voltage angular velocity detector 41 from the output of the rotor angular velocity detector 51. On the other hand, the sign determiner 61 determines whether the output of the subtractor 52 is negative.

The sign judging unit 63 is for judging whether the output of the subtractor 52 is positive. Further, the sign determiner 62 determines whether the q-axis secondary current command value 53 is positive.

Furthermore, the sign determiner 64 determines whether the q-axis secondary current command value 53 is negative. On the other hand, the logical product calculator 65 calculates the logical product of the outputs of the sign determiner 61, the sign determiner 62, and the ground fault detector 10.

Further, the logical product operator 66 is the sign judging unit 6
3, the logical product of each output of the code determination unit 64 and the ground fault detector 10 is calculated. Further, the logical sum operator 6
Reference numeral 7 is for calculating the logical sum of the outputs of the logical product calculator 65 and the logical product calculator 66.

On the other hand, the multiplier 68 increases the q-axis secondary current command value 53. Also, the switch 69
Is the output of the logical sum calculator 67, and inputs the input to the secondary current controller 12 from the q-axis secondary current command value 53 to the multiplier 6
The output is switched to eight.

On the other hand, the switch 58 is the ground fault detector 10
Output of the d-axis secondary current command value 54 to the output of the multiplier 56.

Next, the operation of the control device for the variable speed generator-motor of the present embodiment configured as described above will be described. The description of the operation of the same parts as those of the first embodiment or the third embodiment will be omitted, and only different parts will be described here.

In FIG. 7, assuming that the slip S is S = (synchronous speed-rotor speed) / synchronous speed, when the variable speed operation is performed in the wire wound induction machine 1, the primary side of the wire wound induction machine 1 Let P1 be the output active power of P1 and P2 be the input active power from the secondary side inverter 4 to the winding-type induction machine 1, then the relationship of P2 = S · P1 is established.

Therefore, at the time of power generation, when the rotation speed is higher than the synchronous speed, the slip S becomes negative and the input active power P2 becomes negative, so that power flows from the winding induction machine 1 side to the inverter side, Increase the DC power supply 6 voltage.

When pumping water (when the motor is operating),
When the rotation speed is lower than the synchronous speed, the slip becomes positive and the output active power P1 is negative, so the input active power P
2 becomes negative, and electric power is fed from the wound-rotor induction machine 1 to the inverter 4
Flow to the side and raise the voltage of the DC power supply 6 in the same manner as described above.

At normal times when the power system 3 is sound, the DC power source 6
This electric power is regenerated to the electric power system 3 by the converter of (1) and does not become an overvoltage. However, when a ground fault occurs in the power system 3, the converter is stopped, so that power is not regenerated and an overvoltage is generated. Therefore, during the occurrence of the ground fault, if the q-axis secondary current command value 53 is controlled to be small, the inflow of the input active power P2 can be reduced, and the overvoltage can be suppressed.

That is, in the present embodiment, the subtractor 52
To system voltage angular velocity detector 41 and rotor angular velocity detector 51
Of the code decision unit 61,
It is output to 63 respectively.

The sign judging unit 61 outputs an output signal when the sign of the difference output is negative, and the sign judging unit 63
In the case, the output is output when the sign of the difference output is positive. On the other hand, the sign determiner 62 outputs an output signal when the q-axis secondary current command value 53 is positive (during power generation operation), and the sign determiner 64 determines that the q-axis secondary current command value 53 is negative. Then the output signal is issued.

In the logical product calculator 65, the logical product of the outputs of the sign judging device 61, the sign judging device 62 and the ground fault detector 7 is calculated, and the calculation result is output to the switching device 69 through the logical sum calculating device 67. To be done.

The logical product calculator 66 calculates the logical product of the outputs of the sign determiner 63, the sign determiner 64, and the ground fault detector 7, and the calculation result is passed through the logical sum calculator 67 to the switch 69. Is output to.

In the switch 69, the q-axis secondary current command value 53 is normally input to the secondary current controller 12, but when the output of the logical product calculator 65 occurs, the multiplier 6
8 outputs are switched to be input to the secondary current controller 12.

In this case, if the constant K _P of the multiplier 68 is set to an appropriate value of 1 or less and 0 or more, the secondary current controller 12 receives this and the d-axis of the secondary current component is received. The inverter 4 is controlled so that the q-axis secondary current command value 53 becomes small while the secondary current command value remains unchanged.

For example, if K _P = 0, the output active power P1 = 0 and the input active power P2 also becomes 0. on the other hand,
When the power system 3 is healthy, the d-axis secondary current command value 54
Is input to the secondary current controller 12 through the switch 58. Then, in the secondary current controller 12, the inverter 4 is controlled so that the required secondary current is obtained based on this command value.

Next, when a ground fault occurs in the electric power system 3 during operation in such a state, the voltage of the electric power system 5 drops rapidly and the ground fault detector 10 operates. As a result, the output of the ground fault detector 10 causes the switch 58 to perform the switching operation, and the d-axis secondary current command value 54 is input to the secondary current controller 12 through the multiplier 56.

In this case, if the constant K _Q of the multiplier 56 is set to an appropriate value of 1 or more, the d-axis secondary current command value 5
4 is amplified and input to the secondary current controller 12. Therefore, in the secondary current controller 12, during the ground fault, the inverter 4 is controlled so as to flow a d-axis secondary current larger than that in the normal operation, so that the secondary current of the wound-rotor induction machine 1 is reduced. The absolute value increases.

From the above, during power generation operation, when the slip is operating negatively, or during pumping operation, when the slip is operating positively, by decreasing the q-axis secondary current command value 53, Since the flow of electric power from the wound-rotor induction machine 1 to the inverter 4 is reduced, an increase in the voltage of the DC power supply 6 is reduced, and an overvoltage is less likely to occur.

On the other hand, as the q-axis secondary current of the wound-rotor induction machine 1 decreases, the absolute value of the secondary current decreases, but d
By increasing the axial secondary current, the absolute value of the secondary current obtained by combining the q-axis and the d-axis increases, so that the alternating current component of the primary current increases.

As described above, in the present embodiment, in the first embodiment or the third embodiment,
When the q-axis secondary current command value 53 is positive and the difference between the system voltage angular velocity and the rotor angular velocity is negative, q occurs when a ground fault occurs.
The axis secondary current axis command value 53 is switched to a smaller value,
When the q-axis secondary current command value 53 is negative and the difference between the system voltage angular velocity and the rotor angular velocity is positive, the q-axis secondary current command value 53 is switched to be large when a ground fault occurs, that is, If the system voltage angular velocity is smaller than the rotor angular velocity during the power generation operation of the wound-rotor induction machine 1, the q-axis secondary current command value 53 is decreased when a ground fault occurs, and the winding-type induction motor 1 operates during the pumping operation. Is larger than the rotor angular velocity, the q-axis command value is increased when a ground fault occurs,
Further, during the occurrence of the ground fault, the output of the ground fault detector 10 is switched so that the output of the multiplier 56 is input to the secondary current controller 12, and the absolute value of the secondary current (d The axial component) is to be increased.

Therefore, in addition to the same operational effect as the control device for the variable speed generator-motor according to the first embodiment or the third embodiment, the fourth embodiment can be obtained. , And a fifth form of implementation. It is possible to obtain the same effects as the control device for the variable speed generator-motor in the state.

That is, since it is possible to suppress an increase in the voltage of the DC power supply 6 due to the flow of electric power into the inverter 4 in the operation state where the slip is large, it is possible to avoid the inverter stop due to the overvoltage protection and to continue the inverter operation, Moreover, since the d-axis secondary current command value 54 is increased to amplify the AC component of the primary current, the zero-cross of the ground fault current can be obtained more easily, and the AC circuit breaker can interrupt the ground fault current. , DC interruption can be avoided. As described above, the ground fault current can be interrupted by a small and inexpensive AC circuit breaker without using a particularly expensive and large DC circuit breaker.

[0166]

As described above, in the control device for the variable speed generator-motor, which controls the secondary current of the secondary winding of the winding type induction machine in which the primary winding is connected to the electric power system,
According to the control device of the variable speed generator motor of the invention corresponding to the above, when the ground fault occurs in the power system, the output of the proportional-plus-integral unit in the PLL control unit is held at the value immediately before the occurrence of the ground fault, and , The secondary current of the wire-wound induction machine is controlled by the phase calculated by the held output of the proportional-plus-integral means, so even if the system voltage drops significantly, the system voltage phase and system voltage can be temporarily reduced. The angular velocity can be simulated, and continuous operation can be performed without stopping the inverter.

As a result, the secondary current of the wire-wound type induction machine is continuously flowed, so that the AC component of the primary side ground fault current is prevented from decreasing and the current passes through the zero point. It is possible to protect the system by cutting off the ground fault current with a small and inexpensive AC circuit breaker without using the DC circuit breaker.

According to the control device for the variable speed generator-motor of the invention according to claim 2, when the ground fault occurs in the power system, the output of the system voltage angular velocity detecting means is held at the value immediately before the occurrence of the ground fault, During the occurrence of a ground fault, the hold output of the grid voltage phase detection means, the integrated value of the hold output of the grid voltage angular velocity detection means immediately before the occurrence of the ground fault, and the hold output of the grid voltage angular velocity detection means immediately before the occurrence of the ground fault By the value obtained by adding the phase correction value multiplied by the time difference between the time when the fault occurs and the time immediately before the occurrence of the ground fault,
Since the secondary current of the wire wound induction machine is controlled, even if the system voltage drops significantly, it is possible to temporarily simulate the system voltage phase and system voltage angular velocity, and continue without stopping the inverter. You can drive.

As a result, the secondary current of the wire-wound type induction machine is continuously flowed, so that the AC component of the primary side ground fault current is prevented from decreasing and the current passes through the zero point, which is particularly expensive and large. It is possible to protect the system by cutting off the ground fault current with a small and inexpensive AC circuit breaker without using the DC circuit breaker.

On the other hand, according to the control device of the variable speed generator-motor of the invention corresponding to claim 3, in the control device of the variable speed generator-motor of the invention corresponding to claim 1 or claim 2, a ground fault occurs. Since the absolute value of the secondary current of the wound-rotor induction machine is increased, the same operational effect as the control device for the variable speed generator-motor of the invention according to claim 1 or 2 can be obtained. In addition to that, by increasing the absolute value of the secondary current of the wire wound induction machine while the ground fault is occurring, the alternating current component of the primary current can be increased, and the zero cross of the primary current is further generated. Therefore, it is possible to protect the system by reliably cutting off the ground fault current with a small and inexpensive AC breaker without using a particularly expensive and large DC breaker.

According to the control device of the variable speed generator-motor of the invention corresponding to claim 4, in the controller of the variable speed generator-motor of the invention corresponding to claim 1 or 2, the occurrence of a ground fault occurs. Since the d-axis component of the secondary current of the wound-rotor induction machine is increased, the same operational effect as the control device for the variable speed generator-motor of the invention according to claim 1 or 2 can be obtained. In addition to that, the AC component of the primary current can be increased more effectively, the zero cross of the primary current can be generated more easily, and thus, without using a particularly expensive and large DC breaker. A small and inexpensive AC breaker can cut off the ground fault current more reliably and protect the system.

Further, according to the control device of the variable speed generator-motor of the invention corresponding to claim 5, in the control device of the variable speed generator-motor of the invention corresponding to claim 1 or 2, the q-axis secondary When the current command value is positive and the difference between the system voltage angular velocity and the rotor angular velocity is negative, when a ground fault occurs,
If the q-axis secondary current command value is switched to a smaller value, and if the q-axis secondary current command value is negative and the difference between the system voltage angular velocity and the rotor angular velocity is positive, q When the winding-type induction machine switches to a larger axial secondary current command value, that is, when the system voltage angular velocity is smaller than the rotor angular velocity during power generation operation, the q-axis secondary current command value is reduced when a ground fault occurs, When the system voltage angular velocity is larger than the rotor angular velocity during the pumping operation, the q-axis command value is increased when a ground fault occurs, so that the variable speed generator motor according to the invention according to claim 1 or 2 is provided. In addition to achieving the same effects as the control device, it is possible to suppress the rise of the DC power supply voltage due to the flow of power to the inverter in the operating state where the slippage is large, and the inverter does not become an overvoltage. The operating conditions for switching the GTO element of the inverter do not exceed the rating, the inverter does not have to be stopped, and the secondary current of the wire wound induction machine can continue to flow even when a ground fault occurs. As a result, the AC component of the primary current is not reduced, and the ground fault current can be reliably cut off by a small and inexpensive AC breaker without using a particularly expensive and large DC breaker.

Furthermore, according to the invention corresponding to claim 6, the control device for the variable speed generator-motor of the invention corresponding to claim 1 or claim 2 corresponds to claim 1 or claim 2. In addition to the same operational effects as the control device for the variable speed generator-motor of the invention,
It is possible to achieve the same effects as those of the control device for a variable speed generator-motor according to the inventions corresponding to claims 4 and 5, that is, while the ground fault occurs, the phase control is continued by the virtual system voltage phase. In addition, since it is possible to prevent an increase in the DC power supply voltage due to the flow of electric power into the inverter in an operating state with large slip, it is possible to avoid the inverter stop due to overvoltage protection and continue the inverter operation, and d Since the axial secondary current command value is increased to amplify the AC component of the primary current, it becomes easier to obtain the zero crossing of the ground fault current, and it is possible to reduce the size without using a particularly expensive and large DC breaker. It is possible to cut off the ground fault current with an inexpensive AC breaker and avoid DC breakage.

As described above, it is possible to prevent the inverter from stopping when a ground fault occurs in the power system, to enable continuous operation of the inverter, to prevent the AC component of the ground fault current from decreasing due to the inverter stop, and to make the primary short-circuit current zero-cross. Therefore, the ground fault current can be interrupted by a small and inexpensive AC breaker.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of a phase control circuit in a control device for a variable speed generator-motor according to the present invention.

FIG. 2 is a diagram for explaining an operation effect in the control device for the variable speed generator-motor according to the first embodiment.

FIG. 3 is a block diagram showing a second embodiment of a phase control circuit in a control device for a variable speed generator-motor according to the present invention.

FIG. 4 is a block diagram showing a third embodiment of a phase control circuit in a control device for a variable speed generator-motor according to the present invention.

FIG. 5 is a block diagram showing a fourth embodiment of a phase control circuit in a control device for a variable speed generator-motor according to the present invention.

FIG. 6 is a block diagram showing a fifth embodiment of a phase control circuit in a control device for a variable speed generator-motor according to the present invention.

FIG. 7 is a block diagram showing a sixth embodiment of a phase control circuit in a control device for a variable speed generator-motor according to the present invention.

FIG. 8 is a circuit diagram showing a configuration example of a control device for a variable speed pumped storage generator motor.

FIG. 9 is a block diagram showing a configuration example of a conventional phase control circuit in a control device for a variable speed generator-motor.

FIG. 10 is a diagram for explaining the operation of a conventional phase control circuit.

[Explanation of symbols]

1 ... Winding type induction machine, 2 ... Breaker, 3 ... power system, 4 ... Inverter, 1D to 6D ... diode, 1G to 6G ... GTO element, 5 ... Capacitor, 6 ... DC power supply, 7D to 12D ... Diode, 7G to 12G ... GTO element, 7 ... Transformer, 8 ... Grid voltage phase detector, 9 ... Rotor phase detector, 10 ... Ground fault detector, 11 ... Inverter control device, 12 ... Secondary current controller, 13G ... GTO element, 13 ... Discharge resistor, 22 ... Subtractor, 31 ... Subtractor, 32 ... Differentiator, 33 ... Proportional integrator, 34 ... integrator, 35 ... switch, 41 ... System voltage angular velocity detector, 42 ... a switch, 43 ... integrator, 44 ... Multiplier, 45 ... adder, 51 ... Rotor angular velocity detector, 52 ... Subtractor, 55, 56 ... Multiplier, 57 ... switch, 58 ... switcher, 61, 62, 63, 64 ... Code determiner, 65, 66 ... AND operator, 67 ... Logical sum calculator, 68 ... Multiplier, 69 ... switch, 81 ... System voltage phase detector.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-7-123795 (JP, A) JP-A-3-261398 (JP, A) JP-A-4-325831 (JP, A) JP-A-1- 274698 (JP, A) JP-A-2-65697 (JP, A) JP-A-1-243895 (JP, A) JP-A-3-173399 (JP, A) JP-A-6-284798 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H02P 9/00 H02H 7/06

Claims (6)

(57) [Claims] 1. A controller of a variable speed generator-motor for controlling a secondary current of a secondary winding of a winding type induction machine, wherein a primary winding is connected to a power system, for detecting a system voltage phase of the power system. System voltage phase detection means, rotor phase detection means for detecting the rotor phase of the wound induction machine, based on the output of the system voltage phase detection means and the output of the rotor phase detection means, the winding A secondary current phase calculating means for determining a phase reference of a secondary current that becomes a voltage in which a primary voltage of a linear induction motor is synchronized with a system voltage, and a phase reference of a secondary current determined by the secondary current phase calculating means. Based on the secondary current control means for controlling the phase of the secondary current of the wire wound induction machine, the ground fault detection means for detecting the occurrence of the ground fault in the power system, the differentiating means, the differentiating means Proportional to integrate output proportionally Integrating means, integrating means for integrating the output of the proportional integrating means, and using the difference output between the output of the integrating means and the output of the system voltage phase detecting means, which is a phase feedback value, as the input of the differentiating means. When a ground fault occurs in the power system, the output of the proportional integrator is held at a value immediately before the occurrence of the ground fault, and a PLL control unit configured as described above is provided, During the occurrence of the ground fault, the input to the secondary current phase calculating means is changed from the output of the system voltage phase detecting means to the PLL.
A control device for a variable speed generator-motor, characterized in that a secondary current of a wire wound induction machine is controlled by switching to a phase feedback value of a control means. 2. A control device for a variable speed generator-motor that controls a secondary current of a secondary winding of a wound-rotor induction machine in which a primary winding is connected to a power system, and detects a system voltage phase of the power system. System voltage phase detection means, rotor phase detection means for detecting the rotor phase of the wound induction machine, based on the output of the system voltage phase detection means and the output of the rotor phase detection means, the winding A secondary current phase calculating means for determining a phase reference of a secondary current that becomes a voltage in which a primary voltage of a linear induction motor is synchronized with a system voltage, and a phase reference of a secondary current determined by the secondary current phase calculating means. Based on the secondary current control means for controlling the phase of the secondary current of the wire wound induction machine, the ground fault detection means for detecting the occurrence of a ground fault in the power system, the system voltage angular velocity of the power system System voltage angular velocity to detect Degree detecting means, integrating means for integrating the output of the system voltage angular velocity detecting means, multiplying means for multiplying the output of the system voltage angular velocity detecting means by a constant, output of the system voltage phase detecting means and output of the integrating means. And an output of the multiplication means, and when an earth fault occurs in the power system, the output of the earth fault detection means outputs the output of the system voltage phase detection means and the system voltage angular velocity detection. The output of the means is held at a value immediately before the occurrence of the ground fault, and during the occurrence of the ground fault, the input to the secondary current phase calculation means is changed from the output of the grid voltage phase detection means to the grid voltage phase detection means. Phase correction value obtained by multiplying the hold output and the hold output of the system voltage angular velocity detection means by the time difference between the hold output of the system voltage angular velocity detection means and the ground fault detection time and the time immediately before the ground fault detection. By switching to the value obtained by adding,
A control device for a variable speed generator-motor, characterized in that the secondary current of a wound-rotor induction machine is controlled. 3. The control device for a variable speed generator-motor according to claim 1, wherein: q-axis multiplying means for increasing the q-axis secondary current command value; and d-axis secondary current command value for increasing the q-axis secondary current command value. D axis multiplying means for adding the output of the q axis multiplying means and the d axis multiplying means to the secondary current control means by the output of the ground fault detecting means during the occurrence of the ground fault. A control device for a variable speed generator-motor, characterized in that the absolute value of the secondary current of the wire wound induction machine is increased by switching. 4. The variable speed generator motor controller according to claim 1 or 2, wherein d axis multiplying means for increasing a d axis secondary current command value is added, and during the occurrence of the ground fault, The absolute value of the secondary current of the wire wound induction machine is increased by switching the output of the d-axis multiplication means to the secondary current control means according to the output of the ground fault detection means. Control device for variable speed generator-motor. 5. The control device for a variable speed generator-motor according to claim 1, wherein the system voltage angular velocity detection means detects a system voltage angular velocity of the power system, and the rotor of the wire wound induction machine. Rotor angular velocity detecting means for detecting the angular velocity, subtracting means for subtracting the output of the system voltage angular velocity detecting means and the output of the rotor angular velocity detecting means, the output of the subtracting means, the q-axis secondary current command value , A sign determination means for determining whether it is positive or negative, and during the occurrence of the ground fault, when the output of the subtraction means is negative and the q-axis secondary current command value is positive, Alternatively, when the output of the subtraction means is positive and the q-axis secondary current command value is negative, the q-axis secondary current command value is decreased by the output of the ground fault detection means to perform the secondary current control. Switch to input to means Control device for a variable speed generator-motor, characterized in that had Unishi. 6. The control device for a variable speed generator-motor according to claim 1 or 2, wherein d-axis multiplication means for increasing a d-axis secondary current command value, and system voltage angular velocity of the power system is detected. System voltage angular velocity detection means, rotor angular velocity detection means for detecting the rotor angular velocity of the wound induction machine, subtraction means for subtracting the output of the system voltage angular velocity detection means and the output of the rotor angular velocity detection means And a sign determination means for determining whether the output of the subtraction means and the q-axis secondary current command value is positive or negative, and the output of the ground fault detection means during the occurrence of the ground fault. The output of the d-axis multiplying means is switched to be input to the secondary current control means to increase the absolute value of the secondary current of the wire wound induction machine, and the output of the subtracting means is negative and q Axis secondary current command value When it is positive or when the output of the subtracting means is positive and the q-axis secondary current command value is negative, the q-axis secondary current command value is decreased by the output of the ground fault detecting means. A control device for a variable speed generator-motor, characterized in that switching is performed so as to input to the secondary current control means.