JPH019279Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to improvements in synchronous machines such as synchronous motors and synchronous generators.

An example of a conventional synchronous motor is shown in FIG.

In the figure, 1 is a synchronous motor casing, 2 is a synchronous motor casing;
a is an inverter that supplies power to the synchronous motor in order to drive the synchronous motor; 3 is a rotor of the synchronous motor; the rotor 3 is rotatably attached to the casing 1 via a bearing or the like (not shown); There is. 4 is a stator of a synchronous motor, and this stator 4 is fixed to the casing 1. When this synchronous motor is driven by an inverter, the rotor 3 may become unstable due to disturbances.

In order to suppress this rotor imbalance, conventionally,
Measures have been taken to stabilize the rotor by attaching a damper winding to the rotor, but with this method of stabilizing the rotor by attaching a damper winding to the rotor, the supplied electrical energy is lost in the damper winding. As a result, there was a drawback that the operating efficiency of the synchronous motor decreased.

This idea was made with the aim of suppressing the aforementioned disturbance of the rotor, that is, disturbance of the entire synchronous machine, without reducing the operating efficiency of the synchronous machine. ) and configured to feed back the amount of displacement of the stator relative to the casing to the inverter to control the output of the inverter. That is, by detecting the displacement state of the stator due to rotor disturbance, and controlling the phase, amplitude, etc. of the power supplied from the inverter to each phase of the synchronous machine based on the amount of stator displacement state. Therefore, it is an object of the present invention to provide a synchronous machine that is controlled so that the amount of displacement of the stator becomes small, that is, the internal phase difference angle of the synchronous machine approaches zero.

As is well known, when a synchronous motor is connected to a large-capacity power source and continues synchronous operation, if its internal phase difference angle δ changes periodically with a certain period, the generated torque The part that changes △
T is expressed by the following equation, and the magnitude of this ΔT corresponds to the magnitude of the disturbance.

ΔT=IdΩ/dt+TdΩ+Ts∫Ωdt... However, in the above equation, I is the moment of inertia, Td is the damping coefficient, Ts is the synchronization force coefficient during transient, and Ω is dδ/dt, that is, the change in angular velocity. Also, the first term in the above equation is the torque due to inertia,
The second term indicates braking torque, and the third term indicates synchronization torque.

In order to prevent disturbances, it is necessary to appropriately select the inertia of the rotor and appropriately separate the frequency of the natural vibration it has when connected to a power source from the frequency of the forced vibration that causes disturbances. At the same time, it is necessary to increase the braking torque of the rotor, and in conventional systems, a damper winding was used to increase the braking torque. By increasing the coefficient of the second term, the braking torque is increased overall.

An embodiment in which this invention is applied to a synchronous motor will be described below with reference to the drawings.

In Figures 2 and 3, 1 is the casing, 2
is the inverter, 3 is the rotor, 3a is the rotor shaft, 4
is a stator, and this stator 4 is made up of a plurality of leaf springs 5.
The rotor 3 is rotatably supported by the casing 1 around the axis of the rotor 3. 6 is a sensor that detects the movement of the stator 4, and a device that uses this sensor 6 to feed back at least one of displacement, velocity, and acceleration (hereinafter referred to as movement) of the stator 4 to the inverter 2 via a measuring amplifier 7. is configured.

In the synchronous motor configured as described above, when the rotor 3 causes torsional vibration due to disturbance during rotation, the stator 4 receives a reaction force from this. In this device, since the stator 4 is rotatably supported on the casing 1 by the spring 5, the stator 4 moves due to the reaction force received by the stator 4, causing torsional vibration. By detecting this movement with the sensor 6, amplifying it with the measuring amplifier 7, and providing feedback compensation to the inverter 2, the torsional vibration of the rotor 3 can be stabilized, and the disturbance of the synchronous motor can be stabilized. .

This disturbance can be stabilized by, for example, increasing the coefficient of the term corresponding to TdΩ in the second term of Equation 1 using the feedback of the inverter 2. In other words, the phase, amplitude, etc. of the power supplied from the inverter 2 can be stabilized. This control is used to change the internal phase difference angle of the synchronous machine. That is, the inverter 2 distributes and outputs the phase, amplitude, etc. to each of the three phases based on the current command signal, but it outputs a signal equivalent to the speed signal of the signal input from the sensor 6 via the measurement amplifier 7. The phase, gain, etc. are adjusted by converting the signal into a current command signal, and the phase is compensated for by feeding back to the current command signal.

Since the stator 4 moves due to the reaction force of the rotor 3, the sign of the feedback signal at this time is in the direction of suppressing this movement. For example, by feeding back the displacement signal of the stator 4 to the inverter 2, advancing its phase using a well-known differential circuit using an operational amplifier built into the inverter 2, and equivalently feeding it back within the inverter 2 as a speed signal. , stabilizes the out-of-order state by damping. Then, in the case of a speed signal, feedback may be performed as is, and in the case of acceleration, it is integrated by a well-known integration circuit using an operational amplifier built in the inverter 2, and is made equivalent to the speed signal, and then feedback is applied. In addition, the frequency of the natural vibration can be changed by feeding back the acceleration signal to equivalently change the first term IdΩ/dt in the above equation, or by changing the third term using a mutation signal, to reduce the forced vibration that is the cause of the disturbance. It is also possible to stabilize the disturbance by appropriately separating the signal from the frequency.

In the above-described embodiment, the stator is supported by a plate-shaped spring, but the present invention can also be applied to a structure in which the stator is rotatably supported around the axis of the rotor and supported by a spring. In addition, in the example, the number of springs is 2.
Although only one example is shown, any number may be used, and the sensor may be a displacement meter, speedometer, accelerometer, etc.

Furthermore, although the above-described embodiments are applied to synchronous motors, this invention can be applied to synchronous generators as well.

As explained above, this invention consists of a device that allows the stator to rotate relative to the rotor axis and supports the stator in the direction of rotation with a spring, and a device that detects the movement of the stator and applies feedback to the inverter. This makes it possible to stabilize rotor irregularities.

[Brief explanation of the drawing]

FIG. 1 is a schematic side sectional view of a conventional synchronous motor, and FIG. 2 is a schematic side sectional view showing an embodiment of this invention.
FIG. 3 is a sectional view taken along the - line in FIG. 2. 1...Casing, 2...Inverter, 3...
Rotor, 4...Stator, 5...Spring, 6...Sensor, 7...Measurement amplifier. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] An inverter that drives a synchronous machine, a rotor of the synchronous machine, a casing of the synchronous machine, a stator of the synchronous machine disposed opposite to the rotor and supported so as to be displaceable with respect to the casing, and displacement of the stator with respect to the casing. means for detecting the amount of state and feeding back a value based on the amount of displacement state to the inverter, and controlling the amount of power supplied from the inverter to each phase of the synchronous machine based on the amount of displacement state of the stator. A synchronous machine characterized in that the internal phase difference angle of the synchronous machine is controlled to approach zero by controlling the phase, amplitude, etc.