JPS5845279B2 - Semiconductor motor control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor motor that uses a controlled rectifier to control the current flowing through an armature winding according to the relative position between the armature and the field of the synchronous motor, and particularly relates to a semiconductor motor that controls the current flowing through the armature winding using a controlled rectifier. The present invention relates to a control device for a semiconductor motor that operates in a highly efficient state.

A semiconductor motor that generates electric torque or braking torque by controlling the current flowing through the armature winding according to the relative position of the armature of the synchronous motor and the field, and generates electric torque most efficiently. In order to do this, the phase of the armature current must be delayed by π/2 with respect to the effective field flux.

Furthermore, in order to generate braking torque most efficiently, the phase of the armature current must lead the effective field flux by π/2.

By the way, in order to detect the mechanical relative position between the armature and the field, a proximity switch, a Hall element, a magnetically sensitive element,
Alternatively, a switching element such as a photoelectric element was used.

However, the effective field magnetic flux is the vector sum of the magnetic flux due to the current flowing in the field winding and the magnetic flux due to the current flowing in the armature winding, and there is a phase difference of approximately π/2 between the two, so the effective field flux is The phase of the magnetic flux will be significantly affected by the magnitude of the armature current.

Therefore, in the conventional system in which the armature current was controlled by simply detecting the relative mechanical position between the armature and the field, sufficient performance could not be obtained.

Therefore, an object of the present invention has been made in view of the above points, and is to detect the relative mechanical position between the armature of a synchronous motor and a field using an AC rotating electrical machine, such as a celsine or an alternating current generator. By shifting the phase of the detected signal according to the armature current value, the relative position between the armature and the effective field flux is detected, and this detection signal is used to control the phase of the armature current, thereby adjusting the armature current. It is an object of the present invention to provide a control device for a semiconductor motor that can always maintain the phase of armature current and effective field flux at π/2 regardless of the magnitude of the current and operate the semiconductor motor in a state with the best power factor and efficiency.

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

FIG. 1 is a block diagram showing one embodiment of the present invention.
0 is a synchronous motor whose field winding 11 is energized by an excitation device (not shown), and whose armature winding 12 is energized by a well-known semiconductor converter 13.

A is a first device that detects the mechanical relative position between the armature 12 of the synchronous motor and the field 11, and this first device A
A second device to which an output signal of the synchronous motor 10 and a signal K related to the armature current of the synchronous motor 10, which will be described later, is applied detects a phase change in the effective field flux of the synchronous motor 10, which changes in accordance with the armature current.

Next, to explain the details of the first and second devices, reference numeral 14 is a Sersin oscillator (hereinafter simply referred to as Sersin), and a three-phase winding 1.
5 and an excitation winding 16, which is energized by an excitation power supply 17.

The Sershin 14 is mechanically connected to the synchronous motor 10, and the armature winding 12 of the synchronous motor 10 and the output of the three-phase winding 15 of the Sershin 14 are coupled so that their electrical phases and frequencies are equal.

Also, the frequency of the excitation power source 1T is sufficiently large compared to the frequency generated by the rotation of the synchronous motor 10.

The respective output ends of the three-phase winding 15 of the Sershin 14 are connected to the ground potential bus 21 via resistors 18, 19, and 20 separately, and the phase voltages are synchronized with each other by taking out each phase voltage with respect to the ground potential. Apply to rectifier 22°23.24.

The synchronous rectifiers 22, 23, and 24 receive signals from the excitation power source 17 and synchronously rectify the three-phase winding output of the Sershin 14 in synchronization with the excitation power source 17.

The outputs of the synchronous rectifiers 22, 23, 24 are smoothed by smoothing circuits 25, 26, .
27 respectively.

The output W1 of the smoothing circuit 270 is added to one input of the multiplier 28, the output U of the smoothing circuit 25 is added to one input of the multiplier 29, and the output v1 of the smoothing circuit 260 is added to one input of the multiplier 30. A signal K is commonly applied to the other input of .30.

The outputs of the smoothing circuits 25, 26 and 27 are connected to resistors 31 and 27 respectively.
In addition to the operational amplifier 34° 35.36 through 32.33,
Furthermore, the operational amplifiers 34, 35° 36 are provided with multipliers 28, 29,
30 outputs are applied through resistors 37, 38 and 39, respectively.

Also, a feedback resistor 40 is connected in parallel to the operational amplifiers 34, 35, and 36.
．． Connect 41.42 and operational amplifier 34.35 respectively.
, 36 respectively to U3. ■3°W3, and this signal U3. U3. W3 controls the phase of armature current.

Further, the resistance values of the resistors 31 to 33, 37 to 39, 40 to 42 are set to 1.

The present invention having the above configuration will be described in detail below.

If all the synchronous motors 10 are rotating at a speed of Since they are coupled as described above so that ω (rad/sec), for example, the output of the U-phase winding of the Selsyn 14 has a waveform as shown by the solid line in FIG. 2a.

This waveform is synchronously rectified by the synchronous rectifier 22 and converted into the waveform shown by the solid line in FIG. 2, and by passing it through the smoothing circuit 25, it becomes the waveform U1 shown in FIG. 2C.

Also, the output ■ of the smoothing circuit 26 and the output W1 of the smoothing circuit 27
Similarly, the electrical angular frequency becomes a sinusoidal waveform of ω (rad/5ec), and the respective outputs U1j V, , Wl are expressed by the following formulas.

This output U1. Vl and wl indicate the mechanical relative positions of the armature of the synchronous motor and the field.

That is, the mechanical relative positions of the U-phase armature winding and field winding 11 of the synchronous motor 10 in FIG. Assuming that the U-phase winding is rotating at the electrical angular frequency ω in the direction shown in the figure, and that it does not interlink with the field flux at the position shown, this position is
This is the P1 position shown in the figure.

P2 is the position where the U-phase winding is rotated clockwise from the position shown, P8 is the position where the U-phase winding is further rotated clockwise from the P2 position, and P8 is the position where the U-phase winding is rotated further clockwise from the P3 position. The position where the U-phase winding is rotated by 2π from the illustrated position is P4.

Therefore, when the armature current is small, P2 in the U-phase winding
If we make a sinusoidal current flow so that the maximum positive current flows at the position P4, and the maximum negative current flows when it reaches the P4 position, the phase of the armature current will be approximately - with respect to the effective field flux. Maximum torque can be produced with a delay.

However, as mentioned above, the effective field flux is the vector sum of the magnetic flux due to the current flowing in the field winding and the magnetic flux due to the current flowing in the armature winding, so as the armature current increases, the phase of the effective field flux changes. , it is necessary to compensate for this phase change by increasing the phase of the armature current by 11 legs.

Each output U3°V8j W of operational amplifiers 34, 35, and 36
8 is a signal used to control the phase of the armature current, and this output U3#V3jW3 is extracted as follows.

That is, each output U1 svl of the smoothing circuits 25, 26, 27
, W1 are expressed by the above equations (1), (2), and (3), and since the above W1 and the signal K are applied to the multiplier 28, the output W2 of the multiplier 28 is a tonal.

The aforementioned U1j V□# W1# U2# V2jW2 and -U3. -V3. -W3 relationship is shown in FIG. 3.

Therefore, since (11) and (12) are functions of K, the value of A and the value of θ change as shown in FIG. 4 as K changes.

That is, when the value of K is changed from O to 1, θ changes from O to -
will change until.

For example, if = 0.5 (from formula 12, 7 guns x 0.5
1 π θ=tm 1- =tan 2-0.5 J"' j Vl and Wl have a -leading phase by π.

In this way, by changing the value of K, the operational amplifier 34
, 35.36 output-U3. -V3. The phase of -W3 can be changed in the range from 0 to - with respect to the output U1j V1# Wl of the smoothing circuit 25°26.27.

If we consider again the change in the phase of the effective field flux as the armature current increases, this phase change is not directly proportional to the armature current due to the effects of the characteristics of the motor's magnetic circuit. Once the motor is determined, the phase change corresponding to the armature current can be found.

For example, if it is known that the phase of the effective field flux changes by θ when the armature current is Δ, then this phase change in the effective field flux can be compensated for by advancing the phase of the armature current by θ.

Therefore, the signal K given to the multipliers 2B, 29, 30 may be converted into a predetermined function by adding a signal proportional to the armature current of the synchronous motor 10 to the function generator FG shown in FIG.

As a result, for example, if a current flows through the armature, the operational amplifiers 34, 35° 36, -U, , -V3. -Ul for the output of W3.

Since a signal whose phase is θ more advanced than Vl and Wl is obtained, if the phase of the armature current of the synchronous motor 10 is controlled by this signal -U3j-V3j-W3, the phase of the effective field flux and armature current can always be - Since the motor can be maintained at a constant temperature, the motor can be operated with good power factor and efficiency without being affected by armature reaction.

In the above explanation, the case where the synchronous motor 10 generates an electric torque was explained as an example, but when the synchronous motor 10 generates a braking torque, for example, the output U1. V1.
Outputs of operational amplifiers 34, 35, 36 for W□-U3.
-V3. - Requires output of delayed phase as W3.

In this case, the signals may be connected as indicated by dotted lines so that the signal Vl is applied to the multiplier 28, the signal Wl is applied to the multiplier 29, and the signal Uo is applied to the multiplier 30.

Then, when generating the electric torque and when generating the dynamic torque, it is only necessary to switch between them using a switch (not shown) or the like.

When using a Selsyn, the frequency of the Selsyn excitation power source must be sufficiently high compared to the frequencies of Ul, Vl, and Wl, so there are some restrictions when operating a synchronous motor at high speed.On the other hand, when an AC generator is used, Since the induced voltage is low, low-speed operation is limited to some extent, but unlike when using Cersin, there is no restriction due to excitation frequency, so it is suitable for high-speed operation.

Therefore, when the speed is low, the Selsyn is subjected to AC excitation, and the voltage obtained in the three-phase winding is synchronously rectified to produce the signal U.
1. v1. W1, and at high speeds, it is switched to DC excitation and used as an alternating current generator to directly obtain signals Ul aVl and Wl, making it possible to control over a wide range from zero speed to high speed.

Furthermore, it can be applied not only to three-phase synchronous motors but also to multi-phase synchronous motors.

As explained above, the present invention detects the phase change of the effective field flux that changes depending on the armature current, and controls the armature current with this detection signal, thereby controlling the armature current regardless of the size of the armature current. It is possible to provide a control device for a semiconductor motor that can operate with good power factor and effectiveness by always maintaining the phase with the effective field flux at -.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the invention, and FIGS. 2 to 4 are diagrams for explaining the invention in detail. A...first device, B...second device, 10...
Synchronous motor, 13... Conversion device, 14... Sershin, 17... Excitation power supply, 22, 23, 24... Synchronous rectifier, 25.26, 27... Smoothing circuit, 28, 29,
30... Multiplier, 34, 35, 36... Operational amplifier.

Claims (1)

[Scope of Claims] 1. A synchronous motor energized by a semiconductor conversion device, an AC rotating electric machine having a three-way armature winding and an excitation winding, the rotating shaft of which is connected to the synchronous motor, It is composed of a high-frequency excitation power source that excites the excitation winding of the rotating electric machine, and a synchronous rectifier circuit that demodulates the output of the three Japanese-style armature windings, and is configured to adjust the relative mechanical position of the armature of the synchronous motor and the field. 3 responded
a first device for deriving a phase signal; and a signal obtained by multiplying the output signal of the first device by a signal related to the armature current of the synchronous motor, and the output signal of the first device. a second device for deriving a three-phase electric signal corresponding to an effective magnetic field flux of the synchronous motor that changes according to an armature current of the motor, and controlling the semiconductor conversion device with an output signal of the second device; A control device for a semiconductor motor, characterized in that the phase between the armature current of the synchronous motor and the effective field flux can be controlled in accordance with the armature current of the synchronous motor. 2. A synchronous motor energized by a semiconductor converter, 3. An AC rotating electric machine having a Japanese-style rotor winding and an excitation winding, the rotating shaft of which is connected to the synchronous motor, and the excitation winding of this AC rotating electric machine. a high-frequency excitation power source and a DC excitation power source for exciting the AC rotating electric machine; a synchronous rectifier circuit for demodulating the output of the three Japanese-style armature windings; and a synchronous rectifier circuit for demodulating the output of the three Japanese-style armature windings; a first device configured with a bypass circuit that directly outputs the output of the synchronous motor and derives a three-phase electric signal according to the mechanical relative position between the armature of the synchronous motor and the field; and the output of the first device. A multiplication signal of the signal and a signal related to the armature current of the synchronous motor corresponds to an effective field flux of the synchronous motor that changes according to the armature current of the synchronous motor from the output signal of the first device. a second device for deriving a three-phase electric signal, and controlling the semiconductor conversion device with an output signal of the second device to determine the phase of the armature current and effective field flux of the synchronous motor. The excitation winding of the AC rotating electrical machine is excited by the high frequency excitation power source when the synchronous motor is operating at low speed, and is excited by the DC excitation power source during high speed operation. A control device for a semiconductor motor, characterized in that the synchronous rectifier circuit is bypassed and the output of the AC rotating electric machine is directly derived.