JPS5959091A - Operating method for commutatorless motor - Google Patents

Abstract

PURPOSE:To start a commutatorless motor without using a particular starter and a position detector by generating starting torque by operating a wound-rotor induction machine used as an exciter of a main synchronous motor as a motor at the starting time to generate a starting torque. CONSTITUTION:A switch 6a is first closed at the starting time, 3-phase voltages (a)-(c) are applied in the sequence of the phases becoming the same as the rotating direction of a rotor in the rotating direction of a magnetic field produced by the primary coil 3a, an induction machine is operated as a motor to generate a torque. When the speed rises to several % of the maximum speed to reach the speed so that sufficient counterelectromotive force is generated at the main synchronous motor due to commutation of the power inverter, the switch 6a is opened, the switch 6b is closed, the voltage is applied to the primary coil 3a through a voltage regulator 8 in the sequence of the phases reverse to the rotating direction of the rotor in the rotating direction of the magnetic field, the secondary induced voltage generated as a generator is applied through a rectifier 4 to the field 2b. A variable frequency voltage is applied from the power inverter to the armature 2a, thereby starting generating torque by the main synchronous motor.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a commutatorless motor.7. Especially regarding its operating method.

[11 points between the technical background of the invention and the background art] There are two types of drive circuits for non-commutated motors: DC and AC.However, in the case of a DC drive circuit, the commercial power source must be converted to DC once. After that, it is inversely converted to a variable frequency voltage, and the motor is operated at variable speed. The commutation operation that transfers the current from one phase (human phase) to another phase (B phase) for reverse conversion uses the back electromotive force from the electric motor. , This back electromotive force is caused by the back electromotive force.Therefore, a method for starting each scale was devised.

The most common method is what is called the intermittent starting method. This selects the phase to be applied in the desired direction σN/rukku based on the signal from the rotor position detector directly connected to the motor.
The thyristor elements of that phase are ignited, and then when the rotor moves and it becomes necessary to commutate the recurrent to the next phase, the voltage on the DC side is temporarily reduced to zero and all thyristor elements are turned off. This is a method of igniting the necessary thyrisk element again. Although this method is widely adopted because it is simple, it has the following drawbacks.

(a) Torque ripple occurs due to intermittent current flow.

(b) A rotor position detector is required.

However, recently, as motor operating technology, a control method has been developed that calculates commutation timing from motor terminal voltage, current, etc. without using a rotor position detector in order to improve power factor, efficiency, and reduce torque ripple in high-speed ranges. is being adopted. This is an excellent control method 11 in that it is not affected by failures caused by the rotor position detector because it does not use the []-evening position detector in the high speed range. However, in the city □ motive start roll IN), the position detector is used, so let's talk about it first! It had the same drawbacks as .

In order to start the motor without using any position detector, there is a method of directly connecting another starting device such as a hydraulic morph or pony motor to the electric motor, but this method has the disadvantage that the device becomes very complicated.

[Purpose of the invention]

The object of the present invention is to solve the above-mentioned problems and to provide an operating method capable of starting a commutatorless motor without using a separate starting device or a position detector.

[Summary of the invention]

The method of operating a commutatorless motor according to the present invention uses a C winding and an Iy barrel machine as the exciter of the main synchronous motor, and connects the secondary winding, the field of the main motor, and the rectifier to the rotor. At the time of starting, the induction machine is operated in conjunction with the electric motor to generate starting torque, and after the completion of starting, the induction motor is generated. Excite the induction machine so that the rotation speed matches the rotation speed of the rotor, and the secondary induction 1; 1, the river! Apply to the field of the main synchronous motor via li′ξ current 2:÷! 1' is blasphemous.

[Embodiments of the invention]

FIG. 1 shows a stator/a and a rotor/b of a commutatorless electric motor. As shown in the figure, the heating parts 6ti', 71 (, motive/
are the main synchronous motor λ and the winding swelling conductor 3, , q+'2
Including Nagasaki Rito. Main motor armature, 2a and induction motor 3
The primary winding 3a is provided on the stator la side, and the field 2b of the main motor unit, the secondary winding 3b of the induction machine 3, and the rectifier are provided on the rotor lb side.

A variable frequency three-phase voltage is applied to the armature 2a of the main motor from a main drive circuit S as shown in FIG. In the illustrated example, this main drive circuit is of the DC type, and includes a forward converter (left) a that converts three-phase AC (alternating current) al b, c to direct current, a direct current reactor (tb), and a reverse converter (left) that converts direct current to variable frequency alternating current. It has a converter Sc.

Fig. 3 shows the excitation power supply circuit connected to the primary winding 3a of the induction machine 3. When the induction machine is operated as a lightning motor, the switch 6a is closed and the secondary winding 3a is connected to the primary winding 3a. Three-phase voltages a, b, and c are applied in a phase order such that the direction of rotation of the magnetic field is the same as the direction of rotation of the rotor. On the other hand, when the induction 414 is operated as a generator, the switch Ab is closed and the voltage regulation circuit is connected to the phase 11j3 opposite to the above, that is, in a phase order in which the direction of rotation of the magnetic field is opposite to the direction of rotation of the rotor. A voltage is applied through g. Induction machine works as a generator 1. 7, the secondary induced voltage is applied to the field 2b via the rectifier 2b, as shown in FIG. Note that ri is a discharge resistor. The secondary induced voltage of the induction machine increases in proportion to the slip by 5 tc, as shown in FIG. 5, when the negative secondary voltage is kept constant. For example, if the magnitude of the rotational speed of the field and the magnitude of the rotor speed are the same (because the rotational directions are opposite as above), the slip is When the rotational speed is //10, the slips are /, /, and the quadratic induction 117.corresponds to the points S=λ, s−i, and i, respectively. A river occurs. The voltage adjustment circuit g is used to adjust the voltage applied to the -order winding 3a so that the excitation applied to the field S is constant regardless of the speed of the rotor.

Non-commutated electric in! with the above configuration! To start the + position, first close the switch 4a and operate the induction machine as an electric motor to generate l.r.k., increase the speed to several points above the maximum speed (highest value of the variable range), When a sufficient back electromotive force is generated in the main motor for commutation of the reverse converter &c, the switch Aa is opened and the switch 6b is closed. Then, the voltage adjusted by the adjustment circuit g is applied to the primary winding 3a, and the generated secondary induced voltage is applied to the field 2b via the rectifier g.

On the other hand, armature 2a has a reverse converter! ;A variable frequency voltage is applied from C, and the traction motor begins to generate torque.

In the above embodiment, the four voltages applied to the induction machine were supplied from the fixed frequency power supplies a, b, and e, but at the time of starting or after the completion of starting, It may also be supplied from a variable frequency power supply. If a variable frequency power source is used during starting, the starting torque can be increased even further. Further, if a variable frequency power source is used after the start is completed, this power source can also have the role of voltage adjustment, and the voltage adjustment circuit g can be omitted.

In addition, in the above embodiment, when the induction W town is operating as a power generation VW, the rotation direction of the magnetic field or the rotation direction of the rotor is reversed. If the height or direction) do not match, that is, there is slippage (
, if this multiplicity is satisfied, even if the rotation direction is the same, the number of poles and rotation speed range of the induction machine can be appropriately selected, and the rotation speed of the induction machine's magnetic field when operating as a generator (long). The rotation speed of the rotor must match the rotation speed of the rotor. This is good. This platform also uses a variable frequency power source, and its frequency can be increased or decreased in accordance with the frequency used to drive the main motor. By doing so, it is easy to avoid coincidence of the rotational speed of the rotor and the rotational speed of the magnetic field as described above.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to start a motor instantly without using a position value detector or without using a separate mechanical starting device rT. Can be done.

[Brief explanation of the drawing]

The first port 1 is a thermal rectifier I1 (i, a schematic diagram showing the stator 5 and the rotor of the motor, Fig. Figure 7 is a diagram showing the power supply circuit, Figure 7 is a diagram showing the connection between the induction machine and the main motor when operating with a generator, and Figure S is a diagram showing the characteristics of the induction machine. ... Main motor 1.2h... Field, 3... Induction machine, 3b... Secondary winding, l... Rectifier, 4a, 4b.
...Switch, g...Voltage adjustment circuit. Applicant's agent Kiyoshi Inomata Figure 1 Figure 5

Claims (1)

[Claims] (Using four winding swelling machines as an exciter for the main synchronous motor of the Shunbu commutator motor, and providing the secondary winding, the field of the main synchronous motor, and the rectifier on the rotor side, At startup, the induction machine operates as an electric motor to generate starting torque, and after completion of the start, the induction machine operates as a generator so that the rotation speed of the magnetic field matches the rotation speed of the rotor. A method of operating a commutatorless motor in which If!j 'B'Q is used to excite the motor and apply a secondary induced voltage to the field of the main synchronous motor via a rectifier. In the method described in item 1, after completion of starting, the induced QR machine is excited so that the rotation direction of the magnetic field of the induction machine is opposite to the rotation direction of the rotor.
How to use it as a sign.