JPS6070982A - Brushless synchronous motor - Google Patents

Abstract

PURPOSE:To suppress the variation in the torque of a brushless synchronous motor by holding symmetry in the polarity for a voltage induced in a main field winding and a current flowed by the voltage during asynchronous starting operation. CONSTITUTION:When a slip becomes a low value such as approx. 5%, a main field winding 42 abruptly becomes always open state. At this time, the voltage of a main field winding 42 is applied to the induced voltage detecting resistor 511 of an adaptive phase connecting controller 51, and a thyristor 11 of a rotary rectifier 1 is turned ON through an excitation signal holding circuit 52 and a gate circuit 53. At this time an exciter field winding 22 is already excited, and the winding 42 may be immediately DC-excited. Thus, asymmetrical state due to the polarity of the induced voltage of the winding 42 does not become in all asymmetrical states.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a brushless synchronous motor device capable of suppressing torque pulsation caused by field circuit asymmetry of a main engine synchronous motor.

[Technical background of the invention and its problems]

Recently, planless synchronous motors have become common for the purpose of reducing maintenance and inspection. However, when starting a brushless synchronous motor using a lever, an asynchronous start is used, similar to an induction motor, but conventionally, due to the asymmetry of the field circuit, transient torque consisting of pulsating torque is coupled to the load. Torsional vibration is applied to the rotating shaft, which may lead to a serious accident such as the rotating shaft breaking due to repeated action.The rotating shaft must be thick and strong, and has the disadvantage of being extremely expensive. As a result of investigating the cause of this torsional vibration, the inventor found the cause, which will be explained with reference to FIG.

FIG. 1 is a circuit diagram of an example of a conventional brushless synchronous motor device with a so-called automatic synchronization closing circuit in which automatic synchronization pull-in is performed. In diagram W&1, (1) is a rotating rectifier consisting of a thyristor (01) and a diode (2).
) is an AC exciter consisting of an excitation armature winding Cυ and an exciter field winding (2 hot currents), (3) is a short-circuit control thyristor circuit with a thyristor Oυ and a diode 0″3 in antiparallel, (4)
is a main machine synchronous motor consisting of a main machine armature winding (40) and a main machine field winding (4). A rotor (not shown) having an excitation armature winding Cυ of the machine (2), a rotating rectifier (1), and a short-circuit control thyristor circuit (
3) etc. are provided coaxially with a rotating shaft (not shown). At the initial stage of startup, the thyristor (II) of the rotary rectifier (1) is in the off state, and the short-circuit control thyristor circuit (3) short-circuits the main machine field winding (421) via the discharge resistor (c), causing abnormal induced voltage. However, near the synchronous speed at the end of starting, the value of the voltage induced in the main engine field winding (431 knee) becomes small, and when one terminal (J) has a negative polarity voltage, the diode is shorted at the terminal (J)
When is a positive polarity voltage, if the voltage is lower than the voltage (also called clip voltage) that operates the constant voltage diode 0!19 and turns on the thyristor Gυ, the thyristor Gυ is turned off. Such a state occurs when the slippage is between about 5% and about 2%. Further: When the second slip decreases to about 2%, the appropriate phase input control circuit (51) issues a signal to turn on the thyristor (11J) of the rotary rectifier (1), and the main machine field winding (43 turns on DC excitation). The synchronizing force causes the synchronous speed to be pulled in. However, between 5% and 2% slip, when the one terminal (J) is positive, the main engine field winding (4 is open because thyristor c31) is off, and when it has negative polarity, it is short-circuited by the discharge resistor (c), and depending on the polarity, the main machine field winding (4z (corresponding to the secondary side of an asynchronous machine) At this time, an intermittent current flows in a fixed direction in the main machine field winding (4 forces), which increases the torque fluctuation of the motor and causes a large twist with respect to the rotating shaft. This causes vibrations, increases fluctuations in the armature current, and disturbs the power supply.

[Purpose of the invention]

The present invention eliminates asymmetry in the current flowing through the main machine field winding not only at the initial stage of startup, but also when the slippage before synchronous pull-in is between about 5% and 2%.
It is an object of the present invention to provide a brushless synchronous motor device that reduces disturbance to a power source and has smooth starting characteristics.

[Summary of the invention]

Invention? =, the rotor of the main machine synchronous motor, the rotor of the AC exciter, and the rotary rectifier are coaxially arranged, and the main machine field winding of the rotor of the main machine synchronous motor is connected to the exciter machine of the rotor of the AC exciter. In a brushless synchronous motor device that supplies excitation current by converting the output of a child winding into DC ζ2 using a rotary rectifier C2, a short-circuit control thyristor circuit with two thyristors arranged in anti-parallel is connected in parallel with the main machine field winding. The gate circuit of each thyristor of this short-circuit control thyristor circuit is connected with a constant voltage diode that operates at approximately the same predetermined voltage, and the gate circuit of each thyristor of this short-circuit control thyristor circuit is connected with a constant voltage diode that operates at approximately the same predetermined voltage. When the voltage exceeds the voltage value, the thyristor becomes short-circuited, and the thyristor becomes conductive.
It is composed of electronic components such as resistors, capacitors, and diodes, and has an appropriate phase input control circuit that detects the field induced voltage and issues a conduction signal from the appropriate frequency and phase port to the main machine field winding of the rotary rectifier. When the main engine synchronous motor is started, the voltage induced in the main engine field winding decreases, and the appropriate phase switching control circuit is operated in a rotational speed range above which the short-circuit control thyristor becomes non-conducting. By making the excitation current flow through the field winding ζ2, the asymmetry of the current flowing through the main field winding is eliminated and smooth startup is achieved.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention (two examples) will be explained with reference to FIG. 2. In FIG. (2) is an AC exciter consisting of an excitation armature winding (21) and an exciter field winding (221). (3) is an AC exciter consisting of two thyristors Cl1),
This is a short-circuit control thyristor circuit in which C14) are connected in antiparallel.

(4) is the main machine armature winding (41) and the main machine field winding (42).
This is a main synchronous motor consisting of 1. Main engine synchronous motor (4
) main machine field winding (a rotor (not shown) having a four-way
A rotor (not shown) having an excitation armature winding (CI) of the AC exciter (2), a rotating rectifier (1), a short-circuit control thyristor circuit (3), etc. are coaxially mounted on a rotating shaft (not shown). ing. The output of the excitation armature winding (2υ) is connected to the AC input side of the rotary rectifier (1).The DC output side of the rotary rectifier (1) is connected to the main machine field winding (421) and the short-circuit control thyristor circuit. Discharge resistor (to) is connected in series with (3) 3
connected in a parallel circuit with the second one. Let one terminal be (J) and the other terminal be (J). Each thyristor (31) of the short-circuit control thyristor circuit (3), C
The gate circuit 34) is connected to each anode through constant voltage diodes O2 and C161 which operate at approximately the same predetermined voltage. In addition, C2 between both terminals (J) and (K) is an induced voltage detection resistor (511
It is composed of electronic components such as resistors, capacitors, diodes, etc., and detects the field induced voltage and issues a conduction signal to the main machine field winding (42) of the rotary rectifier a1) at an appropriate frequency and phase. A proper phase input control circuit (51) is connected.From this proper phase one phase input control circuit (51),
As in the conventionally known system, an excitation input signal holding circuit (52
) and a gate circuit (53), the rotary rectifier (1
) is configured to be able to give an ignition signal that turns on the thyristor 0υ.

Next, I will explain the effect of one soldier.

The rotational speed of the main engine synchronous motor (4) increases from an asynchronous start (secondary stop (slip = 1.0). At this time, an AC voltage is induced in the main engine field windings (four terminals (J )
, (K) is open state (induced voltage detection resistor (511)
A very high voltage will be induced if there is a short circuit (which can be ignored because the resistance is high), but if there is a short circuit, an induced current will flow. Now, one terminal (J)! = If a positive polarity voltage is induced, the short-circuit control thyristor circuit (3)
Since the thyristor aυ on the left side of FIG. 2 is non-conducting, it attempts to generate a high voltage. However, when the constant voltage diode (c) exceeds its operating voltage (clip voltage), the impedance becomes small, turning on the thyristor Gυ,
The main machine field winding 0 is short-circuited by a discharge resistor (c). Therefore, a short circuit current flows, and the voltage across the main machine field winding (6) is suppressed to a voltage determined by this current and the discharge resistance value. In the next half cycle, the one terminal (J) becomes negative polarity C2, so the left thyristor Gυ turns off, and a high voltage with the opposite polarity to that in the previous half cycle is about to be induced. However, this time, when the operating voltage of the constant voltage diode (to) of the right thyristor (b) suddenly decreases, the impedance of the right thyristor (b) suddenly decreases.
When the main machine field winding is turned on, the main machine field winding is short-circuited by the discharge resistor (to), and a short-circuit current flows. Defining voltage diode Gtsu, (
Since the operating voltages of the main machine field windings (43) are almost the same, the above operation means that either polarity is equivalent to the short-circuited state from the main machine field winding (43), and the symmetry of the polarity (= .

Next (2) The rotational speed increases and the slippage is at a low value of about 5% (
=, the induced voltage at the main machine field winding (4) decreases.Then, its value is equal to that of the constant voltage diode (3!it).

When the voltage falls below the operating voltage (clipping voltage) of (to), none of the thyristors G1) and (G1) are turned on anymore.

That is, the main machine field winding (42) turns around and is always in an open state. However, unlike the conventional case shown in FIG. 1, it does not become an asymmetric state due to polarity. (51) Induced voltage detection resistor (511
) -2 is the main machine field winding (43 voltage is applied, and as per the conventionally known mechanism, the function of detecting the slip frequency and phase is demonstrated, and the combination of electronic components such as resistors, capacitors, diodes, etc.) An excitation closing signal is generated at a slip frequency and phase timing of approximately 2% determined by the excitation closing signal, and the thyristor (111) of the rotary rectifier (1) is turned on through the excitation closing signal holding circuit (52) and the gate circuit (53). At this time, the exciter field winding (=) of the AC exciter (2) has already been energized, and power has been established in the excitation armature winding 29. It is also conventionally known that the main machine field winding (4) can be excited with direct current immediately. This exciting current generates a synchronizing force, changing the main machine synchronous motor (4) from an asynchronous state to a synchronous state. The engine is pulled in and starting is completed.

The effects of this embodiment will be described as follows.

Any asynchronous state, that is, each thyristor 61), (b) of the short-circuit control thyristor circuit (3) is turned on 5
The polarity of the induced voltage in the main machine field winding (43 There is no asymmetry at all.

Therefore, compared to the conventional configuration shown in FIG. 1, fluctuations in torque and armature current are significantly improved. This will reduce the torsional vibrations generated on the rotating shaft connected to the load, increasing the stability of the mechanical system and improving reliability.Especially around 5 to 2% of the synchronous speed. In case of slippage, this is the region where the torque generated by the main engine synchronous motor (4) is the largest (see Figure 3), and this is also the region where the load reaction torque increases, so reducing torque fluctuations will result in smooth acceleration. For example, Fig. 3 shows the relationship between the generated torque and slip during asynchronous starting, but the conventional example shown in Fig. 1 in the range of 5 to 2% slip is the main engine industry standard. Asymmetry in the induced voltage and short-circuit current of the magnetic winding (44) The pulsating torque width varies in the widths of Tpmin and Tpmax shown by the broken line, intersects at the intersection point A' with the load reaction torque curve, and the pulsating torque width of the magnetic winding (44) The rotational speed may not increase until it slips.In contrast,
In this example, as shown in the curve shown as the motor generated torque in Fig. 3, since there is no pulsation in the torque, the curve intersects with the load reaction torque curve at point A and accelerates to a speed where the slip is less than 2%. This makes synchronous pull-in possible.

In the embodiment shown in FIG. 4, the discharge resistor 03 of FIG. 2 is removed. The number is as shown in Figure 2.

The effects of doing so include the following points.

(1) Since one of the parts (discharge resistor) attached to the rotating shaft is eliminated, the structure of the rotor is simple, and there is an advantage of miniaturization such as shortening of the axial length.

This will improve mechanical structural reliability,
This is especially advantageous for high-speed aircraft.

(2) Since there is no loss or heat generation within the discharge resistor (to), there is no influence on the appropriate phase input control circuit (51), etc., which is comprised of semiconductors, etc. that are relatively lacking in heat resistance, and the dimensional C A control circuit device with a high degree of freedom in selecting the placement location can be constructed using only two hands.

Other functions and effects are similar to those of the embodiment shown in FIG.

In the embodiment shown in FIG. 5, the rotary rectifier (1) shown in FIG. 4 has a complete bridge configuration with six diodes at side a, and an excitation input thyristor (6) is provided in the DC excitation circuit. It is configured to have a function of being turned on and excited by a signal from the gate circuit (53) when it is off and synchronously pulled in.

Even in this case, the same effect as the embodiment shown in FIG. 4 can be obtained.

〔Effect of the invention〕

As explained above, according to the present invention, during the asynchronous start of the main engine synchronous motor from a stopped state to start completion synchronous pull-in, the voltage induced in the main engine field winding and the current caused by the voltage On the other hand, since the symmetry due to polarity is maintained, it is particularly effective in suppressing torque fluctuations in the region where slippage is small and the torque generated by the motor is highest, and the life is extended against torsional vibration fatigue applied to the rotating shaft. ,
It is possible to provide a brushless synchronous 11-machine device that is highly reliable over a long period of time.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing a conventional brushless synchronous motor device, FIG. 2 is a circuit diagram showing an embodiment of the brushless synchronous motor device of the present invention, and FIG. 3 is a starting-up of the device shown in FIGS. 1 and 2. A curve diagram that compares and shows torque characteristics! J4 diagram and! J
FIG. 5 is a circuit diagram showing other different embodiments. 1... Rotating rectifier 2... AC exciter 21... Armature winding for excitation 3... Short circuit control thyristor circuit 31. 34... Two thyristors 35, 36... Constant voltage diode 4... Main machine synchronous motor 41... Main machine armature winding 42... Main machine field winding 51... Appropriate phase closing control circuit 52... Excitation closing signal holding circuit 53... Gate circuit Agent Patent Attorney Inoue - Male

Claims (1)

[Claims] The rotor of the main synchronous motor, the rotor of the AC exciter, and the rotary rectifier are coaxially arranged, and the output of the exciter armature winding of the rotor of the AC exciter is connected to the main field winding of the rotor of the main synchronous motor. In a brushless synchronous motor device that supplies excitation current by converting the current into direct current using a rotary rectifier, a short-circuit control thyristor circuit in which two thyristors are arranged in anti-parallel is provided in parallel with the main machine field winding, and this short-circuit control thyristor circuit The gate circuit of each thyristor is connected to each anode with a constant voltage diode that operates at approximately the same predetermined voltage, and when a predetermined voltage value or more is applied in the forward direction to each short-circuit control thyristor, the thyristor becomes short-circuited. It is configured to conduct, and is further configured with electronic components such as resistors, capacitors, and diodes in parallel with the main machine field winding, and detects field induced voltage.
An appropriate phase input control circuit is provided to issue a conduction signal to the main machine field winding of the rotary rectifier at an appropriate frequency and phase, so that during starting of the main machine synchronous motor, the voltage induced in the main machine field winding C2 decreases; The brushless synchronizer is characterized in that the short-circuit control thyristor is in a non-conducting state (C2) to operate the appropriate phase input control circuit in a range of rotational speed or higher, and to cause an exciting current to flow through the main machine field winding. Electric motor equipment.