JPH0326040B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for a non-commutator motor generator that controls the non-commutator motor generator using a power source obtained by rectifying alternating current.

First, a conventional control device for a commutatorless motor will be explained. Figure 1 shows an example of a control circuit for a conventional non-commutator motor generator, where 1 and 1' are terminals connected to the power supply, 2 is a filter reactor, 3 is a switch, 4 is a current smoothing reactor, and 5 is a current smoothing reactor. A filter capacitor 6 is a separately excited inverter connected in a three-phase Gretz connection, and is constituted by thyristors 61 to 66. 7 is a commutation auxiliary circuit, 7a is a diode, 7b is a thyristor, 7c is a commutation capacitor, and 7d is a commutation reactor. 8,
9 is a starting resistor for limiting the input current at startup, 10 is the armature winding on the motor side, 10a, 10
b, 10c indicate the armature windings of each phase, 11
is the generator side armature winding. The motor-side armature winding 10 and the generator-side armature winding 11 are provided on the stator side. 12 is a field common to the electric motor and generator provided on the rotating side. 13 is an armature winding of a rotating armature exciter, 14 is a field winding of an exciter provided on the stator side, and 15 is a field winding for pre-excitation of the exciter (hereinafter referred to as a field for pre-excitation). 16 is a control unit that controls the generator voltage to a predetermined value;
17 to 19 are rectifying diodes. The filter reactor 2, the current smoothing reactor 4, and the filter capacitor 5 constitute a T-type filter, which functions to suppress harmonics generated by the switching operation of the inverter from flowing into the DC power source.

Furthermore, the reason why the starting resistors 8 and 9 are divided is as follows. In other words, if only one resistor is inserted, when the voltage fluctuation of the DC power supply occurs while the switch 3 is closed and operating, a resonance phenomenon will occur between the filter reactor 2 and the filter capacitor 5, and the problem will easily occur. It will no longer attenuate. In order to prevent such problems, the attenuation of the resonance phenomenon is accelerated by inserting the parts separately in both parts.

In the control circuit shown in FIG. 1, the switch 3 is open at the start of starting, and the armature winding 10 on the motor side
is connected to separately excited inverter 6 via starting resistors 8 and 9.
Electric power converted to alternating current is supplied. At this time, current also flows through the pre-excitation field winding 15 of the exciter, so the exciter generates electricity.As a result, current flows through the field 12, generating voltage in the generator-side armature winding 11, and the motor A back electromotive force is also generated in the side armature winding 10. Note that while the back electromotive force is low, the separately excited inverter 6 cannot smoothly commutate, but during this time, the commutation action is performed by the operation of the commutation auxiliary circuit 7.

When the back electromotive force becomes high enough, separately excited inverter 6
becomes capable of self-commutation. When the back electromotive force further increases, the switch 3 closes, and the starting resistors 8, 9 and the pre-excitation field winding 15 of the exciter are short-circuited, and the motor accelerates further to reach a steady rotation speed.

By the way, the commutation effect of the separately excited inverter 6 due to the back electromotive force of the motor will be explained with reference to FIG. In Fig. 2, 10A, 10B, and 10C indicate the back electromotive force waveforms generated in the motor-side armature windings 10a, 10b, and 10c of each phase with the neutral point as a reference, and the thick solid line indicates the neutral point. The thick broken line indicates the potential of the one-side DC terminal. Just before time _t1 , thyristor 61 and thyristor 62 are ignited, and therefore the motor side armature winding 10 is connected to the DC + side terminal of the inverter.
A waveform of the back electromotive force of the motor side armature winding 10c appears at the one side terminal.

When the thyristor 63 is turned on at time _t1 , the potential of the back electromotive force 10B is lower than the potential of the back electromotive force 10A, so the current flowing through the thyristor 61 is commutated to the thyristor 63, and the thyristor 61 is turned off. . The reverse bias time of the thyristor 61 is the time from time t ₁ to time t ₂ .

Figure 3 is a power supply circuit diagram of a motor generator for a general AC electric vehicle in Japan. It is an example of a power supply circuit that rectifies alternating current and outputs direct current.
They are respectively connected to terminals 1 and 1' in the figure. 31 is a transformer, and 32 is a full-wave rectifier circuit composed of a diode.

By the way, when a non-commutator motor generator is used in an AC overhead contact line section, the following problems occur. In other words, when the load of the non-commutator motor generator is small,
The filter capacitor 5 is peak-charged by the AC full-wave power source and becomes overvoltage. In such a case, if the time t ₁ in Fig. 2 is controlled to be as close to time t ₂ as possible, the DC side voltage of the separately excited inverter 6 (corresponding to the back electromotive force of the DC motor) will increase and balance will be maintained. try to keep it. However, since it is necessary to secure the reverse bias time of the thyristor, the time between time t ₁ and time t ₂ is required to be several hundred microseconds or more, and it becomes virtually impossible to maintain balance. That is, when the overhead line voltage is high and the load on the motor/generator is low, a balanced state cannot be maintained, resulting in overspeed.

The present invention has been made to solve the above-mentioned problems, and the present invention will be explained below based on the drawings of the embodiments.

FIG. 4 is a control circuit connection diagram of a non-commutator motor generator showing an embodiment of the present invention, in which the same parts as in FIG. 1 are given the same reference numerals. The difference between the figure and FIG. 1 is that a thyristor 7e is used in place of the diode 7a constituting the commutation auxiliary circuit 7, and a resistor 20 is added. Note that a power supply circuit as shown in FIG. 3 is connected to the terminals 1 and 1' in the same manner as described above.

In the control circuit of FIG. 4, as shown in the figure, the DC terminal of the separately excited inverter 6, the current smoothing reactor (first reactor), the switch 3, the filter reactor 2 (second reactor), and the AC A closed circuit consisting of a DC power source obtained by rectification is constructed. For the DC power supply, between the current smoothing reactor 4 and the filter reactor 2,
A filter capacitor 5 is connected to form a T-type filter circuit. A starting resistor 9 is connected between the filter capacitor 5 and one end of the switch 3.
(first resistor) is connected. Its starting resistor 9
A starting resistor 8 (second resistor) is inserted between the connection point between the filter capacitor 5 and the other end of the switch 3. A thyristor 7e (the first
thyristor), thyristor 7b (second thyristor), and commutation reactor 7d,
A commutating capacitor 7c is provided in parallel with the thyristor 7b and the commutating reactor 7d, one end of a resistor 20 is connected to the connection point between the thyristor 7e and the thyristor 7b, and the other end of the resistor 20 is a starting resistor. Connected to the intermediate terminal of 9.

That is, at startup when commutation cannot be performed due to the back electromotive force of the motor side armature winding 10, the thyristor 7e
By applying a gate pulse to act as a diode, it operates as a commutation auxiliary circuit in the same way as in the conventional system, and when the separately excited inverter 6 becomes capable of self-commutation due to back electromotive force, commutation starts. Stop the auxiliary operation. After that, when the back electromotive force increases further, the starting resistors 8 and 9 and the pre-excitation field winding 15 of the exciter are short-circuited by closing the switch 3, which accelerates further and reaches a steady state. are the same. By the way, in the conventional system, a commutation auxiliary circuit 7 consisting of expensive parts such as a thyristor, a diode commutation reactor, and a commutation capacitor was provided only during startup, but in the present invention, it is actively used even in a steady state. This is to prevent the problem of acceleration mentioned above.

According to the present invention, when the overhead line voltage is high and the load is light, the charge in the filter capacitor 5 is discharged via the resistor 20 and the thyristor 7b by firing the thyristor 7b. Of course, in this case, the thyristor 7e remains off. The operating frequency of the thyristor 7e may be constant, or if it is variable, the resistor 20 acts as if it were a variable resistor, making it possible to do so without having to keep the capacitor voltage constant. In addition, in contrast to the case where the resistor 7 functions as a commutation auxiliary circuit, the resistor 20 has many advantages such as also functioning as an auxiliary charging resistor.

[Brief explanation of drawings]

Fig. 1 is a control circuit connection diagram of a conventional non-commutated motor generator, Fig. 2 is an explanatory diagram of voltage waveforms at each part to explain its operation, and Fig. 3 is a power supply circuit diagram of a non-commutated motor generator. , FIG. 4 is a control circuit connection diagram of a non-commutator motor generator showing an embodiment of the present invention. 2...filter reactor, 3...switch,
4... Current smoothing reactor, 5... Filter capacitor, 6... Separately excited inverter, 7... Commutation auxiliary circuit, 8, 9... Starting resistor, 10... Motor side armature winding, 11... Generator side armature winding, 1
2... Field, 13... Armature winding of rotating armature type exciter, 14... Field winding of rotating armature type exciter, 15... Field winding for pre-excitation of exciter, 16...
Control unit, 17 to 19...diode, 20...resistor, 31...transformer, 32...full wave rectifier circuit.

Claims (1)

[Claims] 1. Motor-side armature winding of a commutatorless motor-generator that is equipped with the armature windings of the motor side and the generator side on the stator side and also has a built-in rotating armature type exciter that supplies power to the rotating field. A separately excited inverter with a three-phase Gretzz connection that commutates due to a back electromotive force generated in the inverter, a first reactor, a switch, and a second reactor, a first resistor and a second resistor provided in parallel with the switch.
a series connection body of resistors, the first resistor and the second resistor;
A filter capacitor connected between the connection point of the resistor and the anti-reactor side terminal of the DC power supply, and a first polarity added to the inverter input DC current bypass between the DC terminals of the separately excited inverter.
A thyristor, a second thyristor, and a commutation reactor are connected in series, and a commutation capacitor is connected in parallel to the second thyristor and the commutation reactor, and the first thyristor and the second thyristor are connected in series.
A control device for a non-commutator motor generator, comprising a third resistor having one end connected to a connection point of the thyristor and the other end connected to one of the terminals of the first resistor.