CN108880363A - Three-level formula brushless synchronous machine asynchronous starting control method and system - Google Patents

Abstract

The invention discloses a kind of three-level formula brushless synchronous machine asynchronous starting control method and systems, the control method is passed through three-phase alternating current to main generator threephase armature winding by starter controller in the starting-generating system start, starting exciting current is not provided, it only relies on the induction torque generated due to Damper Winding and realizes start-up function, starter controller is powered by starting power unit.The system start stage is passed through alternating current to main generator armature winding, due to the Damper Winding on main motor rotor, will generate induction torque, and the start-up function of system is realized by induction torque.Such method for starting-controlling only needs a set of three-phase inverter that start-up function can be realized, and simplifies method for starting-controlling, reduces the complexity of whole system.

Description

Three-stage brushless synchronous motor asynchronous start control method and system

technical field

The invention relates to an aviation starting and generating system, in particular to a starting method of a three-stage brushless synchronous starting and generating system, belonging to the technical field of aviation motors.

Background technique

At present, most aircraft AC power systems use a three-stage brushless synchronous motor as a generator, and the engine is started by a DC starter, an air turbine starter or a gas turbine starter. However, such a starting system has a large volume and weight and low reliability. A simple and feasible way to realize the integration of starting and power generation is to directly omit the special starter on the basis of the existing power supply system, and run the three-stage brushless synchronous generator in the electric state according to the principle of reversibility of the motor. to start the engine.

However, when the three-stage brushless synchronous motor is used as the starter of the engine, there are the following problems: when the motor is stationary, if DC excitation is used, the armature of the exciter cannot deliver excitation power to the excitation winding of the main motor; when the motor is running at a low speed, this DC excitation can be used to provide excitation for the main motor, but the excitation power cannot meet the starting requirements.

In view of the above problems, the patent US7687928 discloses a three-stage brushless synchronous motor excitation structure and control method. An additional set of three-phase AC excitation windings is added on the stator side of the exciter. During the starting process, the three-phase AC excitation windings work and generate electricity. During the process, the DC field winding works. The three-phase AC excitation scheme can provide a large main motor excitation current, a large output torque of the main motor, and a small required inverter capacity. But this solution has obvious disadvantages, that is, it needs to change the structure of the main exciter, including the structure of the iron core and winding, which will make the three-stage synchronous motor, which is already very complicated in structure, more complicated. Patent US7821145 discloses a single three-phase AC excitation winding to achieve dual functions of AC and DC excitation. Three-phase AC excitation is used in the initial stage of starting, and the three-phase windings are connected in series to form a set of windings by controlling the contactor in the later stage of starting and power generation. DC excitation mode. This method improves the utilization rate of the excitation winding, but the coordinated control of the three-phase AC excitation control and the single-pole double-throw switch increases the complexity of the AC and DC excitation switching. Patent US6906479 discloses a single-phase AC excitation method that uses multiple sets of excitation windings wound on each stator pole of the exciter. In order to obtain the optimal performance of the starter generator: when generating power, the excitation windings are connected in series through the controller; When starting, they are connected in parallel to reduce the impedance, reduce the amplitude of the starting AC voltage, reduce the size and weight of the inverter, and change the original exciter slightly, but the switching control of the starting generator is complicated, and the contactor More, low reliability, single-phase AC excitation efficiency is low when the motor is stationary and at low speed. Patent CN103532454B discloses a two-phase brushless exciter structure and a control method in the process of starting power generation. The exciter adopts a brushless exciter with excitation windings that are two-phase symmetrical windings with a space difference of 90° electrical angle, and adopts 4 contacts The relay connects the two-phase excitation windings of the exciter to the two-phase inverter and the generator control unit respectively. Compared with single-phase AC excitation, this scheme has higher excitation efficiency, but the winding connection method is complicated, and an additional inverter is required to provide two-phase symmetrical power supply. Patent CN102420560 discloses an excitation structure and AC and DC excitation control method for a variable frequency AC starter power generation system. The three-phase winding of the AC excitation stator is set as an open-circuit structure, and a group of three-phase full-bridge converters are installed at both ends of the winding. In the start-up phase, three-phase AC excitation is realized by controlling two sets of converters. In the power generation phase, the converter control strategy is switched, and each phase winding is controlled independently, which is equivalent to a DC series structure and adopts DC excitation. This scheme sets two sets of power converters to improve the utilization rate of the excitation winding, but the two sets of power converters make the excitation control process more cumbersome and increase the complexity of the system structure.

The existing three-stage brushless synchronous motor asynchronous start control methods all require start excitation control. At the same time, in order to obtain sufficient excitation current at zero speed and low speed, the start excitation control methods used are quite complicated and need to adjust the main The structure of the exciter adds a large number of power devices, and the switching process of starting and generating is complicated.

Contents of the invention

In view of the above technical problems, the present invention aims to simplify the starting control strategy of the three-stage brushless synchronous motor, cancel the starting excitation, and simplify the starting controller.

In order to realize above-mentioned technical purpose, technical scheme of the present invention is:

The three-stage brushless synchronous motor 1 utilizes the asynchronous torque brought by the rotor damping winding of the main generator 5 to realize the starting function. The three-stage brushless synchronous motor is composed of a permanent magnet auxiliary exciter 2, a main exciter 3, a rotary rectifier 4 and a main generator 5 in three stages. During power generation operation, the permanent magnet auxiliary exciter 2 provides excitation current for the stator excitation winding of the main exciter 3, and the main exciter 3 is a rotating armature generator, and the main generator 5 is connected to the rotating rectifier 4 through the rotating rectifier 4 connected to the armature winding. The field winding supplies the field current. During start-up operation, the permanent magnet sub-exciter 2 of the traditional three-stage brushless synchronous motor does not work, and the starter controller 6 supplies alternating current to the excitation winding of the main exciter 3 to excite an alternating magnetic field to make the main exciter 3 electrically The armature winding obtains the induced potential, so as to provide excitation current for the main generator 5, and the starter controller 6 supplies three-phase alternating current to the armature winding of the main generator 5 to obtain torque. The invention realizes the starting function by using the full damping winding on the rotor of the main generator 5 to feed three-phase alternating current to the armature winding to generate asynchronous torque. The main exciter 3 and the permanent magnet auxiliary exciter 2 do not work during the starting process, which simplifies the starting control strategy and the starting controller 6 .

The beneficial effect brought by adopting the above-mentioned technical scheme:

The invention uses the asynchronous torque of the main generator of the three-stage brushless synchronous motor to realize the starting function of the system. The power generation operation is the same as that of the traditional three-stage synchronous starter generator. Since the motor does not rotate during the starting operation, the main generator cannot obtain excitation. current, so complex starting control strategies are required, and starting control is a key technology for starter-generators. In the present invention, all the torques are provided by the asynchronous torque when the motor starts running, and neither the main exciter nor the permanent magnet auxiliary exciter work. This action cancels the start excitation control and simplifies the start excitation strategy. The start controller only needs to supply three-phase AC power to the armature winding of the main generator instead of providing AC excitation current to the excitation winding of the main exciter, which simplifies the start controller. , simplifies the structure of the starting system.

Description of drawings

Figure 1 is a block diagram of the starting system of the three-stage brushless synchronous motor;

Figure 2, Figure 3 and Figure 4 are the structural diagrams of the main generator rotor of the three-stage brushless synchronous motor;

Fig. 5 is a schematic diagram of the armature current control strategy of the main generator in the asynchronous starting stage;

In the figure, 1-three-stage brushless synchronous motor, 2-permanent magnet auxiliary exciter, 3-main exciter, 4-rotary rectifier, 5-main motor, 6-starting controller, 7-starting power unit, 8 -Auxiliary power unit, 9-resolver, 10-current transformer, 11-voltage sensor;

5.1-rotor core, 5.2-excitation winding, 5.3-pressure plate, 5.4-damping strip.

Detailed ways

The present invention provides a three-stage brushless synchronous motor asynchronous start control method and system. In order to make the purpose and thinking of the present invention clearer and clearer, the present invention is further described in detail with reference to examples. It should be understood that the specific implementations described here are only used to explain the present invention, not to limit the present invention.

FIG. 1 is a block diagram of a three-stage brushless synchronous motor starting system for an auxiliary power unit 8 . The starting system consists of three parts, which are a three-stage brushless synchronous motor 1 , a starting controller 6 and a starting power unit 7 . During the starting process, the starting power unit 7 converts the input power into high-voltage direct current, and inputs it into the starting controller 6 . The starter controller 6 supplies three-phase alternating current to the armature winding of the main motor 5 of the three-stage brushless synchronous motor according to the rotational speed and position information provided by the resolver 9, and the current transformer 10 and the voltage sensor 11 are responsible for returning the current and voltage signals . The composite vector speed of the three-phase current fed into the main generator 5 is faster than the rotor speed, and there is a slip between the rotor and the stator current vector, and the rotor damping winding will generate induced electric potential and induced current due to cutting the magnetic induction line, thereby generating torque and driving The auxiliary power unit 8 realizes the starting function. During the whole starting process, the permanent magnet auxiliary exciter 2, the main exciter 3 and the rotating rectifier 4 all do not work.

Copper damping windings are installed on the main generator (5) rotor of the three-stage brushless synchronous motor (1), and the damping windings are connected to each other through pressure plates or end rings to form a full damping winding. The full damping winding is similar to the squirrel cage bars of the squirrel cage asynchronous motor, so when the three-phase current is passed into the stator armature of the main generator (5), the damping winding will play the role of the squirrel cage bars in the squirrel cage asynchronous motor. The rotation speed of the stator current vector of the main generator (5) is faster than that of the rotor, and there is a slip with the rotor. The rotor damping winding will generate an induced potential due to the cutting of the magnetic induction line, thereby generating an induced current and generating an asynchronous torque. The principle of asynchronous torque generated by the main generator (5) of the three-stage brushless synchronous motor (1) is similar to the operating principle of a squirrel-cage asynchronous motor.

Figures 2 to 4 are structural diagrams of the main generator rotor of the three-stage brushless synchronous motor. The main generator rotor is mainly composed of rotor core 5.1, excitation winding 5.2, damping strip 5.4 and pressure plate 5.3, and also includes structural parts such as sheath. The damping strip 5.4 and the pressing plate 5.3 are made of copper, and the damping strip 5.4 is placed in the groove on the rotor pole. A pressing plate 5.3 is installed at both axial ends of the rotor pole, and the two ends of the pressing plate 5.3 and the damping strip 5.4 are in close contact. Each damping strip 5.4 forms a circuit through the pressing plate to form a damping winding.

Fig. 5 is a schematic diagram of the power supply voltage changing with the frequency when the constant voltage frequency ratio starts. When starting with asynchronous torque, change the power supply voltage U ₁ while changing the power supply frequency f ₁ , and keep the ratio of the two at a constant value, that is Among them, W ₁ is the number of turns in series for each phase of the armature winding, K _w1 is the winding factor of the armature winding, Φ _m is the main magnetic flux, and K is a constant.

The method of the invention is simple to realize, and the excitation in the starting process is provided by the power generation controller, which can greatly simplify the starting control strategy, reduce the volume and weight of the starting controller, and meanwhile have no influence on the power generation performance of the motor.

There are many specific application ways of this patent. The above description is only the preferred implementation of this patent, and does not limit the implementation and protection scope of this patent. For those skilled in the art, equivalent replacement and The solutions obtained by obvious changes shall all be included in the protection scope of the patent.

Claims (7)

1. three-level formula brushless synchronous machine asynchronous starting control method, it is characterised in that：The control method passes through at the start Starter controller (6) is passed through three-phase alternating current to main generator (5) threephase armature winding, does not provide starting exciting current, only according to The induction torque generated by Damper Winding realizes start-up function, and the starter controller (6) is powered by starting power unit (7).

2. three-level formula brushless synchronous machine asynchronous starting control method according to claim 1, which is characterized in that application pair As for aircraft auxiliary power plant (8).

3. three-level formula brushless synchronous machine asynchronous starting control method three-level formula brushless synchronous machine according to claim 1 Asynchronous starting control method, which is characterized in that the control method is specially：

The power supply of input is converted to high voltage direct current and is input in starter controller (6) by starting power unit (7), starting control The information that device (6) is provided according to rotary transformer (9) is passed through three to the armature winding of three-level formula brushless synchronous machine main motor (5) Phase alternating current, current transformer (10) and voltage sensor (11) are responsible for return current and voltage signal；

The induction torque that three-level formula brushless synchronous machine (1) is generated by main generator (5) part, drives auxiliary power unit (8) start-up function is realized, in starting process, permanent magnetic auxiliary exciter (2), main exciter (3) and rotating rectifier (4) not work Make.

4. three-level formula brushless synchronous machine asynchronous starting control method according to claim 3, which is characterized in that main power generation The three-phase alternating current being passed through in armature winding uses constant voltage constant frequency control.

5. three-level formula brushless synchronous machine asynchronous starting control method according to claim 4, which is characterized in that utilizing When induction torque is started, changing supply frequency f₁While change supply voltage U₁, keeping the two ratio is a constant, I.e.Wherein W₁It is often connected in series the number of turns for armature winding, K_w1For armature winding winding coefficient, Φ_m For main flux, K is constant.

6. three-level formula brushless synchronous machine asynchronous starting control system, which is characterized in that the three-level formula brushless synchronous starts system System includes three-level formula brushless synchronous machine (1) and starter controller (6)；The three-level formula brushless synchronous machine (1) includes permanent magnetism Pilot exciter (2), main exciter (3), rotating rectifier (4) and main generator (5) are pacified on the rotor of the main generator (5) Equipped with absolute damping winding；

The rotor coaxial of the permanent magnetic auxiliary exciter (2), main exciter (3) and main generator (5) three is installed, the permanent magnetism pair The three-phase alternating current output access electricity generating controller of exciter (2), the excitation winding of main exciter are controlled under generating state from power generation Device processed obtains DC excitation electric current；The rotating rectifier (4) is mounted on main exciter (3) rotor, and the three of main exciter (3) Mutually exchange output is converted to DC current by rotating rectifier (4), is supplied to main generator (5) excitation winding, thus based on Generator (5) provides excitation；

The starter controller (6) three-phase alternating current output access main generator (5) stator armature winding, in starting process to Main generator (5) stator armature winding provides three-phase alternating current.

7. three-level formula brushless synchronous machine asynchronous starting control system according to claim 6, which is characterized in that described three The main generator (5) of grade formula brushless synchronous machine (1) includes rotor core, excitation winding, amortisseur bar, pressing plate or end ring, is gone back Including jacket structure part；Wherein, rotor pole is equidistantly equipped in the rotor core, the excitation winding is wrapped in rotor pole On；

The amortisseur bar is equipped with several, in rotor pole peripheral side, is arranged along rotor axial direction；

The amortisseur bar and laminate material are copper, and rotor axial both ends are mounted on a block pressur plate, and pressing plate and amortisseur bar both ends are tight Contiguity touching；Each amortisseur bar is formed into a loop by pressing plate, forms Damper Winding.