CN112003517A - Two-stage brushless electric excitation starting power generation system topology and control strategy thereof - Google Patents

Abstract

The invention relates to a topology of a two-stage brushless electric excitation starting and generating system and its control strategy. The system includes an exciter, a rotating rectifier, a main motor, a starting controller, a generating control unit and a switch. The input terminal of the generating control unit is connected to The output terminal of the main motor stator winding to generate electricity. In the starting stage of the system, the power output end of the starting controller is connected to the exciter and the stator winding of the main motor, providing excitation for the exciter and driving the main motor to run in an electric state to drive the aero-engine to start; after the start is completed, the starting controller and the stator winding of the main motor are disconnected. Open the connection, and no longer provide excitation for the exciter; when entering the power generation stage, the main motor stator armature winding is connected to the bus bar of the on-board power system, and the starter controller provides DC excitation for the exciter, until the input voltage of the power generation control unit meets the exciter. After the excitation control is required, the excitation winding connection of the exciter is switched from the starting controller to the output terminal of the generator control unit, and the generator control unit provides excitation for the exciter.

Description

A two-stage brushless electric excitation starter-generating system topology and its control strategy

technical field

The invention belongs to the field of motor systems, in particular to a structure topology and a control strategy of a novel two-stage brushless electric excitation starting and generating system.

Background technique

The aviation starter power generation system can save the special starting mechanism used in traditional engine starting, reduce the volume and weight of the system, and improve the system integration, which is an important development trend of aeroengine-power system. The three-stage starter-generator system has become the focus of research and application of aviation starter-generator integration due to its excellent reliability and power generation quality. European and American research institutions have been at the forefront of the world in the research and application of aviation three-stage starter-generating systems. The aviation three-stage starter-generating system has been successfully applied to the Boeing 787 aircraft, which represents the highest level of current multi-electric large aircraft. In China, there is no installed application of the aviation three-stage starter power generation system, and it is still in the stage of basic theoretical exploration and key technology research.

The three-stage brushless synchronous generator consists of an auxiliary exciter, an exciter, a rotating rectifier, a main generator and a power generation control unit. Among them, the auxiliary exciter is a low-power permanent magnet generator, which provides DC excitation for the exciter through GCU; the exciter is a pivot-type electric excitation generator, which provides excitation current to the main motor through a rotating rectifier; the main motor is an electric excitation synchronous motor , driven by the engine to run in the power generation state to supply power to the airborne equipment. The three motor rotors are installed coaxially, and the rotating rectifier is also installed on the rotor side to form the rotating part of the system. The significance of the three-stage brushless synchronous generator requiring a three-stage structure is that: in order to realize the brushless of the main motor (electric excitation synchronous motor) and the adjustable excitation current, the exciter (electric excitation generator) and the rotating rectifier are added as The rotor winding of the main motor provides adjustable excitation current; in order to cancel the external power supply of the exciter and realize the generator system as an independent power generation source, an auxiliary exciter (permanent magnet generator) is added to provide excitation for the exciter through the power generation control unit.

From the structure and operation principle of the three-stage brushless synchronous generator, it can be seen that the advantages of this motor system in the application of large aviation aircraft are: 1) When the motor or load has a short-circuit fault, it can be realized by cutting off the excitation of the exciter. The main motor is directly demagnetized to prevent the spread of faults and has high reliability. 2) The excitation current of the main motor can be adjusted in real time through the excitation control of the exciter, the system power factor is high, and the power generation quality is good. 3) The advantage of easy adjustment of the excitation current of the main motor makes the system suitable for a variety of aviation power systems, including variable-speed variable-frequency systems, constant-speed and constant-frequency systems, and high-voltage DC systems, with wide applicability.

On the basis of the three-stage brushless synchronous generator, a three-stage starting and generating system can be realized by adding the starting function. Compared with the pure generator, the three-stage starter-generating system adds a starter controller, which is used for system start-up control. In the starting stage of the system, the exciter is AC excited by the starting controller (or directly excited by an external AC power source), and the auxiliary exciter is not connected to the system; the main motor is controlled by the starting controller in the electric operation mode, and the output torque drives the aero-engine start. After the start is completed, the system is switched to the state consistent with the pure generator structure by starting/generating switching. It can be seen that the three-stage starting and power generation system realizes the integration of starting and power generation on the basis of maintaining the advantages of high reliability and high quality power generation of the three-stage brushless synchronous generator. However, this configuration is complex in structure, large in volume and weight, which affects the power density of the system, and urgently needs to be optimized and improved.

SUMMARY OF THE INVENTION

technical problem to be solved

The complex structure and topology of the traditional three-stage starter-generator system directly affects the power density and reliability of the system. In order to improve the power density and high reliability of the starter-generator system, it is necessary to redesign the structure topology and control strategy of the traditional three-stage starter-generator system on the premise of ensuring that the system's starting function and power generation characteristics meet the requirements, so that it can be more Well suited to high power density and high reliability requirements in aerospace applications.

Technical solutions

A two-stage brushless electric excitation starting and generating system topology, comprising an exciter, a rotating rectifier, a main motor, a starting controller, and a power generation control unit, and is characterized in that it also includes a No. 1 switch and a No. 2 switch, and the No. 1 switch and the excitation The motor stator excitation winding is connected, the No. 1 switch has two contacts E1 and E2, the E1 contact is connected to the output of the generator control unit, the E2 contact is connected to the excitation control output of the starter controller; the No. 2 switch is connected to the main motor stator armature winding Connection, the No. 2 switch has two contacts G1 and G2, the G1 contact is connected to the starting control output of the main motor of the starter controller, the G2 contact is connected to the bus bar of the on-board power system, and the input side of the power generation control unit is connected to the No. 2 switch connected to the G2 contact.

The types of the No. 1 switch and No. 2 switch include: relays, contactors, and power electronic switching devices.

The types of the exciter include: single-phase exciter, two-phase exciter, and three-phase exciter.

A control strategy for the topology of a two-stage brushless electric excitation starting and generating system is characterized in that the steps are as follows:

Step 1: In the starting stage, the starting controller is powered by an external power supply, the E2 contact of the No. 1 switch is connected to the starting controller, and the G1 contact of the No. 2 switch is connected to the starting controller, that is, the excitation winding of the exciter stator is connected to the main motor stator. The armature winding is connected to the output end of the starter controller; on the one hand, the starter controller outputs alternating current or direct current to provide excitation for the exciter, and on the other hand, according to the motor speed and rotor position, the main motor inputs variable frequency alternating current, so that the main motor generates electromagnetic torque to drive aero-engine start;

Step 2: After the start is completed, that is, the aero-engine reaches the start-up completion speed; the E2 contact of the No. 1 switch continues to be connected to the starting controller, while the G1 contact of the No. 2 switch is disconnected and is in a floating state, that is, the starting controller and the The armature winding of the main motor is disconnected and continues to be connected to the excitation winding of the exciter; at this time, the starter controller no longer supplies power to the exciter, and the starter power generation system is driven by the aero-engine to accelerate to the system power generation stage;

Step 3: When the system enters the power generation stage, that is, the aero-engine reaches the power generation running speed; the E2 contact of the No. 1 switch continues to be connected to the starter controller, and the No. 2 switch is switched to the G2 contact, that is, the main motor armature winding and the power generation control unit At this time, the starter controller provides DC excitation current for the exciter again. After the input voltage of the power generation control unit reaches the excitation control requirement of the exciter, the No. 1 switch is switched from the E2 contact to the E1 contact, that is, the exciter excitation winding is connected to the exciter. The starting controller is disconnected and connected to the output of the power generation control unit; after that, the system completely enters the power generation stage, and the power generation control unit provides DC excitation for the exciter.

beneficial effect

The topology of a two-stage brushless electric excitation starting and generating system proposed by the invention removes the auxiliary exciter in the traditional three-stage brushless electric excitation motor topology, and on the basis of maintaining the advantages of high reliability and high quality power generation of the system, The advantages are reflected in: 1) Directly reduce the weight of the auxiliary exciter; 2) Directly reduce the weight of the auxiliary exciter installation and fixing structural parts; 3) Shorten the axial length of the motor system, easy to install; 4 ) The coaxial series installation of three motors is simplified to the coaxial series installation of two motors, which reduces the complexity of the system; 5) The auxiliary exciter (permanent magnet motor) is removed, so that the system is no longer relatively fragile and easy to come out. The faulty permanent magnet improves the system reliability.

Description of drawings

Figure 1 is a schematic diagram of the topology structure of a two-stage brushless electric excitation starting and generating system;

Figure 2 is a schematic structural diagram of a two-stage brushless electric excitation starting and generating system based on a single-phase exciter;

FIG. 3 is a schematic diagram of the control flow of the two-stage brushless electric excitation starting and generating system.

Detailed ways

The present invention will now be further described in conjunction with the embodiments and accompanying drawings:

The schematic diagram of the topology of the proposed two-stage brushless electric excitation starter-generator system is shown in Figure 1. The system consists of an exciter, a rotating rectifier, a main motor, a starting controller, a power generation control unit and a switch. The input end of the power generation control unit is connected to the output end of the main motor stator winding. The starting controller is powered by an external power supply and mainly realizes the starting control of the system; the power generation control unit mainly realizes the power generation control of the system. The structure and function of the exciter, the rotating rectifier, the main motor, the starter controller and the power generation control unit are the same as those in the traditional three-stage brushless electric excitation starter power generation system, which is not the content of the invention of this patent.

The No. 1 switch connected to the excitation winding of the exciter stator has two contacts, the E1 contact is connected to the output of the generator control unit, and the E2 contact is connected to the excitation control output of the starter controller. The No. 2 switch connected to the stator armature winding of the main motor has two contacts, the G1 contact is connected to the main motor starting control output of the starter controller, and the G2 contact is connected to the on-board power system bus bar. In addition, the input side of the power generation control unit is also connected to the G2 contact of the No. 2 switch.

A two-stage brushless electric excitation starter-generating system based on a single-phase exciter is selected as an embodiment for detailed description, and its structural schematic diagram is shown in FIG. 2 . The system consists of exciter, rotating rectifier, main motor, starting controller, power generation control unit and switch. The main motor is an electric excitation synchronous motor, the rotor winding is a single-phase excitation winding, and the stator winding is a three-phase armature winding; the rotating rectifier is a diode rectifier; the exciter is a rotary armature generator, and the rotor winding is a three-phase armature winding. The winding is a single-phase excitation winding. The exciter and the rotor of the main motor are installed coaxially, and the rotating rectifier is also installed on the rotating shaft. The three-phase winding of the rotor of the exciter is connected to the input side of the rotating rectifier, and the rotor winding of the main motor is connected to the output side of the rotating rectifier. The input end of the power generation control unit is connected to the power generation output end of the stator winding of the main motor.

The No. 1 switch connected to the excitation winding of the exciter stator selects a two-way SPDT switch, the No. E1 contact is connected to the output of the generator control unit, and the No. E2 contact is connected to the excitation control output of the starter controller. The No. 2 switch connected to the stator armature winding of the main motor selects a three-way SPDT switch, the No. G1 contact is connected to the starting control output of the main motor of the starting controller, the No. G2 contact is connected to the on-board load, and the power generation control unit The input side is also connected to the G2 contact of switch 2.

The starting controller is powered by an external power supply and mainly realizes the starting control of the system; the power generation control unit mainly realizes the power generation control of the system. The starting controller and the power generation control unit can select the relevant hardware structures used in the three-stage starting and power generation system.

For the two-stage brushless electric excitation starting and generating system based on the single-phase exciter shown in Figure 2, the schematic diagram of the control strategy adopted is shown in Figure 3, specifically:

(1) In the starting stage, the starting controller is powered by an external power supply, the No. 1 switch is connected to the E2 contact, and the No. 2 switch is connected to the G1 contact, that is, the exciter stator excitation winding and the main motor stator armature winding are connected to the starting controller output. On the one hand, the starter controller outputs 210V/200Hz single-phase AC power to provide AC excitation for the single-phase winding of the exciter, and on the other hand, the vector control strategy is used to input variable frequency AC power to the main motor according to the motor speed, so that the main motor generates electromagnetic torque to drive the aero-engine. start.

(2) After the starter power generation system is brought to the aero-engine to accelerate to 4000r/min, the start of the aero-engine is completed. The No. 1 switch continues to be connected to the E2 contact, while the No. 2 switch is disconnected from the G1 contact and is in a floating state, that is, the starter controller is disconnected from the main motor armature winding, and continues to be connected to the exciter field winding. At this time, the starter controller no longer supplies power to the exciter, and the starter power generation system is driven by the aero-engine to accelerate to the system power generation stage.

(3) When the aero-engine drives the starter power generation system to accelerate to 8000r/min, the system enters the power generation stage. The No. 1 switch continues to be connected to the E2 contact, and the No. 2 switch is connected to the G2 contact, that is, the main motor armature winding is connected to the power generation control unit. At this time, the starter controller outputs 5A DC power to provide DC excitation for the excitation winding of the exciter. When the effective value of the input voltage of the power generation control unit (that is, the output voltage of the stator winding of the main motor) reaches 115V, the No. 1 switch is switched from the E2 contact to the E1. The contact, that is, the excitation winding of the exciter is disconnected from the starting controller, and is connected to the output of the generator control unit. After that, the starter-generating system completely enters the power-generating stage, and the power-generating control unit performs closed-loop regulation on the excitation current of the exciter according to the output voltage of the stator winding of the main motor, so that the effective value of the output voltage of the main motor is stable at 115V.

Claims (4)

1. A two-stage brushless electric excitation starting and generating system topology, comprising an exciter, a rotary rectifier, a main motor, a starting controller, a power generation control unit, and is characterized in that it also includes No. 1 switch and No. 2 switch, and No. 1 switch It is connected with the excitation winding of the exciter stator. The No. 1 switch has two contacts E1 and E2. The E1 contact is connected to the output of the power generation control unit, and the E2 contact is connected to the excitation control output of the starter controller. The No. 2 switch is connected to the main motor stator circuit. The pivot winding is connected, the No. 2 switch has two contacts G1 and G2, the G1 contact is connected with the starting control output of the main motor of the starting controller, the G2 contact is connected with the bus bar of the on-board power system, and the input side of the power generation control unit is connected with the 2 The G2 contact of the number switch is connected. 2 . The topology of a two-stage brushless electric excitation starting and generating system according to claim 1 , wherein the types of the No. 1 switch and No. 2 switch include: relays, contactors, and power electronic switching devices. 3 . 3 . The topology of a two-stage brushless electric excitation starting and generating system according to claim 1 , wherein the types of the exciter include: single-phase exciter, two-phase exciter, and three-phase exciter. 4 . 4. A control strategy for the topology of the two-stage brushless electric excitation starting and generating system according to claim 1, characterized in that the steps are as follows: Step 1: In the starting stage, the starting controller is powered by an external power supply, the E2 contact of the No. 1 switch is connected to the starting controller, and the G1 contact of the No. 2 switch is connected to the starting controller, that is, the excitation winding of the exciter stator is connected to the main motor stator. The armature winding is connected to the output end of the starter controller; on the one hand, the starter controller outputs alternating current or direct current to provide excitation for the exciter, and on the other hand, according to the motor speed and rotor position, the main motor inputs variable frequency alternating current, so that the main motor generates electromagnetic torque to drive aero-engine start; Step 2: After the start is completed, that is, the aero-engine reaches the start-up completion speed; the E2 contact of the No. 1 switch continues to be connected to the starting controller, while the G1 contact of the No. 2 switch is disconnected and is in a floating state, that is, the starting controller and the The armature winding of the main motor is disconnected and continues to be connected to the excitation winding of the exciter; at this time, the starter controller no longer supplies power to the exciter, and the starter power generation system is driven by the aero-engine to accelerate to the system power generation stage; Step 3: When the system enters the power generation stage, that is, the aero-engine reaches the power generation operating speed; the E2 contact of the No. 1 switch continues to be connected to the starter controller, and the No. 2 switch is switched to the G2 contact, that is, the main motor armature winding and the power generation control unit At this time, the starter controller provides DC excitation current for the exciter again. After the input voltage of the power generation control unit reaches the excitation control requirement of the exciter, the No. 1 switch is switched from the E2 contact to the E1 contact, that is, the exciter excitation winding is connected to the exciter. The starting controller is disconnected and connected to the output of the power generation control unit; after that, the system completely enters the power generation stage, and the power generation control unit provides DC excitation for the exciter.

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