阅读说明：本技术 一种航空三相交流励磁系统直流励磁闭环控制方法 (Direct-current excitation closed-loop control method for aviation three-phase alternating-current excitation system ) 是由 张赞 栗伟周 马军磊 吕存杰 殷志锋 田尚永 刘志坤 齐明峻 陈帅 于 2019-09-30 设计创作，主要内容包括：本发明提供一种航空三相交流励磁系统直流励磁闭环控制方法,利用励磁机定子两相开路绕组的相电压计算出主电机励磁电流作为反馈,将计算出的主电机励磁电流与主电机励磁电流期望值作差,通过调节励磁机定子直流励磁电压实现主电机励磁电流的闭环控制。本发明方法中采用的主电机励磁控制方法,仅仅对采集励磁机定子两相开路绕组电压进行直流滤波后即可进行积分运算,可以避免从直流绕组进行积分时直流偏置无法滤除的问题。本发明方法中采用的主电机励磁控制方法,通过对主电机励磁电流的闭环控制,消除了主电机直轴电流变化对主电机励磁电流的影响。(The invention provides a direct-current excitation closed-loop control method of an aviation three-phase alternating-current excitation system, which is characterized in that phase voltage of a two-phase open-circuit winding of an exciter stator is utilized to calculate main motor excitation current as feedback, the calculated main motor excitation current is differed from a main motor excitation current expected value, and closed-loop control of the main motor excitation current is realized by adjusting direct-current excitation voltage of the exciter stator. The method for controlling the excitation of the main motor adopted in the method can perform integral operation only after the direct current filtering is performed on the collected voltage of the two-phase open-circuit winding of the stator of the exciter, and can avoid the problem that direct current bias cannot be filtered when integration is performed from the direct current winding. The method for controlling the excitation of the main motor eliminates the influence of the direct axis current change of the main motor on the excitation current of the main motor by closed-loop control of the excitation current of the main motor.)

1. A direct-current excitation closed-loop control method of an aviation three-phase alternating-current excitation system is characterized by comprising the following steps: the method comprises the following steps:

s1: the direct-current excitation power supply is connected with one phase winding of the three-phase winding of the exciter stator and provides direct-current excitation current for the exciter, and the remaining two phase winding of the exciter stator is in an open-circuit state;

s2: two-way voltage sensor respectively collects phase voltages u of two-phase windings in an open-circuit state in three-phase windings of an exciter stator₁And u₂The position sensor collects exciter rotor position information theta, and the voltage sensor and the position sensor send the collected data to the main motor exciting current controller;

s3: the main motor exciting current controller collects the voltage signal u of the current sensor₁And u₂Performing direct current filtering, and calculating three-phase current i of the exciter rotor by using an exciter stator flux linkage equation_rA、i_rBAnd i_rCAnd main motor excitation current i_f(ii) a S4: calculating the value i of the exciting current of the main motor_fWith reference value of main motor exciting currentDifference e between_ifFed to a PID controller, error e_ifThe voltage amplitude of the exciter direct-current excitation power supply is generated through a PID control link,the exciting current of the main motor reaches a desired value under the regulation of the exciting voltage of the stator of the exciter, and the closed-loop control of the exciting current of the main motor is realized.

2. The aviation three-phase alternating current excitation system direct current excitation closed-loop control method as claimed in claim 1, characterized in that: the exciter rotor three-phase current and the main motor exciting current are calculated by the following formula:

Technical Field

The invention belongs to the technical field of aviation alternating current motors, and particularly relates to a direct current excitation closed-loop control method of an aviation three-phase alternating current excitation system.

Background

With the rapid development of the large airplane technology, a high-voltage wide-frequency-conversion power generation system with a starting/power generation integrated function is an important development direction of future aviation alternating-current power supply systems. At present, three-stage brushless synchronous motors (a functional block diagram is shown in figure 1) are mostly adopted as generators in the aircraft alternating current power supply system in China, the generators generally have no function of starting an aircraft engine, and the engine is started by an independent starter. If the three-stage machine uses a three-phase ac exciter as its excitation power source (see fig. 2 for a schematic block diagram), the excitation system can provide a sufficient field current to the main machine during start-up. When the exciter adopts an aviation three-phase alternating current power supply as an input power supply of the exciter, the system has high reliability and small volume and weight. However, the excitation current of the main motor output by the three-phase ac excitation system at this time changes with the rotation speed, and when the excitation current of the main motor changes while the system is operating in a high rotation speed region, the weak magnetic pressure of the main motor is increased (or the excitation is insufficient), so that the starting capability of the starting/generating system is affected.

Aiming at the exciter problem, the main solutions at home and abroad at present comprise: 1. the exciter and the main motor body are optimally designed, so that the influence of the change of the exciting current of the main motor on the starting performance of the main motor in the starting process is reduced; 2. in the static and low-speed running stage of the main generator motor, the exciter stator winding adopts three-phase alternating current excitation, and in the high-speed running stage of the motor, the exciter stator winding adopts single-phase alternating current excitation; 3. in the static and low-speed operation stage of the main generator motor, the exciter stator adopts three-phase alternating current excitation, and in the high-speed operation stage of the motor, the exciter stator winding adopts direct current open-loop excitation, and the exciting current of the main generator reaches an expected value by inquiring open-loop control methods such as off-line formulated tables and the like. Scheme 1 can reduce the influence of the main machine field current variation on the system starting performance to some extent, but generally reduces the performance of the starting/generating system in the generating stage. In the scheme 2, the excitation current of the main motor needs to be limited by changing the excitation mode in the starting process, but the excitation current of the main motor after switching is still uncontrollable, and the starting performance of the starting/generating system can be seriously influenced by the excitation current oscillation of the main motor caused in the switching process. Scheme 3 is that three-phase/direct-current excitation mode switching is performed in the starting process, a stator winding of a main motor after excitation mode switching is connected with a frequency converter, closed-loop control over the excitation current of the main motor is difficult to perform through a method for detecting the stator voltage of the main motor, control over the excitation current of the main motor is usually achieved through open-loop methods such as table inquiry and offline establishment, although the open-loop control can limit the excitation current of the main motor to a certain extent, the direct-current output of an excitation system can be directly influenced by the change of the direct-axis current of the main motor in the starting process, the excitation current of the main motor still cannot be effectively controlled, and the starting performance of the starting/generating system is limited.

Disclosure of Invention

In order to avoid the defects of the prior art, the direct-current excitation closed-loop control method of the aviation three-phase alternating-current excitation system is provided, the phase voltage of the two-phase open-circuit winding of the stator of the exciter is used for calculating the exciting current of the main motor as feedback, the calculated exciting current of the main motor and the expected value of the exciting current of the main motor are subtracted, and the direct-current exciting voltage of the stator of the exciter is adjusted to realize the closed-loop control of the exciting current of the main motor.

The object of the invention is achieved in the following way:

a closed-loop control method for direct-current excitation of an aviation three-phase alternating-current excitation system,

s1: the direct-current excitation power supply is connected with one phase winding of the three-phase winding of the exciter stator and provides direct-current excitation current for the exciter, and the remaining two phase winding of the exciter stator is in an open-circuit state;

s2: two-way voltageThe sensor respectively collects phase voltages u of two-phase windings in an open-circuit state in three-phase windings of an exciter stator₁And u₂The position sensor collects exciter rotor position information theta, and the voltage sensor and the position sensor send the collected data to the main motor exciting current controller;

s3: the main motor exciting current controller collects the voltage signal u of the current sensor₁And u₂Performing direct current filtering, and calculating three-phase current i of the exciter rotor by using an exciter stator flux linkage equation_rA、i_rBAnd i_rCAnd main motor excitation current i_f(ii) a S4: calculating the value i of the exciting current of the main motor_fWith reference value of main motor exciting current

Difference e between_ifFed to a PID controller, error e_ifThe voltage amplitude of the direct-current excitation power supply of the exciter is generated through a PID control link, and the exciting current of the main motor is adjusted to a desired value under the condition of the exciting voltage of the stator of the exciter, so that the closed-loop control of the exciting current of the main motor is realized.

The exciter rotor three-phase current and the main motor exciting current are calculated by the following formula:

the invention has the beneficial effects that: 1) the method for controlling the excitation of the main motor adopted in the method can perform integral operation only after the direct current filtering is performed on the collected voltage of the two-phase open-circuit winding of the stator of the exciter, and can avoid the problem that direct current bias cannot be filtered when integration is performed from the direct current winding.

2) The method for controlling the excitation of the main motor eliminates the influence of the direct axis current change of the main motor on the excitation current of the main motor by closed-loop control of the excitation current of the main motor.

Drawings

FIG. 1: a three-stage brushless synchronous power generation system structure diagram;

FIG. 2: the structure diagram of an aviation three-stage starting/generating integrated system adopting a three-phase excitation system;

FIG. 3: the principle of closed-loop control of the exciting current of the main motor is shown schematically.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

A direct-current excitation closed-loop control method for an aviation three-phase alternating-current excitation system comprises the following steps:

step 1: the direct-current excitation power supply is connected with one phase winding of the three-phase windings of the exciter stator and provides direct-current excitation current for the exciter, and the remaining two-phase windings of the exciter stator are in an open-circuit state.

Step 2: two-way voltage sensor respectively collects phase voltages u of two-phase windings in an open-circuit state in three-phase windings of an exciter stator₁And u₂The position sensor collects exciter rotor position information theta, and the voltage sensor and the position sensor send collected data to the main motor exciting current controller.

And step 3: the controller collects the voltage signal u of the current sensor₁And u₂And D, performing direct current filtering and calculating the three-phase current of the exciter rotor by using the following formula:

and 4, step 4: the main motor exciting current controller calculates the main motor exciting current by using the following formula:

and 5: the main motor exciting current controller makes the main motor exciting current reference value

Calculated value i from main motor exciting current_fDifference is made to obtain error e_ifError e_ifThe voltage amplitude of the direct-current excitation power supply is generated through a PID control link, and the excitation system realizes closed-loop control of the excitation current of the main motor through the change of the excitation voltage.

As shown in fig. 3, the two-phase open-circuit winding phase voltage (assumed to be u) of the exciter stator collected by the voltage sensor₁And u₂) And exciter rotor position information (assumed to be theta) is sent to a main motor exciting current controller (hereinafter referred to as a controller), and the controller controls a two-phase open-circuit winding phase voltage (u)₁And u₂) Performing DC filtering, and calculating three-phase current (i) of the exciter rotor by using the exciter stator flux linkage equation_rA、i_rBAnd i_rC) And main motor field current (i)_f) Then, the main motor exciting current is calculated to be value (i)_f) With reference value of main motor exciting current

Difference e between_ifAnd the voltage amplitude of the direct-current excitation power supply of the exciter is generated by sending the voltage amplitude to a PID controller, and the excitation current of the main motor reaches a desired value under the regulation of the excitation voltage of the stator of the exciter.

The method for controlling the excitation of the main motor adopted in the method can perform integral operation only after the direct current filtering is performed on the collected voltage of the two-phase open-circuit winding of the stator of the exciter, and can avoid the problem that direct current bias cannot be filtered when integration is performed from the direct current winding.

2) The method for controlling the excitation of the main motor eliminates the influence of the direct axis current change of the main motor on the excitation current of the main motor by closed-loop control of the excitation current of the main motor.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various changes and modifications can be made without departing from the overall concept of the present invention, and these should also be considered as the protection scope of the present invention.