CN102882455B - Excitation control method and device used in starting process of aeronautical tertiary brushless AC synchronous motor - Google Patents

Abstract

The invention relates to an excitation control method and device for the starting process of an aviation three-stage brushless AC synchronous motor. When the motor is stationary, the controller excites the exciter with the maximum output AC excitation. The amount starts to decrease linearly, and at the same time, the DC excitation amount is regulated by a PI regulator. The upper limit of the adjustment is determined by the size of the AC excitation component and the bus voltage of the controller. When the method of the present invention is applied to the starting function of the three-stage brushless AC synchronous motor, it avoids the fluctuation of the main generator rotor flux chain caused by the exciter directly switching the excitation mode, and can effectively improve the time when the unit performs excitation switching during the starting process. smooth running.

Description

Excitation control method and device in the starting process of aviation three-stage brushless AC synchronous motor

technical field

The invention relates to an excitation control method and device in the starting process of an aviation three-stage brushless AC synchronous motor, which is a control method for solving the excitation problem of an aviation three-stage brushless AC synchronous motor in the starting process by using single-phase space vector modulation The method belongs to the technical field of AC motor transmission.

Background technique

The dual-function integration of starting/generating is an important development direction of the future aviation AC power system. At present, in the aviation high-power AC power supply system, three-stage brushless AC synchronous motors (see Figure 1 for the schematic block diagram) are widely used as generators. When this motor is used to realize the starting function of the aeroengine, the main generator will Due to the brushless structure of the motor, when the motor is stationary, if the exciter still adopts the DC excitation mode in the power generation state, the rotor excitation of the main generator will not be realized, resulting in the failure of the motor to start. In the article "Study on Single-phase AC Excitation in Electric State of Aircraft Start/Generation Dual Function System" (author Chen Baolin, etc.) published on pages 3-8 of the first issue of "Journal of Electrotechnical Technology" in 2001, it was proposed that in the stator winding of the exciter The single-phase alternating current is introduced to solve the excitation problem of the main generator when the unit is in a static state. The advantage of this method is that there is no need to change the structure of the motor. Experiments have shown that when the appropriate excitation frequency and control method are selected, the excitation current output by the exciter can ensure the smooth start of the unit under a certain blocking torque. The appropriate excitation frequency mentioned here refers to the premise that the excitation voltage is equal. When single-phase AC excitation with this frequency is used, the main generator can obtain the maximum excitation current.

However, when the exciter adopts the single-phase AC excitation method, it still faces the following problems: 1) At a suitable excitation frequency, due to the large inductive reactance of the exciter, the stator excitation current of the exciter is much smaller than its rated value, and cannot effectively exert The excitation output capability of the exciter causes the rotor excitation of the main generator to be weak, which affects the load capacity of the main generator in the motoring state; 2) Compared with the DC excitation method, the rotor of the main generator in the single-phase AC excitation method Fluctuation of the flux linkage is large, which affects the running stability of the main generator in the motoring state; 3) When the unit reaches a certain speed, the excitation output capacity of the exciter using the DC excitation method will be better than that using the single-phase AC excitation method , when the DC excitation method is adopted at this time, the load operation performance of the main generator can be effectively improved. Based on the above reasons, when the unit reaches a certain speed, it is necessary to switch the exciter from the AC excitation mode to the DC excitation mode. The flux linkage of the generator rotor fluctuates greatly, and the generated torque ripple can easily lead to the failure of the unit to start.

Contents of the invention

technical problem to be solved

In order to avoid the deficiencies of the prior art, the present invention proposes an excitation control method and device for the starting process of an aviation three-stage brushless AC synchronous motor, which can effectively improve the load performance of the three-stage brushless AC synchronous motor during the starting process and the unit smooth running.

Technical solutions

A method for controlling the excitation of an aviation three-stage brushless AC synchronous motor in the starting process, characterized in that the steps are as follows:

Step 1: According to the measured current speed value ω _r of the motor and the curve of the set AC excitation quantity changing with the speed, obtain the modulation degree M _A of the current output AC excitation component, and then obtain the modulation upper limit of the modulation degree of the DC excitation component M _DMAX = 1-M _A ;

Step 2: Perform PI adjustment on the difference between the rated current i ^* of the exciter and the excitation current value i of the current exciter e _i = i ^* -i to obtain the modulation degree of the DC excitation control quantity Among them, K _ps is the proportional coefficient of the excitation current PI controller, K _ps >0; K _{is is} the integral coefficient of the excitation current PI controller, K _is >0; Output the modulation degree M _D of the DC excitation quantity of the exciter at the current speed after limiting processing;

Step 3: Obtain the voltage phase angle θ=∫ωdt of the current AC excitation component according to the angle integrator of the AC excitation component of the exciter, where ω=2πf, f is the frequency of the AC excitation component;

Step 4: Calculate the action time of the active vector and the zero vector, the specific steps are as follows:

Step a: Calculate the inverter output reference voltage as V _ref = M _D V _DC + M _A V _DC cosθ, where V _DC is the bus voltage of the exciter controller;

Step b: According to the principle of volt-second balance, set the switching period of the inverter as T _s , and the action time of the effective vector as T ₁ , there is: V _ref T _s = V _DC T ₁ ; then within one switching period, the effective vector and zero The action times of the vectors are: $\left\{\begin{array}{c}{T}_1=m_{\mathrm{D.}}{T}_{\mathrm{the\; s}}+m_A{T}_{\mathrm{the\; s}}\cos \mathrm{\ωt}\\ T_0=T_{\mathrm{the\; s}}-T_1\end{array}\right.;$

Step 5: Calculate the control quantity of the H-bridge inverter, and control the H-bridge inverter to drive the exciter with this control quantity:

When using a zero vector and V _ref > 0, the control amount of the H-bridge inverter $\left\{\begin{array}{c}\mathrm{CMP}\_a=T_0/2\\ \mathrm{CMP}\_b=T_{\mathrm{the\; s}}/2\end{array}\right.;$

When adopting a zero vector and V _ref <0, the control amount of the H-bridge inverter $\left\{\begin{array}{c}\mathrm{CMP}\_a=T_{\mathrm{the\; s}}/2\\ \mathrm{CMP}\_b=T_0/2\end{array}\right.;$

When two zero vectors are used and V _ref >0, the control amount of the H-bridge inverter $\left\{\begin{array}{c}\mathrm{CMP}\_a=T_0/4\\ \mathrm{CMP}\_b=T_0/4+T_1/2\end{array}\right.;$

When using two zero vectors and V _ref <0, the control amount of the H-bridge inverter $\left\{\begin{array}{c}\mathrm{CMP}\_a=T_0/4+T_1/2\\ \mathrm{CMP}\_b=T_0/4\end{array}\right..$

The modulation degree M _D of the DC excitation component at the current moment is obtained by the following steps:

e _i = i ^* -i;

${\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}^{<span\; class="notranslate">\; *</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; ps</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; e</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; is</span>}}<span\; class="notranslate">\; \&Integral;</span>{\mathrm{<span\; class="notranslate">\; e</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}\mathrm{<span\; class="notranslate">\; dt</span>}$

${\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}<span\; class="notranslate">\; =</span>\left\{\begin{array}{cc}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}^{<span\; class="notranslate">\; *</span>}& {\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}^{<span\; class="notranslate">\; *</span>}<span\; class="notranslate">\; <</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}\\ \mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}& {\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}^{<span\; class="notranslate">\; *</span>}<span\; class="notranslate">\; \&Greater\; Equal;</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}\end{array}\right.<span\; class="notranslate">\; .</span>$

The AC excitation component modulation degree M _A satisfies: 1≥M _A ≥0.

The DC excitation component modulation degree M _D satisfies: 1-M _A ≥ M _D ≥ 0.

The AC excitation quantity angular velocity ω satisfies: ω=200π.

K _ps and K _is are set according to the exciter characteristics and system performance requirements of the three-stage brushless AC synchronous motor, and K _ps >0, K _is >0.

A device for realizing the excitation control method in the starting process of the aviation three-stage brushless AC synchronous motor, characterized in that it includes a rectifier circuit, a filter circuit, a three-phase full-bridge inverter, a single-phase H-bridge inverter, a position sensor, A central controller, an isolated driver and a current acquisition circuit; the rectifier circuit rectifies the input three-phase alternating current and outputs it to a filter circuit connected to it, and the filter circuit is respectively connected to a three-phase full-bridge inverter and a single-phase H-bridge inverter; The single-phase H-bridge inverter is connected to the stator winding of the exciter to drive the exciter to realize the excitation of the main generator; the three-phase full-bridge inverter is connected to the main generator to control the starting and running of the main generator; the position sensor is installed to detect the motor rotor at the position, its output end is connected to the central controller; the current acquisition circuit is connected to the output end of the single-phase H-bridge inverter and the three-phase full-bridge inverter, and its output end is connected to the central controller; the output end of the central controller The isolated driver is connected, and the output terminals of the isolated driver are respectively connected to a three-phase full-bridge inverter and a single-phase H-bridge inverter.

The position sensor adopts a rotary transformer.

Beneficial effect

The invention proposes an excitation control method and device for the starting process of an aviation three-stage brushless AC synchronous motor. When the motor is stationary, the controller excites the exciter with the maximum output AC excitation. The excitation volume begins to decrease linearly, and at the same time, the DC excitation volume is regulated by a PI regulator. The upper limit of the adjustment is determined by the magnitude of the AC excitation component and the bus voltage of the controller. When the AC component decreases to 0, the exciter enters the DC excitation mode . When the method of the present invention is applied to the starting function of the three-stage brushless AC synchronous motor, it avoids the fluctuation of the main generator rotor flux chain caused by the exciter directly switching the excitation mode, and can effectively improve the time when the unit performs excitation switching during the starting process. smooth running.

The invention has the following advantages: 1) When switching between the AC excitation mode and the DC excitation mode, both the AC excitation component and the DC excitation component are realized in a gradual in and gradual out manner, and there is no impact when switching; 2) The modulation algorithm combines AC modulation And the characteristics of DC modulation, there is no change in the modulation algorithm in the whole excitation process; 3) The PI regulator is used to adjust the DC excitation output, and at the same time, the AC excitation output is used to limit the maximum value of the DC excitation output, which can effectively use the bus in the switching process At the same time, it can effectively avoid the influence of the speed change on the exciter at high speed.

Description of drawings

Figure 1: Block diagram of a three-stage brushless AC synchronous motor

Fig. 2: block diagram of the principle of the method of the present invention

Fig. 3: System hardware principle diagram of the embodiment of the present invention

Figure 4: H-bridge inverter schematic

Figure 5: Output voltage vector diagram of an H-bridge inverter

Figure 6: Vector diagram of H-bridge inverter single-phase AC modulation

Figure 7: Vector diagram of H-bridge inverter DC modulation

Figure 8: Vector diagram of AC modulation with DC bias for H-bridge inverter

Figure 9: Vector diagram of DC modulation with AC component for H-bridge inverter

Figure 10: When V _ref > 0, the PWM schematic diagram when using two zero-vector modulation

Figure 11: When V _ref > 0, the PWM schematic diagram when using a single zero-vector modulation

Figure 12: Excitation current waveform in pure AC excitation mode

Figure 13: Excitation current waveform in AC excitation mode with DC bias

Figure 14: Excitation current waveform of AC excitation method with AC component

Figure 15: DC excitation mode excitation current waveform

Fig. 16: The on-load starting acceleration curve diagram of the motor when the method of the present invention is adopted

Detailed ways

Now in conjunction with embodiment, accompanying drawing, the present invention will be further described:

The excitation control method of the aviation three-stage brushless AC synchronous motor starting process in this embodiment (Fig. 2):

The principle block diagram of the method of the present invention is shown in Figure 2, the modulation degree of the AC excitation component is determined by the motor speed ω _r , and the modulation degree of the DC excitation component is determined by the rated excitation current i ^* of the exciter and the actual excitation current i through the PI regulator The adjustment is obtained, and its adjustment upper limit M _Dmax is determined by the modulation degree M _A of the AC excitation component. Finally, after the obtained AC/DC excitation output is synthesized according to the modulation algorithm proposed by the present invention, the variable value for controlling the H-bridge inverter is obtained. , to realize the excitation control of the exciter. Wherein, the excitation frequency of the AC excitation component satisfies: ω=2πf.

The system hardware structure of the embodiment of the present invention is shown in Figure 3, including: rectification circuit, filter circuit, three-phase full-bridge inverter, single-phase H-bridge inverter (Figure 4), isolation drive circuit, current and voltage detection circuit, central controller, man-machine interface circuit and position sensor, the resolver is used in this system to detect the position and speed of the rotor of the motor. Wherein, the single-phase H-bridge inverter is connected to the stator winding of the exciter, drives the exciter to realize the excitation of the main generator, and the three-phase full-bridge inverter is connected to the main generator, and the effect of the method of the present invention is observed by controlling the starting operation effect of the main generator Excitation control performance.

In order to verify the method of the present invention, the 2PT115-T/2PT115-P loading platform of MAGTROL Company was used to simulate the load of the aeroengine, and a three-stage brushless AC synchronous motor was used to build a verification platform.

The method in this embodiment controls the magnitude of the AC component and the DC component in the excitation signal of the exciter respectively, and uses the new modulation method proposed by the present invention that combines single-phase AC modulation and DC modulation to calculate the switch signal of the H-bridge inverter. Drive the H-bridge inverter to operate, and realize the exciter control of the three-stage brushless AC synchronous motor during the starting process, which contains the following steps in turn:

1. Measure the current rotational speed ω _r of the motor through the rotor position sensor and the signal processing circuit;

2. According to the current motor speed look-up table, the magnitude of the AC excitation component modulation M _A is obtained, and the output AC excitation component amplitude is V _A , the bus voltage of the controller is V _DC , and M _A satisfies M _A = V _A /V _DC ;

3. The voltage phase angle θ of the current AC excitation component is obtained by the angle integrator of the AC excitation component of the exciter, namely:

θ=∫ωdt

Among them, ω=2πf, f is the frequency of the AC excitation component;

4. Calculate the adjustment upper limit M _DMAX of the modulation degree of the DC excitation component according to the modulation degree of the AC excitation component output by the current controller;

5. The degree of modulation of the DC excitation component is calculated by the following steps:

(5.1). Set the adjustment parameters of the DC excitation component PI regulator of the exciter controller as K _ps = 0.1, K _is = 0.05;

(5.2). Obtain the modulation degree of the exciter controller output DC excitation component by the following steps:

(5.2.1). e _i = i ^* -i

(5.2.2). $m_{\mathrm{D.}}^{*}=K_{\mathrm{ps}}\&Center\; Dot;e_i+K_{\mathrm{is}}{\&Integral;e}_i\mathrm{dt}$

(5.2.3). The modulation degree M _D of the DC excitation component output by the exciter controller is obtained by limiting the upper limit MDMAX of the modulation degree of the _DC excitation component. The processing method is as follows:

${\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}<span\; class="notranslate">\; =</span>\left\{\begin{array}{cc}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}^{<span\; class="notranslate">\; *</span>}& {\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}^{<span\; class="notranslate">\; *</span>}<span\; class="notranslate">\; <</span>\mathrm{<span\; class="notranslate">\; 1</span>}{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}\\ \mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}& {\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}^{<span\; class="notranslate">\; *</span>}<span\; class="notranslate">\; \&Greater\; Equal;</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}\end{array}\right.$

Where M _D =V _D /V _DC , V _D is the voltage of the current output DC excitation component.

(5.3). Calculate the output reference voltage in the current state by the following formula:

V _ref = V _D + V _A cos ωt = M _D V _DC + M _A V _DC cos ωt

When V _D = 0, that is, when the exciter is in AC excitation mode, the vector diagram output by the controller is shown in Figure 6;

When V _A =0, that is, when the exciter is in DC excitation mode, the vector diagram output by the controller is shown in Figure 7;

When V _D < _VA , that is, when the exciter is in the AC excitation mode with DC bias, the vector diagram output by the controller is shown in Figure 8. At this time, the exciter has started to switch from the AC excitation mode to the DC excitation mode;

When V _D > _VA , that is, when the exciter is in the DC excitation mode with AC components, the vector diagram output by the controller is shown in Figure 9. At this time, the exciter is about to complete the switch from the AC excitation mode to the DC excitation mode;

(5.4). Let the PWM switching period be T _s , and the effective vector action time be T ₁ . According to the volt-second balance principle, there are:

V _ref T _s = V _DC T ₁

Then the action times of the active vector and the zero vector are:

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&omega;t</span>}\\ {\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\end{array}\right.$

Among them, _T1 satisfies the following relationship:

T ₁ ≤ _{T s}

(5.5). Determine the two-phase switch control signals S _A and S _B of the H-bridge inverter according to the basic voltage vector and zero vector and their respective action times. It is stipulated that "1" means that the upper switch tube of the same bridge arm is turned on, and the lower switch The tube is turned off, "0" indicates that the lower switch tube of the same bridge arm is turned on, and the upper switch tube is turned off:

The two-phase switching signals corresponding to the effective voltage vector and zero vector generated by the inverter are v _i (S _A , S _B ): v ₁ (1,0), v ₂ (0,1) and two zero-voltage See Figure 5 for vectors v ₀ (0,0), v ₃ (1,1); see Figure 10 and Figure 11 for the action sequence of the basic voltage vector and zero vector in a switching cycle T _s . Among them, the switching sequence shown in Figure 10 is the case when both zero vectors v ₀ (0,0) and v ₃ (1,1) act, and the switching sequence at this time is:

v ₀ (0,0) acts on T ₀ /4→v ₁ (1,0) acts on T ₁ /2→v ₃ (1,1) acts on T ₀ /2→v ₁ (1,0) acts on T ₁ / 2→v ₀ (0,0) acts on T ₀ /4;

Figure 11 shows the case where only the v ₀ (0,0) vector is used, and the switching sequence at this time is:

v ₀ (0,0) acts on T ₀ /2 → v ₁ (1,0) acts on T ₁ → v ₀ (0,0) acts on T ₀ /2;

(5.6). After the two-phase switching signals S _A and S _B undergo corresponding isolation, signal processing, and amplification circuits, they control the action of the single-phase H-bridge inverter, drive the exciter, and realize the excitation function of the three-stage brushless AC synchronous motor. .

Figure 12-Figure 15 is the excitation current waveform of the exciter in each excitation stage when the modulation algorithm proposed by the present invention is adopted, wherein Figure 12 is a pure AC excitation mode, and Figure 13 is an AC excitation mode with a DC bias, Fig. 14 is a DC excitation method containing an AC component, and Fig. 15 is a DC excitation method.

Fig. 16 is a curve diagram of on-load starting acceleration of the unit when the method of the present invention is adopted.

Claims (8)

1. an aviation three-stage brushless AC synchronous motor starting process excitation control method is characterized in that the steps are as follows: Step 1: According to the measured current speed value ω _r of the motor and the curve of the set AC excitation quantity changing with the speed, obtain the modulation degree M _A of the current output AC excitation component, and then obtain the modulation upper limit of the modulation degree of the DC excitation component M _DMAX = 1-M _A ; Step 2: Perform PI adjustment on the difference between the rated current i ^* of the exciter and the excitation current value i of the current exciter e _i = i ^* -i to obtain the modulation degree of the DC excitation control quantity Among them, K _ps is the proportional coefficient of the excitation current PI controller, K _ps >0; K _{is is} the integral coefficient of the excitation current PI controller, K _is >0; Output the modulation degree M _D of the DC excitation quantity of the exciter at the current speed after limiting processing; Step 3: According to the angular integrator of the AC excitation component of the exciter, the voltage phase angle θ=∫ωdt of the current AC excitation component is obtained, where the AC excitation angular velocity ω=2πf, and f is the frequency of the AC excitation component; Step 4: Calculate the effective vector and zero vector action time, the specific steps are as follows: Step a: Calculate the inverter output reference voltage as V _ref = M _D V _DC + M _A V _DC cosθ, where V _DC is the bus voltage of the exciter controller; Step b: According to the principle of volt-second balance, set the switching period of the inverter as T _s , and the action time of the effective vector as T ₁ , there is: V _ref T _s = V _DC T ₁ ; then within one switching period, the effective vector and zero The action times of the vectors are: $\left\{\begin{array}{c}{T}_1=m_{\mathrm{D.}}{T}_{\mathrm{the\; s}}+m_A{T}_{\mathrm{the\; s}}\cos \mathrm{\&omega;t}\\ T_0=T_{\mathrm{the\; s}}-T_1\end{array}\right.;$ Step 5: Calculate the control quantity of the H-bridge inverter, and control the H-bridge inverter to drive the exciter with this control quantity: When using a zero vector and V _ref > 0, the control amount of the H-bridge inverter $\left\{\begin{array}{c}\mathrm{CMP}\_a=T_0/2\\ \mathrm{CMP}\_b=T_{\mathrm{the\; s}}/2\end{array}\right.;$ When adopting a zero vector and V _ref <0, the control amount of the H-bridge inverter $\left\{\begin{array}{c}\mathrm{CMP}\_a=T_{\mathrm{the\; s}}/2\\ \mathrm{CMP}\_b=T_0/2\end{array}\right.;$ When two zero vectors are used and V _ref >0, the control amount of the H-bridge inverter $\left\{\begin{array}{c}\mathrm{CMP}\_a=T_0/4\\ \mathrm{CMP}\_b=T_0/4+T_1/2\end{array}\right.;$ When using two zero vectors and V _ref <0, the control amount of the H-bridge inverter $\left\{\begin{array}{c}\mathrm{CMP}\_a=T_0/4+T_1/2\\ \mathrm{CMP}\_b=T_0/4\end{array}\right..$ 2. According to the described aviation three-stage brushless AC synchronous motor starting process excitation control method of claim 1, it is characterized in that: the modulation degree M of the _DC excitation quantity of the exciter under the described current speed is obtained by the following steps: e _i = i ^* -i; ${\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}^{<span\; class="notranslate">\; *</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; ps</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; e</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; is</span>}}<span\; class="notranslate">\; \&Integral;</span>{\mathrm{<span\; class="notranslate">\; e</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}\mathrm{<span\; class="notranslate">\; dt</span>}$ ${\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}<span\; class="notranslate">\; =</span>\left\{\begin{array}{cc}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}^{<span\; class="notranslate">\; *</span>}& {\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}^{<span\; class="notranslate">\; *</span>}<span\; class="notranslate">\; <</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}\\ \mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}& {\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}^{<span\; class="notranslate">\; *</span>}<span\; class="notranslate">\; \&Greater\; Equal;</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}\end{array}\right.<span\; class="notranslate">\; .</span>$ 3. According to claim 1 or 2, the excitation control method during the starting process of the aviation three-stage brushless AC synchronous motor is characterized in that: the modulation degree _MA of the current output AC excitation component satisfies: _1≥MA≥0 . 4. According to claim 1, the said aviation three-stage brushless AC synchronous motor starting process excitation control method is characterized in that: the modulation degree M of the DC excitation quantity of the exciter under the current rotating speed satisfies: 1-M _{A ≥} M _D ≥ 0. 5. The excitation control method during the starting process of the aviation three-stage brushless AC synchronous motor according to claim 1, characterized in that: the angular velocity ω of the AC excitation quantity satisfies: ω=200π. 6. According to claim 1, said aviation three-stage brushless AC synchronous motor starting process excitation control method is characterized in that: said K _ps is set according to the characteristics of the exciter itself and the system performance requirements of the three-stage brushless AC synchronous motor , K _is , and K _ps >0, K _is >0. 7. A device for realizing the excitation control method of the aviation three-stage brushless AC synchronous motor starting process described in any one of claims 1 to 6, characterized in that it includes a rectifier circuit, a filter circuit, a three-phase full-bridge inverter, a single Phase H-bridge inverter, position sensor, central controller, isolation driver and current acquisition circuit; the rectifier circuit rectifies the input three-phase AC and outputs it to the filter circuit connected to it, and the filter circuit is respectively connected to the three-phase full-bridge inverter Inverter and single-phase H-bridge inverter; the single-phase H-bridge inverter is connected to the stator winding of the exciter to drive the exciter to realize the excitation of the main generator; the three-phase full-bridge inverter is connected to the main generator to control the main generator Start operation; the position sensor is set at the place where the rotor position of the motor is detected, and its output end is connected to the central controller; the current acquisition circuit is connected to the output end of the single-phase H-bridge inverter and the three-phase full-bridge inverter, and its output end is connected to the a central controller; an output end of the central controller is connected to an isolation driver, and an output end of the isolation driver is respectively connected to a three-phase full-bridge inverter and a single-phase H-bridge inverter. 8. The device according to claim 7, characterized in that: the position sensor adopts a rotary transformer.