A multi-stage starting system position sensorless controllable rectification power generation voltage building control method

Abstract

The application relates to a multi-stage starting system position-sensor-free controllable rectification power generation voltage building control method, which firstly adopts main motor non-controllable rectification and builds voltage through excitation machine excitation adjustment, and estimates main motor rotor position and rotating speed information in the non-controllable rectification stage. The rotor position and rotating speed information estimated in the non-controllable rectification stage are used for estimating the rotor position for controllable rectification control in the initial controllable rectification stage, and a rotor position estimation method based on back electromotive force is synchronously used for estimating the rotor position; after a short transition, the rotor position information obtained based on the back electromotive force is used for main motor controllable rectification power generation control, and the position-sensor-free controllable rectification power generation steady voltage building and power generation are completed. The method can realize stable switching from non-controllable rectification to controllable rectification under the position-sensor-free multi-stage starting system, and guarantees the position-sensor-free controllable rectification power generation steady voltage building and power generation.

Description

Technical Field

[0001] This invention belongs to the field of motor control technology and relates to a sensorless controllable rectifier power generation voltage building control method for a multi-stage starting system. Background Technology

[0002] With the increasing capacity and variety of airborne electrical equipment, multi-electric / all-electric aircraft place ever higher demands on the high power density and high reliability of their aviation power systems. Integrated starter-generator systems combine engine starting and onboard power supply functions, eliminating the need for dedicated engine starting equipment and simplifying the aircraft's power system structure. This is a key technology for multi-electric / all-electric aircraft power systems. During the start-up phase, the starter generator drives the aircraft engine in electric motor mode; once the engine reaches its self-sustaining speed, the starter generator switches to generator mode, where the engine drives the generator to produce electricity.

[0003] Traditional multi-stage brushless synchronous motor power generation uses uncontrolled rectification of the main motor, with output voltage stabilization achieved through excitation regulation by the exciter. This method is simple in structure and easy to control, but its dynamic response and efficiency are limited. To further improve dynamic response and optimize efficiency, controlled rectifier power generation using PWM (Pulse Width Modulation) of the main motor is required. Controlled rectifier power generation requires rotor position information. Since position sensors are susceptible to interference and have poor reliability under aerospace conditions, sensorless detection technology can be used to estimate rotor position to ensure high-reliability power generation in multi-stage starting and generating systems.

[0004] Rotor position estimation in the high-speed section of synchronous motors mainly relies on back EMF observers as the primary detection technology, such as sliding mode observers, Kalman filters, or model reference adaptation methods. Therefore, when the aerospace motor system fully enters the stage of controllable rectifier power generation, various methods can be used to achieve sensorless detection and prediction of rotor position, and the technology is relatively mature.

[0005] Sensorless detection primarily relies on back-EMF observers, such as sliding mode observers, Kalman filters, or model reference adaptation methods. Therefore, when aerospace motor systems fully transition to controlled rectification power generation, various methods can be used to achieve sensorless detection and rotor position estimation, and the technology is relatively mature. However, during the initial voltage build-up process of high-power aerospace power systems, the output DC bus voltage builds up from 0. Because it is difficult to obtain an accurate initial position during the initial power generation phase, and the electrical cycle is extremely short at high speeds, a large initial position error can lead to convergence to the actual rotor position over multiple electrical cycles. Under sensorless conditions, controlled rectification is difficult to achieve smoothly and reliably, easily leading to voltage build-up failure and system collapse, preventing power generation.

[0006] To address this problem, this invention proposes a sensorless controllable rectification power generation voltage build-up control method for a multi-stage synchronous motor. The method involves using uncontrolled rectification based on exciter excitation regulation to build up and stabilize the system voltage before switching to PWM controllable rectification of the main motor. Simultaneously, the rotor position information extracted during the uncontrolled rectification stage is used as a reference initial value for the controllable rectification stage to estimate the rotor position during the transition phase. Then, the method switches to the rotor position obtained through back-EMF observation, ultimately completing the stable voltage generation of the motor. Simulation verification shows that this method can achieve a stable switching of the main motor from uncontrolled to controlled rectification without a position sensor, solving the problem of difficult stable voltage build-up in sensorless controllable rectification power generation of multi-stage synchronous motors. Summary of the Invention

[0007] Technical problems to be solved To overcome the shortcomings of existing technologies, this invention proposes a sensorless controllable rectification power generation voltage build-up control method for multi-stage starting and generating systems. The technical problem this invention aims to solve for the smooth voltage build-up and power generation of multi-stage starting and generating systems with sensorless controllable rectification is: accurately estimating the rotor position information of the main motor during the uncontrolled rectification stage and the initial stage of switching to controlled rectification, thereby achieving a smooth transition from uncontrolled rectification voltage build-up to sensorless controllable rectification power generation.

[0008] Technical solution A sensorless controllable rectifier power generation voltage build-up control method for a multi-stage generator system, characterized by the following steps: Step 1: Using the uncontrolled rectification mode of the main motor, the system voltage is built up by adjusting the excitation of the exciter, and the motor system is regulated to stabilize the system output voltage; The uncontrolled rectification mode of the main motor is: the controllable rectifier power circuit switching device in the starter generator controller is turned off, and only the anti-parallel diode in the switching device is turned on. At this time, the controllable rectifier power circuit operates in the uncontrolled rectification mode. Step 2: After the system output voltage stabilizes, the main motor rectification mode switches from uncontrolled rectification to controlled rectification. This moment is recorded as the trigger control mode conversion. Time, and lock Main motor rotor position at any given time and the speed of the main motor ; Main motor rotor position Calculation:

[0009] Main motor speed Calculation:

[0010] in: for The direction of the current vector at time t. for Torque angle at time; Step 3: Set one Time, as the transition time between the two control modes, is determined by the latched rotor position. and rotational speed Estimate Main motor rotor position within a time period for:

[0011] in: relative to the reference time Time offset; Will The controllable rectifier control circuit, acting as the rotor position input for the main motor, enables the main motor to perform controllable rectification and power generation control. Simultaneously, the rotor position is estimated using the conventional back-EMF observation method. ; The sensorless controllable rectifier operation mode is as follows: the excitation regulation outer loop is switched to a given fixed excitation current of the exciter, the input signal of the controllable rectifier power circuit switching device is switched to a switching signal output by PWM control, and the back EMF observation method starts to sample the signal and estimate the rotor position. Step 4: When the rotor position is estimated using the back EMF observation method... When the absolute value of the error between the rotor position and the actual rotor position is less than or equal to a preset threshold, the value at that moment will be... Replace rotor position The input control circuit completes the closed-loop control of the synchronous motor's sensorless controllable rectifier power generation.

[0012] Step 1, which involves regulating the exciter excitation to build up system voltage and stabilize the motor system, involves: using the difference between the sampled load voltage signal and the output voltage reference value as the basis for outputting the exciter excitation current reference value via a PI controller; calculating the difference between the exciter excitation current reference value and the sampled exciter excitation current, inputting this difference into the PI controller to obtain the duty cycle D of the H-bridge power circuit, and outputting a PWM wave to act on the H-bridge power circuit; and finally, the exciter excitation voltage output by the H-bridge power circuit acting on the exciter in the generator to complete the system voltage regulation.

[0013] The direction of the current vector in step 2 The calculation is as follows: based on the three-phase current in the armature current. The direction of the current composite vector in the stationary coordinate system is obtained through Clark coordinate transformation and arctangent function. : .

[0014] The torque angle in step 2 The calculation is as follows: ,in for The angle of work at time t is given by the formula: In the formula: for The terminal phase voltage at that moment; for Stator phase current at time; Let be the synchronous reactance of the motor in the q-axis direction; This refers to the motor frequency; The inductance of the stator on the q-axis; The power factor angle.

[0015] The system output voltage stability is defined as follows: after the uncontrolled rectification phase ends and the DC bus voltage reaches the preset rated generation voltage, the voltage remains stable for a continuous period of time. The internal fluctuation amplitude is less than a preset percentage threshold; the target value is the rated DC bus voltage.

[0016] The continuous duration The duration is 5ms to 20ms.

[0017] The percentage less than the preset percentage threshold is ±2% to ±5%.

[0018] The The response time required for the rotor position estimated by the back EMF observation method to converge to the point where the error between the rotor position and the actual rotor position is less than a preset threshold.

[0019] The preset threshold is 20° electrical angle.

[0020] The The stator phase current at time t is calculated as follows: ,in: It represents the three-phase current in the armature current.

[0021] The The terminal phase voltage at time t is calculated as follows: ,in: and They are respectively DC bus voltage and DC bus current at time t. for Stator phase current at time t.

[0022] The preset threshold in step 4 should satisfy the following: after the estimated position is fed back to the control system, the fluctuations in the phase current and speed of the system are suppressed within the preset ratio range of the rated value, so as to ensure that the system operates stably without losing control.

[0023] The preset ratio range is <5%.

[0024] The data flow of the control circuit under the controllable rectification state is as follows: through vector space decomposition and synchronous rotating coordinate transformation, the six-phase stator current is... Mapped to and Subspaces are defined, and independent closed-loop control is performed on the current components of each subspace. For The subspace control loop consists of an outer voltage loop and an inner current loop. The outer voltage loop is used to control the load voltage. Tracking reference voltage The inner current loop is used to regulate the stator current of the main motor. , Tracking reference current , The sampled load voltage value Compared with reference voltage value The difference is fed into the outer loop PI controller, and the output is... q Shaft current reference value ,Will , and , The difference is input to the inner loop PI controller and output. , After performing coordinate transformation, we obtain , ;for Plane controller, , The difference between the current and the reference value is input to the PI controller, and the output is... , .Will The input is sent to the SVPWM module, and the output switching signal controls the turn-on and turn-off of the six-phase controllable rectifier power transistors.

[0025] Beneficial effects This invention proposes a sensorless controllable rectifier power generation voltage build-up control method for multi-stage starting systems. Addressing the difficulty in achieving stable voltage build-up during the initial stage of power generation in sensorless controllable rectifier power generation systems, this method proposes a sensorless power generation voltage build-up control method that involves uncontrolled rectification followed by switching to controlled rectification. This method first uses uncontrolled rectification of the main motor and excitation regulation of the exciter to build up system voltage, estimating the rotor position and speed of the main motor during the uncontrolled rectification stage. After the system output voltage stabilizes, the main motor rectification mode switches from uncontrolled to controlled rectification. In the initial stage of controlled rectification, the rotor position and speed information estimated during the uncontrolled rectification stage are used to predict the rotor position for controlled rectification control, and a rotor position estimation method based on back EMF is simultaneously used for rotor position estimation. After a brief transition, the rotor position information obtained based on back EMF is used for controlled rectification power generation control of the main motor, completing the stable voltage build-up and power generation of the sensorless controllable rectifier power generation system. This method enables a stable switching from uncontrolled rectification to controlled rectification in a multi-stage generator system without position sensors, ensuring smooth voltage build-up and power generation in the sensorless controlled rectification power generation system.

[0026] This paper proposes a sensorless controllable rectifier power generation voltage build-up control method for multi-stage starter generator systems based on rotor position estimation. This method can achieve stable switching of multi-stage synchronous motors in aviation from uncontrolled rectification to sensorless controllable rectification, solving the problem of difficult stable voltage build-up in sensorless controllable rectifier power generation of multi-stage starter generators and improving the reliability of aviation power systems. Attached Figure Description

[0027] Figure 1 Sensorless Controlled Rectifier Voltage Buildup Power Generation Control Flowchart Figure 2 Control diagram for switching between uncontrolled and controlled rectification in power generation Figure 3 Spatiotemporal vector diagram of a salient-pole synchronous motor Figure 4 : Angle vector diagram of a salient-pole synchronous motor Figure 5 Output voltage waveform diagram Figure 6 Estimating the rotor position error during the pressure build-up process Figure 7: Waveforms of estimated rotor position and actual rotor position during the uncontrolled rectification stage, and the magnitude of the error; (a) Estimated rotor position vs. actual rotor position (b) Magnitude of rotor position error Figure 8 Waveforms of estimated and actual rotational speeds during the uncontrolled rectification phase. Figure 9: Waveforms of estimated rotor position and actual rotor position during the transition phase, and the magnitude of the error; (a) Estimated rotor position vs. actual rotor position (b) Magnitude of rotor position error Figure 10: Waveforms of SMO-estimated rotor position and actual rotor position, and the magnitude of the error; (a) Estimated rotor position vs. actual rotor position (b) Magnitude of rotor position error Detailed Implementation The present invention will now be further described in conjunction with the embodiments and accompanying drawings: The sensorless controllable rectifier power generation voltage building-up control based on rotor position estimation proposed in this invention is applicable to various synchronous motors. After the system voltage building-up is completed and the output voltage is stabilized by the exciter excitation regulation, the estimated rotor position and rotor angular velocity are used to complete the rectification mode switching transition, and then the main motor enters PWM controllable rectification operation.

[0028] Taking an aviation-type three-stage dual three-phase synchronous starter / generator as an example, the present invention will now be further described in conjunction with embodiments and accompanying drawings: Step 1: Uncontrolled rectifier voltage build-up and estimation of rotor position and speed. Uncontrolled rectifier power generation control based on exciter excitation regulation is performed on a three-stage dual three-phase starter / generator. The control block diagram is as follows: Figure 2 As shown.

[0029] When uncontrolled rectification is performed, that is, when the main motor voltage is stabilized only by the exciter excitation regulation, the switching devices of the dual three-phase main power conversion circuit in the starter generator controller are turned off, and natural rectification is performed only by the anti-parallel diodes integrated inside the switching devices. At this time, the main power conversion circuit is controlled to operate in the uncontrolled rectification mode.

[0030] The system output voltage stability is defined as follows: after the uncontrolled rectification phase ends and the DC bus voltage reaches the preset rated generation voltage, the voltage remains stable for a continuous period of time. The internal fluctuation amplitude is less than the preset percentage threshold, and the continuous duration is... The time is 5ms to 20ms, and the preset percentage threshold is ±2% to ±5%; the target value is the rated DC bus voltage.

[0031] The difference between the sampled load voltage signal and the output voltage reference value is used by the PI controller to output the exciter excitation current reference value, which is then subtracted from the sampled exciter excitation current. This difference is input to the PI controller to obtain the duty cycle D of the H-bridge power circuit, and a PWM wave is output to the H-bridge power circuit. The exciter excitation voltage output by the H-bridge power circuit is applied to the exciter in the generator to complete the system voltage regulation.

[0032] Sample the main motor armature current, and Perform Clark coordinate transformation to obtain Current components in the coordinate system:

[0033] The direction of the current vector is obtained through the arctangent function.

[0034]

[0035] The electromotive force balance equation for the armature circuit of a salient-pole synchronous motor is:

[0036] In the formula: This is the no-load electromotive force inside the motor; This is the voltage composite vector; This is the composite vector of currents; Armature resistance; , These are the d-axis (direct axis) and q-axis (quadrature axis) current components of the motor, respectively. , These are the synchronous reactances of the motor on the d-axis and q-axis, respectively. From this, we obtain... Figure 3 The spatiotemporal vector diagram of the salient-pole synchronous motor is shown.

[0037] Neglecting armature resistance The simplified electromotive force balance equation is obtained:

[0038] Addition and subtraction on the right side of the equation get:

[0039] According to the simplified formula, we obtain Figure 4 The diagram shows the motor vector diagram. The power angle δ represents the phase difference angle between the no-load electromotive force E0 inside the motor and the terminal voltage U; the power factor angle... The angle between the current vector and the terminal voltage vector; torque angle. It is the electrical angle between the direction of the current magnetomotive force on which the motor generates torque and the direction of the magnetic flux linkage (d-axis) of the rotor permanent magnet.

[0040] The formula for calculating the angle of work is:

[0041] In the formula: This represents the effective value of the phase voltage at the generator terminals; This represents the effective value of the stator phase current; Let be the synchronous reactance of the motor in the q-axis direction; This refers to the motor frequency; The inductance of the stator on the q-axis; The power factor angle.

[0042] When the main motor is running with a diode-controlled uncontrolled rectifier load, due to the load characteristics of the diode rectifier, the phase difference between the fundamental phase voltage and the phase current is small under steady-state operating conditions, which can be approximated as the power factor angle. Therefore, the stator voltage space vector and the current space vector are approximately in the same direction, and their included angle can be ignored. Thus, the formula for calculating the power angle can be further simplified to:

[0043] Among them, the effective value of phase current Sum phase voltage RMS value None of these can be measured directly; calculations are required based on the system's sampleable signals. The system can directly acquire three-phase stator currents. Therefore, the effective value of the phase current can be expressed as:

[0044] Based on the power balance relationship between the AC and DC sides, and neglecting system losses, we have: ,Right now

[0045] In the formula, and These represent the DC bus voltage and DC bus current, respectively. The double-Y six-phase winding uses two sets of three-phase windings to share the output power. The AC side power of a single three-phase winding is half the DC side output power. Therefore, the effective value of the phase voltage can be obtained as follows:

[0046] The formula for calculating the angle of work can be simplified to:

[0047] Since the power factor angle is approximately 0, the torque angle can be approximated as:

[0048] Right now

[0049] In the uncontrolled rectification stage, the current vector direction is used. Subtract torque angle Rotor position information can then be obtained. :

[0050] Right now

[0051] By estimating the rotor position The angular velocity of a synchronous motor can be estimated. The formula for the electrical angular velocity of a motor is:

[0052] When the main motor operates under uncontrolled rectifier power generation, the harmonics caused by the uncontrolled rectification will have a certain impact on the calculation of the torque angle. This invention performs low-pass filtering on the armature current of the main motor and performs phase compensation on the estimated rotor position based on the phase frequency characteristics of the filter, so as to reduce the impact of filtering delay on the position estimation accuracy and improve the stability of system operation and the accuracy of position estimation.

[0053] Step 2: Switching between uncontrolled rectification and controlled rectification modes. After the uncontrolled rectification phase ends and the DC bus voltage reaches the preset rated generation voltage, ... Control mode switching is triggered at any time. Latching. rotor position at time and motor speed The back EMF observation method begins to sample the signal and estimate the rotor position.

[0054] The latched rotor position at this time Calculation: ; Main motor speed Calculation:

[0055] in: for The direction of the current vector at time t. for Torque angle at time; The torque angle The calculation is as follows: ,in for The angle of work at time t is given by the formula: In the formula: for The terminal phase voltage at that moment; for Stator phase current at time; Let be the synchronous reactance of the motor in the q-axis direction; This refers to the motor frequency; The inductance of the stator on the q-axis; The power factor angle.

[0056] The The stator phase current at time t is calculated as follows: ,in: It represents the three-phase current in the armature current.

[0057] The The terminal phase voltage at time t is calculated as follows: ,in: and They are respectively DC bus voltage and DC bus current at time t. for Stator phase current at time t.

[0058] When field weakening regulation is not required, the outer loop of the excitation regulation is switched to a given fixed excitation current of the exciter, and the input signal of the switching device of the dual three-phase main power conversion circuit is the switching signal output by the SVPWM module.

[0059] For the control circuit under controllable rectification, the six-phase stator current is transformed through vector space decomposition and synchronous rotating coordinate transformation. Mapped to and Subspaces are defined, and independent closed-loop control is performed on the current components of each subspace. For The subspace control loop consists of an outer voltage loop and an inner current loop. The outer voltage loop is used to control the load voltage. Tracking reference voltage The inner current loop is used to regulate the stator current of the main motor. , Tracking reference current , The sampled load voltage value Compared with reference voltage value The difference is fed into the outer loop PI controller, and the output is... q Shaft current reference value ,Will , and , The difference is input to the inner loop PI controller and output. , After performing coordinate transformation, we obtain , ;for Plane controller, , The difference between the current and the reference value is input to the PI controller, and the output is... , .Will The input is fed into the SVPWM (Space Vector Pulse Width Modulation) module, and the output switching signal controls the turn-on and turn-off of the six-phase controllable rectifier power transistors.

[0060] Step 3: Transition process control. In After the control mode switch is completed, the system enters the controllable rectification stage. Due to the duration of the transition phase during the rectification mode switch... The time interval is extremely short, and the motor's mechanical inertia is relatively large. It can be reasonably assumed that the motor speed remains constant during this time, meaning the rotor angular velocity is approximately constant. This is achieved by locking the rotor position. and rotational speed Estimate Main motor rotor position within a time period for:

[0061] in: relative to the reference time Time offset; .

[0062] The The response time required for the rotor position estimated by the back EMF observation method to converge to the point where the error between the rotor position and the actual rotor position is less than a preset threshold.

[0063] The transition phase will be estimated. The controllable rectifier control circuit, acting as the rotor position input for the main motor, enables the main motor to perform controllable rectification and power generation control. Simultaneously, the rotor position is estimated using the conventional back-EMF observation method. ; The preset ratio range is <5%.

[0064] The conventional back EMF observation method first constructs an observer based on the motor voltage equation to estimate the back EMF component in the stationary coordinate system in real time. Then, the back EMF signal is subjected to arctangent operation to extract the phase information, and the continuous position angle of the rotor is obtained by decoupling. Alternatively, it can be further shaped by zero-crossing detection combined with a phase-locked loop (PLL) to obtain high-precision position information.

[0065] Step 4: Switch to sensorless controllable rectifier power generation control for the main motor. After the response time, the rotor position is estimated based on the back EMF observation method. If the absolute value of the error between the rotor position and the actual rotor position is less than the maximum allowable position deviation of the system, then the rotor position during the transition phase will be... Switch to The control circuit is then engaged to ultimately complete the closed-loop control of the synchronous motor's power generation. The maximum allowable position deviation of the system is determined by the motor parameters and the control loop gain; within this deviation range, [the system will...]. By employing closed-loop control, the system can be prevented from losing synchronization or experiencing current oscillations, thereby ensuring operational robustness. This invention uses a sliding mode observer as an example. The rotor position during the transition phase will be determined after the response time. Switch to Continue to complete the controllable rectifier power generation control of the motor.

[0066] The operating status of the motor under this method was observed through simulation experiments, and the estimated rotor position at each stage was compared with the actual rotor position. Figure 5 The DC voltage waveform output by the three-stage synchronous motor is shown. When the control mode is switched from uncontrolled rectification to controlled rectification, the rotor position is estimated based on the initial value calculated by uncontrolled rectification, and the maximum oscillation is maintained within 250~270V. When switching to rotor position estimated using SMO, the oscillation is around 251~254V, and finally a stable output of 270V is maintained. This indicates that the present invention can achieve sensorless voltage stabilization and power generation control by switching from uncontrolled rectification to controlled rectification after voltage build-up and stabilization.

[0067] like Figure 6 The figure shows the error between the estimated rotor position and the actual rotor position during the voltage build-up process of sensorless power generation. It can be seen that under this method, the absolute value of the error between the estimated rotor position and the actual rotor position remains within 8°, which meets the rotor position requirements for controlled rectification of the main motor, verifying the reliability of this method.

[0068] Figure 7 shows the waveforms of the estimated rotor position and the actual rotor position during the uncontrolled rectification stage, as well as the magnitude of the error. The absolute value of the error is approximately 4°, which is relatively small, verifying the accuracy of the method for estimating rotor position information during the uncontrolled rectification stage proposed in this invention. Figure 8 The image shows a comparison between the motor angular velocity estimated from rotor position information during the uncontrolled rectification stage and the actual speed. The error between the estimated angular velocity and the actual speed is within 0.01 rad / s, which is extremely small, verifying the effectiveness of the method of estimating the rotational speed using the initial value of uncontrolled rectification in this invention.

[0069] Figure 9 shows the waveforms of the estimated rotor position and the actual rotor position during the transition phase, as well as the magnitude of the error. The absolute value of the error is approximately 4°, which is relatively small. This verifies that the method of estimating the rotor position in a very short time based on the latched initial value is effective, and the output result is relatively accurate.

[0070] Figure 10 shows the waveforms and error magnitudes of the estimated rotor position and the actual rotor position after switching from controlled rectification to SMO. Under regulated conditions, the absolute value of the rotor position error of SMO is approximately 4°, with minimal chattering, indicating a relatively accurate rotor position estimation. Experimental results demonstrate that this invention can achieve stable switching of the motor from uncontrolled rectification to controlled rectification at high speeds, completing the system's stable power generation through sensorless controlled rectification.

Claims

1. A sensorless controllable rectifier power generation voltage build-up control method for a multi-stage starting system, characterized in that... The steps are as follows: Step 1: Using the uncontrolled rectification mode of the main motor, the system voltage is built up by adjusting the excitation of the exciter, and the motor system is regulated to stabilize the system output voltage; The uncontrolled rectification mode of the main motor is: the controllable rectifier power circuit switching device in the starter generator controller is turned off, and only the anti-parallel diode in the switching device is turned on. At this time, the controllable rectifier power circuit operates in the uncontrolled rectification mode. Step 2: After the system output voltage stabilizes, the main motor rectification mode switches from uncontrolled rectification to controlled rectification. This moment is recorded as the trigger control mode conversion. Time, and lock Main motor rotor position at any given time and the speed of the main motor ; Main motor rotor position Calculation: Main motor speed Calculation: in: for The direction of the current vector at time t. for Torque angle at time; Step 3: Set one Time, as the transition time between the two control modes, is determined by the latched rotor position. and rotational speed Estimate Main motor rotor position within a time period for: in: relative to the reference time Time offset; Will The controllable rectifier control circuit, acting as the rotor position input for the main motor, enables the main motor to perform controllable rectification and power generation control. Simultaneously, the rotor position is estimated using the conventional back-EMF observation method. ; The sensorless controllable rectifier operation mode is as follows: the excitation regulation outer loop is switched to a given fixed excitation current of the exciter, the input signal of the controllable rectifier power circuit switching device is switched to a switching signal output by PWM control, and the back EMF observation method starts to sample the signal and estimate the rotor position. Step 4: When the rotor position is estimated using the back EMF observation method... When the absolute value of the error between the rotor position and the actual rotor position is less than or equal to a preset threshold, the value at that moment will be... Replace rotor position The input control circuit completes the closed-loop control of the synchronous motor's sensorless controllable rectifier power generation.

2. The sensorless controllable rectifier power generation voltage building control method for a multi-stage starting system according to claim 1, characterized in that: Step 1, which involves regulating the exciter excitation to build up system voltage and stabilize the motor system, involves: using the difference between the sampled load voltage signal and the output voltage reference value as the basis for outputting the exciter excitation current reference value via a PI controller; calculating the difference between the exciter excitation current reference value and the sampled exciter excitation current, inputting this difference into the PI controller to obtain the duty cycle D of the H-bridge power circuit, and outputting a PWM wave to act on the H-bridge power circuit; and finally, the exciter excitation voltage output by the H-bridge power circuit acting on the exciter in the generator to complete the system voltage regulation.

3. The sensorless controllable rectifier power generation voltage building control method for a multi-stage starting system according to claim 1, characterized in that: The direction of the current vector in step 2 The calculation is as follows: based on the three-phase current in the armature current. The direction of the current composite vector in the stationary coordinate system is obtained through Clark coordinate transformation and arctangent function. : in: yes The three-phase current is collected at all times.

4. The sensorless controllable rectifier power generation voltage building control method for a multi-stage starting system according to claim 1, characterized in that: The torque angle in step 2 The calculation is as follows: ,in for The angle of work at time t is given by the formula: In the formula: for The terminal phase voltage at that moment; for Stator phase current at time; Let be the synchronous reactance of the motor in the q-axis direction; This refers to the motor frequency; The inductance of the stator on the q-axis; The power factor angle.

5. The sensorless controllable rectifier power generation voltage build-up control method for a multi-stage starting system according to claim 1, characterized in that: The system output voltage stability is defined as follows: after the uncontrolled rectification phase ends and the DC bus voltage reaches the preset rated generation voltage, the voltage remains stable for a continuous period of time. The internal fluctuation amplitude is less than a preset percentage threshold; the target value is the rated DC bus voltage.

6. The sensorless controllable rectifier power generation voltage build-up control method for a multi-stage starting system according to claim 1, characterized in that: The The response time required for the rotor position estimated by the back EMF observation method to converge to the point where the error between the rotor position and the actual rotor position is less than a preset threshold.

7. The sensorless controllable rectifier power generation voltage build-up control method for a multi-stage starting system according to claim 1, characterized in that: The The stator phase current at time t is calculated as follows: ,in: It represents the three-phase current in the armature current.

8. The sensorless controllable rectifier power generation voltage build-up control method for a multi-stage starting system according to claim 1, characterized in that: The The terminal phase voltage at time t is calculated as follows: ,in: and They are respectively DC bus voltage and DC bus current at time t. for Stator phase current at time t.

9. The sensorless controllable rectifier power generation voltage build-up control method for a multi-stage starting system according to claim 1, characterized in that: The preset threshold in step 4 should satisfy the following: after the estimated position is fed back to the control system, the fluctuations in the phase current and speed of the system are suppressed within the preset ratio range of the rated value, so as to ensure that the system operates stably without losing control.

10. The sensorless controllable rectifier power generation voltage building control method for a multi-stage starting system according to claim 1, characterized in that, The data flow of the control circuit under the controllable rectification state is as follows: through vector space decomposition and synchronous rotating coordinate transformation, the six-phase stator current is... Mapped to and Subspaces, and perform independent closed-loop control on the current components of each subspace; for The subspace control loop consists of an outer voltage loop and an inner current loop. The outer voltage loop is used to control the load voltage. Tracking reference voltage The inner current loop is used to regulate the stator current of the main motor. , Tracking reference current , ; The sampled load voltage value Compared with reference voltage value The difference is fed into the outer loop PI controller, and the output is... q Shaft current reference value ,Will , and , The difference is input to the inner loop PI controller and output. , After performing coordinate transformation, we obtain , ;for Plane controller, , The difference between the current and the reference value is input to the PI controller, and the output is... , ;Will The input is sent to the SVPWM module, and the output switching signal controls the turn-on and turn-off of the six-phase controllable rectifier power transistors.

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