CN-122026490-A - Control method and control system for static frequency converter of distributed phase modulation unit

CN122026490ACN 122026490 ACN122026490 ACN 122026490ACN-122026490-A

Abstract

The invention discloses a control method and a control system for a static frequency converter of a distributed phase modulation unit, wherein the control method comprises the following steps of. The control method of the static frequency converter of the distributed phase modulation unit comprises the following steps of determining a target phase modulation unit according to a starting instruction and calling a corresponding sequential control fixed value, sequentially closing a power loop switch according to the sequential control fixed value to establish an exciting power supply passage, detecting the initial position of a rotor after the exciting power supply passage is established, determining the correct initial triggering sequence, unlocking pulse output and starting output power, dragging the target phase modulation unit to start by adopting a forced phase conversion mode, monitoring the machine end voltage frequency of the target phase modulation unit in real time, switching the phase conversion mode from the forced phase conversion mode to a load phase conversion mode when the machine end voltage frequency is higher than a preset phase conversion threshold value, and continuing to drag the target phase modulation unit to rise to a target rotating speed.

Inventors

CAI XI
YUAN HONGPING
LI HAIJUN
LIU PAN
CHEN FEIYU
ZHAO JUNJIE
REN ZHONGJIE
YE LIWEN
ZHANG BING

Assignees

中国三峡建工(集团)有限公司
南京南瑞继保工程技术有限公司

Dates

Publication Date: 20260512
Application Date: 20260211

Claims (10)

1. A control method of a static frequency converter of a distributed phase modulation unit is characterized by comprising the following steps, According to the starting instruction, determining a target phase modulation unit and calling a corresponding sequential control fixed value; Sequentially closing a power loop (400) switch according to the sequential control fixed value to establish an excitation power supply path; After an excitation power supply passage is established, detecting the initial position of the rotor, determining a correct initial trigger sequence, unlocking pulse output and starting output power; Dragging a target phase modulation unit to start by adopting a forced phase conversion mode; Monitoring the voltage frequency of the machine end of the target phase modulation unit in real time; when the voltage frequency of the machine end is higher than a preset commutation switching threshold value, switching the commutation mode from the forced commutation mode to the load commutation mode, and continuously dragging the target phase modulation unit to rise to the target rotating speed.
2. The method for controlling a stationary frequency converter of a distributed phase modulation unit according to claim 1, wherein said sequence control constant comprises at least a start command waiting time, a stop command waiting time, a target rotation speed, a cooling system start delay, and an excitation input threshold.
3. The method for controlling the static frequency converter of the distributed phase modulation unit according to claim 1 or 2, wherein the detecting of the initial position of the rotor comprises sending an excitation step signal to an excitation system of a target phase modulation unit, detecting a transient terminal voltage induced by the excitation step signal, calculating an initial electrical position of the rotor according to phase information of the transient terminal voltage, and determining an initial triggering sequence according to the initial electrical position.
4. The method for controlling a stationary frequency converter of a distributed phase modulation unit according to claim 3, wherein the preset phase switching threshold is 10% of the rated frequency of the target phase modulation unit.
5. The method for controlling a stationary frequency converter of a distributed phase modulation unit according to claim 1 or 4, further comprising a fault handling step, Monitoring IP signals and PF signals reported by a thyristor (301) valve group in real time; if the number of simultaneously lost IP signals on a single valve arm exceeds a first fixed value, or the number of thyristors (301) of the simultaneous PF exceeds a second fixed value, the system trip is triggered immediately.
6. The method of claim 5, wherein the IP signal is a ready signal sent by a thyristor unit (300) after successful power up, and the first fixed value is a maximum number of thyristors (301) that allow simultaneous loss of the return IP signal on a single valve arm, and tripping is triggered beyond the maximum number.
7. The method of claim 6, wherein the PF signal is a maximum number of thyristors (301) that the thyristor unit (300) will force to protectively trigger when the forward voltage experienced by the thyristor (301) exceeds its hardware setting, and the second setting is a maximum number of thyristors (301) that allow simultaneous protectively triggering on a single valve arm, beyond which tripping is triggered.
8. A control system of a static frequency converter of a distributed phase modulation unit is suitable for the control method of the static frequency converter of the distributed phase modulation unit according to any one of claims 1 to 7, and is characterized by comprising, A control unit (100) configured to execute a control method and comprising a sequence control constant value library; The valve control unit (200) is in communication connection with the control unit (100) and is used for receiving a trigger instruction and expanding a trigger pulse; The thyristor units (300) are in communication connection with the valve control unit (200) and are used for driving a thyristor (301) valve group; a power circuit (400) including at least a grid-side converter (401), a machine-side converter (402), and a smoothing reactor (403); Wherein, the outlet end of the control unit (100) is connected into the power loop (400) through a cable for outputting an opening and closing instruction, and the control unit passes through the formula Performing a torque calculation, wherein In order to output the electromagnetic torque, Is a motor constant, is a fixed value according to the structural parameters of the motor, In order to control the control current output by the system, For the magnetic flux of the stator, Cosine function of the power factor angle. Wherein the method comprises the steps of The actual working angle is obtained by considering various factors such as the phase change overlapping angle.
9. The stationary frequency converter control system of a distributed phase modulation unit according to claim 8, wherein said control unit (100) comprises, A CPU plug-in (101) for task management, communication and wave recording; A DSP plug-in (102) for high-speed sampling and control computation; an analog quantity acquisition plug-in (103) for voltage and current signal sampling; A switching value input/output plug-in (104) for an external signal interface; The CPU plug-in (101), the DSP plug-in (102), the analog acquisition plug-in (103) and the switching value input/output plug-in (104) are all arranged on the backboard.
10. The system of claim 9, wherein the valve control unit (200) is configured to count the number of thyristors (301) of the PF for each valve arm simultaneously, and send a trip request to the control unit (100) when the number exceeds a fixed value; The number of thyristors (301) which simultaneously lose IP signals for each valve arm is counted, and when the number exceeds a fixed value, a tripping request is sent to the control unit (100).

Description

Control method and control system for static frequency converter of distributed phase modulation unit Technical Field The invention relates to the technical field of static frequency converters, in particular to a static frequency converter control method and a static frequency converter control system of a distributed phase modulation unit. Background A Static Frequency Converter (SFC) is a key device for starting a large synchronous motor and a phase modulation unit. In a conventional centralized camera station (a single high-capacity unit), the control strategy of SFC is relatively mature, and generally adopts fixed control parameters and unified fault protection logic. With the development of the power grid structure, the distributed phase modulation unit is increasingly widely applied. Distributed phase modulation units generally refer to multiple small-medium capacity cameras operating in parallel at the same site. However, the traditional SFC adopts mechanical position sensors such as a rotary transformer and a photoelectric encoder to detect the position of a rotor, has the problems of complex installation and maintenance, weak electromagnetic interference resistance, high cost and the like, is easy to fail in a strong electromagnetic environment of a distributed phase modulation unit, and cannot flexibly adapt to the differentiated starting parameters of a plurality of phase modulation units. Disclosure of Invention The present invention has been made in view of the above-mentioned problem of easy failure of the existing distributed phase modulation unit. Therefore, one of the purposes of the invention is to provide a control method of a static frequency converter of a distributed phase modulation unit, which aims to improve the reliability and the starting efficiency. In order to solve the technical problems of insufficient reliability and low starting efficiency, the invention provides the following technical scheme that the control method of the static frequency converter of the distributed phase modulation unit comprises the following steps, According to the starting instruction, determining a target phase modulation unit and calling a corresponding sequential control fixed value; sequentially closing a power loop switch according to the sequential control fixed value to establish an excitation power supply path; After an excitation power supply passage is established, detecting the initial position of the rotor, determining a correct initial trigger sequence, unlocking pulse output and starting output power; Dragging a target phase modulation unit to start by adopting a forced phase conversion mode; Monitoring the voltage frequency of the machine end of the target phase modulation unit in real time; when the voltage frequency of the machine end is higher than a preset commutation switching threshold value, switching the commutation mode from the forced commutation mode to the load commutation mode, and continuously dragging the target phase modulation unit to rise to the target rotating speed. As an optimal scheme of the control method of the static frequency converter of the distributed phase modulation unit, the sequential control fixed value at least comprises a start waiting time, a stop waiting time, a target rotating speed, a cooling system start delay and an excitation input threshold. The method for controlling the static frequency converter of the distributed phase modulation unit comprises the steps of detecting the initial position of a rotor, sending an excitation step signal to an excitation system of a target phase modulation unit, detecting transient state machine end voltage induced by the excitation step signal, calculating the initial electrical position of the rotor according to phase information of the transient state machine end voltage, and determining an initial triggering sequence according to the initial electrical position. As a preferable scheme of the control method of the static frequency converter of the distributed phase modulation unit, the preset phase switching threshold value is 10% of the rated frequency of the target phase modulation unit. As a preferable scheme of the control method of the static frequency converter of the distributed phase modulation unit, the invention further comprises a fault processing step, wherein the IP signal and the PF signal reported by the thyristor valve group are monitored in real time; if the number of simultaneously lost IP signals on a single valve arm exceeds a first fixed value or the number of thyristors of the concurrent PF exceeds a second fixed value, the system trip is triggered immediately. The invention relates to a control method of a static frequency converter of a distributed phase modulation unit, which is characterized in that an IP signal is a ready signal sent by a thyristor unit after successful power taking, a first fixed value is a maximum number of thyristors which allow a single valve arm to simultaneo