CN-114583994-B - EAST fast control power supply output current control method and device

CN114583994BCN 114583994 BCN114583994 BCN 114583994BCN-114583994-B

Abstract

The invention discloses an EAST fast control power supply output current control method and device, the method comprises the steps of predicting current values after two periods according to EAST fast control power supply output current sampling values, establishing a multi-objective optimization cost function with constraint conditions, searching an optimal solution of the multi-objective optimization cost function on line by utilizing a particle swarm algorithm, obtaining an output voltage coefficient by comparing the optimal solution obtained by the particle swarm algorithm with an output voltage amplitude of a single-branch H-bridge inverter circuit of the EAST fast control power supply, obtaining a modulation value by multiplying the output voltage coefficient by a carrier amplitude, and controlling the single-branch H-bridge inverter circuit of the EAST fast control power supply by comparing the modulation value with the carrier modulation to obtain an optimal duty ratio.

Inventors

HUANG HAIHONG
CHEN ZHAO
WANG HAIXIN

Assignees

合肥工业大学

Dates

Publication Date: 20260512
Application Date: 20220318

Claims (6)

1. An EAST fast control power supply output current control method, which is characterized by comprising the following steps: predicting a current value after two periods according to an EAST fast control power supply output current sampling value; By the formula (1) Establishing an output voltage equation of the single-branch H-bridge inverter circuit, wherein, In order to output the current flow, In order to output the load inductance, Is the internal resistance of the load inductance; In one switching cycle In the inner part of the inner part, Discretizing an output voltage equation at the moment, and expressing the discretized output voltage equation known at the last moment as (2) Predicting the next cycle time output current to be expressed as (3) The predicted output current at the next two cycle times is expressed as (4) Wherein, the Inverter circuit for single-branch H bridge The output voltage at the moment in time is, Inverter circuit for single-branch H bridge Output current at a moment; step two, establishing a multi-objective optimization cost function with constraint conditions; the purpose of the whole EAST fast control power supply is that the output current value follows a given reference signal current Therefore, the output current at the next two periods is consistent with the current value of the reference signal, so that a cost function is established (5) Limiting the amplification of the output voltage of the single-branch H-bridge inverter circuit, and establishing the weight as Multi-objective optimization cost function of (2) (6) Limiting the output current to establish a multi-objective optimized cost function with constraint conditions (7); Thirdly, online searching an optimal solution of the multi-objective optimization cost function by utilizing a particle swarm algorithm; And step four, comparing the optimal solution obtained by the particle swarm optimization with the output voltage amplitude of the single-branch H-bridge inverter circuit of the EAST fast control power supply to obtain an output voltage coefficient, multiplying the output voltage coefficient with the carrier amplitude to obtain a modulation value, and comparing the modulation value with the carrier modulation to obtain an optimal duty ratio to control the single-branch H-bridge inverter circuit of the EAST fast control power supply, so that the EAST fast control power supply outputs a current value following a given signal.
2. The EAST fast control power supply output current control method according to claim 1, wherein the third step comprises: Setting initial parameters of a particle swarm algorithm, taking output voltage of a single-branch H-bridge inverter circuit as population individual particles, taking a multi-objective optimization cost function with constraint conditions as an adaptability function of the particle swarm algorithm, executing the particle swarm algorithm within a particle optimization parameter limit range, and outputting an optimal position of the population as an optimal solution of the multi-objective optimization cost function with constraint conditions after iteration reaches the maximum number of times.
3. The EAST fast control power supply output current control method according to claim 2, wherein the initial parameters of the particle swarm algorithm are set, the number of the groups is 200, and the maximum iteration number is 30.
4. The EAST fast control power supply output current control method according to claim 2, wherein the particle optimizing parameter limiting range comprises: setting the limiting range of the particle optimizing position parameter as (8) The limiting range of the speed parameter is set to be +/-1.
5. The method for controlling output current of fast power supply according to claim 2, wherein executing the particle swarm algorithm, after the iteration reaches the maximum number, the optimal position of the output swarm is the optimal solution of the multi-objective optimization cost function with constraint condition, comprises: And executing a particle swarm algorithm, iteratively calculating the self-adaptive degree value of each particle, finding an individual optimal position which enables the self-adaptive degree value to be minimum, continuously updating the whole group optimal position when the particle seeks the minimum individual optimal position, finding a group optimal position which enables the group self-adaptive degree value to be minimum through comparison of each individual minimum adaptive degree value, updating the individual speed within a speed parameter limit range after updating each individual optimal position and the group optimal position, continuously executing an optimizing process within an iteration frequency range, and outputting the group optimal position as a multi-objective optimizing cost function optimal solution with constraint conditions after the iteration reaches the maximum frequency.
6. An EAST fast control power supply output current control device, characterized in that the device comprises: The current prediction module is used for predicting the current value after two periods according to the sampling value of the output current of the EAST fast control power supply; By the formula (1) Establishing an output voltage equation of the single-branch H-bridge inverter circuit, wherein, In order to output the current flow, In order to output the load inductance, Is the internal resistance of the load inductance; In one switching cycle In the inner part of the inner part, Discretizing an output voltage equation at the moment, and expressing the discretized output voltage equation known at the last moment as (2) Predicting the next cycle time output current to be expressed as (3) The predicted output current at the next two cycle times is expressed as (4) Wherein, the Inverter circuit for single-branch H bridge The output voltage at the moment in time is, Inverter circuit for single-branch H bridge Output current at a moment; the objective function building module is used for building a multi-objective optimization cost function with constraint conditions; the purpose of the whole EAST fast control power supply is that the output current value follows a given reference signal current Therefore, the output current at the next two periods is consistent with the current value of the reference signal, so that a cost function is established (5) Limiting the amplification of the output voltage of the single-branch H-bridge inverter circuit, and establishing the weight as Multi-objective optimization cost function of (2) (6) Limiting the output current to establish a multi-objective optimized cost function with constraint conditions (7); The solving module is used for searching an optimal solution of the multi-objective optimization cost function on line by utilizing a particle swarm algorithm; And the output current control module is used for comparing the optimal solution obtained by the particle swarm optimization with the output voltage amplitude of the single-branch H-bridge inverter circuit of the EAST fast control power supply to obtain an output voltage coefficient, multiplying the output voltage coefficient with the carrier amplitude to obtain a modulation value, and comparing the modulation value with the carrier modulation to obtain an optimal duty ratio to control the single-branch H-bridge inverter circuit of the EAST fast control power supply, so that the EAST fast control power supply outputs a current value following a given signal.

Description

EAST fast control power supply output current control method and device Technical Field The invention relates to the technical field of EAST fast control power supply operation, in particular to an EAST fast control power supply output current control method and device. Background Under the current age background with outstanding energy problems, nuclear fusion power generation has wide development prospect due to the characteristics of wide and easily available fusion raw materials and pollution-free fusion products. The full-superconducting tokamak nuclear fusion experimental device (Experimental Advanced SuperconductingTokamak, EAST) is an important component of nuclear fusion power generation. Nuclear fusion power generation is completed by means of reaction between plasmas, and plasma displacement control is a key problem of nuclear fusion power generation. The plasma vertical displacement active feedback controller detects the plasma vertical displacement, a given signal of a fast control power supply (Fast Control Power Supply, FCPS) is calculated according to the displacement of the plasma, the fast control power supply excites the active feedback coil according to the given signal, and a fast-changing magnetic field is generated to perform closed-loop feedback control on the plasma in the vertical direction, so that the stability of the plasma in the vertical displacement is ensured. The given voltage signal of the fast control power supply and the output current of the fast control power supply are in linear correspondence, the given voltage signal of +/-10V corresponds to the total output current of +/-9000A, and the whole fast control power supply system consists of 6 parallel branches, so that the given voltage signal of +/-10V corresponds to the single branch output current of +/-1500A. The power supply voltage of a single branch of the fast control power supply is obtained by the three-phase voltage of a power grid through uncontrolled rectification, and the single branch is formed by cascading three H-bridge inverter circuits, so that the output voltage value of the single branch is +/-1620V. A plasma control system (Plasma Control System, PCS) sends out corresponding voltage command signals according to the displacement of the plasma, and an EAST fast control power supply rapidly outputs current according to the voltage command signals so as to establish a required magnetic field to ensure the balance of the displacement of the plasma. In the EAST fast control power supply system, fast output voltage and current signals are an important index performance, but are limited by the switching loss of a high-power device, the switching frequency of the power supply is difficult to increase, and the fast performance of the output voltage and current is limited. In order to realize rapid output of voltage and current, the control duty ratio of a switching device in a circuit is suddenly changed, but in the initial stage of current establishment, overshoot may occur, so that the output current exceeds a rated current value, which is unfavorable for long-term operation of a power device. Meanwhile, in order to quickly establish a magnetic field, the voltage of the output end may be suddenly changed greatly in adjacent working periods, so that the ripple wave of the output current is also increased, and the stable operation of the circuit is influenced. Therefore, in the process of rapidly outputting voltage and current, the problems of excessive output current and overlarge ripple wave may be accompanied, so that a great challenge is brought to the operation of the power device, and even a temporary overcurrent phenomenon occurs to burn the power device in severe cases. The EAST fast control power supply has a six-way parallel structure, wherein the six ways of parallel structures are similar and are single-stage H-bridge inverter circuits, and the detailed description of the EAST fast control power supply can be referred to the research and optimization of the EAST new fast control power supply control system in the 'filling paper' of Bi Nanxia 2018 4 of the university of the combined fertilizer industry. The model prediction control is an advanced prediction method, is also applied to a cascade H-bridge inverter circuit, and can predict the voltage and current values of the output end of the lower stage according to the current sampling signal. However, in order to restrain the ripple of the output current and restrain overshoot, a multi-objective optimization term needs to be added, meanwhile, a constraint condition needs to be added in the cost function, and solving of the cost function with the constraint condition has difficulty. At the present stage, no related method can solve the constraint model predictive control equation on line, all the constraint model predictive control equation needs to be manually solved to obtain an optimal analytical solution, and then the optimal analytical soluti