317 results about "Constant power" patented technology

The invention discloses a short-circuit current limiting and short-circuit recovery transient voltage control device and method for an aviation three-stage power generation system, and the device comprises a three-stage power generator, a power generator controller, a current sensor, a voltage and current collection module, and an asymmetric half-bridge excitation control circuit. Collecting the output current iL and voltage UL of the generator through a digital processor of the generator controller; when short circuit occurs, the given voltage USet of the voltage regulating loop is linearly reduced in a piecewise mode according to the relation between the iL and a preset threshold value, so that the generator works in a constant power interval; and when the short circuit is recovered, closing the upper / lower power tubes of the asymmetric half-bridge excitation control circuit according to the relationship between UL and a preset threshold value in a grading manner, and triggering a negative-pressure follow-current mode of a main excitation winding of the generator controller to quickly extinguish the field. The method can adapt to different generators without adjusting hardware circuit parameters, has no motor ablation risk during short circuit, has transient voltage less than 350V after short circuit recovery, has no power supply interruption in the whole process, has response delay less than 1ms, and greatly improves the safety and robustness of an aviation power supply and distribution system.

The invention relates to the technical field of grinding control, in particular to a constant-power grinding control method, system and equipment of a numerical control grinding machine. According to the method, in a preset historical time period of a to-be-regulated moment, a time sequence curve of the deviation of the grinding power of the numerical control grinding machine relative to the preset grinding power is obtained and subjected to time sequence decomposition, and then proportional gain in PID control parameters is obtained according to the change trend of a trend component and the power deviation at the to-be-regulated moment in the trend component; obtaining an integral gain in the PID control parameters according to the periodic fluctuation characteristics of the seasonal components; according to the change trend of the time sequence curve and the fluctuation characteristics of the residual component, and in combination with the proportional gain and the integral gain, obtaining the differential gain in the PID control parameters; and finally carrying out constant-power grinding control on the numerical control grinding machine. The PID control parameters are adaptively adjusted based on the time sequence decomposition result of the power deviation, and the constant power control effect on the numerical control grinding machine is improved.

The invention discloses a virtual impedance compensation-based active-disturbance-rejection control method for a dual-active-bridge converter, and the method comprises the following steps: firstly designing a virtual impedance compensation strategy, connecting an equivalent virtual conductor in parallel with an output capacitor, converting the equivalent virtual conductor into a duty ratio injection amount, and achieving the active counteracting of the negative impedance of a constant-power load and the reconstruction of the damping of a port; an unstable pole of the right half plane is made to move back to the left half plane, and extra power loss is not introduced; an active disturbance rejection control strategy based on virtual impedance compensation is designed, residual uncertainty after virtual impedance compensation is uniformly regarded as total disturbance online observation and feedforward offset, and therefore rapid and smooth voltage tracking is kept under parameter perturbation and external disturbance. Under the working conditions of voltage reference step and load abrupt change, the improved active disturbance rejection control strategy realizes the effects of no overshoot, shortest setting time and minimum oscillation by enhancing disturbance observation and virtual impedance compensation, and has better damping and disturbance rejection performance.

The invention relates to a doubly-fed variable-speed pumped storage unit comprehensive inertia supporting method, device and equipment based on an excitation capacitor. The method comprises the following steps: acquiring a frequency deviation value and a frequency deviation change rate of a grid-connected point after a load connected with a power system is suddenly changed; determining whether to start a comprehensive inertia control strategy according to the frequency deviation value and the frequency deviation change rate; if the comprehensive inertia control strategy is started, dynamically adjusting a DC bus voltage reference value according to the frequency deviation value to determine a d-axis modulation voltage component; acquiring additional electromagnetic increment power; controlling a grid-side converter in the power system to operate according to the d-axis modulation voltage component, controlling a machine-side converter in the power system to operate according to the additional electromagnetic increment power, and providing inertial current impact support for the power system; and if the comprehensive inertia control strategy is not started, the frequency of the power system is kept stable and synchronous, and the doubly-fed variable-speed pumped storage unit of the power system is controlled to work in a constant power state.

The invention relates to the technical field of lasers, and provides a double-gain-medium Q-switched laser and a constant-power pulse width adjusting method.The laser comprises a first pumping source, a second pumping source, an optical fiber beam combiner, a beam shaping system and a laser resonant cavity, the laser resonant cavity comprises a reflecting mirror, a first gain medium, a second gain medium, a polarization selector, a quarter-wave plate, a Q switch and an output mirror which are arranged in sequence; the first gain medium is used for absorbing first pumping light, the second gain medium is used for absorbing second pumping light, and the pumping power of the first pumping source and the pumping power of the second pumping source can be independently controlled. By changing the pumping power of the two pumping sources, real-time adjustment of the pulse width of the laser under the constant output power is achieved, the structure is compact, and control is easy and convenient.

The invention discloses an electrosurgical radio frequency inverter based on model predictive control and a frequency conversion control method thereof, and the method comprises the steps: building a discrete output voltage prediction model based on a topological structure of the electrosurgical radio frequency inverter, and judging a switching frequency switching point and voltage peak output power through single sampling period iterative calculation. Constructing an output power prediction model; obtaining instantaneous prediction output power and theoretical reference output power obtained by real-time sampling and calculation when the output voltage is changed to a periodic peak value, and constructing a model prediction control evaluation function; according to the evaluation function, real-time voltage sampling and multi-frequency iteration prediction are combined with a set control target, the switching frequency of the radio frequency inverter is predicted and updated in real time, and constant-power frequency conversion control over the radio frequency inverter is achieved by continuously obtaining the control quantity at the next moment. The system can adapt to constant power output of a power supply under biological impedance change, can predict and control constant power output of an electrosurgical inverter in real time based on real-time updating of switching frequency, has good dynamic response performance, guarantees high efficiency and safety of clinical operations, and can be applied to various electrosurgical working platforms.

The invention relates to the technical field of new energy and energy storage, and provides a renewable energy hydrogen production control system based on dynamic power matching and hydrogen storage collaboration, which comprises a power conversion system with a constant voltage mode and constant power mode millisecond switching capability; the modularized electrolytic cell array is formed by connecting a plurality of proton exchange membrane electrolytic cells in parallel; the hydrogen storage cooperation unit comprises a high-pressure hydrogen storage tank group, a solid oxide fuel cell and a hydrogen purification device; the intelligent control unit is used for executing a three-stage control strategy; the real-time control layer is used for executing proton exchange membrane electrolytic cell power instruction tracking and power grid frequency deviation compensation; the optimization scheduling layer adopts a reinforcement learning model prediction control algorithm to perform rolling optimization on the power distribution proportion of hydrogen production and power generation; and the planning layer is used for generating a proton exchange membrane electrolytic cell start-stop plan and a hydrogen storage scheduling plan in combination with meteorological prediction and electricity market transaction data. The problems that wind-solar power generation fluctuation is large, and a traditional hydrogen production system is slow in response and insufficient in economical efficiency can be solved.

The invention relates to the technical field of intelligent regulation and control of energy storage power stations, in particular to a peak regulation and frequency modulation cooperative control method for an energy storage power station. Comprising the steps of multi-source data acquisition and preprocessing, multi-model fusion prediction and error pre-judgment, rolling optimization and three-level linkage error correction, multi-time scale layered cooperative control based on SoC dynamic optimization, parameter adaptive comprehensive frequency modulation and hybrid energy storage execution. According to the method, a five-stage cascade fusion prediction framework is constructed, a dynamic weight fusion mechanism and a Cornish-Fisher series error pre-judgment model are combined, the problem of pain points of multi-scale prediction independent operation and error accumulation conduction in the prior art is solved, and through the rolling optimization characteristic of MPC model prediction control and a three-stage linkage error correction mechanism, the prediction accuracy is improved. And in cooperation with adaptive error compensation of DDPG reinforcement learning, the execution accuracy of a peak regulation and frequency modulation instruction is improved, the problem of load curve distortion caused by a traditional constant-power peak regulation mode is effectively avoided, and the stability of power grid operation is greatly improved.

The invention discloses a method for determining a self-consuming power curve of a wind turbine generator, which comprises the following steps of: performing conversion according to an actually-measured wind speed and an actually-measured air density to obtain an equivalent wind speed under a standard air density, and segmenting the equivalent wind speed into various wind speed sections according to a standard power curve; self-consuming equipment is divided into constant-power equipment and variable-load equipment; working condition coefficients of all the constant-power devices and all the variable-load devices in the corresponding wind speed sections are determined; according to the rated power of each constant power device and each variable load device and the working condition coefficient of the corresponding wind speed section, respectively determining the self-consuming power of each wind speed section of each constant power device and each variable load device; summing the self-consumed power of the same wind speed section of all the constant power equipment and the self-consumed power of the same wind speed section of all the variable load equipment to obtain the self-consumed power of the whole machine in each wind speed section, and generating a wind speed section-self-consumed power curve. The actual operation condition is dynamically captured, and the accuracy and efficiency of generating capacity evaluation are improved.

The invention relates to a DC-DC converter control method based on an intelligent agent reinforcement learning algorithm, and the method comprises the steps: firstly building an intelligent agent for a DC-DC buck converter which supplies power to a constant-power load, obtaining a state observation quantity formed by all preset environment variable values of the DC-DC buck converter through the intelligent agent, and obtaining the state observation quantity of the DC-DC buck converter; and a reward value corresponding to a difference value between the output voltage and a preset reference voltage is processed by the intelligent agent, and a corresponding action signal is output and used for controlling the DC-DC buck converter. And then through reinforcement learning training of the intelligent agent, the trained model controls the DC-DC buck converter, so that the output voltage of the DC-DC buck converter has good adaptivity and dynamic response characteristics under different working conditions, and the designed intelligent agent has good steady-state performance in application, so that the stability of the DC-DC buck converter is improved. Model parameter uncertainty caused by component aging can be dealt with, and the stability in practical application is ensured.

This invention proposes a battery pack balancing control method for long-endurance drones, which can dynamically adjust the actual output power of each individual battery and the battery pack to achieve balanced discharge. The invention employs an autonomous balancing control unit and a constant output control unit. The autonomous balancing control unit dynamically adjusts the actual output power of each battery pack to achieve balanced discharge. This avoids the problem of excessive discharge of individual battery packs due to uneven discharge among multiple battery packs, which can lead to a rapid decrease in the overall battery capacity and effectively extend the drone's flight time. The constant output control unit ensures a constant power output from the drone's power system to meet the stable power supply requirements of the long-endurance drone's onboard electronics and power equipment.

Techniques are provided for automatically determining when voltage and current levels occur when a DC input of a radio is drawing substantially constant power through electrical conductors from a DC voltage converter. Such voltage and current level occurring when such power draw is substantially constant can then be used to determine a resistance of the electrical conductors. Subsequently, the resistance can be used to vary an output voltage of the DC voltage converter when the power draw, and thus the direct current drawn through the electrical conductors, varies.

This invention discloses an active damping control method for bipolar DC distribution systems based on modulus decomposition. It incorporates line coupling into the system's stability criteria and active damping parameter design, deriving the pole-mode transformation matrix of the metal-return bipolar DC distribution system and obtaining a decoupling model of the bipolar DC line in the modulus component space. The modulus models of the source-side converter and load are also derived. Based on the established decoupling model of the bipolar DC distribution system in the modulus component space, an active damping control method based on modulus decomposition is proposed. This invention considers the impact of DC distribution lines on stability, incorporating line coupling into the system's stability criteria and active damping parameter design. The modulus damping control scheme proposed in this invention can more effectively suppress instability caused by the negative impedance characteristics of constant power loads and also provides a basis for parameter adjustment.

The invention discloses a plasma source control system and method based on a frequency cluster in the technical field of plasma sources. An LSF load impedance prediction model and a frequency cluster modulation module are arranged in a control unit of the control system, and a PWM driving unit is controlled to output pulse signals; the holding circuit is used for keeping the bus voltage stable after entering the constant power stage; the sampling unit collects resonant output voltage and current; the multi-sensor module monitors the gas flow Q, the pressure P and the temperature T of the reaction cavity; the LSF model outputs a load impedance predicted value Zs based on Q, P and T; and the frequency cluster modulation module adjusts the switching frequency in sections at the constant power stage. According to the control system, accurate prediction of load impedance can be achieved through an LSF load impedance prediction model, switching frequency is controlled and adjusted in a segmented mode through a frequency cluster modulation module, non-overshoot smooth response of the switching frequency is achieved, load changes are accurately adapted, a process window is expanded, and constant-power stable operation of a plasma source is guaranteed.

The wind turbine generator power optimization control method comprises the steps of collecting operation data of a wind turbine generator; the rotating speed of the generator is compared with the cut-in rotating speed and the rated rotating speed, and the running state of the wind turbine generator is divided into a standby state, a maximum power tracking area and a constant power control area; in the maximum power tracking area, based on the rotating speed and power change relation of the previous control period and the current control period, a first torque instruction is generated through dynamic step length tentative logic; in the constant power control area, the power upper limit set value is adjusted to generate a second torque instruction based on comparison between the state parameters of the generator and the converter and the preset temperature boundary; when the vibration amplitude enters the early warning interval, avoiding adjustment is executed in combination with the rotating speed or the variable pitch rate of the generator to generate a third torque instruction; and taking the minimum value of the torque instruction meeting the boundary constraint as a final control instruction. Under the condition that a complex mathematical formula and an AI model are not used, the thermal capacity margin and the mechanical vibration margin of the unit are used for dynamically adjusting a power output target, and the potential power generation capacity of the excavator unit is guaranteed under the condition that safety is guaranteed.

The invention provides a switching system for vehicle power supply modes and a vehicle, the switching system comprises a controller power supply contact, a switching piece and at least two power supply mode contacts, the controller power supply contact is connected to a power supply input end of a vehicle controller through a wire; wherein one power supply mode contact is electrically connected with a constant power line of a vehicle wire harness system, and the other power supply mode contacts are electrically connected with at least one of an ACC-gear power line, an ON-gear power line and an STAR-gear power line of the vehicle wire harness system; and the controller power supply contact is switched to be electrically connected with different power supply mode contacts through the switching piece. Compared with the prior art, the switching system does not depend on a central control screen or a diagnostic instrument on the vehicle, does not depend on programs, does not need complex opening and screen page operation, can achieve switching of the vehicle power supply modes through simple mechanical structural parts, is easy and convenient to operate, and meets switching of the vehicle power supply modes in any scene.

The invention relates to the technical field of energy storage configuration, in particular to a network construction type SVG super capacitor configuration method, system and device based on a direct current side direct-hanging super capacitor and a storage medium. Acquiring grid-connected voltage, target instantaneous active power and continuous discharge time; selecting the specification of a super capacitor monomer, determining a single cluster rated voltage and setting a branch current-limiting threshold value; establishing a single-cluster supercapacitor discharge model, simulating a process from constant-power discharge to a current-limiting threshold value, considering the influence of internal resistance voltage division, calculating single-cluster release energy through power-time integration, and obtaining single-cluster constant discharge power; calculating the number of super capacitor clusters; the number of parallel branches and the number of series clusters are determined by combining the topological direct-current side voltage range of the MMC, and the direct-current side rated voltage is set. By establishing a discharge model considering internal resistance voltage division, accurately calculating the actual discharge capacity of a single cluster, and systematically planning super capacitor configuration in combination with MMC topological characteristics, the problems that an existing method is insufficient in configuration precision and lack of topological adaptability are solved, and the reliability of a network-forming SVG is improved.

The present disclosure relates to low power detection and power loss management for devices with limited available power, such as a thermostat, an equipment interface module, a control board, other device having a battery backup for operating in non-constant power conditions, etc. In an exemplary method of power management in a device including a display, the method comprises automatically turning off power to the display in response to detection of a power loss and / or inadequate power condition for the device. The device may comprise a thermostat, an equipment interface module (EIM), a control board, other device having a battery backup for operating in non-constant power conditions, etc.

The purpose of this invention is to disclose a power supply and distribution method and system for a gas-fired micro power station. By dividing the generator sets into a constant power output group and other supplementary groups, when the power changes, only one of the constant power output group or the other supplementary groups needs to be controlled. This solves the technical problem that generator sets in the power station come from different manufacturers, the gas control systems are different, and multiple systems are incompatible, making parallel operation impossible. Peak shaving and valley filling are achieved through energy storage modules. Energy storage resists load changes and seamlessly switches with diesel generator start-up, reducing the number of generators used and forming a hybrid power supply mode that combines generators and energy storage. This avoids problems such as generator tripping, motor overheating, and large energy loss in the power station caused by load impacts.

The utility model discloses a water-cooling heat exchange assembly used for simulating a load. The water-cooling heat exchange assembly comprises a heat collection plate assembly, at least two layers of heat exchange tubes arranged in the heat collection plate assembly, a PTC (Positive Temperature Coefficient) resistor disc assembly positioned between two adjacent layers of heat exchange tubes, a liquid inlet tube, a liquid outlet tube and a connecting tube, wherein the liquid inlet tube and the liquid outlet tube are matched with each other; and the connecting tube is used for connecting the two adjacent layers of heat exchange tubes. The beneficial effects of the utility model are that the PTC resistor disc assembly heat dissipation device is used with a matched water cooling system to realize efficient heat dissipation of the PTC resistor disc assembly, so that the PTC resistor disc assembly works at a constant power to ensure smooth system test in a machine room; and each layer of PTC resistor disc assembly is located between the two layers of heat exchange tubes, so that the heat dissipation effect of the PTC resistor disc assemblies is ensured.

The invention belongs to the field of semiconductor lasers, and provides a semiconductor laser diode driving circuit and a driving method. Comprising a single-pole multi-throw analog switch, a power triode driving circuit, a constant current mode feedback loop, a constant voltage mode feedback loop, a constant power mode feedback loop and an incoherent control circuit. The power triode driving circuit comprises a controller, a digital-to-analog converter, a power triode Q1, an integrator circuit based on an operational amplifier, a voltage source VCC, a laser diode V1 and a power resistor R2; the single-pole multi-throw analog switch is connected with the controller, and the controller controls the digital-to-analog converter; the single-pole multi-throw analog switch is respectively connected with the constant current mode feedback loop, the constant voltage mode feedback loop and the constant power mode feedback loop, and switching control of a constant current mode, a constant voltage mode and a constant power mode is realized through channel opening and closing of the single-pole multi-throw analog switch. According to the invention, the defects of single working mode, lack of coherence regulation and control capability and insufficient digitization degree in the prior art are overcome.

The invention relates to the technical field of electric heating materials, and discloses a graded adjustable resistance type composite electrothermal film material and a preparation method and application thereof. The electrothermal film adopts a multi-layer composite structure and comprises an electrode layer, a polymer-conductive carbon composite functional layer (forming an adjustable resistor R1), an inorganic glass powder-conductive carbon composite functional layer (forming a stable resistor R2) and an electrode layer from top to bottom. The core is that the total resistance R is equal to R1 + R2, constant power output and linear temperature control under fixed voltage are realized by presetting the R value in the preparation stage, and an external regulation and control circuit is not needed. The material fundamentally eliminates the risk of electrode short circuit, has the advantages of high temperature resistance, good flexibility, low driving voltage, fast response, high safety and the like, and is especially suitable for high-power-density flexible heating devices in the working environment of 40-120 DEG C. The preparation method comprises the steps of inorganic layer / polymer layer ink preparation, layer-by-layer forming sintering and composite packaging, and is easy and convenient to operate and suitable for industrial large-scale production.

The application discloses a power tracking method and system of a string type photovoltaic inverter. The method comprises the following steps: obtaining corresponding second power through data processing; when the corresponding second power is less than corresponding power, adjusting corresponding voltage instruction; when the power difference of each photovoltaic string is reduced to zero, the string type photovoltaic inverter is in a constant power control mode; when the corresponding second power is greater than the corresponding power, adjusting the corresponding voltage instruction; when the absolute value of the power difference of each photovoltaic string is reduced to the minimum, the string type photovoltaic inverter is in a maximum power tracking mode. Only the corresponding voltage instruction is adjusted according to the corresponding second power, so that power tracking and smooth switching between modes are realized, and the application scenarios and operation conditions of the string type photovoltaic inverter are widened. The application can integrate maximum power tracking and constant power control, and simplify the algorithm module.

The invention provides a message wake-up circuit, a message wake-up method and a vehicle-mounted controller. The message wake-up circuit comprises a bus transceiving circuit, a conversion circuit and a main chip power supply circuit, the bus transceiver circuit is configured to be capable of converting a message wake-up signal into a wake-up pulse signal; the conversion circuit is configured to be capable of converting a wake-up pulse signal into a hard wire wake-up signal; and the main chip power supply circuit is configured to convert a constant power supply into a main chip power supply voltage to supply power to the main chip when a hard wire wake-up signal is input into the control end of the main chip power supply circuit. For a controller with a plurality of CAN / CANFD channel functions, CAN message remote wakeup is realized with the lowest hardware cost, and only the interface voltage of the CAN transceiver is constant power, so that complete power-off of the MCU and power-off of the main power supply of the SOC are realized, the service life of the controller is prolonged to a great extent, and the reliability of the controller is improved.

The invention discloses a method and a device for testing the specific heat capacity of a cylindrical battery. The method comprises a test stage and an analysis stage: in the test stage, a cylindrical battery pasted with a heating sheet is placed in cylindrical foam to form an assembly, constant-power heating and natural cooling experiments are sequentially performed in a constant-temperature environment, and the temperature of the surface of the battery, the temperature of the outer wall of the foam and the temperature of the environment are synchronously collected; in the analysis stage, a slope parameter is obtained by setting an initial value of the specific heat capacity and fitting cooling data in a partition mode so as to calculate system thermal conductance, a true value of the specific heat capacity is iteratively solved based on an energy conservation equation, and convergence is optimized through a dichotomy. The device comprises a constant-power heating system, a cylindrical foam heat insulation structure, a distributed temperature sensing system and a data acquisition and processing system. By establishing the temperature-dependent thermal conductivity model and the intelligent iterative algorithm, accurate measurement of the specific heat capacity of the cylindrical battery is achieved, and the problems that equipment is complex, operation is tedious and precision is insufficient in a traditional method are solved.

The invention relates to the technical field of battery modeling, and discloses a battery multi-dimensional parameter identification method, a battery multi-dimensional parameter identification device and battery multi-dimensional parameter identification equipment for electric power energy storage. Determining to-be-identified parameters of the to-be-detected electric energy storage battery, wherein the to-be-identified parameters comprise an instant response parameter, a fast polarization parameter, a medium polarization parameter and a slow polarization parameter; performing a constant current mixed pulse power characteristic test on the to-be-tested electric energy storage battery to obtain a constant current test result, and obtaining an instant response parameter and a fast polarization parameter according to the constant current test result; performing constant-power mixed pulse power characteristic test on the to-be-tested electric energy storage battery to obtain a constant-power test result; and optimizing and calibrating a constant-current test result by combining the instantaneous response parameter, the fast polarization parameter and the constant-power test result to obtain an identification parameter of the to-be-tested electric energy storage battery. The battery parameters obtained through identification are closer to the operation condition of the electric energy storage battery, and distortion is reduced.

A series-resonant dual-active-bridge (SR-DAB) converter with an interleaved integrated-bidirectional-converter (IBC) and its associated control strategy is configured to improve transient response and stabilize a converter system in the presence of an input filter and cabling. The associated control strategy incorporates three parts. A main feedback control loop regulates the output voltage based on a reference signal by adjusting the frequency and phase shift of the SR-DAB converter. Virtual impedance control and active damping is provided by a feedforward controller configured to modify the reference signal. An IBC controller includes two loops, a slower outer voltage loop and a faster inner current loop, and is configured to improve transient response. In buck mode the IBC controller stores energy on an auxiliary capacitor when the output voltage is rising and in boost mode the stored energy is returned to the load when the output voltage is falling.

This invention discloses a multi-stage adjustable speed power shunt motor system and its control method, relating to the field of motor technology. The system includes at least two stages of motor units arranged sequentially along the axial or radial direction; the rotor of the first-stage motor unit serves as the total power output end; the rotor of the second-stage motor unit is driven by the stator of the previous-stage motor unit, driving the stator to rotate; except for the last stage, all other stators are rotatable structures. By controlling the rotation direction and speed of the rotors of the second-stage and subsequent motor units, the relative speed between the stator and rotor of the previous-stage motor unit is adjusted, achieving electromagnetic coupling and power shunt, thus changing the system's total output torque, speed, and back electromotive force. This invention has a compact structure, achieves optimized efficiency under all operating conditions, balances low-speed high torque and high-speed constant power operation, and optimizes both drive and power generation performance, making it suitable for electric vehicles, wind power generation, industrial transmission, and other fields.

A stepless adjustable constant power load, comprising a power resistance adjustment device, a heat dissipation system, and a controller. The power resistance adjustment device comprises at least three fixed-value resistors having different resistance values, and a primary-circuit frequency converter; each fixed-value resistor is connected in series with a contactor to serve as a load module, and load modules are connected in parallel; an input end of the primary-circuit frequency converter is connected to a test power supply, the load modules are connected in parallel and then connected to an output end of the primary-circuit frequency converter, and the primary-circuit frequency converter serves as an adjustable-voltage power consumption unit. The controller selects a loading combination from the load modules on the basis of the magnitude of a target power, the loading combination is configured to enable combined power consumption to be less than the target power and a difference between the combined power consumption and the target power to be the minimum, and the controller outputs a PWM signal to adjust an output voltage of the primary-circuit frequency converter until power consumption of the primary-circuit frequency converter is equal to the difference.

This invention provides a constant power heating cable for rail transit. The constant power heating cable for rail transit includes: a cable body; a conductor core located at the innermost layer of the cable body; an inner insulation layer disposed on the outer surface of the conductor core; a heat insulation buffer layer disposed on the outer surface of the inner insulation layer; and a heating element disposed on the outer surface of the heat insulation buffer layer. The constant power heating cable for rail transit provided by this invention can flexibly adjust the heating mode of the heating element through a power supply control device according to the heating requirements of different parts of rail transit such as turnouts, contact wires, and signal cables, without the need for additional heating equipment. It adapts to complex working conditions, resulting in more reasonable energy consumption. The heating element can switch working modes as needed, avoiding ineffective energy consumption. While ensuring anti-freezing and anti-condensation effects and uniform heating, it significantly reduces energy consumption compared to traditional single-heating-core structures, achieving the dual benefits of energy saving and practicality.