Flywheel-super capacitor hybrid power supply flash evaporation Joule heat system and control method thereof

Abstract

The invention relates to the technical field of electric heating material preparation, and discloses a flywheel-super capacitor hybrid power supply flash evaporation Joule heat system and a control method thereof.The system comprises a mains supply unit, a flywheel energy storage unit, a super capacitor unit, a bearing unit and a controller; the commercial power supply unit, the flywheel energy storage unit, the super capacitor unit and the bearing unit are respectively connected to a common DC bus through contactors. The flywheel energy storage unit charges the super capacitor through the third contactor; the super capacitor bank is connected to the common direct current bus through the second contactor and discharges to the flywheel energy storage unit through the third contactor; the controller is used for controlling the on-off state of each contactor and the power instruction of each converter. According to the scheme, the instantaneous ultrahigh-power current of the material can be realized, so that the material is subjected to ultrahigh temperature and ultrafast cooling within the time from millisecond to second, the flash evaporation of the material is completed, and meanwhile, the direct-current bus voltage violent drop caused by ultrahigh current pulse can be effectively inhibited.

Description

Technical Field

[0001] This invention relates to the field of electrothermal material preparation technology, specifically to a flash Joule heating system powered by a flywheel-supercapacitor hybrid power supply and its control method. Background Technology

[0002] Flash Joule heating is a heat treatment technology that applies a transient, ultra-high-power current to materials, causing them to undergo ultra-high temperatures and ultra-rapid cooling within milliseconds to seconds. This technology shows great potential in fields such as graphene preparation, high-entropy alloy synthesis, and solid waste resource utilization.

[0003] Currently, the industry is working to scale this technology from gram-level production in the laboratory to kilogram-level and even hundred-kilogram-level continuous production. However, the core bottleneck for large-scale production lies in the power system: processing 1 kilogram of material typically requires 7.2 MJ of energy, with instantaneous power demands reaching megawatt levels. The current mainstream pure supercapacitor power supply solution faces a fundamental contradiction: Taking kilogram-scale flash graphene as an example, if a low-power 20kW AC mains power is used for charging, it takes 6 minutes to replenish 2kWh of energy, resulting in an excessively long production cycle and low capacity. If a high-power 300kW AC mains power is used for fast charging, although the charging time can be shortened, it will cause a huge instantaneous surge current to the power grid, resulting in abnormally high harmonic content (THD>15%). This not only requires expensive grid capacity expansion and continuous capacity charges, but also requires the configuration of active filters for harmonic mitigation, thus increasing the total life cycle cost.

[0004] Furthermore, existing solutions are mostly designed for a single "full-power flash evaporation" mode, which cannot flexibly adjust the heating power and time, making it difficult to adapt to the diverse process requirements of different materials for heating curves and holding times, resulting in poor equipment versatility. At the same time, the energy utilization efficiency of existing solutions is also not high. After the supercapacitor discharges, the residual electrical energy inside is usually dissipated as heat through the discharge resistor, resulting in energy waste. Moreover, it is impossible to accurately control the depth of discharge, which is detrimental to the capacitor's lifespan.

[0005] Therefore, there is an urgent need in this field for an innovative power system architecture and control method that can achieve grid-friendly access while meeting the requirements of instantaneous ultra-high power pulse output, and has multi-mode process adaptability and high energy utilization efficiency. Summary of the Invention

[0006] The present invention aims to provide a hybrid power supply flash joule heating system and its control method to solve the problem that the current flash joule heating system using pure supercapacitor power supply has too long charging time, resulting in long production cycle and low production capacity.

[0007] To achieve the above objectives, this invention provides a flash Joule heating system powered by a flywheel-supercapacitor hybrid power supply, comprising: a mains power supply unit, a flywheel energy storage unit, a supercapacitor unit, a load-bearing unit, and a controller. The mains power supply unit, flywheel energy storage unit, supercapacitor unit, and load-bearing unit are each connected to a common DC bus via contactors. The mains power supply unit converts AC power obtained from the AC grid into DC power and outputs it to the DC bus. The flywheel energy storage unit includes a third contactor and a flywheel energy storage device, a bidirectional AC-DC converter, and a bidirectional DC-DC converter connected in sequence. The system includes a supercapacitor unit and a first contactor. The bidirectional AC-DC converter and the bidirectional DC-DC converter are connected in series. The flywheel energy storage unit is connected to the common DC bus through the first contactor. The flywheel energy storage unit charges the supercapacitor through the third contactor. The supercapacitor unit includes a supercapacitor bank and a second contactor. The supercapacitor bank is connected to the common DC bus through the second contactor and discharges to the flywheel energy storage unit through the third contactor. The controller is used to control the opening and closing states of each contactor, the power command of the bidirectional AC-DC converter, and the power command of the bidirectional DC-DC converter.

[0008] The mains power supply unit converts AC power from the grid into DC power and outputs it to the DC bus, drawing energy from the grid at a gradual power output. The flywheel energy storage unit stores DC power transmitted from the common DC bus, then converts the stored energy back into DC power for output to the common bus or to charge the supercapacitor unit. This allows for controllable energy exchange between the flywheel energy storage device and the system's common DC bus, enabling rapid charging of the supercapacitor while simultaneously supplying power to the carrier unit, thus compensating for the time spent by the supercapacitor unit supplying power to the carrier unit. The voltage fluctuation of the common DC bus effectively suppresses the drastic voltage drop of the DC bus caused by ultra-large current pulses; the supercapacitor unit is used to supply power to the carrier unit through the common DC bus, realizing instantaneous ultra-high power current to the material, so that it undergoes ultra-high temperature and ultra-fast cooling of more than 3000°C within milliseconds to seconds, completing the flash evaporation of the material; the supercapacitor unit is used to discharge to the flywheel energy storage unit, the flywheel energy storage unit is used to store the DC power released by the supercapacitor unit, the flywheel energy storage unit recovers the residual energy of the supercapacitor, and the resistance dissipates the waste, while placing the capacitor in the best maintenance state to extend its life.

[0009] Preferably, the controller controls the opening and closing states of each contactor, the power command of the bidirectional AC-DC converter, and the different operating modes of the bidirectional DC-DC converter power command switching system. Each operating mode includes at least a Joule heating mode, a supercapacitor charging mode, and a flywheel charging mode. The Joule heating mode includes a flash Joule heating mode, a rapid Joule heating mode, and / or a long-term Joule heating mode, with the power decreasing sequentially from flash Joule heating mode to rapid Joule heating mode to long-term Joule heating mode. In flash Joule heating mode, the controller controls the supercapacitor unit to discharge to the carrier unit, while simultaneously enabling the bidirectional AC-DC converter of the flywheel energy storage unit to operate in voltage source mode to stabilize the voltage of the common DC bus. In rapid Joule heating mode, the controller controls the first contactor to close, allowing only the flywheel energy storage unit to supply power to the carrier unit. In long-term Joule heating mode, the controller controls the contactor between the mains power supply unit and the common DC bus to close, allowing only the mains power supply unit to supply power to the carrier unit. In this scheme, the above three Joule heating modes can be coupled together or selected individually using production materials. In supercapacitor charging mode, the controller controls the flywheel energy storage unit to charge the supercapacitor unit. In flywheel charging mode, the controller enables the mains power supply unit to charge the flywheel energy storage unit.

[0010] Preferably, in the flywheel charging mode, the flywheel energy storage unit is powered by mains electricity at a first power, the average of which does not exceed the threshold power of the AC power grid that does not require capacity expansion. This avoids the increased equipment modification costs due to excessive power and is also conducive to the stable operation of the public AC power grid.

[0011] Preferably, the system also includes a liquid cooling system, which comprises a flywheel energy storage cooling circuit and a supercapacitor cooling circuit, as well as a shared pump station and radiator. The radiator is used to cool the flywheel energy storage cooling circuit and the supercapacitor cooling circuit, and the pump station is used to control the operation of the flywheel energy storage cooling circuit and the supercapacitor cooling circuit. The control switch of the pump station is electrically connected to the controller. The liquid cooling system cools the flywheel energy storage device and the supercapacitor bank in a timely manner, ensuring the stable operation of the flywheel energy storage device and the supercapacitor bank.

[0012] To achieve the above objectives, the present invention also provides a control method for a flash Joule heating system powered by a flywheel-supercapacitor hybrid power supply, comprising: Step 1: Execute the flywheel charging mode. The controller controls the contactor between the bearing unit and the common DC bus to open, and the contactor between the mains power supply unit and the common DC bus to close. At the same time, it controls the first contactor to close and the second and third contactors to open, so that the mains power supply unit charges the flywheel energy storage unit. Step 2: Execute the supercapacitor charging mode. The controller controls the contactor between the mains power supply unit and the common DC bus to open, and the third contactor to close, so that the flywheel energy storage unit charges the supercapacitor unit. Step 3: Execute flash Joule heating mode, rapid Joule heating mode and / or long-term Joule heating mode to complete the material preparation within a single production cycle; Step 4: Repeat steps 1-3 above until the material preparation is complete.

[0013] Preferably, in step 4, after the material preparation is completed and power supply to the bearing unit is stopped, the supercapacitor energy feedback mode is executed. The controller controls the closing of the third contactor to discharge the supercapacitor unit to the flywheel energy storage unit. The flywheel energy storage unit recovers the residual energy of the supercapacitor, avoids resistance dissipation and waste, and simultaneously places the capacitor in the optimal maintenance state to extend its lifespan.

[0014] Preferably, in the flash Joule heating mode, the controller controls the third contactor to open and the second contactor to close; the supercapacitor unit discharges to the carrier unit, and at the same time, the bidirectional AC-DC converter of the flywheel energy storage unit operates in voltage source mode to stabilize the voltage of the common DC bus; thus completing the material preparation within a single production cycle.

[0015] Preferably, in the fast Joule mode, the controller closes the first contactor, allowing only the flywheel energy storage unit to power the carrier unit. The fast Joule mode provides a heating mode with medium power and a longer duration, which can expand the applicability of the process.

[0016] Preferably, in long-joule mode, the controller closes the contactor between the mains power supply unit and the common DC bus, allowing only the mains power supply unit to supply power to the carrier unit. Long-joule mode enables precise low-temperature, slow-speed heat treatment to further enhance the equipment's versatility.

[0017] Preferably, after the flash joule heating mode of the previous production cycle, the flywheel charging mode or supercapacitor charging mode of the next production cycle is executed immediately.

[0018] Preferably, in step 3, under the flash Joule heating mode, the controller controls the second contactor to close according to a preset timing and pulse width, releasing distributed pulse current to achieve MW-level flash evaporation while ensuring power supply quality.

[0019] The beneficial effects of this plan are: 1. This application innovatively combines the "power-type" characteristics of flywheel energy storage with the "energy-type" characteristics of supercapacitors to construct a two-stage "power-energy" buffer architecture. This architecture decouples the instantaneous megawatt-level power demand required for flash evaporation from the long-term average power supply on the grid side. The peak power on the grid side can be reduced from 300kW in a pure capacitor solution to 20kW, and the harmonic content from >15% to <5%. This allows the system to avoid expensive grid expansion, significantly reduce capacity charges, and eliminate the investment and operating costs of independent APF equipment, resulting in a 15-20% reduction in the estimated cost per ton over the entire lifecycle.

[0020] 2. The technical solution of this application effectively suppresses the drastic drop in DC bus voltage caused by ultra-large current pulses through a closed-loop collaborative control strategy of real-time dynamic voltage regulation of the flywheel and step-by-step precise pulse of the supercapacitor. It can stably control the bus voltage fluctuation from more than ±30% during pure capacitor discharge to within ±5%. On the one hand, it reduces the voltage stress of key power devices (IGBT) by about 50%, improving system reliability; on the other hand, it ensures the extreme consistency of energy delivery for each pulse, thereby optimizing the process repeatability deviation (σ) of batch flash evaporation from ±2.5 layers to ±0.5 layers, and increasing the batch production qualification rate from about 70% to more than 98%.

[0021] 3. The three-mode automatic sequential cycle of flash evaporation-fast charging-slow replenishment in this application's technical solution scientifically allocates energy replenishment time. The 300kW fast charging task is efficiently completed by the flywheel within 24 seconds, while the slow replenishment task, which lasts up to 400 seconds, is carried out smoothly by the mains power at a low power. This design allows the energy recovery time to be fully embedded in the production cycle, solving the paradox of "fast charging affecting the power grid and slow charging affecting production capacity," and providing a key technical foundation for the fully automatic and continuous production of kilogram-level materials.

[0022] 4. This application provides three Joule heating modes: flash evaporation, rapid heating, and long-term heating, which can cover different temperature control process curves from graphene flash evaporation and metal powder sintering to material preheating and annealing, achieving multi-functionality. The newly added energy feedback mode can effectively recover the residual electrical energy of the supercapacitor before shutdown to the flywheel, instead of converting it into waste heat through resistance, thereby improving the overall energy efficiency of the system. At the same time, this mode maintains the capacitor voltage within the optimal storage range, which helps to extend its cycle life. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention. Detailed Implementation

[0024] The following detailed description illustrates the specific implementation method: Example: This embodiment provides a flash Joule heating system powered by a flywheel-supercapacitor hybrid power supply, as shown in the schematic diagram below. Figure 1 As shown, it includes: a mains power supply unit, a flywheel energy storage unit, a supercapacitor unit, a load-bearing unit, and a controller. The mains power supply unit, the flywheel energy storage unit, the supercapacitor unit, and the load-bearing unit are each connected to a common DC bus via contactors.

[0025] The mains power supply unit is used to convert AC power obtained from the AC grid into DC power output to the DC bus. As the system's energy input port, the mains power supply unit consists of a low-power (20kW), high-performance grid-side AC-DC charger and a grid-connected contactor. The grid-connected contactor is a frame-type AC contactor K0. The AC-DC charger preferably uses a three-phase three-level VIENNA rectifier with THDi < 5%. This unit is designed to obtain energy from the grid only in the most grid-friendly mode, with a gradual power output.

[0026] The flywheel energy storage unit includes a third contactor and a flywheel energy storage device, a bidirectional AC-DC converter, a bidirectional DC-DC converter, and a first contactor connected in sequence. The bidirectional AC-DC converter and the bidirectional DC-DC converter are connected in series. The flywheel energy storage unit is connected to the carrier unit through the first contactor, and the flywheel energy storage unit charges the supercapacitor through the third contactor. The flywheel energy storage device includes a high-speed rotor, a permanent magnet synchronous motor, a vacuum chamber, and a magnetic bearing system. The specific structure and connection relationship refer to existing technology. During the charging process of the flywheel energy storage unit, the external motor of the flywheel energy storage device drives the flywheel to rotate, converting electrical energy into the kinetic energy of the flywheel. During the discharging process of the flywheel energy storage unit, the kinetic energy of the flywheel drives the motor to work in reverse to generate electricity, converting kinetic energy into electrical energy, and outputting DC conductance to the common DC bus or the supercapacitor unit. Subsequently, the flywheel speed decreases.

[0027] The bidirectional AC-DC converter adopts a two-level voltage source topology and uses field-oriented control (FOC) to achieve bidirectional control of motor drive and power generation. The bidirectional DC-DC converter preferably uses a phase-shifted full-bridge PSFB topology to achieve controllable energy exchange between the flywheel DC bus and the system's common DC bus. The first contactor is a high-performance AC contactor K1, used to connect or isolate this unit from the common DC bus. The third contactor is a high-performance AC contactor K3.

[0028] The flywheel energy storage unit is used to store DC power transmitted from the common DC bus. Then, the flywheel energy storage unit is used to convert the stored energy into DC power and output it to the common bus or to charge the supercapacitor unit. The flywheel energy storage unit realizes controllable energy exchange between the flywheel energy storage device and the system's common DC bus. While realizing rapid charging of the supercapacitor, it can also supply power to the carrier unit to compensate for the voltage fluctuation of the common DC bus when the supercapacitor unit supplies power to the carrier unit, and effectively suppress the severe voltage drop of the DC bus caused by ultra-large current pulses.

[0029] The supercapacitor unit includes a supercapacitor bank and a second contactor. The supercapacitor bank is connected to a common DC bus via the second contactor and discharges to the flywheel energy storage unit via a third contactor. In this embodiment, the supercapacitor bank is nominally 60F / 600V, composed of hundreds of 2.7V cells connected in series and parallel, with an operating voltage range of 100V-500V. The second contactor is a high-power pulse switch K2, preferably a thyristor or IGCT with strong reverse blocking capability, used to control the switching of 20ms-level pulse currents with peak values ​​reaching kA. The supercapacitor bank integrates a high-voltage BMS with active balancing function and a high-efficiency liquid cooling system.

[0030] The supercapacitor unit is used to supply power to the carrier unit through a common DC bus, enabling instantaneous ultra-high power current to the material, causing it to undergo ultra-high temperature and ultra-fast cooling within milliseconds to seconds, completing the flash evaporation of the material, with temperatures reaching over 3000°C; the supercapacitor unit is used to discharge to the flywheel energy storage unit, which stores the DC power released by the supercapacitor unit, recovers the residual energy of the supercapacitor, eliminates resistance dissipation and waste, and simultaneously places the capacitor in the optimal maintenance state to extend its lifespan.

[0031] The carrying unit includes a multi-station continuous feeding mechanism, such as an eight-station turntable, and its connection switch, a high-performance AC contactor K4. Each station is equipped with a conductive heating device, which contains materials. In this embodiment, each station is equipped with a conductive graphite crucible for loading kilogram-level materials.

[0032] In this embodiment, the liquid cooling system can be used to dissipate heat from the flywheel energy storage device and the supercapacitor bank. The liquid cooling system and the controller are electrically connected. The liquid cooling system promptly cools the flywheel energy storage device and the supercapacitor bank, ensuring their stable operation. The liquid cooling system includes a flywheel energy storage cooling circuit and a supercapacitor cooling circuit, as well as a shared pump station and radiator. The radiator is used to cool the flywheel energy storage cooling circuit and the supercapacitor cooling circuit, and the pump station is used to control the operation of the flywheel energy storage cooling circuit and the supercapacitor cooling circuit. The control switch of the pump station is electrically connected to the controller. The specific details of the liquid cooling system are based on existing technology and will not be described in detail here.

[0033] The controller is used to control the opening and closing states of each contactor, the power commands of the bidirectional AC-DC converter, and the power commands of the bidirectional DC-DC converter. Based on a preset process sequence, the controller precisely controls the opening and closing of each contactor and the power commands of the converter, achieving seamless switching between modes. Specifically, an industrial-grade programmable logic controller (PLC), such as the Siemens S7-1500 series, can be used. It also includes digital input / output modules, a communication processing module, and a host computer connected to the controller. The digital input / output modules are used to collect the status of each contactor's auxiliary contacts, buttons, and sensors, and drive each contactor coil. The communication processing module exchanges data in real time with the flywheel controller, supercapacitor BMS, human-machine interface (HMI), and host computer via industrial buses such as PROFINET, CAN, or EtherCAT. The HMI is used for setting process parameters, selecting operating modes, monitoring system status, and managing alarms.

[0034] In this embodiment, the controller controls the opening and closing states of each contactor, the power command of the bidirectional AC-DC converter, and the switching of the bidirectional DC-DC converter power command between different operating modes of the system. This embodiment's controller has six preset system configuration modes: Six system configuration modes model name Contactor (K0-K4) status Power flow 1 Flash pyrolysis mode [0,1,1,0,1] Capacitor-controlled main amplifier, flywheel voltage regulator 2 Supercapacitor charging mode [0,0,0,1,0] Flywheel → Capacitor 3 Flywheel slow charging (powered by grid) [1,1,0,0,0] AC power → flywheel 4 Fast Joule thermal mode [0,1,0,0,1] flywheel discharge 5 Long-term Joule heating mode [1,0,0,0,1] Direct power supply from the city 6 Supercapacitor energy feedback mode [0,0,0,1,0] Capacitor → Flywheel In Mode 1, the supercapacitor releases a step-by-step pulse current to the carrying unit via K2. In this embodiment, this pulse current is 10 × 20 ms, with a total energy of 2 kWh. The flywheel compensates for bus voltage fluctuations in real time through its AC-DC converter, achieving MW-level flash evaporation while ensuring power quality and improving process consistency. In Mode 2, the flywheel charges the discharged supercapacitor to the set voltage in approximately 24 seconds with a constant power of 300 kW through the DC-DC converter, rapidly restoring pulse energy within the cycle time to support continuous production. In Mode 3, during the long window of material loading / unloading and system cooling (400 seconds in this embodiment), the mains power unit replenishes energy to the flywheel with a small power of 20 kW. Energy is drawn smoothly from the grid during idle time, avoiding grid impact and achieving peak shaving and valley filling. In Mode 4, only the flywheel unit outputs an adjustable power of up to 300 kW for several seconds to tens of seconds through its AC-DC converter for heating. This provides a heating mode with medium power and longer duration, expanding the applicability of the process. In Mode 5, the AC-DC converter outputs a low-power DC output of up to 20kW for several minutes from the mains power unit for preheating or heat preservation, achieving precise low-temperature slow heat treatment and further enhancing the equipment's versatility. In Mode 6, before system shutdown, the supercapacitor is controlled to discharge through the flywheel DC-DC converter, actively and controllably discharging its voltage to the optimized storage voltage of 100V, approximately 20% SOC; residual energy is recovered, avoiding resistive dissipation and waste, while simultaneously placing the capacitor in optimal maintenance condition to extend its lifespan.

[0035] In Mode 1, the controller synchronously issues the following commands: 1) Control the flywheel bidirectional AC-DC converter to operate in "voltage source" mode to stabilize the common DC bus voltage; 2) Control the supercapacitor pulse switch K2 to close according to a preset timing and pulse width, releasing the step-by-step pulses. This strategy ensures that under extremely high di / dt pulse loads, bus voltage fluctuations are suppressed to within ±5%. The PLC precisely controls the width and interval of the 10 step-by-step pulses of K2 through high-speed output points or dedicated process modules, for example, 20ms pulses with 2ms intervals, and synchronizes with the flywheel voltage regulation control in real time. Strict interlocking logic is programmed into the controller, for example: K0, K1, and K2 must not close simultaneously; power commands are only allowed to be issued to the flywheel after the K1 auxiliary contact is confirmed to be closed. These interlocks are the cornerstone of the system's safe operation.

[0036] In the flywheel charging mode, the flywheel energy storage unit is powered by the mains electricity at a first power level. The average value of this first power level does not exceed the threshold power of the AC power grid that does not require capacity expansion. This avoids the increased equipment modification costs due to excessive power and also contributes to the stable operation of the public AC power grid.

[0037] To achieve the above objectives, the present invention also provides a control method for a flash Joule heating system powered by a flywheel-supercapacitor hybrid power supply, comprising: Step 1: Execute the flywheel charging mode. The controller controls the contactor between the bearing unit and the common DC bus to open, and the contactor between the mains power supply unit and the common DC bus to close. At the same time, it controls the first contactor to close and the second and third contactors to open, so that the mains power supply unit charges the flywheel energy storage unit.

[0038] Step 2: Execute the supercapacitor mode. The controller controls the contactor between the mains power supply unit and the common DC bus to open, and the third contactor to close, so that the flywheel energy storage unit charges the supercapacitor unit.

[0039] Step 3: Execute flash joule heating mode, rapid joule heating mode and / or long-term joule heating mode to complete the material preparation within a single production cycle.

[0040] In the flash Joule hot mode, the controller opens the third contactor and closes the second contactor; the supercapacitor unit discharges to the carrier unit, while simultaneously enabling the bidirectional AC-DC converter of the flywheel energy storage unit to operate in voltage source mode to stabilize the voltage of the common DC bus. In fast Joule mode, the controller closes the first contactor, allowing only the flywheel energy storage unit to supply power to the carrier unit. In long Joule mode, the controller closes the contactor between the mains power supply unit and the common DC bus, allowing only the mains power supply unit to supply power to the carrier unit.

[0041] In this step, the controller directs the second contactor to close according to a preset timing and pulse width, releasing the distributed pulse current. This achieves extremely high-power flash evaporation while ensuring power supply quality and improving process consistency.

[0042] Step 4: Repeat steps 1-3 above until the material preparation is complete.

[0043] In this embodiment, the PLC has a built-in master state machine synchronized with the production cycle (480 seconds). A typical automatic cycle is: Mode 3 (flywheel charging) → Mode 2 (capacitor fast charging) → Mode 1 (flash evaporation) → (material loading / unloading cooling period) → Mode 3… Mode switching is automatically triggered by the PLC based on process completion signals or timers, ensuring tight production cycle continuity. After the flash evaporation Joule heating mode following the previous production cycle, the flywheel charging mode of the next production cycle is immediately executed, utilizing the material loading / unloading cooling period for flywheel charging. This tight production cycle continuity ensures production efficiency.

[0044] In this step, after material preparation is completed and power supply to the carrier unit is stopped, mode 6, the supercapacitor energy feedback mode, is executed. The controller controls the closing of the third contactor to discharge the supercapacitor unit to the flywheel energy storage unit. The flywheel energy storage unit recovers the residual energy of the supercapacitor, avoids resistive dissipation and waste, and simultaneously places the capacitor in optimal maintenance condition to extend its lifespan.

[0045] In step 3, after selecting the flash Joule heating mode, modes 4, 5, and 6 can be manually or automatically activated according to the process formula. For example, when long-term continuous heating is required, mode 4 (fast Joule mode) can be selected to further heat the material. In fast Joule mode, the controller closes the first contactor, allowing only the flywheel energy storage unit to power the carrying unit. The fast Joule mode provides a heating mode with medium power and a longer duration, expanding the applicability of the process. For example, when long-term heat preservation is required, mode 5 (long Joule mode) can be used to further heat the material. In long Joule mode, the controller closes the contactor between the mains power supply unit and the common DC bus, allowing only the mains power supply unit to power the carrying unit. The long Joule mode enables precise low-temperature slow heat treatment, further enhancing the equipment's versatility.

[0046] The following is an implementation method for achieving kilogram-scale continuous production of graphene based on an 8-minute cycle time using this system: The system achieves an annual production capacity of 45 tons of flash-evaporated graphene. The system configuration is as described above: Supercapacitor pack: 60F / 600V Flywheel system: Rated power 300kW, energy storage capacity 3kWh, short-term overload capacity ≥1.2MW (seconds). Mains power unit: 20kW VIENNA rectifier.

[0047] Production cycle time: 480 seconds / workstation.

[0048] PLC: Siemens CPU 1515-2 PN.

[0049] PLC-controlled automatic cycle: 1. Workstation ready, start cycle: The HMI issues a start command. The PLC first checks the safety conditions, then enters mode 2. The PLC closes K3 and commands the flywheel DC-DC converter to charge the supercapacitor at a constant power of 300kW via PROFINET communication. The PLC monitors the capacitor voltage, and when it reaches 500V, it opens K3, completing mode 2 (approximately 24 seconds).

[0050] 2. Perform flash evaporation: The PLC automatically switches to mode 1. K0 is controlled to open, K1 and K4 to close in sequence; the flywheel is started to stabilize the voltage; then K2 is controlled to be switched on and off 10 times strictly according to the preset timing to complete the flash evaporation (takes about 0.22s).

[0051] 3. Energy Replenishment and Preparation: After flash evaporation, the PLC controls the turntable to rotate to the next station and immediately enters mode 3. The PLC closes K0 and K1, starting the 20kW grid-side charger to replenish the flywheel's power. During the remaining approximately 455 seconds of loading, unloading, and cooling time, the flywheel is slowly fully charged.

[0052] 4. Cycle: At the start of the next cycle, repeat steps 1-3. The PLC ensures that the grid-side power remains stable at around 20kW throughout the entire 480s cycle.

[0053] Process and energy flow timing: From 0 to 24 seconds, Mode 2 is used: the previous flash cycle ends, and the supercapacitor voltage drops to 100V. The system switches to Mode 2, and the flywheel charges the supercapacitor at 300kW. After 24 seconds, the capacitor voltage rises to 500V, and the charging energy is approximately 2kWh.

[0054] At the 25th second, mode 1 is activated: material is in place, and the system switches to mode 1. The flywheel AC-DC converter starts voltage regulation. The supercapacitor discharges to the material in approximately 0.22 seconds through 10 step pulses, each pulse lasting 20ms with a 2ms interval, completing flash evaporation.

[0055] From seconds 26 to 480, mode 3 is used: the loading, unloading, and cooling phase begins. The system switches to mode 3, and the mains power unit charges the flywheel at 20kW, replenishing approximately 2.2kWh of energy within 396 seconds, restoring it to its initial state, ready for the next cycle.

[0056] Through precise scheduling by the PLC, the instantaneous power demand of 300kW is completely shielded from the power grid, manifesting only as an average load of 20kW, thus eliminating the need for capacity expansion and maintenance costs. Calculations show that the energy and equipment amortization cost per ton of product is reduced by approximately 16% compared to a 300kW direct charging solution.

[0057] The following is an implementation method for achieving rapid sintering of high-entropy alloy powder using this system: Rapid solid-state sintering of a high-entropy alloy powder is required, with the following process: uniformly heating to 1800°C within 30 seconds and holding at that temperature for 10 seconds.

[0058] System configuration: With the above-mentioned graphene production parameters configured, the supercapacitor can serve as a power backup.

[0059] PLC Control Process: The operator selects "Mode 4" on the HMI and inputs the power curve. The PLC controls the closure of K1 and K4, and sets the flywheel AC-DC output power in real time via communication according to the curve. For example, it linearly increases from 0 to 250kW within 0-30s, and then maintains 250kW for 10s. Throughout the process, the flywheel is independently powered, and the supercapacitor does not participate in the discharge. Under PLC control, this system can flexibly execute non-pulsating, precise power programs to meet diverse material synthesis processes, achieving "one machine, multiple functions."

[0060] This invention provides a flywheel-supercapacitor hybrid power supply flash Joule heating system, which constructs a hybrid DC microgrid with intelligent power flow reconfigurability. The system includes a mains power supply unit, a flywheel energy storage unit, a supercapacitor unit, and a load-bearing unit. These four physical units are connected to a common DC bus through the coordinated switching of contactors (K0, K1, K2, K3, K4), forming a reconfigurable power flow network. Through a central control system with a programmable logic controller as its core, the energy flow is precisely scheduled, realizing the automatic and safe switching of six predetermined operating modes. In this solution, the mains power supply unit, flywheel energy storage unit, supercapacitor unit, and load-bearing unit are connected to a common DC bus through coordinated switching of contactors, forming a reconfigurable power flow network. This network allows for flexible adjustment of heating power and time, adapting to the diverse process requirements of different materials for heating curves and holding times, resulting in good equipment versatility. After the supercapacitor discharges, its residual energy is stored through the flywheel energy storage unit, avoiding energy waste and ensuring the capacitor is in optimal maintenance condition to extend its lifespan. Energy is obtained from the AC grid through the flywheel energy storage unit to recharge the supercapacitor unit, avoiding the problem of excessively long charging time in the traditional pure capacitor mode, effectively ensuring production efficiency. At the same time, the flywheel energy storage unit can utilize idle time to smoothly draw energy from the grid, avoiding grid impact and achieving "peak shaving and valley filling".

[0061] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention. In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; or they can refer to the internal closure of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A flash Joule heating system powered by a flywheel-supercapacitor hybrid power supply, characterized in that, include: The system includes a mains power supply unit, a flywheel energy storage unit, a supercapacitor unit, a load-bearing unit, and a controller. The mains power supply unit, flywheel energy storage unit, supercapacitor unit, and load-bearing unit are each connected to a common DC bus via contactors. The mains power supply unit is used to convert AC power obtained from the AC grid into DC power and output it to the DC bus; the flywheel energy storage unit includes a third contactor and a flywheel energy storage device, a bidirectional AC-DC converter, a bidirectional DC-DC converter, and a first contactor connected in sequence. The bidirectional AC-DC converter and the bidirectional DC-DC converter are connected in series. The flywheel energy storage unit is connected to the common DC bus through the first contactor, and the flywheel energy storage unit charges the supercapacitor through the third contactor; the supercapacitor unit includes a supercapacitor bank and a second contactor. The supercapacitor bank is connected to the common DC bus through the second contactor and discharges to the flywheel energy storage unit through the third contactor; The controller is used to control the opening and closing states of each contactor, the power command of the bidirectional AC-DC converter, and the power command of the bidirectional DC-DC converter.

2. The flash Joule heating system powered by a flywheel-supercapacitor hybrid power supply according to claim 1, characterized in that: The controller controls the opening and closing states of each contactor, the power command of the bidirectional AC-DC converter, and the different operating modes of the bidirectional DC-DC converter power command switching system. Each operating mode includes at least Joule heating mode, supercapacitor charging mode, and flywheel charging mode. The Joule heating mode includes flash Joule heating mode, rapid Joule heating mode, and / or long-term Joule heating mode, and the power of the flash Joule heating mode, rapid Joule heating mode, and long-term Joule heating mode decreases sequentially.

3. The flywheel-supercapacitor hybrid power supply flash Joule heating system and its control method according to claim 2, characterized in that: In the flywheel charging mode, the flywheel energy storage unit is powered by the mains power at a first power, and the average value of the first power is not greater than the threshold power of the AC grid that does not require capacity expansion.

4. The flash Joule heating system powered by a flywheel-supercapacitor hybrid power supply according to claim 1, characterized in that: It also includes a liquid cooling system, which includes a flywheel energy storage cooling circuit and a supercapacitor cooling circuit, as well as a shared pump station and radiator. The radiator is used to cool the flywheel energy storage cooling circuit and the supercapacitor cooling circuit, and the pump station is used to control the operation of the flywheel energy storage cooling circuit and the supercapacitor cooling circuit. The control switch and controller of the pump station are electrically connected.

5. The control method for a flywheel-supercapacitor hybrid power supply flash Joule heating system according to claim 1, characterized in that: Step 1: Execute the flywheel charging mode. The controller controls the contactor between the bearing unit and the common DC bus to open, and the contactor between the mains power supply unit and the common DC bus to close. At the same time, it controls the first contactor to close and the second and third contactors to open, so that the mains power supply unit charges the flywheel energy storage unit. Step 2: Execute the supercapacitor charging mode. The controller controls the contactor between the mains power supply unit and the common DC bus to open, and the third contactor to close, so that the flywheel energy storage unit charges the supercapacitor unit. Step 3: Execute flash Joule heating mode, rapid Joule heating mode and / or long-term Joule heating mode to complete the material preparation within a single production cycle; Step 4: Repeat steps 1-3 above until the material preparation is complete.

6. The control method for a flywheel-supercapacitor hybrid power supply flash Joule heating system according to claim 5, characterized in that: After the material preparation is completed in step 4 and the power supply to the bearing unit is stopped, the supercapacitor energy feedback mode is executed. The controller controls the closing of the third contactor to make the supercapacitor unit discharge to the flywheel energy storage unit.

7. The control method for a flywheel-supercapacitor hybrid power supply flash Joule heating system according to claim 5, characterized in that: In the flash Joule heating mode, the controller controls the third contactor to open and the second contactor to close; the supercapacitor unit discharges to the carrier unit, and at the same time, the bidirectional AC-DC converter of the flywheel energy storage unit operates in voltage source mode to stabilize the voltage of the common DC bus; thus completing the material preparation within a single production cycle.

8. The control method for a flywheel-supercapacitor hybrid power supply flash Joule heating system according to claim 5, characterized in that: In the rapid Joule thermal mode, the controller controls the first contactor to close, so that only the flywheel energy storage unit supplies power to the carrier unit.

9. The control method for a flywheel-supercapacitor hybrid power supply flash Joule heating system according to claim 5, characterized in that: In the long-term Joule thermal mode, the controller controls the contactor between the mains power supply unit and the common DC bus to close, so that only the mains power supply unit supplies power to the carrier unit.

10. The control method for a flywheel-supercapacitor hybrid power supply flash Joule heating system according to claim 5, characterized in that: After the flash joule heating mode following the previous production cycle, immediately execute the flywheel charging mode or supercapacitor charging mode for the next production cycle.

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