650 results about "Dc bus voltage" patented technology

The invention discloses a CPLD-driven IGBT short-circuit current dynamic monitoring method and system, and relates to the technical field of power electronics, and the method comprises the specific steps of S100 real-time data acquisition, S200 dynamic threshold calculation, S300 short-circuit state judgment, S400 rapid protection execution, and S500 fault data recording and uploading. Accurate and prospective judgment of the short circuit state of the IGBT is achieved, two stress parameters including the direct-current bus voltage and the junction temperature serve as independent variables, when the bus voltage rises, the voltage stress borne by the IGBT in the turn-off period is increased, meanwhile, the current peak at the short circuit moment is more remarkable, early warning is conducted in advance by dynamically lowering the threshold value, and therefore the short circuit state of the IGBT is accurately judged. According to the mechanism, the monitoring system does not simply respond to the occurred overcurrent, but can pre-judge the safety boundary of the device under the current working condition, so that intervention is implemented before the current really reaches a dangerous peak value, and a protection blind area under a severe working condition is effectively avoided.

The invention relates to the technical field of electric power operation and maintenance, in particular to a distributed optical storage unit cooperative scheduling control method and system, the method is applied to a distributed optical storage system comprising a plurality of optical storage units, each optical storage unit comprises a photovoltaic unit, an energy storage unit and a load unit, and is configured with a local unit controller. Comprising the following steps: collecting real-time operation data of an optical storage unit, and extracting local collaborative scheduling characteristics and a local DC bus voltage instantaneous fluctuation ratio from the real-time operation data; each unit controller inputs the corresponding local cooperative scheduling feature into a preset local scheduling strategy generation model, and outputs an initial scheduling action instruction set; and performing global voltage stability evaluation on the distributed optical storage system based on the local direct current bus voltage instantaneous fluctuation rates corresponding to all the optical storage units, and calculating to obtain a system voltage fluctuation index. The distributed local control capability and the global collaborative demand are organically fused, and the global voltage stability and the collaborative scheduling consistency are ensured.

The invention belongs to the technical field of power electronics, and relates to an energy feedback high-power-factor air conditioner compressor driving system. Comprising a direct-current bus, a direct-current bus electrolytic capacitor, a motor driving circuit, a shutdown energy feedback circuit, a permanent magnet synchronous motor and a motor control module, wherein the two ends of the direct-current bus electrolytic capacitor are connected with the positive electrode and the negative electrode of the direct-current bus respectively; in the energy feedback control module for driving the combined switch device in the shutdown energy feedback circuit, the motor driving circuit and the shutdown energy feedback circuit, the second connecting end I of each phase of bridge arm is connected with the positive electrode of the direct-current bus, and the second connecting end II of each phase of bridge arm is connected with the negative electrode of the direct-current bus; the first connecting end of the phase bridge arm of the shutdown energy feedback circuit is connected with the phase power grid voltage through the phase filter inductor. The method can maintain the stability of the DC bus voltage, and reduces the influence of the power grid voltage fluctuation and the air conditioner compressor load fluctuation.

The invention discloses a cooperative control system for an input-series output-parallel dual-active-bridge inverter, and relates to the technical field of power electronic converter control, an input voltage equalizing control IVSC loop is set for m-1 DAB sub-modules, and input voltage equalization of the DAB sub-modules is realized by adjusting phase shift angles of the sub-modules; an output voltage control OVC loop is set for the output DC bus voltage of the whole ISOP-DAB system to stabilize the DC bus voltage, a PIR controller is adopted in the OVC loop, and the resonant frequency is set to be twice of the fundamental frequency of the AC side, so that selective high gain is provided at the position, the frequency doubling fluctuation of the DC bus voltage is inhibited, and the frequency doubling fluctuation of the DC bus voltage is inhibited. According to the method and the device, the regulation quantity of the IVSC loop and the regulation quantity of the OVC loop are superposed to carry out cooperative control, so that the effective suppression of the frequency doubling fluctuation of the DC bus voltage and the automatic equalization of the power of each module are accurately realized on the premise of not increasing the hardware complexity.

The invention belongs to the field of new energy, and particularly discloses a direct-current bus voltage control method and system of a flywheel energy storage system. Comprising the following steps: if DC bus voltage is in a normal range, DC voltage forms a q-axis current reference signal after being adjusted by a PI controller, the q-axis current reference signal generates a q-axis voltage instruction signal after being adjusted by a current control loop PI, and a dq-axis voltage instruction value is generated through decoupling; if the current control loop slightly deviates from the normal range, parameters of a PI controller are adjusted, so that an integration link plays a leading role in control output, a virtual impedance link connected to the current control loop in parallel is adjusted, and a dq-axis voltage instruction value is generated; and if the voltage is seriously deviated from the normal range, a grid-side power signal is fed forward to a machine-side direct-current voltage control loop, virtual resistance in a virtual impedance link is adjusted, and a dq-axis voltage instruction value is generated. According to the invention, the control mode is automatically switched according to different conditions of the DC bus voltage by adopting a threshold-grading regulation and control strategy, and the adaptability to large disturbance is improved while the steady-state precision of the system is maintained.

A control system for a direct current (DC) microgrid is described. The control system includes a DC bus with a positive bus line and a negative bus line, DC battery circuits with a positive coupler connected to the positive bus line and a negative coupler connected to the negative bus line, switches including a control input terminal located in each DC battery circuit, a distributed generator circuit connected to the DC bus, a constant load power circuit connected to the DC bus, a computing device connected to each control input terminal, the DC bus, the distributed generator circuit and the constant load power circuit. The computing device includes an electric circuitry, a memory, and at least one processor to determine a DC bus voltage, determine the SoC of the DC battery circuits, generate PWM signals that control the DC bus voltage, and balance the SoC of the DC battery circuits.

The invention relates to the technical field of bidirectional PCS, and discloses a bidirectional PCS converter multi-target power balance optimization method and system based on model predictive control. According to the method, real-time operation parameters are analyzed by using a first-order lag initial model, prediction of power disturbance in a plurality of control periods in the future is realized, power balance optimization is converted from passive response to active pre-judgment, and a linear time-varying prediction model is constructed, so that the real-time performance of power balance optimization is improved. According to the method, the evolution trajectory of the direct current bus voltage in a period of time in the future is predicted, the power balance optimization behavior is continuous and prospective through a rolling optimization mechanism of prediction, evaluation and preferential selection, and meanwhile, the three targets of ensuring voltage stability, reducing switching loss and suppressing current harmonic content are fused into power balance optimization, so that the power balance optimization efficiency is improved. The problems of control hysteresis and target singleness existing in a traditional control method are solved, and quick and accurate power balance control of the bidirectional PCS is realized.

The invention discloses a current distribution regulation and control voltage balance SOC optimization method, and the method comprises the specific steps: determining the type of a balance strategy according to the SOC difference between battery modules; according to the determined equalization strategy, the total cluster current of the system is distributed to each module according to SOC, and module reference current is generated and calculated; and finally, converting the module reference current into a bus voltage reference instruction, and controlling each module to track a voltage target to realize current distribution. According to the current distribution regulation and control voltage balance SOC optimization method provided by the invention, the target current is calculated, and then the current reference is converted into the bus voltage reference, so that the dynamic response speed and stability of the DC bus voltage are improved.

The invention relates to the technical field of logistics warehouse storage equipment, in particular to a speed reduction control method for a high-speed motor driven hydraulic system, which comprises the following steps: S1, the output torque of a high-speed motor is transmitted to a gear pump through a motor shaft, a planetary reducer and a planet carrier in sequence to drive the gear pump to work; s2, acquiring a three-phase current instantaneous signal and a direct current bus voltage signal, and performing preprocessing and frequency spectrum conversion to determine a current frequency spectrum; s3, in the current frequency spectrum, extracting an energy value in a preset frequency band with the meshing frequency and harmonic waves of the planetary gear as the center, and calculating to obtain a disturbance characterization value of the planetary gear; s4, determining a torque smooth adjustment coefficient according to the planet wheel disturbance characterization value; and S5, dynamically adjusting a dynamic response parameter of a torque control ring of the high-speed motor according to the torque smooth adjustment coefficient. The problems that in the prior art, a high-rotating-speed motor and a hydraulic pump are not matched in rotating speed, and mechanical disturbance is difficult to restrain are solved.

The application discloses a control method and device of a vehicle and a storage medium, and belongs to the technical field of vehicle control. The method comprises the following steps: in response to the fault level being a target level and the first detection result indicating that the engine and the ISG motor are in a series working mode, setting the charging target power of the power battery connected in the high-voltage loop to 0, and performing speed closed-loop control on the ISG motor with a speed threshold value as a target speed; in response to the actual torque of the engine being less than 0 and the direct-current bus current being less than a current threshold value, controlling the power battery to be disconnected from the high-voltage loop, performing speed closed-loop control on the engine and voltage closed-loop control on the ISG motor; and supplying power to the traction motor (TM) motor by the ISG motor. The DC bus voltage can be stabilized in the case that the power battery is disconnected, so that the TM motor can stably drive the vehicle to safely travel in the case that the power battery fails.

The invention discloses a multivariable model predictive control method for a photovoltaic inverter grid-connected system, which comprises the following steps of: establishing a mathematical model of an inverter under a rotating coordinate system, and setting a discrete mathematical model on the basis of traditional model predictive control to obtain a predictive value of output current; and taking the predicted value, the current error at the sampling moment and the error of the direct current bus voltage as control factors of the value function, and seeking the minimum solution of the value function to achieve the optimal control effect. According to the multivariable model predictive control method for the photovoltaic inverter grid-connected system, through the steps, the photovoltaic grid-connected response efficiency can be improved, the total harmonic distortion rate can be reduced, the stability and the anti-interference performance of the direct-current bus voltage can be enhanced, the grid-side current can be controlled at a lower total harmonic distortion level, and the effect is obvious.

The invention belongs to the technical field of power grid control, and relates to a transformer area flexible interconnection system three-phase imbalance control method and device and a medium. Taking the transformer area converter controlled by the PQ control algorithm as a target transformer area converter; collecting a first control parameter output by an active power PI controller of the target transformer area converter; based on the upper and lower limits of the voltage target value of the DC bus, performing amplitude limiting setting on the first control parameter of the target transformer area converter to obtain the voltage target value; subtracting the voltage target value from the actual voltage value of the direct-current bus, inputting the difference value into the PI controller, and outputting a second control parameter of the target transformer area converter; taking the second control parameter as a direct-axis current target value, subtracting the direct-axis current target value from a direct-axis current actual value, and taking the difference value as the input of a direct-axis current PI controller; and controlling the target transformer area converter based on the voltage modulation signal output by the PQ control framework. The scheme can effectively improve the power supply reliability of the power distribution area and stabilize the DC bus voltage.

The invention discloses a power control method, system, equipment and medium for a modular multilevel converter, and belongs to the technical field of power electronics and power system application, and the method comprises the steps: collecting the bridge arm current, the sub-module capacitor voltage, the DC bus voltage and the AC side power of the modular multilevel converter; calculating a power error according to the AC side power and a power reference value, and calculating a sub-module capacitor voltage error according to the sub-module capacitor voltage and a voltage reference value; constructing a Lyapunov function comprising a plurality of control targets, wherein the Lyapunov function comprises a power error term, a sub-module capacitor voltage error term, a circulating current suppression term and a total energy balance term; and determining a control law on the basis that the Lyapunov function meets a stability condition, and controlling the modular multilevel converter according to the control law. According to the method, the coupling control problem of multi-terminal direct current system power distribution and sub-module energy balance is considered and improved.

The invention discloses a grading diagnosis method, system and device for a charging module and a storage medium, which are used for reducing unnecessary charging interruption and improving the adaptive capacity of the charging module to external disturbance. The method comprises the steps that when it is monitored that the voltage of a direct-current bus drops and the change rate exceeds a preset change rate threshold value, it is judged that a transient event is triggered, a triggering timestamp of the transient event is obtained, and a plurality of operation parameters at the moment before the transient event is triggered are obtained and determined as a stable baseline; evaluating a synchronous change trend of the plurality of operation parameters relative to the stable baseline, and classifying each operation parameter into a preset state label according to an evaluation result; based on the correlation among the plurality of operation parameters and the combination of the state labels, the event source category of the transient event is diagnosed, and the event source category at least comprises a power grid side sag event, a load side sudden load event and a module internal fault event; and executing a hierarchical response strategy matched with the event source category.

The invention relates to a multi-level pulse power supply and semiconductor process equipment. The multi-level pulse power supply comprises a high-frequency isolation conversion module and a switch module, wherein the high-frequency isolation conversion module is electrically connected with the switch module; the high-frequency isolation conversion module is used for accessing a direct-current bus voltage and performing voltage conversion processing on the direct-current bus voltage to generate a plurality of pre-processing voltages; and the switch module is used for responding to an externally input control signal and switching the state of the switch module so as to perform voltage amplitude modulation based on the plurality of pre-processing voltages and output a target voltage. The multi-level pulse power supply can output multi-level pulses.

The invention discloses a photovoltaic off-grid hydrogen production system operation mode switching instant DC bus voltage stability control method, which comprises the steps of collecting a DC bus voltage signal, and reconstructing a high-dimensional phase space trajectory; calculating real geometric features such as phase space curvature and torsion of the trajectory; searching a historical similar trajectory segment in a historical trajectory database, and generating a final prediction trajectory at a future moment according to a known evolution path of the historical similar trajectory segment; and generating a feedforward control signal according to the deviation between the final prediction track and the reference voltage, and combining the feedforward control signal with traditional feedback control to form a final control instruction. The method does not depend on an accurate system mathematical model, and realizes rapid, smooth and stable control of voltage under mode switching by deeply excavating dynamic geometric information of voltage signals.

The invention provides a satellite power supply system topology architecture and a maximum power point tracking control method thereof, and aims to improve the energy utilization efficiency of a solar cell array of a spinning body spacecraft under a complex illumination condition. The architecture adopts a combined topology architecture of a preceding-stage sequence switch maximum power point shunt regulation (S3MPR) circuit and a backward-stage four-switch Buck-Boost (FSBB) converter, and is suitable for a special operation environment of a spinning body spacecraft power supply system. The system adopts a bus full adjustment mode, enables the DC bus voltage to be stabilized near the maximum power point voltage of the photovoltaic array through a double closed-loop control strategy, and carries out real-time shunting adjustment on an S3MPR circuit in combination with a multi-peak maximum power point tracking (MPPT) algorithm, thereby ensuring the efficient operation of the photovoltaic array. According to the invention, high-efficiency energy tracking and stable charging can be realized under a complex illumination condition, and the reliability and the energy utilization rate of a spinning body spaceflight power supply system are remarkably improved.

The invention relates to the technical field of generator control, and discloses an intelligent vehicle-mounted high-power self-generating control method and system. The method comprises the following steps: acquiring operating parameters of a generator set, performing high-precision digital processing, realizing constant-rotating-speed control through cooperation of multiple controllers based on a rotating-speed fluctuation characteristic value, performing power factor correction through coordinate transformation and active rectification to obtain a direct-current bus voltage, performing precise voltage stabilization by adopting a multi-phase interleaving converter, and outputting the direct-current bus voltage. And finally, outputting a high-quality three-phase alternating-current power supply through space vector modulation and closed-loop feedback control. The technical problems in the prior art that the power supply quality control capability is insufficient, the intelligent level is low, the environmental adaptability is poor, the load adaptability is limited, and the maneuverability is limited are solved.

The invention relates to the field of capacitor monitoring, and provides a capacitor quasi-online state monitoring method and system for a wind power converter, and the method comprises the steps: extracting a data slice comprising DC bus voltage, capacitor branch current, housing temperature and output power from a data buffer area; furthermore, output power data is utilized, intelligent screening is carried out through a quasi-steady-state slice trigger, and only effective data with the power average value large enough and the fluctuation small enough are reserved. And for the screened effective data slices, extracting the DC bus voltage and the capacitance branch current, and accurately identifying the voltage, current amplitude and phase information of the main harmonic through fast Fourier transform. Based on the key harmonic data, the complex impedance of the capacitor is calculated, and then the original ESR and capacitance estimation value are calculated. And finally, in combination with the capacitor shell temperature extracted from the same data slice, performing temperature compensation on the original parameters, and outputting a final result capable of truly reflecting the aging state of the capacitor.

According to the doubly-fed wind turbine generator fault ride-through control method and system provided by the invention, a refined interval segmentation mechanism based on a voltage amplitude is introduced, reactive power coefficients under different falling or lifting depths are dynamically adjusted, and reactive power limits of the rotor-side converter and the grid-side converter are combined, so that the fault ride-through control of the doubly-fed wind turbine generator is realized. Reactive power optimal distribution of rotor side priority and network side auxiliary coordination is realized; furthermore, active feed-forward compensation is introduced to the grid side to quickly suppress DC bus voltage fluctuation, and a dynamic amplitude limiting strategy based on a current circle is adopted to the rotor side, so that the risks of rotor overcurrent and DC overvoltage are effectively suppressed while the power grid voltage recovery is supported in a full-force manner, and the reliability of the system is improved. Therefore, the ride-through capability and the operation safety of the doubly-fed wind turbine generator in the power grid fault period are remarkably improved, and reliable technical guarantee is provided for avoiding large-area off-grid of the generator.

The invention relates to the technical field of power systems, and discloses a self-adaptive equalization control method, system and device for the state of charge of energy storage units of an optical storage direct current micro-grid and a medium, and the method comprises the steps: building a system model comprising a photovoltaic power generation assembly and a plurality of parallel energy storage units, constructing a droop control coefficient adjustment mechanism associated with the state of charge of each energy storage unit, and realizing dynamic nonlinear adjustment of the control coefficient along with the state of charge; meanwhile, a bus voltage secondary compensation mechanism based on the average value of the output voltage of the energy storage unit and a current balance adjustment mechanism based on the virtual voltage drop difference are constructed; and overlapping the two types of compensation quantities to a voltage control instruction of each energy storage unit, and synchronously realizing the voltage stabilization of the direct-current bus and the rapid equalization of the charge states of the energy storage units. Manual intervention is not needed, uneven power distribution caused by line impedance difference or operation condition change is effectively restrained, the system reliability can be improved, and the energy storage service life can be prolonged.

The invention discloses a rapid frequency support control method and device for an offshore wind power uncontrolled rectification sending-out system, and the method comprises the steps: obtaining the frequency of a receiving-end AC power grid, and obtaining an improved receiving-end converter DC bus voltage instruction value based on the frequency information when the frequency change of the receiving-end AC power grid is detected; on the basis of the instruction value, the direct current bus voltage of the receiving end converter is regulated and controlled, so that the direct current bus voltage of the receiving end converter tracks the direct current bus voltage reference value of the receiving end converter, and the amplitude change of the alternating current voltage of the offshore wind field is caused; based on the change of the AC voltage amplitude of the offshore wind field, constructing a power outer ring of the active power-voltage amplitude and the reactive power-voltage phase angle of the similar synchronous machine, determining the terminal voltage reference value of the offshore wind turbine, regulating and controlling the terminal voltage of the offshore wind turbine, enabling the terminal voltage of the wind turbine to track the terminal voltage reference value, and controlling the active output of the offshore wind field. According to the invention, the inertia supporting capability of the offshore wind power uncontrolled rectification sending-out system to the receiving end power grid is improved.

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 provides a DRU-MMC sending end AC fault ride-through method and system, and the method comprises the steps: enabling a receiving end MMC to maintain the DC voltage to be constant in an outer loop fixed DC bus voltage / reactive power control mode during normal operation; sampling a sending-end AC power grid voltage effective value in real time, and calculating a deviation between the effective value and a nominal value; if the deviation shows that the voltage is lower than 90% of the nominal value (determining a fault), calculating a receiving end MMC direct current bus preset voltage instruction value according to the relation between the alternating current voltage and the direct current voltage; and the outer loop voltage control module is switched to a direct current bus preset voltage / reactive power control mode, and the direct current voltage is adjusted to a preset value by adjusting the input number of the sub-modules, so that closed-loop control is formed. According to the invention, continuous power transmission during a fault period can be realized, and the problem of off-network of new energy equipment caused by power congestion in a traditional scheme is avoided.

The invention provides a permanent magnet direct drive fan bus voltage oscillation suppression method after power grid fault recovery, and belongs to the technical field of permanent magnet direct drive fans. The technical problem of DC bus voltage oscillation after symmetric fault recovery is solved. According to the technical scheme, the method comprises the following steps that S1, the power difference value P between a computer side and a network side during a fault period and the maximum unbalanced power Pmax absorbed by the rotational inertia of a fan rotor are included, if P is smaller than or equal to Pmax, the step S2 is executed, and if P is larger than Pmax, the step S3 is executed; s2, controlling a direct-current bus voltage outer ring by a grid-side converter, and turning to S5; s3, a DC bus voltage outer ring is controlled by a fuzzy PI adaptive controller; and S4, carrying out fuzzy processing. According to the invention, adaptive adjustment of DC bus voltage outer loop PI parameters is realized, the dynamic response capability is enhanced, voltage oscillation is effectively suppressed, and the stability is improved.

The invention provides a power supply and distribution control method for an offshore wind-solar complementary direct supply type seabed data center, and the method comprises the steps: collecting wind power and photovoltaic electric energy to an ashore substation through a same AC power transmission channel, converting the wind power and photovoltaic electric energy into a first AC voltage, and generating a DC bus voltage; the direct-current bus directly supplies information processing load, and the first alternating-current voltage drives the cooling system; configuring a multi-time-scale energy storage system comprising a super capacitor, a flow battery and a standby power supply, and stabilizing second-level, minute-to-hour-level and longer-period power fluctuations respectively; based on wind and light output prediction and the energy storage charge state, load and charge and discharge are dispatched cooperatively. According to the method, the power transmission cost and conversion loss are reduced, the green power consumption rate and the power supply quality are improved, the dependence on outsourcing power is reduced, and efficient, stable and low-carbon operation is realized.

The invention discloses a grid-connected inverter double-closed-loop control method based on a two-stage coupling expansion state observer, and belongs to the field of three-phase photovoltaic grid-connected inverters, and the method comprises the steps: building an inverter mathematical model, and determining that id is a control signal of stable DC bus voltage Udc; establishing a novel LADRC controller based on a two-stage coupling extended state observer; a high-performance double-closed-loop grid-connected control system is constructed based on an LADRC controller and a QPR controller, the LADRC controller acting on a voltage outer loop carries a two-stage coupling expansion state observer, more efficient suppression and compensation can be achieved aiming at interference components of different frequency bands, and the LADRC controller is matched with the QPR controller acting on a current inner loop, so that the high-performance double-closed-loop grid-connected control system is achieved. And the robustness and the stability of the grid-connected system controller are improved.

The invention relates to the field of low voltage ride-through control, and particularly discloses a wind power converter low voltage ride-through cooperative control method and system, which starts conventional LVRT response through a fault detection module, provides basic reactive power support and inhibits active power, and evaluates a power grid recovery state through a power grid recovery state evaluation module. Key indexes such as grid-connected point voltage recovery slope, frequency deviation and system short-circuit capacity are comprehensively analyzed, and a power grid recovery health degree index is quantitatively generated. Then, based on the index, a self-adaptive active power recovery slope is decided by combining local states such as a direct current bus voltage of the fan itself and the like. And finally, the active power recovery module smoothly recovers power output according to the adaptive slope. Through the mode, the power recovery behavior of the fan is tightly coupled with the real-time bearing capacity of the power grid, cooperative recovery control of low voltage ride through is realized, the stability of the power grid is ensured, and the efficiency and safety of power recovery are improved.

The invention discloses a silicon carbide power device junction temperature online accurate extraction method based on a double-sensor Kalman filtering weighted average algorithm, and the method comprises the following steps: 1, enabling a loss model of a power device to receive the phase current, the DC bus voltage, the duty ratio, the phase current and the DC bus voltage from an inverter; the on resistance of the SIC MOSFET, the reference direct current bus voltage, the on loss energy and the off loss energy under the on current and the on threshold voltage of the Schottky diode are obtained from a data manual of the chip, and the gate driving resistor is used for extracting the junction temperature and monitoring operation in real time; and step 2, obtaining an estimated junction temperature through loss calculation of a power device and a thermal network model, and weighting the junction temperatures estimated at different measurement points through a Kalman filtering weighted average algorithm to obtain a more accurate junction temperature for next iterative calculation. According to the method, the limitation of a traditional single sensor in a dynamic working environment can be effectively compensated, and the accuracy and the real-time performance of junction temperature monitoring are improved.

A DC microgrid has increased DC bus voltage inertia without adding large physical capacitors. A Virtual Inertia Enhancement Controller (VIEC) of a DC-DC converter emulates a DC machine's mechanical inertia characteristics through a virtual capacitor which compensates for a power imbalance causing DC bus voltage fluctuations. When a battery charges and generated photovoltaic (PV) power is more than the load power, VIEC controls the PV's DC-DC converter to the DC bus. When the battery discharges and generated PV power is less than load power, VIEC controls the battery's DC-DC converter to the DC bus. VIEC controls both the PV's DC-DC converter and battery's DC-DC converter to the DC bus when generated PV power is more than the load power and battery is fully charged. VIEC emulates an additional virtual capacitance in parallel with DC link capacitors. DC bus voltage fluctuations are significantly reduced by the VIEC emulating virtual capacitors.