105 results about "Dc link voltage" patented technology

The invention discloses a variable frequency motor load testing device and method, and relates to the technical field of variable frequency motor testing, and the device comprises a motor testing installation platform, a fastening T-shaped bolt, two variable frequency speed regulation asynchronous motors of the same model, a drum-shaped coupler, two inverters, a rectifier, a three-phase voltage regulator, a frequency converter and an intermediate DC link. According to the invention, two frequency conversion speed regulation asynchronous motors of the same model are coaxially connected, and the power generation electric energy of the accompanying test motor is fed back to an intermediate direct current link through an inverter, so that the cyclic utilization of the electric energy and the dual-motor structural design are realized, complex load equipment does not need to be configured, and the fixed asset investment is reduced; for motors of different models, only corresponding accompanying test motors need to be replaced, the universality is improved, through voltage and current monitoring in an intermediate direct current link and motor rotating speed and torque parameter collection, and by combining a multi-dimensional performance evaluation model, precise evaluation of the motor load performance is achieved, the test efficiency is improved, and the strict test requirements are met.

A power conversion apparatus includes: a rectifying unit that rectifies an AC voltage input from an AC power supply to convert the AC voltage into a DC link voltage; a capacitor that is charged with a DC link voltage converted by the rectifying unit; a power application unit that converts the DC link voltage with which the capacitor is charged into an AC voltage by switching the DC link voltage, and outputs the AC voltage to a motor; and a control unit that controls the power application unit. The control unit controls the power application unit such that a second beat is superimposed on a motor current, the second beat having a second frequency different from a first beat having a first frequency included in the motor current and having at least one of an amplitude or a phase aligned with the first beat.

A control system and a method for controlling a direct current (DC) link voltage of a hybrid energy storage system (HESS) includes a fractional-order proportional integral (FOPI) controller receives a voltage difference between the DC link voltage and a predetermined reference voltage and generate a reference charging current based on the voltage difference, a hysteresis controller receives a current difference between the reference charging current and a charging current of the HESS and generate a control signal based on the current difference, and a logic circuit receives the control signal and manage charging and discharging procedures of the HESS based on the control signal, so that the DC link voltage of the HESS is constant at the predetermined reference voltage, where the FOPI controller has parameters based on a metaheuristic technique.

The invention discloses a control method and device for a quasi-Z-source network inverter circuit, an inverter and a medium. The control method comprises the following steps: firstly, acquiring a direct-current chain voltage of a quasi-Z-source network, an instantaneous output power of an IPM module and an input voltage of an alternating-current power supply access module; determining an initial reference current according to the instantaneous output power and the input voltage; then, according to the direct-current chain voltage and a preset voltage threshold value, current correction is determined; then, sampling the input voltage to obtain voltage phase information, and correcting the initial reference current according to the voltage phase information and the current correction amount to obtain target reference current; according to the embodiment of the invention, a target reference current is generated, a PWM modulation signal is generated according to the target reference current, and an IPM module is driven according to the PWM modulation signal, so that the inductive current of a first inductor reaches the target reference current, and therefore, the power factor of the Z-source network inverter circuit can be effectively improved under the condition that an alternating current power supply is used as input.

The invention relates to the technical field of high-voltage direct-current power transmission, and discloses a surplus power consumption control method and device for an island new energy system, and the method comprises the steps: monitoring the output energy and direct-current link voltage of a transmitting-end converter station, and carrying out the control of the surplus power consumption when the island new energy system has an alternating-current fault; controlling the receiving-end converter station to perform optimal distribution of receiving-end current and dynamic adjustment of a direct-current voltage reference value so as to preferentially absorb surplus power, and further raising output energy and direct-current link voltage; when it is detected that the output energy meets the energy requirement and the direct-current link voltage meets the voltage requirement, the sending-end converter station is controlled to correct an energy reference value so that the sending-end converter station can consume surplus power through new energy, and after the alternating-current fault is removed, the sending-end converter station and the receiving-end converter station are controlled to perform sequential energy release so that the surplus power can be eliminated. When the energy consumption device is not used, the consumption control of the surplus power of the system is realized through cooperative inertia response and sequential energy release.

The present disclosure provides a power supply device for supplying, using a DC link voltage of a high-voltage unit of a semiconductor transformer, a control power to a transformer control unit for controlling the high-voltage unit, the power supply device comprising: a converter unit which includes a transformer unit and a switch connected in series to a primary side of the transformer unit, is connected to a DC link of the high-voltage unit, and is configured to convert the DC link voltage and output the converted DC link voltage to a transformer control unit; and a converter control unit configured to control on / off of the switch to convert the DC link voltage, wherein the converter unit comprises a first to a (n+1)th converter (wherein, n is an integer greater than or equal to 1) connected in series.

The invention discloses a grid-connected distributed photovoltaic inverter control method and system. The method comprises the following steps: selecting a first control object, and establishing a first controller based on the first control object; establishing a first equivalent control signal, and updating the first controller based on the first equivalent control signal to obtain a second controller; and controlling the grid-connected distributed photovoltaic inverter according to the second controller. Through the control method, the power grid operation state change when the voltage of the power grid drops can be effectively handled, and the stability and reliability of the grid-connected distributed photovoltaic inverter are improved. When the voltage of the power grid drops, the voltage of the direct current link capacitor is kept constant, so that the voltage of the direct current link can be prevented from exceeding the voltage limit of the capacitor, and the off-network phenomenon caused by triggering the protection device is avoided.

A system includes an observer configured to estimate passive components parameters based on digital twin, where the observer is designed based on a dynamic response difference between a physical system and the digital twin. The observer is configured to estimate a lumped disturbance vector (LDV) comprising one or more parameter changes, the one or more parameter changes are caused when i) a resistance variation changes a grid currents to DC link voltage ratio in the physical system; ii) DC side capacitors change a transient time of a DC link voltage, and / or iii) inductors change a transient time of grid currents.

The invention relates to the field of automatic sanding, and provides a hybrid power locomotive adhesion control method and system, and the method comprises the steps: obtaining locomotive data and a working condition of a locomotive; in response to an idling or sliding trend of the locomotive under the working condition, judging the locomotive data according to a preset comprehensive judgment condition, executing a corresponding power battery charging and discharging strategy, and performing an active adhesion suppression mode; according to a preset sanding judgment condition, a corresponding automatic sanding strategy is executed, and automatic sanding is activated or stopped; and in response to the condition that the idling or sliding trend of the locomotive under the working condition disappears and the traction force or the braking force is recovered, judging the locomotive data according to a preset range judgment condition, executing a corresponding power battery charging and discharging strategy, and exiting the idling or sliding inhibition mode. According to the method, stable and rapid adhesion control is realized by judging the charging and discharging power of the power battery in different scenes and considering the voltage of the intermediate direct-current link.

A pedal control device and method for a chainless electric bicycle are provided. A pedal control device includes a detector (10) configured to detect a DC link voltage, a pedal speed, and a wheel speed (S410, S510), and an adjuster (120) configured to adjust at least one of a pedal torque (S620, S630) and a wheel torque based on the pedal speed and the wheel speed (S410, S510), and configured to compare the detected DC link voltage with a target voltage (S610), and further adjust at least one of the pedal torque (S620, S630) and the wheel torque based on a voltage comparison result (S420).

An energy transfer system for wireless energy transfer includes a transmitter unit having a primary coil supplied with a supply voltage and a receiver unit separate from the transmitter unit having a secondary coil to which a DC link capacitor is connected by a rectifier. The energy transfer system further includes a first device configured to determine a value of a DC link voltage applied on the DC link capacitor when the supply voltage is applied on the primary coil, and a second device configured to perform at least one function based on the determined value of the DC link voltage or a variable derived therefrom. A receiver unit is configured to interact for wireless energy transfer with a transmitter unit separate from the receiver unit.

An uninterruptible power supply device (100) comprises: a converter (4) that converts AC power supplied from an AC power supply (12) to DC power; an inverter (8) that converts the DC power to AC power and supplies the converted AC power to a load (14); a DC link (5) connected between the converter (4) and the inverter (8); and a bidirectional chopper (7) that performs DC voltage conversion between the DC link (5) and an energy storage device (13). The bidirectional chopper (7) executes a charging operation of storing DC power at the DC link (5) in the energy storage device (13) when the AC power supply (12) is healthy. When executing the charging operation in a situation where an end-of-charge voltage of the energy storage device (13) is higher than a DC link voltage of the DC link (5) and an end-of-discharge voltage of the energy storage device (13) is lower than the DC link voltage, the bidirectional chopper (7) switches between a first buck operation for bucking the DC link voltage and a first boost operation for boosting the DC link voltage, depending on the voltage of the energy storage device (13).

A control system (200) for a switched reluctance (SR) motor (206), the control system (200) comprising: a direct current source (202); a power converter (204) coupled on its input side to the DC power source (202) and coupled on its output side to the SR motor (206), wherein the power converter (204), which operates primarily as an inverter, is configured to receive DC voltage (DC) from the DC power source (202) and to supply AC current (AC) to the SR motor (206); a user interface configured to enable an operator to specify a desired torque output and generate signals indicative of the desired torque output; a controller (216) communicatively coupled to the SR motor (206), the DC power source (202), the power converter (204), and the user interface, the controller (216) being configured to converting a direct current from the alternating current supplied to the SR motor (206) from the power converter (204); to estimate the actual power output of the SR motor (206) based on at least the DC voltage and the converted DC current; to determine the speed of the SR motor (206); to estimate the actual torque output based on the actual power output and the speed of the SR motor (206); receive the signals indicating the desired torque output from the user interface; compare the actual torque output and the desired torque output to determine the torque deviation; to set the torque output limit based on the determined torque deviation and adjust the speed of the SR motor (206) based on the set torque output limit.

An image display apparatus is disclosed. The image display apparatus according to an embodiment of the present disclosure includes: a display; and a power supply to supply a driving voltage to the display, wherein the power supply includes: an AC / DC converter comprising at least one switching device and configured to convert an input AC voltage into a DC voltage and output the DC voltage to a dc link; a dc link capacitor disposed at the dc link; an input voltage detector to detect the input AC voltage; a dc link voltage detector to detect a dc link voltage; and a controller to control the AC / DC converter, wherein in response to the detected input AC voltage exceeding a first reference value and the detected dc link voltage being lower than or equal to a second reference value lower than the first reference value, the controller is configured to turn off the switching device in the AC / DC converter. Accordingly, burnout of the dc link capacitor may be prevented.

This invention relates to a voltage limiting control method for a series-type offshore wind power DC collector system, comprising: superimposing a low-voltage DC link voltage control loop on the power control loop of the wind turbine generator-side converter, and obtaining a reference value for the d-axis component of the generator-side converter voltage. umsd_ref and q-axis component reference value umsq_ref The control signal for the generator-side converter is generated through sinusoidal pulse width modulation to maintain stable low-voltage DC link voltage while ensuring stable power output. The grid-side converter of the wind turbine adopts voltage / frequency control to obtain the d-axis reference value of the grid-side converter output voltage. uod _ ref and q-axis reference value uoq _ ref The grid-side converter control signal is generated by sinusoidal pulse width modulation. By setting the d-axis setpoint of the grid-side converter output voltage, the AC output voltage of the grid-side converter is limited, thereby controlling the DC output voltage of the wind turbine generator within the limit value.

A system may include a power component, the power component including at least one device processor configured to: obtain load data, wherein the load data comprises a power characteristic associated with at least one of a high-load element or a low-load element, obtain a trained power management artificial intelligence (AI) and / or machine learning (ML) model, based at least on the load data and the trained power management Al and / or ML model, infer a direct current (DC) link voltage adjustment, wherein the DC link voltage adjustment is correlated with a predicted load cycle parameter; and cause the power component to alter a DC link voltage from an initial level to an adjusted level based on the DC link voltage adjustment.

A method (100) for determining optimized operating point control parameters for controlling an inductive transformer (1) with a buck converter (12) and bridge circuit (13) for driving a rotor (40) of a separately excited electrical machine is disclosed, comprising: acquiring transmission powers (110) of the inductive transformer (1); acquiring temperatures (110) of a transformer (30) of the inductive transformer (1); acquiring cooling temperatures (110) of at least one power semiconductor element of the buck converter (12) and / or at least one power semiconductor element of the bridge circuit (13); acquiring primary DC link voltages (110) of the inductive transformer (1); determining an operating characteristic map (120) of the inductive transformer using the transmission power, the temperatures, the cooling temperatures and the primary DC link voltages;Determining a minimum operating point control parameter and a maximum operating point control parameter (130) using the operating characteristic map corresponding to an operating point to provide a required transmission power of the inductive transformer (1); determining a total power loss (140) of the inductive transformer (1) using the operating characteristic map corresponding to the operating point; and determining the optimized operating point control parameter (150) for the operating point at which the total power loss is minimized, using the minimum operating point control parameter and the maximum operating point control parameter.

To operate a turbine type flow volume control device in a stable manner at an early stage even when a state in which a flow volume of a fluid is low occurs.SOLUTION: A main circuit 91 of a turbine type flow volume control device 10 recovers a regenerative electric power generated by a rotation of a turbine 31 of a generator 30, and controls a rotation of the turbine 31 by inputting an electric power to the generator 30. The main circuit 91 includes a DC link capacitor 91A and outputs the regenerative power according to a DC link voltage Vm. Circuits 92A to 92E control the operation of the main circuit 91 and operate by the regenerative power output from the main circuit 91. When the DC link voltage Vm is lower than Vm2, a first power supply part 95C supplies a power stored in a first power storage unit 95B to the main circuit 91 to charge the DC link capacitor 91A. A second power supply part 96D operates the circuits 92A to 92E by supplying the power stored in a second power storage part 96B to the circuits 92A to 92E when the DC link voltage Vm is lower than Vm2.SELECTED DRAWING: Figure 2

The invention discloses an open winding motor power decoupling control device and method based on a Z-source inverter, and relates to the technical field of motor control. The control device is controlled by a power supply hybrid open winding motor; the method comprises three core links: 1, direct-current chain voltage closed-loop control with a reference value updating link, wherein the amplitude of a direct-current chain can be dynamically stabilized only by sampling capacitor voltage; according to the Z-source inverter modulation strategy, specific switch switching points are calculated for different sectors, and harmonic interference introduced by straight-through vectors is restrained; and 3, separating active and reactive voltage components based on a power decoupling algorithm of vector coordinate operation to realize power distribution. According to the invention, the complexity of a control algorithm is simplified, the feedback input quantity is reduced, and the anti-interference capability and the operation stability of the system are improved.

Techniques are described to continuously calculate an inverter DC power of a synchronous machine, e.g., motor or generator, based on the individual phase currents, DC link voltage, and gate signals, which can be compared against the commanded mechanical power based of the estimated rotor speed and commanded torque. A controller can determine whether to shut down the inverter, such as the pulse width modulation (PWM), if the DC power is greater than a threshold value. Such a threshold can be defined to allow an acceptable position and speed estimation error margin.

This power conversion device comprises: a chopper that has a switching element, and bidirectionally converts a battery voltage and a DC link voltage using the switching element; an inverter that bidirectionally converts the DC link voltage and an AC voltage; and a control device that controls the inverter and the chopper. The control device can select, as an operating mode for controlling the chopper, one of a first mode in which the DC link voltage is controlled in accordance with a voltage command value by turning on / off the switching element, and a second mode in which the switching element is always in an on state. The control device reduces the voltage command value when the operating mode is shifted from the first mode to the second mode.

The invention discloses a control method, device and equipment for an energy storage converter of an electric vehicle charging station and a medium, and the method comprises the steps: measuring reactive power and actual voltage through a voltage regulation module, and obtaining reference voltage; inputting the reference voltage into an inertia control module, and determining a reference frequency through the inertia control module based on Q-V droop control; the reference voltage and the reference frequency are sent to a double-layer current and voltage inner loop controller, and the output voltage is determined through the double-layer current and voltage inner loop controller; the output voltage is input into a DC / DC module, a battery charging and discharging instruction is determined through the DC / DC module based on P-f droop control, and the two-stage electric vehicle charging station energy storage converter is controlled through the battery charging and discharging instruction. According to the invention, Q-V droop control is utilized by the inertia control module, the output frequency is adjusted according to the deviation of the DC link voltage, and a power grid is supported through capacitance inertia in a network construction mode; and the DC / DC module detects the DC link voltage deviation, and the voltage proportion controller realizes P-f droop control to ensure that the DC link voltage is adjusted within an allowable safety range, so that the energy storage converter can adjust energy storage and energy release in time when the power demand changes, and the energy storage efficiency is improved. And instability and unreliability of power supply are improved.

The present invention pertains to a power electronic converter, such as an inverter or converter, for an electric application such as a motor drive, electrolyzer or charger. The power electronic converter includes a DC link and an active front end (AFE) connected to grid via a filter and a grid board with a first inrush relay with a resistive device. The resistive device may be a resistor, more specifically an NTC resistor or a PTC thermistor. The grid board further includes a second inrush relay, wherein at least one of the inrush relays is controlled to engage or disengage during startup phase of the power electronic converter and during abnormal grid voltage conditions, such that the DC link is charged via the resistive device or by bypassing the resistive device, and such that the AFE is provided for boosting the DC link voltage to a save level and under controlled conditions. The invention also pertains to an electric motor drive according and a method for operating a power electronic converter.

The invention relates to a method for controlling wind turbine transients. The wind turbine generator includes a power converter including a machine-side converter and a line-side converter and a DC link. A grid voltage reference for controlling the line-side converter is determined, and the power (PLsc) supplied to the grid is controlled by the line-side converter using a grid formation controller. The machine-side converter and the generator are controlled according to the power reference (PMsc). An error between the measured DC link voltage value and a DC link reference value is determined, and a voltage correction component is derived in response to the error signal. The voltage correction component is added to an output voltage of the grid formation control, and the line-side converter is operated according to the combined output voltage.

The invention relates to a two-stage grid-connected converter DC voltage stabilization coordination control method, which comprises the steps of initializing an adaptive filtering algorithm and a PI controller, sampling or reconstructing voltages and currents at two ends of an LC filter, and calculating a prediction coefficient matrix so as to obtain prediction values of an inductive current and a capacitor voltage. And calculating the output power of the DAB converter by using the predicted values, and obtaining the compensation amount of the phase shift ratio between the bridges through a feed-forward coefficient. Meanwhile, PI control is carried out on the intermediate direct-current link voltage to obtain a DAB converter inter-bridge shift ratio, and the DAB converter inter-bridge shift ratio and the compensation amount are added to obtain a final inter-bridge shift ratio. And in combination with an in-bridge phase shift ratio obtained by an inductive current stress optimization method, eight switching tubes of the DAB converter are controlled through an expansion phase shift method, so that quick response of output power and voltage stability of an intermediate direct-current link are realized. According to the method, the minimum mean square error adaptive filtering algorithm is introduced, so that the prediction precision and the response speed are improved, and the system stability is ensured.

Systems and apparatuses include one or more processing circuits comprising one or more memory devices coupled to one or more processors, the one or more memory devices configured to store instructions thereon that, when executed by the one or more processors, cause the one or more processors to: determine a pantograph bounce event based on an input voltage and an input voltage frequency; automatically disable a rectifier in response to determining the pantograph bounce event; record an instant DC link voltage at the time the rectifier is disabled; and set a reference DC voltage to the instant DC link voltage.

This improves the efficiency of the power converter while suppressing shocks and unstable operation during mode switching. [Solution] The power converter 1 has switching elements 41 and 42, and uses these switching elements to convert the battery voltage V BAT and DC link voltage V DC A chopper 4 that converts the voltage bidirectionally, and a DC link voltage V DC The system includes an inverter 5 that converts AC voltage bidirectionally, and a control device 8 that controls the inverter 5 and the chopper 4. The control device 8 controls the DC link voltage V by switching elements 41 and 42 on and off as an operating mode for controlling the chopper 4. DC The voltage command value V DCref It is possible to select either SW mode, which controls according to the voltage, or TH mode, which keeps the switching element 41 in a constantly ON state, and when the operation mode of the chopper 4 is switched from SW mode to TH mode, the voltage command value V DCref Reduce.

The invention relates to a method for operating power electronics (1), in particular of an inverter or rectifier, the at least one half bridge (2) having two semiconductor switches (3, 4) connected in series, and at least one DC link capacitor (6) connected in parallel to the series connection of semiconductor switches (3, 4) wherein, to perform a discharging operation for electrically discharging the at least one DC link capacitor (6), the two semiconductor switches (3, 4) are activated to generate a plurality of discharge pulses such that they are simultaneously switched to conductive for each discharge pulse for a predetermined duration (ton), characterized in that in that the semiconductor switches (3,4) are activated as a function of an electrical DC link voltage of the power electronics (1) applied to the DC link capacitor (6), such that the pulse energy (E) of the discharge pulses of the discharging process is equal or nearly equal.

This motor drive device comprises: an inverter composed of a three-phase bridge circuit in which a switching element is provided to each of an upper arm and a lower arm in each of three phases; a smoothing capacitor provided to the DC-input side of the inverter; a dynamic brake circuit that closes a switch provided between the input terminals of the motor and short-circuits the input terminals via a dynamic brake resistor, thereby braking the motor; an inverter control unit that controls the on / off operation of the switching element; and a dynamic brake control unit that controls the opening / closing of the switch. The motor drive device closes the switch of the dynamic brake circuit and turns on only a switching element of the upper arm in one phase or two phases within the inverter and a switching element of the lower arm in the two phases or the one phase other than the aforementioned one phase or the aforementioned two phases, thereby discharging DC power of the smoothing capacitor.

Techniques are described to continuously calculate an inverter DC power of a synchronous machine, e.g., motor or generator, based on the individual phase currents, DC link voltage, and gate signals, which can be compared against the commanded mechanical power based of the estimated rotor speed and commanded torque. A controller can determine whether to shut down the inverter, such as the pulse width modulation (PWM), if the DC power is greater than a threshold value. Such a threshold can be defined to allow an acceptable position and speed estimation error margin.