70 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 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.

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 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.

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.

The present invention 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 relates to a drive system (1, 1') for operating a traction motor (6) of an electric vehicle, comprising; - a vehicle battery (2), - an intermediate circuit capacitor (3) in an intermediate circuit connected to the vehicle battery (2) so that an intermediate circuit voltage (U dc ) essentially the battery voltage (U Bat ) corresponds to the vehicle battery (2); - a charging circuit (7) with a supply DC / DC converter (73) configured to convert a supply DC voltage (U) buffered in a supply capacitor (72) HV ) to convert into the intermediate circuit voltage, wherein the supply DC / DC converter (73) is designed for bidirectional operation; - a power driver (4) designed to operate the traction motor (6) with electrical energy from the intermediate circuit; - a control unit (10) designed to operate the supply DC / DC converter (73) in reverse in the event of an overvoltage in the intermediate circuit, so that electrical energy is discharged from the intermediate circuit into the supply capacitor (72) and thus the intermediate circuit voltage (U) dc ) is reduced.

The present application provides a kind of motor driving device (1), with: converter (11), which converts alternating current power of alternating current input side into direct current power, and the direct current power is output to DC link;Inverter (12), it is controlled to be connected and disconnected to the switching element arranged in upper arm and lower arm, to convert the direct current power of DC link into alternating current power for driving motor;DC link voltage detection unit (13), it detects DC link voltage;DC link voltage determination unit (14), it determines whether DC link voltage exceeds voltage threshold value;Alarm signal output unit (15), it outputs alarm signal when abnormal;And switch control unit (16), it is controlled to be connected and disconnected to the switching element, wherein, in the case where alarm signal is output from alarm signal output unit (15) and DC link voltage exceeds voltage threshold value, switch control unit (16) is controlled to connect all switching elements of lower arm.

Method for controlling a battery system that includes a battery with at least one string of battery modules connected in series. Each battery module including a number of battery cells connected in parallel and / or in series. At least a number of battery modules including a power electronics unit connected in series via their respective power electronics unit. The power electronics unit having a DCDC converter operable at least in buck mode, boost mode, and bypass mode. The method includes specifying a DC link voltage for the battery; specifying a first distribution of the set DC link voltage for all modules; determining a state of charge and / or a temperature for all modules; determining a deviation of the state of charge and / or of the temperature of each module from an average value; specifying a second distribution of the set DC link voltage. The set voltage for each module is corrected depending on deviation of state of charge and / or of temperature of each module from the average value.

Techniques for implementing an adaptive DC link voltage regulation scheme are described. By adopting an adaptive approach to DC link voltage regulation, such as where the DC link voltage is set as a scaling factor multiplied by the battery voltage, the techniques significantly reduce the switching losses and heat present in conventional two-stage power converters. The techniques use a control system that dynamically adjusts the DC link voltage in real-time, in response to variations in the battery's voltage during the charging cycle. This adaptive regulation of the DC link voltage not only minimizes the heat generated due to switching losses but also optimizes the charging process to suit the requirements of the battery.

A charging device, in particular for supplying electrical energy to at least a first energy storage unit and a second energy storage unit, comprises a control device and a mains connection for connecting to a mains power supply. The charging device comprises a rectifier, a power factor correction filter, a preset device with an isolated DC-DC converter and a capacitor for generating an isolated DC link voltage, wherein the preset device comprises at least a first interface and a second interface, wherein each adapter device comprises an adapter interface for connecting to the at least first interface or second interface of the preset device, and wherein each adapter device comprises a fine tuning device with an interface means for connecting to an energy storage unit, and wherein each fine tuning device comprises an adjusted and non-isolated DC-DC converter, so that a power value can be provided at the first interface means and / or the second interface means, and wherein the power value at the first interface means and / or the second interface means corresponds to at least a portion of the total power.

The invention relates to a method of operating an inverter, a controller, a computer program and an inverter system. The inverter (20) comprises a DC link having a DC link capacitor (26), and the inverter is configured for converting a three-phase AC voltage generated by the generator into a DC link voltage to be applied to the DC link capacitor (26). The method comprises: receiving a power reference value representative of power to be provided by the generator; determining an estimated mechanical frequency of the generator; determining a harmonic component of the estimated mechanical frequency; determining a torque reference value from the power reference value and the determined harmonic component, wherein the torque reference value represents a torque to be generated by the generator; generating a switching signal for the inverter according to the determined torque reference value; and operating the inverter by providing the switching signal to the inverter.

This motor drive device comprises: a converter that selectively executes a rectification operation for converting AC power inputted from an AC power supply to DC power and outputting the DC power to a DC link, and a regeneration operation for converting the DC power of the DC link to AC power and returning the AC power to the AC power supply when a DC link voltage exceeds a regeneration start voltage; an inverter that, in accordance with a motor drive command, selectively executes an active drive operation for converting the DC power of the DC link to AC drive power and supplying the AC drive power to a motor, and a regeneration operation for converting AC regenerative power from the motor to DC power and returning the DC power to the DC link; and a converter control unit that controls the operation of the converter. The converter control unit changes the regeneration start voltage in accordance with information related to the motor drive command.

Provided is an electrolyser plant that includes a first DC link with a DC link capacitor and an AC / DC power converter and an electrolyser electrically connected to the first DC link to receive a load current. During normal operation of an AC power network, a controller maintains a pre-event DC link voltage and supplies a pre-event load current to the electrolyser and in response to a detected low voltage event, the controller initially supplies the pre-event load current to the electrolyser to maintain normal operation of the electrolyser, monitors the DC link voltage, and when the monitored DC link voltage falls below a first voltage threshold less than the pre-event DC link voltage, reduces the load current supplied to the electrolyser, by ramping down the load current at a suitable ramp rate.

A power converter system is provided and includes a power converter having a first converter that includes at least a controllable semiconductor switch having a threshold voltage and a gate voltage for normal on-state conduction, DC terminals connected to a DC link, and AC terminals, a controller of the system supplies current to the first converter for short circuiting by controlling the switches to create a short circuit path through the converter that carries the current. At least one switch in a short circuit path is operated with modified on-state conduction to increase conduction losses by applying a modified gate voltage less than the gate voltage for normal on-state conduction, the modified gate voltage equals the threshold voltage plus x volts, where x ranges from 100 mV to 4 V, and when the converter is short-circuited, the DC link voltage is less than that during a normal switching operation.

The invention relates to a method for braking a power tool, which is a battery-operated power tool and can be connected to at least one first power supply and a second power supply so as to be supplied with electrical energy. The electric energy released when the power tool is braked is fed back to the first power supply device and / or the second power supply device of the power tool. The power supplies are connected in series, and the method may include actively controlling the DC link voltage, where a limit value UZwitchenkreis, Limit of the DC link voltage is less than the sum of limit values UAkkuppack, Limit of the voltages of the power supplies. In a second aspect, the invention relates to a power tool for performing the braking method.