30 results about "Dc bus voltage regulation" patented technology

An integrated circuit controls a power converter that includes single stage buck-boost converter and a switching full bridge that may be used to drive an HID lamp. The single stage buck-boost converter reduces the complexity and parts count of the power converter, or electronic ballast, while permitting PFC and DC bus voltage regulation under control of the integrated circuit to maintain constant power on the HID lamp. The integrated circuit simplifies the design of power converters and electronic ballasts in particular, while reducing part count, complexity and cost in conjunction with the single stage buck-boost converter and the full bridge switching circuit.

An integrated circuit controls a power converter that includes single stage buck-boost converter and a switching full bridge that may be used to drive an HID lamp. The single stage buck-boost converter reduces the complexity and parts count of the power converter, or electronic ballast, while permitting PFC and DC bus voltage regulation under control of the integrated circuit. The integrated circuit also provides all the drive signals to operate the switching full bridge circuit to maintain constant power on the HID lamp. A wait timer provides an interval of time between restart attempts for the HID lamp to permit the lamp to cool so that high hot restart voltages are avoided. The integrated circuit simplifies the design of power converters and electronic ballasts in particular, while contributing to reducing part count, complexity and cost in conjunction with the single stage buck-boost converter.

The invention discloses a DC bus voltage adjusting and MPPT unified control system and method of a photovoltaic microgrid, for the purposes of realizing unified control of MPPT control and DC bus voltage adjustment of a photovoltaic grid-connected inverter, improving the photovoltaic grid-connected efficiency and decreasing the operation cost of a photovoltaic microgrid system. According to the invention, unified control of the DC bus voltage adjustment and MPPT of the photovoltaic grid-connected inverter free from a DC/DC link and an energy storage apparatus comprising a DC/DC link under the condition of a common DC bus can be realized, the grid-connected efficiency of the photovoltaic inverter is improved, and the system and method provided by the invention is applied to the field of the photovoltaic microgrid.

The invention discloses a grid-connected photovoltaic inverter device and a control method for improving conversion efficiency thereof and belongs to the field of inverter control. The device comprises N grid-connected photovoltaic inverters, wherein a voltage outer loop control circuit (3) of each grid-connected photovoltaic inverter comprises a bus voltage sampling circuit (301), first and second bus voltage regulators (302 and 303), first and second amplitude limiting circuits (304 and 305) and three voltage loops. The control method comprises that: given voltage in different grades is respectively set for the bus voltage regulators of the plurality of grid-connected inverters; along with the increase of the input power, the inverters work in turn according to the given voltage, and the light load efficiency is improved by reducing the number of the operating inverters under the condition of light load; and different set values and output amplitude limiting values are applied to a linear bus voltage regulator of a single grid-connected inverter so as to ensure that the inverters can operate at the highest efficiency preferentially under different power grades, and the overall efficiency of the system is improved.

The invention provides an iLLC resonant converter. The iLLC resonant converter comprises two LLC resonant converters, a digital controller and two switch control inductors. The power transformers of the two LLC resonant converters are respectively provided with an auxiliary winding, wherein the two switch control inductors are respectively connected with the auxiliary winding in parallel, the parameters and the structure of the two LLC resonant converters are the same, the input ends of the two LLC resonant converters are connected in parallel, the output ends of the two LLC resonant converters are also connected in parallel, and the parameters and the structure of the two switch control inductors are the same. According to the resonant converter provided by the invention, respective output current and common input voltage of the two LLC resonant converters are sampled through the digital controller. The phase angle of the inductor is controlled by the operation adjusting switch to realize current sharing of the resonant cavity current, the direct current voltage gain of the resonant cavity can be adjusted according to the direct current bus voltage during input power failure, andthe power failure maintenance time of the converter is prolonged.

The invention discloses a multi-objective collaborative optimization control method applied to a direct-current three-level converter. The neutral-point voltage fluctuation can be suppressed while thevoltage regulation precision of a direct-current bus can be improved. The method comprises the following steps: 1, flexibly adjusting input power to meet the requirement of multi-port energy storage;2, controlling the voltage of an output-side direct-current bus to be stable; and 3, carrying out voltage-sharing control on the voltage-dividing capacitor at the output side. The method is a multi-objective collaborative optimization control method and is suitable for a direct-current microgrid system containing a direct-current three-level converter.

The invention discloses an LED driving circuit and a dimming control method thereof. The driving circuit is connected with a dimmer so as to acquire an AC input voltage through chopping and is connected with an LED to control a load current passing through the LED. The driving circuit comprises a current control circuit, wherein the current control circuit is used for controlling the load circuitpassing through the LED and adjusting continuous time of the load current in a half-power frequency period according to a DC bus voltage so as to achieve dimming, the current control circuit is used for acquiring a conduction angle range of the dimmer according to a detection value of the load current and selectively works in one of an open-loop mode and a closed-loop mode, the current control circuit is used for maintaining the load current at a reference current in the open-loop mode, and the current control circuit is used for adjusting the load current according to the negative feedback ofthe DC bus voltage in the closed-loop mode. The conduction state of a transistor is controlled according to different modes by the LED driving circuit with regard to different conduction angles of silicon-controlled rectifier in the dimmer, dimming brightness stability can be compatible, and the response speed is adjusted.

The invention relates to a direct-current micro-grid voltage regulation system and particularly relates to a direct-current micro-grid secondary voltage regulation system and a control method thereof, aiming at the solving the problem that voltage of a direct-current bus cannot be regulated to a rated value by a traditional direct-current micro-grid droop voltage regulation system. The direct-current micro-grid voltage regulation system comprises a vanadium battery energy storage system and a voltage regulation controller, wherein the vanadium battery energy storage system comprises a vanadium battery, a bidirectional DC/DC (Direct Current/Direct Current) converter and a vanadium battery detector; the vanadium battery is connected with the direct-current bus through the bidirectional DC/DC converter; the vanadium battery detector is connected with the vanadium battery; and the voltage regulation controller is connected with the direct-current bus, the vanadium battery detector, the bidirectional DC/DC converter in the vanadium battery energy storage system, a second bidirectional DC/DC converter in a mixed energy storage system, and a bidirectional DC/AC (Direct Current/Alternating Current) converter in a connected-grid system. The direct-current micro-grid secondary voltage regulation system is suitable for direct-current micro-grids.

The invention discloses a secondary voltage regulation method suitable for a DC microgrid. The method comprises the following steps: determining a DC bus voltage regulation amount to be undertaken byeach power unit according to a DC bus voltage offset and a voltage regulation coefficient; updating the voltage reference value of droop control through the DC bus voltage regulation amount and the voltage sensitivity of each unit so as to quickly and accurately restore the DC bus voltage to the target value; and setting the current distribution coefficient on the basis according to the system operation requirements and redistributing the load among micro-sources so that the output current of each converter meets the operation requirements. The technical scheme can realize accurate control ofthe DC bus voltage; the load distribution can be performed according to the system operation requirements and the distribution result is not limited by the matching degree of line impedance and droopcoefficient and thus the flexibility of microgrid system operation can be improved; meanwhile, the droop coefficient is allowed to be adjusted within a large range, thus improving the stability of themicrogrid system operation.

The invention relates to a grid-side current balancing control method of a unified power quality conditioner. The method comprises: a three-phase grid voltage, a load voltage, a load current are converted from a three-phase ABC alternating-current coordinate system to a two-phase dq rotation coordinate system and phase information needed by coordinate conversion is obtained by phase locking of a grid voltage; after coordinate conversion, alternating-current components and direct-current components of the grid voltage, the load voltage, and the load current are obtained, and after processing by a low-pass filter, alternating-current components in variables are filtered; according to the filtered direct-current components, a grid-side current fundamental current amplitude is calculated; and the grid-side current fundamental current amplitude and a direct-current bus voltage adjustment result are superposed to obtain a three-phase grid-side reference current amplitude. With the method provided by the invention, the grid-side three-phase current balancing degree can be reduced; the direct-current bus voltage fluctuation can be reduced; the dynamic response speed of the system can be increased; and defects of poor steady-state control effect and slow dynamic response speed of the direct-current bus voltage loop can be overcome.

The invention discloses a bus capacitor pre-charging circuit and method, a frequency converter and air conditioning equipment. The circuit comprises a charging module and a controller, wherein the input end of the charging module is connected with an alternating-current power supply, the output end is connected with a direct-current bus, and the charging module is used for outputting changed current; the input end of the controller is connected with a direct-current bus, the output end of the controller is connected with the charging module, and the controller is used for adjusting current output by the charging module according to the voltage of the direct-current bus. According to the invention, the charging current can be flexibly adjusted, the situation that a cement resistor is burntdown due to overlarge current caused by the fact that direct-current voltage is completely applied to the two ends of the cement resistor at the power-on moment is avoided, and the safety is improved.

A DSVG double-loop control method provided by the invention comprises: a direct current bus voltage regulation is taken as a voltage outer ring, and a regulator output and the load current are taken as a current inner ring, and after the given voltage outer ring and current inner ring is compared to the current feedback, driving signals are generated through the regulator. The DSVG double-loop control method can provide energy and rapidly track the load current, ensure the stable output of the direct current bus voltage and improve the current and voltage waveform.

The invention discloses a motor driving system based on a bidirectional interleaved DC-DC inverter. According to the system, a bus voltage loop is additionally arranged on the basis of a current loopsum. The motor driving system comprises an acquisition module, a voltage loop controller and a direct-current bus voltage regulator, and is characterized in that the bus voltage acquisition module acquires a direct-current bus voltage Uout of a permanent magnet synchronous motor; the voltage loop controller extracts a rotating speed acquisition value of the permanent magnet synchronous motor froma speed loop, subtracts the rotating speed acquisition value from a given rotating speed, and inputs a difference value into a voltage control model; the voltage control model generates a bus voltagecontrol target Uref by taking the minimum total harmonic distortion rate THD as a target, and outputs the bus voltage control target Uref to the direct-current bus voltage regulator; the direct-current bus voltage regulator generates control signals of four switching devices in an inverter by taking the difference value of Uref and Uout as 0 as a control target; and the inverter generates dynamically regulated bus voltage and applies the bus voltage to a power driving module to drive the permanent magnet synchronous motor. According to the invention, the current ripple torque can be reduced, and the precision and stability of low-speed operation of the motor are improved.

The invention discloses a brushless doubly-fed power generation system, and belongs to the field of motor power generation. The system comprises a brushless doubly-fed generator including a power winding and a control winding, an AC-DC-AC frequency converter, an uncontrolled rectification module and an inversion module, wherein the AC-DC-AC frequency converter is connected with the control winding and is used for establishing and maintaining an initial DC bus voltage and adjusting a frequency and a voltage of the control winding; the frequency of the power winding is kept constant under the condition of a variable rotating speed, and the power distribution relation between the control winding and the power winding is adjusted when the capacity of the power winding is insufficient; the uncontrolled rectification module is connected with the power winding and used for rectifying the three-phase alternating current generated by the power winding into a target direct current bus voltage; and the inversion module is connected with the uncontrolled rectification module and is used for inverting the target direct current bus voltage into three-phase alternating current meeting a power utilization quality standard so as to supply power to a connected load or be connected with a main power grid for grid-connected power supply. According to the invention, the DC bus voltage can be kept stable, the dynamic response capability of the system is improved, the complexity of the system is simplified, and the debugging time is shortened.

The invention provides a power grid side voltage fluctuation suppression system and method and a storage medium. The power grid side voltage fluctuation suppression system comprises a voltage acquisition module, a voltage phase locking module, a current acquisition module, a coordinate transformation module, a DC voltage acquisition module, a DC bus voltage regulation module, an active current regulation module, a reactive current given value calculation module, a reactive current regulation module, an inverse coordinate transformation module and a PWM modulation module. According to the power grid side voltage fluctuation suppression system and method and the storage medium, the fluctuation of the power grid side voltage during the temperature rise test of the asynchronous motor can be suppressed, and other loads powered by the power grid are effectively prevented from being damaged.