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.

The invention discloses a DC bus voltage stabilization control method for a micro-grid system. The DC bus voltage stabilization control method comprises the steps of: constructing DC micro-grid models in an energy storage system charging mode and an energy storage system discharging mode based on structural characteristics and operating characteristics of a DC micro9-grid; acquiring mixed potential function models in the charging mode and the discharging mode according to the DC micro-grid models; carrying out voltage stabilization analysis on the mixed potential function models to obtain voltage stabilization control design criteria corresponding to the charging mode and the discharging mode; and setting voltage controller parameters of corresponding convertors according to the obtained voltage stabilization control design criteria, so that the micro-grid system operates in a voltage-stabilized manner. The DC bus voltage stabilization control method for the micro-grid system can ensure that the bus voltage in the DC micro-grid system is always in a stable operating state, and improve the safety performance of system operation.

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.

Provided is an iLLC resonant converter, comprising two LLC resonant converters, a digital controller and two switch control inductors. Power transformers of the two LLC resonant converters are respectively provided with an auxiliary winding, the two switch control inductors are respectively connected in parallel to the auxiliary windings, the parameters and structures of the two LLC resonant converters are the same, input ends of the two LLC resonant converters are connected in parallel, and output ends thereof are also connected in parallel, and the parameters and structures of the two switch control inductors are the same. According to the resonant converter provided in the present invention, the respective output currents and common input voltage of two LLC resonant converters are sampled by means of a digital controller, the phase angle of switch control inductors is adjusted through operation to realize current sharing of a resonant cavity, and the direct-current voltage gain of the resonant cavity can be adjusted according to the voltage of a direct-current bus during input power-down, thereby prolonging the power-down hold-up time of the 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 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 relates to a control method of a single-phase single-stage boost inverter, comprising: obtaining the DC bus voltage, adjusting the frequency of a unipolar triangular carrier signal through a DC bus voltage PI controller to realize the regulation of the DC bus voltage; obtaining the output Voltage, the output waveform and amplitude control are realized through the output voltage PI controller. Compared with the existing method, the method provided by the present invention effectively avoids the large-scale adjustment of the boost duty of the single-phase single-stage boost inverter under the traditional PWM+SPWM modulation mode by changing the control degree of freedom of the system. The output waveform distortion problem caused by the empty ratio is more practical.

The invention relates to a direct current microgrid technology, in particular to a power distribution control method of a direct current microgrid. The direct-current microgrid comprises n direct current power supplies, wherein each direct current power supply is connected with a direct current bus through a DC-DC converter by a connecting wire, and a load is connected to the direct-current bus. The power distribution control method comprises the following steps of: setting a direct current bus voltage controller and a DC-DC converter controller, taking the error of a reference value and the measured value of the direct current bus voltage as the input of the direct current bus voltage controller, taking the output of the direct current bus voltage controller as a compensation voltage, transmitting a compensation voltage to each DC-DC converter through a communication channel, adding the compensation voltage to a droop control equation of the DC-DC converter controller, and compensating the cycle-by-cycle deviation of power distribution to eliminate the output voltage drop caused by droop control. The method simultaneously achieves power distribution and direct current bus voltageregulation, and has the advantages of the simple achievement, reservation of the plug and play characteristic of the microgrid and the like.

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.