61 results about "Single phase converter" patented technology

Disclosed is a controller of a grid coupled type doubly-fed induction generator having a multi-level converter topology, which can control the doubly-fed induction generator having a high voltage specification and can perform a fault ride-through function, an anti-islanding function and a grid voltage synchronization function required for a dispersed power generation facility. The controller makes a H-bridge multi-level converter generate a three-phase voltage waveform resulted from the structure that single-phase converters each being composed of a 2-leg IGBT are stacked in a serial manner, and controls a rotor current so as to make the rotor coil of the doubly-fed induction generator in charge of a slip power only. The boost converter is composed of a 3-leg IGBT and a boost inductor generating a direct current voltage of its source required for the H-bridge multi-level converter.

The invention discloses a three-level inverter of a single-phase mixed bridge, comprising six switching tubes T1 to T6, four diodes D1 to D4, two electrolytic capacitors C1 to C2 and one output filter; wherein the four switching tubes T1 to T4, the two electrolytic capacitors C1 to C2 and the diodes D1 and D2 form a three-level single-phase converter unit of a diode middle point clamping position, the switching tubes T5 and T6, and the two electrolytic capacitors C1 to C2 form a single-phase half-bridge converter unit, a serial-connection branch circuit of D3 and D4 is connected with a serial-connection branch circuit of D1 and D2 in parallel, and the middle point of the D3 and D4 is connected with the middle point of the bridge arm of T5 and T6. The three-level inverter can effectively inhibit ground leakage current of the inverter, and has the advantages of high efficiency and simple modulating method, and the three-level inverter is suitable for a power supply inverter system which has strict ground leakage current, such as no-transformer type photovoltaic grid-connection inverter and the like.

A method of controlling an uninterruptible power supply apparatus (UPS) is provided. The UPS apparatus includes at least an AC input voltage, a DC input voltage and a single-phase AC/AC converter. The single-phase AC/AC converter includes an AC inductor, a bus capacitor, a boost arm, a common arm and a buck arm. The method includes steps of: controlling the bus voltage to have a DC component and full-wave rectifying component, and setting a bus voltage parameter K so that the bus voltage approaches to a full-wave rectifying voltage when K approaches to 1, wherein 0≦K≦1.

The invention discloses an electromagnetic transient mathematical model of a distributed power-flow controller based on an MMC, control system and a modeling method. The distributed power-flow controller comprises a parallel connection side converter composed of a three-phase converter based on the MMC at the parallel connection side and a parallel connection side single-phase converter and a series connection side converter composed of multiple sets of series connection side single-phase converter; the electromagnetic transient mathematical model mainly comprises a parallel connection side converter model and a series connection side converter model; the control system comprises a parallel connection side control model and a series connection side control model, the parallel connection side control model comprises a three-phase converter control module based on the MMC at the parallel connection side and a parallel connection side single-phase converter module, and the series connection side control model comprises a series connection side third harmonic control module and a series connection converter active power reactive power control module. The electromagnetic transient mathematical model is designed by adopting modularization, the sub module switch-on and switch-off frequency is lowered, and the loss is lowered; the control system adapts to different voltage grades, and is applicable to flexible alternating current transmission occasions.

The invention discloses a movable-type static synchronous compensator with a compact structure design. The compensator has high compensation capacity and rapid adjusting speed and compact structure, is convenient for transportation, and can be rapidly transferred, installed and put into operation at the urgent place needs reactive power support, thus the planning, the arrangement and the operation of a dynamic reactive power compensation device of a power grid are more flexible and effective. The movable-type static synchronous compensator comprises three functional module containers with the same structure, an auxiliary equipment container and a movable base, wherein, the functional module container comprises a single-phase converter chain and a converter chain arrester; the auxiliary equipment container comprises a control protective system, a water-cooling system and a three-phase starting loop; and the movable base comprises a connection reactor, a main breaker, an isolation switch and an earthed switch. The compensator provided by the invention has the obvious advantages of rapid response speed, wide adjustment application, low harmonic output content, adoption of compact design, mobility, less occupation area and the like.

A multilevel converter for controlling a multilevel converter is provided. The multilevel converter is a single phase converter with one phase leg, or a three phase converter with three phase legs, the phase legs of the three phase converter are interconnected in a star-configuration. The single phase converter with one phase leg, or each three phase converter with three phase legs, phase leg includes switching cells, and each switching cell includes semi-conductor switches arranged to selectively provide a connection to a corresponding energy storage element. The converter also includes a controller, which is provided to monitor the DC voltage of the energy storage elements, and the controller is provided to control the switching of each switching cell. The phase leg of the single phase converter, or each phase leg of the three phase converter, includes two parallel branches of switching cells, the branches being configured in a closed circuit.

The invention provides an LCL-type active power filter and a control method thereof. The LCL-type active power filter comprises a converter T1 and a control system, wherein one side of the converter T1 is connected in parallel with a DC capacitor C, an LCL filter circuit is arranged at the other side of the converter T1 and comprises a filter capacitor Cf, a converter T1 side is connected with a filter inductor L1, a power grid side is connected with a filter inductor L2, the control system is connected with an output end of the single-phase converter T1, the filter capacitor Cf, the DC capacitor C and a load respectively by a filter inductor L1 current sampling circuit, a filter capacitor voltage sampling circuit, a DC capacitor voltage sampling circuit and a load current sampling circuit, and the control system is used for closed-ring control on a current of the inductor L1 at the converter T1 side. According to the control method of the LCL-type active power filter, a filtering effect of the LCL-type active power filter can be improved by introducing virtual impedance control and phase compensation control.

The invention discloses a railway power regulator based on a half-bridge structure, which comprises two single-phase step-down transformers and a half-bridge inversion module, wherein the half-bridge inversion module comprises a pair of switch arms and a pair of series capacitors, and the switch arms are connected into a back-to-back structure by two capacitors; and the primary sides of the two single-phase step-down transformers are connected with power supply arms at the two secondary sides of a traction transformer, ungrounded lines at the secondary sides of the two single-phase step-down transformers are respectively connected with the switch arms in the half-bridge inversion module by an inductor, and the two single-phase step-down transformers are grounded and are connected with the middle points of the two capacitors in the half-bridge inversion module. Compared with a structure adopting two H-bridge single-phase converters, the cost of the active capacity of the railway power regulator is lowered by one time. Under the precondition that the same function is finished, the cost and the complexity of hardware are decreased, and the reliability of a compensation device is enhanced, so that the invention is greatly beneficial to the high-power modularization of the device and has favorable application prospect.

The invention discloses a DC voltage closed-loop control method and a system of a single-phase converter. The voltage feedback signal of the DC side of the single-phase converter which passes througha sliding average filter as a feedback link is collected. Based on the pre-established transfer model of the voltage outer loop closed-loop system of the single-phase converter, the closed-loop control is carried out according to the voltage feedback signal and the preset voltage. The transfer model includes feedback delay, PI controller, current inner loop closed loop system transfer model and controlled plant model. The integral time constant of PI controller is larger than the integral time constant of feedback delay. The transfer model open-loop cutoff frequency is set based on the response speed of the current inner loop being much greater than the response speed of the voltage outer loop. By introducing a moving average filter as a voltage loop feedback link, the secondary ripple component of the voltage signal is effectively separated, the secondary ripple component is avoided from entering the voltage loop, the adverse effect of the secondary ripple is eliminated, and the control stability of the system is ensured.

The invention relates to a multi-time-scale mathematical model establishing method of a distributed power flow controller. The method comprises: S1, a parallel-side apparatus of a distributed power flow controller is used as one converter groups including a parallel grid-side three-phase converter equivalent circuit, a parallel harmonic-side single-phase converter equivalent circuit, and a parallel-side common direct-current capacitor equivalent circuit in back-to-back connection; S2, a series-side apparatus of the distributed power flow controller is used as one applied to an alternating-current fundamental wave network equivalent circuit, an alternating-current third harmonic network equivalent circuit, and a series-side direct-current capacitor equivalent circuit simultaneously; S3, according to the principle of a voltage type PWM converter switch cycle average model, a dynamic mathematical model of the distributed power flow controller is established; and S4, a multi-time-scale analysis is carried out on the dynamic mathematical model of the distributed power flow controller by combining a singular perturbation principle and a multi-time-scale mathematical model of the distributed power flow controller is established. Therefore, the multi-time-scale characteristic of the whole power system can be analyzed well. The method is suitable for the order reduction analysis of the power system.

The invention relates to an alternating current-direct current conversion technology and discloses a three-phase bridgeless power factor correction (PFC) alternating current-direct current converter. The technical scheme of the invention is as follows: the alternating current-direct current converter comprises an A-phase converter, a B-phase converter, a C-phase converter and a control system for the A-phase converter, the B-phase converter and the C-phase converter, wherein the A-phase converter, the B-phase converter and the C-phase converter are bridgeless double boost power factor correction converters with same structure; the alternating current input ends of the A-phase converter, the B-phase converter and the C-phase converter are respectively connected with an A-phase line, an A-phase central line, a B-phase line, a B-phase central line and a C-phase phase line and a C-phase central line; and the direct current output positive ends and the direct current output negative ends of the converters are respectively connected to form the direct current output end of the three-phase bridgeless PFC alternating current-direct current converter so as to connect a load to provide direct current to the load. Due to the circuit design disclosed by the invention, not only can mutual interference and influence among three single-phase converters be reduced, but also the redundancy characteristics of the converters are realized; if one phase goes wrong, the other two phases still can supply power to the load so that the robustness of the system is greatly enhanced, and thereby the converter is very suitable for three-phase high-power applications.

The invention relates to a three-phase-to-single-phase converter for an electric power traction power supply system. The three-phase-to-single-phase converter comprises a rectification module, an inversion module and a transformation module in sequential connection, wherein the rectification module is a three-phase full-wave bridge rectifier circuit, the inversion module is a bridge type inversion circuit, and the transformation module is a transformer. The three-phase-to-single-phase converter is a device for converting 35KV(10KV) three-phase alternating current electricity into 27.5KV single-phase alternating current, a special power supply system for an electric power traction locomotive, the three phases are used for maintaining the balance to overcome the fatal defect that the existing traction locomotive system form a great amount of negative-sequence current. The three-phase balanced operation is realized, the electric power electric energy quality is improved, and the powerful guarantee is provided for the safe and reliable operation of an electric network system.

The invention discloses a multi-phase critical conduction power converter and a control method thereof; a single-phase critical conduction converter is popularized to multiple phases; and the enablingstates of a plurality of power-stage circuits are controlled along with the change of a load current, so that the switching frequency can be maintained within a preset range when the load current ischanged. The defects of low working frequency and large conduction current of a single-phase critical conduction mode converter during heavy load are overcome; meanwhile, the defects that the workingfrequency is increased and the frequency is lowered of a multi-phase critical conduction mode converter in light load are also overcome. Meanwhile, during single-phase light load, the working frequency of the single-phase converter is reduced through a current intermittent mode, so that the multi-phase converter can keep efficient operation within the whole load range.

The invention relates to a UPQC with an uninterrupted power source function, belonging to the electric power equipment technical field, and comprises three super capacitor energy storage modules, three single-phase converter modules and a bidirectional thyristor module. The super capacitor energy storage modules are all in parallel connection with direct current sides of the single-phase converter modules; the AC output terminals of the single-phase converter modules are all parallelly connected between the output terminal of the bidirectional thyristor module, and a load, and are in connection with the load; the input terminal of the bidirectional thyristor module is in connection with a system power supply, and the output terminal of the bidirectional thyristor module is meanwhile directly in connection with the load. The UPQC of the invention enlarges the scope of solving the problem of electric energy quality, reduces cost, is easy to realize high capacity output, and has the characteristics of fast response speed, high standby efficiency, stable operation, and simple structure; in addition, the UPQC effectively reduces product cost, is convenient to maintain and easy to operate, and has higher cost performance.

The invention discloses a dq active and reactive power cross decoupling-based grid-connected control method of a single-phase converter. The grid-connected control method comprises the steps of designing proportional integral (PI) controller to achieve active and reactive power cross control after a grid-connected control mathematical model of the single-phase converter is simplified; tracking andlocking a phase and amplitude of a power supply voltage by employing a single-phase locked loop (PLL) to obtain an angular frequency Omega(t) same as the frequency of the power supply voltage, a sinesignal sin(Omega)t and a cosine signal cos(Omega)t; processing an active component and a reactive component of a current by a lowpass filter (LPF) with a cutoff frequency being Omega/2Phi to obtain Id and Iq; and finally, taking sum of an active transient AC voltage and a reactive transient AC voltage as a modulation wave, and selecting an appropriate modulation mode to obtain a switch signal forcontrolling on/off of a converter switch tube. By the control method, the controller structure is simplified, and the stability and the dynamic response of the system are improved.

The invention discloses a novel three-phase serial modular multilevel converter HVDC converter, comprising a DC output end, a three-phase AC input end, a first transformer, a second transformer, a third transformer, a first single-phase converter, a second single-phase converter and a third single-phase converter. The novel three-phase serial modular multilevel converter HVDC converter disclosed by the invention has a low cost and can block the DC short circuit current.

The invention belongs to the technical field of smart grid operation and stability control, and specifically relates to a method for determining the value range of the third harmonic current of a distributed power flow controller to ensure the safe, stable and economical operation of a system including the distributed power flow controller. The third harmonic current is an important parameter forrealizing the functions of the distributed power flow controller. The invention provides mathematical relationships between the third harmonic current and the transmission line transmission capacity,between the third harmonic current and the insulation voltage of a parallel-side transformer neutral point, and between the third harmonic output efficiency of a parallel-side single-phase converter and the insulation voltage of the parallel-side transformer neutral point, and concludes the method for acquiring the value range of the economical and safe third harmonic current, and provides theoretical basis and reference for device parameter design.

The invention relates to a power electronic device. The device comprises a first component, a second component and a third component. The first component is a high voltage MOSFET pipe or n high voltage MOSFET pipes which are connected in parallel at a same direction. The second component is a low voltage MOSFET pipe and a third component is a high voltage diode. The first component and the secondcomponent are reversely connected in series. The third component is reversely connected in parallel to the two ends of a series-connection structure formed by the first component and the second component. The grids of the first component and the second component are connected. The invention also relates to a single-phase/three-phase converter adopting the power electronic device. By using the power electronic device, equipment efficiency can be greatly improved, a power density is increased, switch losses are reduced and the performance of equipment adopting the device can be increased. The single-phase/three-phase converter can work at a high switch frequency, a magnetic component volume and weight can be reduced, the power density of the converter is increased, cost is reduced and efficiency is improved.