38 results about "Boost inverter" patented technology

The invention discloses a fractional order second harmonic current suppression method for a single-phase dual-mode boost inverter, and the method comprises the steps: regulating and controlling the bus voltage of the single-phase inverter into a partial sine waveform and a constant direct waveform through dual-mode control, and enabling a front-stage Boost circuit to work at a high frequency and a rear-stage inverter to work at a low frequency in a partial sine waveform interval of the bus; and in a bus constant direct waveform interval, the front-stage Boost circuit works at low frequency, and the rear-stage inverter works at high frequency. The dual-mode control does not need to maintain the bus voltage at a relatively high constant value, so that the required bus capacitance is greatly reduced, the size of the device is reduced, and meanwhile, the switching and conduction loss is reduced. In addition, the fractional order second harmonic current suppression branch circuit is formed by connecting virtual capacitors Cfoc and C1 in series, the virtual capacitor Cfoc is composed of an inductor Lb, a capacitor C2 and half-bridge switching tubes Sb and Sc, and when the instantaneous power of the fractional order suppression branch circuit and the secondary pulsating power output by the inverter are equal in amplitude and complementary in phase, the inverter is switched on. And the complete suppression of the input second harmonic current can be realized.

The invention provides a charging activation device, an energy storage system and an activation method thereof, and belongs to the technical field of energy storage systems. The charging activation device comprises a standby battery pack, a boost inverter circuit, a voltage acquisition circuit and a microcontroller unit. Wherein the standby battery pack is used for providing a power supply for the boost inverter circuit and the microcontroller unit; the boost inverter circuit is used for boosting the input voltage to an activation voltage threshold of a battery management system of the energy storage system; the voltage acquisition circuit is used for acquiring the output voltage of an energy storage battery of the energy storage system; when the microcontroller unit detects that the energy storage system is in a locked state, the microcontroller unit can control to open the boost inverter circuit so as to boost an input voltage of the boost inverter circuit to an activation voltage threshold of a battery management system of the energy storage system and output the input voltage, so that the battery management system recovers a charging and discharging loop, and the energy storage system is activated. Automatic wakeup of the energy storage battery in the dormant state can be achieved, manual intervention is not needed, and dependence on manpower or external equipment is eliminated.

A transformerless, high efficiency, three-level, high power density, wide input voltage range, single-phase DC / AC inverter is provided. The inverter includes a single DC input power supply, a first semiconductor switch, a second semiconductor switch, a third semiconductor switch, a fourth semiconductor switch, a fifth semiconductor switch, a sixth semiconductor switch, a seventh semiconductor switch, an eighth semiconductor switch, a ninth semiconductor switch, a first inductor, and a second inductor.

The invention discloses a single-phase differential Boost inverter voltage zero-crossing compensation method based on a DSP (Digital Signal Processor). According to the method provided by the invention, the single-phase differential Boost inverter works under a discontinuous modulation strategy, and two Boost circuit modules alternately output positive and negative half cycles of alternating current sinusoidal voltage, so that the differential total output is the required alternating current sinusoidal voltage; wherein in the last switching period before the positive-negative half-cycle switching, the bridge arm switch actively turns off the interrupted current so as to eliminate zero crossing point oscillation caused by the residual energy of the inductor after the positive-negative half-cycle zero crossing point; in a first switching period after negative-positive half cycle switching, an initial pulse is widened for eliminating zero crossing point oscillation caused by inductive current mutation after negative-positive half cycle zero crossing.

This invention proposes a method and system for coordinated charging and discharging of electric vehicles based on energy storage substations. This method is used to solve the problems of transformer overload and three-phase load imbalance during charging and discharging. The core steps include: Step 1: The centralized controller acquires real-time substation operation data and uploads it to the cloud service controller for analysis; Step 2: Determines whether load imbalance and transformer overload exist; Step 3: When load imbalance and substation transformer overload are detected, a substation scheduling and control model is established to optimize the charging and discharging loads of energy storage batteries, AC charging piles, and DC charging piles; Step 4: Finds the optimal load switching scheme based on the model; Step 5: Evaluates the load balance improvement effect; If the load imbalance exceeds the adjustment range or exceeds the transformer load rate threshold, the DC charging pile can be connected to the 10kV incoming line via the second branch boost inverter where the inverter is located.

The present invention discloses a dual-boost converter and its modulation method, belonging to the technical field of converters. One end of the inductor L1 of the present invention is connected to the input power supply U in at one end. The other end of the inductor L1 is respectively connected to the anode of the diode D1 and the terminal 1 of the power switch tube S1; the cathode of the diode D1 is respectively connected to the terminal 1 of the power switch tube S3 and one end of the capacitor C1; the other end of the capacitor C1 is connected to the terminal 2 of the power switch tube S1 and the other end of the DC side; one end of the inductor L2 is connected to the input power supply U in at one end. The other end of the inductor L2 is respectively connected to the terminal 1 of the power switch tube S2 and one end of the capacitor C2; the other end of the capacitor C2 is connected to the terminal 2 of the power switch tube S4 and the anode of the diode D2; the cathode of the diode D2 is respectively connected to the terminal 2 of the power switch tube S2 and the other end of the DC side. Aiming at the problems of low boost ratio and leakage current existing in the boost inverter of the prior art, the present invention has high integration and a relatively high boost ratio, and can effectively solve the leakage current problem.

The present invention discloses a feedback boost inverter and control method for suppressing the torque pulsation of a brushless DC motor, and relates to the technical field of brushless DC motor control. The feedback boost inverter for suppressing the torque pulsation of a brushless DC motor includes providing a feedback boost inverter topology with adjustable size and capable of exceeding the power supply voltage. The feedback boost inverter topology includes an electrolytic capacitor, seven diodes, and seven insulated gate bipolar transistors. Compared with a traditional inverter, which only requires an additional insulated gate bipolar transistor, a diode, and an electrolytic capacitor, it has the advantages of simple structure and convenient control. In addition, the energy of the electrolytic capacitor used to raise the bus voltage in this topology comes entirely from the energy fed back by the motor, thereby improving the energy utilization rate of the motor. Based on this feedback boost inverter, a feedback boost inverter control method for suppressing the torque pulsation of a brushless DC motor is proposed, and this control method can achieve good torque pulsation suppression effect over a wide speed range.

The invention relates to the technical field of power electronic devices, in particular to a boost inversion device of a following grid type offshore wind turbine generator and a control method. The three-phase rectifier bridge and the Boost chopper circuit are adopted to form the light topological boost rectifier module, an electrolytic capacitor for stabilizing direct current voltage is not needed, the topological structure of the boost rectifier module is simplified, the first control module adopting MPPT + PFC cooperative control is constructed, mutual cooperation is achieved in a capacitor-free scene, and the power supply efficiency is improved. Maximum power tracking and power factor correction functions are achieved, and the problems that in the prior art, a large-capacity electrolytic capacitor needs to be relied on to maintain voltage stability, and consequently the size of a system is increased, and the service life is shortened are solved. Moreover, the post-stage current source type inverter is directly connected to the power grid, and a single current loop tracking mode is utilized, so that the technical problem that the voltage endurance capability of a power device in the system is relatively high on the basis of relatively high direct current bus voltage in the prior art is solved.

The invention belongs to the field of dielectric loss testing, and provides a high-voltage anti-interference multifunctional dielectric loss tester and an operation method thereof.The high-voltage anti-interference multifunctional dielectric loss tester comprises an integrated core function module, and specifically comprises the following components: a measuring module which adopts a high-precision digital signal processing technology and a frequency conversion measuring circuit; the input module is provided with a multi-channel input interface, supports positive wiring, negative wiring, low-voltage magnetic field, high-voltage magnetic field and CVT self-excitation wiring modes, and is compatible with a built-in standard capacitor and an external high-voltage source; and an adjustable high voltage source is arranged in the power supply module. According to the power supply module, the multi-stage boost inverter topology is adopted, digital closed-loop feedback control is combined, through the IGBT switch tube and the high-voltage-resistance boost transformer, 10-180 kV wide-range voltage output is achieved, the voltage steady-state fluctuation is smaller than or equal to + / -0.5%, the testing requirement of ultrahigh-voltage equipment is met, three modes of positive wiring, negative wiring and a CVT self-excitation method are supported, and safety and accuracy are ensured.

The invention belongs to the field of power supplies, particularly relates to a dual-purpose power supply for an automobile emergency start and an inverter, and aims to solve the problems that an existing emergency start power supply in the market is powered by a built-in lithium battery, is small in battery capacity and limited in use times, and needs to be charged after being used. A traditional inverter needs to be externally connected with a battery to work and is inconvenient to use. In order to solve the problems that in the prior art, in particular an external battery is large in size and not easy to move, the emergency starting power supply comprises a DC / DC converter, a high-frequency boost inverter circuit, a full-bridge rectifier circuit, a DC12V output circuit, an inverter bridge inverter circuit, an absorption loop circuit and a control protection unit, a built-in lithium battery of the emergency starting power supply on the market is omitted, and the cost is reduced. The power supply is flexible, convenient and fast, does not need to be charged, and can be used at any time. The inverter overcomes the defects that a traditional inverter can only be connected with a fixed battery, is fixed in use place, is not universal and the like.

The present invention belongs to the technical field of inverters, and discloses a zero-common-mode current single-phase non-isolated photovoltaic boost inverter and its control method. Its input capacitor C pv has its positive electrode connected to one end of the boost inductor L in ; the other end of the boost inductor L in is connected to the anode of the anti-reverse diode D; the cathode of the anti-reverse diode D is connected to the drain of the first switch tube S1, the drain of the third switch tube S3, and the positive electrode of the bus capacitor C dc ; the source of the third switch tube S3 is connected to the drain of the fourth switch tube S4 and one end of the output filter inductor L1; the source of the fourth switch tube S4 is connected to the negative electrode of the bus capacitor C dc and the source of the second switch tube S2; the negative electrode of the input capacitor C pv is connected to the source of the first switch tube S1 and the drain of the second switch tube S2. It realizes input-output common ground, eliminates common-mode current, has fewer power devices, strong boost ability for solar cells, lower cost, and high safety.

The present invention proposes a three-level boost inverter based on switched capacitors and its modulation strategy, comprising: a switched capacitor voltage regulating circuit and an F-type three-phase full-bridge inverter circuit; the switched capacitor voltage regulating circuit is responsible for increasing the DC bus voltage and generating three voltage levels; and the F-type full-bridge inverter circuit is responsible for converting the three voltage levels into three-phase voltages, and realizing three-phase voltage output through the combined action of the switched capacitor circuit and the three-phase bridge arm. At the same time, based on the characteristics of the inverter, a new SVPWM modulation strategy is proposed to control the on-off of the switch tube and realize the self-balancing of the capacitor voltage. While realizing three-phase three-level output, the present application can double the voltage modulation range, and without large inductance, it can effectively reduce losses and improve power density.

The invention discloses a power loss calculation method and system for a single-stage differential boost inverter. The power loss calculation method comprises the following steps: S1, constructing a three-phase differential boost inverter circuit based on a SiC MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor); s2, analyzing an inductive current in the three-phase differential boost inverter circuit to obtain an expression of a current flowing through an MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor); and S3, obtaining the power loss of the three-phase DBI according to the expression of the current flowing through the MOSFET. By adopting the technical scheme of the invention, the loss of the power device in the circuit is effectively calculated.

The invention discloses a method for determining a parameter stability domain of a main circuit of a low-ripple adjustable direct-current stabilized power supply based on a Buck-Boost inverter circuit. The method comprises the following steps: establishing a mathematical model of a direct-current stabilized power supply main circuit; establishing a state differential equation of the three-phase Buck-Boost inverter circuit by taking a capacitor voltage and an inductor current in the inverter circuit as state variables and taking a PWM (Pulse-Width Modulation) direct-current voltage and an output current of the inverter circuit as input and output variables of the inverter circuit; establishing an equivalent mathematical model between the input current and the input voltage of the three-phase uncontrollable rectification circuit; obtaining a discrete iterative mapping model of the DC stabilized power supply according to a mathematical model of PWM modulation DC voltage, a state differential equation of the three-phase Buck-Boost inverter circuit and an equivalent mathematical model of the three-phase uncontrollable rectification circuit; according to the obtained discrete iteration mapping model, the value range of the main circuit parameters of the direct-current stabilized power supply during stable operation is obtained through numerical simulation, and stable operation of the direct-current stabilized power supply is achieved.

The present invention discloses a dual-input boost inverter and its control method, belonging to the technical field of converters. In one solution of the present invention, one end of the first input side is connected to the anode of D1, the cathode of D1 is connected to one end of L1, the other end of L1 is connected to terminal 1 of S1, one end of L3, and the anode of D3, the cathode of D3 is connected to terminal 2 of S3 and S4, the cathode of D4, and the positive terminal of C1, the anode of D4 is connected to terminal 1 of S2, one end of L4, and one end of L2, the other end of L2 is connected to the cathode of D2, the anode of D2 is connected to one end of the second input side; the other ends of the first input side and the second input side, terminal 2 of S1 and S2, and the negative terminal of C1 are all grounded; the other end of L3 is connected to terminal 1 of S3 at point a, and the other end of L4 is connected to terminal 1 of S4 at point b; nodes a and b form the output side. The present invention uses dual power supplies, can achieve seamless switching of the two power supplies, ensure the normal operation of the inverter, improve the stability of the system, and obtain a higher voltage gain.

The invention discloses a switch capacitor cascade three-phase four-bridge arm boost inverter configuration which comprises a switch capacitor circuit and a three-phase four-bridge arm inverter circuit, and the switch capacitor circuit is connected with the three-phase four-bridge arm inverter circuit. The switched capacitor circuit comprises a controlled switch tube S1, a controlled switch tube S2, a diode D1 and a capacitor C, the positive end of the direct-current voltage source Vdc is connected with the anode of the diode D1 and the collector of the controlled switch tube S1, the cathode of the diode D1 is connected with one end of the capacitor C and the collector of the controlled switch tube S2, and the other end of the capacitor C, the emitter of the controlled switch tube S1 and the emitter of the controlled switch tube S2 are connected with the negative end of the direct-current voltage source Vdc. According to the invention, the switched capacitor boost inverter is adopted, boost can be carried out without using an inductor, and the problems of large inductor weight, high loss, low efficiency and the like of a traditional boost inverter circuit are solved.

The invention discloses a boost inverter system, which relates to the field of photovoltaic power generation and comprises an IGBT (Insulated Gate Bipolar Translator) rectifying circuit, a first capacitor, a second capacitor, a Boost circuit, a third capacitor, an IGBT inverter circuit, a power supply circuit, a Boost driving circuit and an IGBT inverter driving circuit, the voltage input end of the power supply circuit is connected with the output end of the booster circuit; an inversion upper bridge driving voltage output end of the power supply circuit is connected with an upper bridge power supply input end of the inversion driving circuit; an inversion lower bridge-BOOST driving voltage output end of the power supply circuit is connected with a lower bridge power supply input end of the inversion driving circuit and a power supply input end of the Boost driving circuit; a driving signal output end of the inverter driving circuit is connected with a driving signal input end of the inverter circuit; and the driving signal output end of the Boost driving circuit is connected with the driving signal input end of the Boost circuit. The working stability of the inverter circuit is improved.

The invention relates to the technical field of inverters, in particular to a three-phase voltage source inverter which comprises a direct-current voltage source module, an MOSFET control module 1, an MOSFET control module 2, a phase-shifted full-bridge ZVS direct-current conversion module, a three-phase Buck-Boost inversion module and a load based on the two-stage three-phase voltage source inverter. The phase-shifted full-bridge ZVS direct-current conversion module is adopted in the input stage part, fluctuation of output voltage of a photovoltaic panel is restrained, stable operation can be further achieved, meanwhile, a switching tube of the module can achieve the functions of zero-voltage switching-on and zero-voltage switching-off, and the phase-shifted full-bridge ZVS direct-current conversion module has wide application prospects in the field of photovoltaic new energy power generation-energy storage. Compared with the prior art, the high-frequency inverter circuit has the advantages that the switching tube loss of the MOSFET under the high-frequency working condition is reduced, and the Buck-Boost inverter circuit adopted by the high-frequency inverter circuit has a buck-boost function and a larger voltage output range, so that the high-frequency inverter circuit can flexibly adapt to the power supply requirement of a load end and has a wide prospect in the field of photovoltaic inversion.

The invention relates to the technical field of circuit systems, in particular to a three-port boost inverter topology and application thereof. A three-port boost inversion topology is provided, the topology realizes working mode switching by controlling a switch tube, the three-port boost inversion topology structure is cascaded with a traditional Boost converter, according to the change of irradiance, the photovoltaic irradiance range is expanded by using the voltage-multiplying characteristic of a capacitor, the boost multiple of the topology is improved, and the photovoltaic power generation efficiency is improved. The requirement on the capacity of the storage battery is reduced; the common discharge of the photovoltaic device and the storage battery is realized by utilizing the clamping characteristics of the three-port structure and the capacitor; and when the photovoltaic and storage battery output is insufficient to operate the system, the three-phase inverter is used for realizing photovoltaic voltage reduction to charge the storage battery. The objective of the invention is to reduce the power loss of the three-port boost inverter circuit.

The present invention discloses a three-phase buck-boost inverter circuit and a modulation method, which includes a DC power supply circuit, a chopper circuit and a three-phase voltage source circuit. The input of the chopper circuit is connected to the DC power supply circuit, and the output of the chopper circuit is connected to the three-phase voltage source circuit; the DC power supply circuit is used for providing DC power supply for the inverter circuit; the chopper circuit is used to realize inversion in buck / boost / buck-boost mode; the three-phase voltage source circuit is used to absorb energy during inversion. The present invention is applicable to occasions where the input voltage varies within a wide range; the multi-mode modulation method maximally utilizes the DC input voltage, reduces the number of switching tubes operating at high frequencies, reduces switching losses, and improves the conversion efficiency; the volume, weight and cost of the inverter are reduced, and the power density is increased.

A battery heating system (10) and an electric vehicle (1000). The system (10) is a power battery pack comprising a first battery pack (1) and a second battery pack (2) connected in series, and a center line is drawn at the series connection point (A) between the first battery pack (1) and the second battery pack (2). The power battery pack, n buck-boost inverters (3) each comprising an inverter bridge and an inductor, wherein the n inverter bridges are connected in parallel to form a first bus terminal (B) and a second bus terminal (C), and the first bus terminal (B) and the second bus terminal (C) are connected corresponding to the positive and negative electrodes of the power battery pack. One end of the inductor is connected to the midpoint of the corresponding inverter bridge, and the other end of the inductor is connected to the center line, where n is an integer greater than 1. The n buck-boost inverters (3), and a controller (100) connected to the control end of the inverter bridge and configured to perform phase-shift control on the n buck-boost inverters (3) to achieve simultaneous self-heating of the first battery pack (1) and the second battery pack (2).

The invention provides a switched capacitor-based three-level boost inverter and a modulation strategy thereof. The switched capacitor-based three-level boost inverter comprises a switched capacitor voltage regulation circuit and an F-type three-phase full-bridge inverter circuit, the switched capacitor voltage regulating circuit is responsible for increasing the voltage of the direct current bus and generating three voltage levels; and the F-type full-bridge inverter circuit is responsible for converting the three voltage levels into three-phase voltage, and three-phase voltage output is realized through the combined action of the switched capacitor circuit and the three-phase bridge arm. Meanwhile, aiming at the characteristics of the inverter, a novel SVPWM (Space Vector Pulse Width Modulation) strategy is provided to control the on-off of a switch tube and realize the self-balance of the capacitor voltage. While three-phase three-level output is realized, the modulation range of the voltage can be doubled, no large inductance exists, the loss can be effectively reduced, and the power density can be improved.

The invention discloses a single-phase single-stage nonlinear boost inverter circuit topological structure and a control method thereof. The working modes of the inverter circuit comprise a positive half-cycle sine wave output mode and a negative half-cycle sine wave output mode, and the two modes are switched through turn-on of a pair of complementary power frequency switches. The topology provided by the invention has nonlinear output voltage gain, and the functions of boosting and inverting in a single stage can be realized through reasonable design and distribution of the duty ratio of the switch. Compared with a traditional two-stage voltage source inverter, the topological structure provided by the invention reduces the use of passive elements, and has the advantages of low cost, small size, high efficiency, convenience in control and the like. The single-stage topological structure can simplify the structure of a traditional two-stage inverter, reduces the use of components such as a filter and a controller, and avoids the extra loss of energy in the multi-stage transmission and processing.

This invention relates to a reference sampling phase-locked loop (PLL) adapted for low-voltage applications, comprising: a reference sampling phase detector module, a low-pass filter module, a voltage-controlled oscillator (VCO), a frequency divider module, and a clock signal generation module. This invention achieves normal sample-and-hold functionality by employing a high-level boost inverter to reduce the on-resistance of the sampling switch and decrease the sampling time constant under low voltage. Simultaneously, it allows for the use of a larger sampling capacitor to improve noise, enabling normal sampling operation of the PLL under low voltage and superior clock jitter performance. Furthermore, by adding a low-pass filter at the output of the reference sampling phase detector, high-frequency poles are introduced, improving reference spurious signals without affecting the phase margin. Finally, a combination of a current-mode logic divider and a multi-mode programmable divider is used to ensure normal operation of the reference sampling PLL under low voltage and superior spurious and clock jitter performance.

This application relates to the field of circuit system technology, and in particular to a three-port boost inverter topology and its application. By proposing a three-port boost inverter topology, which achieves operating mode switching through controlled switching transistors, the topology is cascaded with a traditional Boost converter. Based on changes in irradiance, the voltage multiplication characteristic of the capacitor is utilized to expand the irradiance range of the photovoltaic system, thereby increasing the boost ratio and reducing the capacity requirements of the battery. The three-port structure and the clamping characteristics of the capacitor enable simultaneous discharge of the photovoltaic system and the battery. When the output from the photovoltaic system and the battery is insufficient to operate the system, a three-phase inverter is used to step down the photovoltaic voltage to charge the battery. The aim is to reduce the power loss of the three-port boost inverter circuit.

The invention provides a high-performance boost inverter suitable for a WPT system and a soft switching method, and belongs to the technical field of wireless power transmission. The problems that in an existing boost inverter, the number of switching tubes is large, the power level is limited, the inverter is sensitive to parameter changes, and the wide-range operation capacity is weak are solved. The inverter comprises an input voltage Vin, an output capacitor Cin, a first Boost circuit, a second Boost circuit, an output node A and an output node B. The soft switching method comprises the following steps: starting the high-performance boost inverter, and converting a receiving end to a transmitting end; switching tube circulation on-off control of switching tubes in the first Boost circuit and the second Boost circuit is started, the inverter is divided into a working state 1-a working state 8, ZVS opening is achieved through sequential circulation of all the working states, and boost inversion output of the wireless electric energy transmission system is completed.

The application discloses a reference sampling phase-locked loop applied to a low-voltage mode, comprising a reference sampling phase detector, a low-pass filter, a voltage-controlled oscillator, a frequency divider module, a clock generator and a high-level voltage boosting inverter connected in sequence. On the basis of the existing reference sampling phase-locked loop, the high-level voltage boosting inverter is added, the sampling and holding switch is optimized, the on-resistance of the sampling switch is greatly reduced, the time constant of sampling under low voltage is reduced, the normal sampling and holding functions of the sampler under low voltage are ensured, meanwhile, a larger sampling capacitor is allowed to be used to improve noise, the normal sampling work and superior clock jitter performance of the phase-locked loop under low voltage are realized; and the low-pass filter is added to the output end of the reference sampling phase detector, a high-frequency pole is introduced, the reference spur is improved without affecting the phase margin, and the performance of the circuit is improved.

This application discloses an interleaved parallel three-phase single-stage boost inverter and its carrier phase-shift modulation method, device, and medium, relating to the field of power electronic converters. The method includes: generating a three-phase modulation wave, the three-phase modulation wave corresponding to the three-phase output of the interleaved parallel three-phase single-stage boost inverter; generating a carrier signal, wherein the three-phase carrier signal is phase-shifted by 120° sequentially, and the carrier signal corresponding to the two interleaved bridge arms in each phase is phase-shifted by 180°; comparing the three-phase modulation wave with the two carrier signals of the corresponding phase respectively to generate a drive signal for each switch; controlling the on / off state of the switch in each interleaved bridge arm according to the drive signal, so that the interleaved parallel three-phase single-stage boost inverter switches between different operating states, realizing current sharing and ripple cancellation. This application reduces input current ripple, inductor volume, and device stress.

The invention discloses a method and a system for controlling a two-stage single-phase three-level boost inverter. The method comprises the following steps of: controlling an input current by using a first proportional integral controller according to an actual value and a reference value of the input current of the two-stage single-phase three-level boost inverter; using a second proportional integral controller to control the flying capacitor voltage according to the actual value and the reference value of the flying capacitor voltage of the two-stage single-phase three-level boost inverter; using a third proportional-integral controller to control the average value of the DC bus voltage according to the average value of the DC bus voltage of the two-stage single-phase three-level boost inverter and the reference average value to obtain a grid-connected current amplitude; controlling the grid-connected current by using a proportional resonance controller according to the grid-connected current amplitude and the grid-connected current of the two-stage single-phase three-level boost inverter; and calculating the duty ratio of each switch according to the input current control result, the flying capacitor voltage control result and the grid-connected current control result. The method does not need a complex algorithm or extra hardware support, and is easy for engineering realization.

This invention discloses a buck-boost integrated inverter and its control method. The buck-boost integrated inverter includes switching transistors S1, S2, S3, and S4, diodes D1, D2, and D3, and a supporting capacitor C. dc and inductor L in The control method of this invention can suppress the impact of DC input voltage fluctuations on output voltage to a certain extent. It can cope with unstable DC input voltage fluctuations within a certain range. When the DC input voltage is large and the AC output voltage is small, it improves the DC side voltage utilization of the inverter, reduces the withstand voltage requirements of switching transistors S2, S3 and S4, and lowers costs. The buck-boost integrated inverter of this invention can be used as a photovoltaic inverter, realizing the boost inverter function in a single stage. It has high integration and improves efficiency.