32 results about "Voltage source inverter" patented technology

This invention discloses a dual-variable symmetrical injection modulation method for a two-phase permanent magnet synchronous motor, belonging to the field of motor drive and control technology. The method includes the following steps: S1, setting motor start-up logic and soft-start parameters; S2, generating two-phase orthogonal line voltage commands; S3, dual-variable symmetrical injection; S4, PWM comparator register mapping and output; S5, periodic execution. This method requires no modification to the hardware topology of a standard three-phase voltage source inverter or the addition of additional circuit components, and can be directly deployed on existing mature hardware platforms. This allows the same three-phase inverter to be used to drive both three-phase and two-phase motors, achieving hardware platform reuse and standardization, significantly reducing system development and bill of materials costs, resulting in low hardware cost and strong versatility.

The application discloses a three-level inverter harmonic suppression method based on zero vector symmetrical reconstruction and spread spectrum composite modulation, and the method comprises the following steps: step 1, signal acquisition and voltage instruction acquisition; step 2, spread spectrum modulation parameter setting; step 3, basic vector action time calculation; step 4, zero vector symmetrical reconstruction of vector sequence; step 5, switch time calculation and register updating; and step 6, PWM signal generation and system closed loop operation. The application realizes full-band suppression of inverter output PWM harmonics by deeply fusing the zero vector symmetrical reconstruction technology and the spread spectrum modulation technology. The application can be applied to a permanent magnet synchronous motor driving system powered by a three-level voltage source inverter, can simultaneously suppress the PWM harmonic amplitude near the odd carrier frequency and the even carrier frequency, effectively reduces electromagnetic vibration and noise, and has extremely high application value in the field of high-power inverters and motor drives.

The invention discloses a virtual two-port-based inverter impedance remodeling and network power flow control method. The virtual two-port-based inverter impedance remodeling and network power flow control method comprises a voltage source type inverter impedance remodeling method and a voltage source type inverter network power flow control method. According to the voltage source inverter impedance remodeling method, system impedance modeling is firstly analyzed, virtual two-port network parameters are designed, then a control signal is calculated and input into an original system, and impedance remodeling is completed; the voltage source type inverter network power flow control method comprises the steps of collecting data, building a line model, calculating power flow control parameters, calculating control signals, inputting the control signals into an original system, and completing power flow control. The invention discloses a virtual two-port-based inverter impedance remodeling and network power flow control method, and aims to solve the problems that parameters of existing virtual impedance control exceed an actual engineering achievable range in a strong negative impedance scene and parameter setting is complicated and stability and robustness are insufficient in an asymmetric impedance scene. According to the technical scheme of impedance remodeling, the problem is effectively solved by processing symmetric and asymmetric systems in a differentiated mode.

A system includes a first motor, a second motor, and a third motor, each respective motor comprising three phases. The system further includes a voltage source inverter circuit comprising multiple respective inverter legs. Each respective inverter leg coupled to drive at least one phase of at least one of the respective motors, with a first shared inverter leg coupled to drive a third phase of the first motor and drive a first phase of the second motor. A second shared inverter leg is coupled to drive a third phase of the second motor and a first phase of the third motor.

The application discloses a kind of double three-phase permanent magnet synchronous motor adaptive model-free predictive control methods with optimal virtual voltage vector, S1, the mathematical model of double three-phase permanent magnet synchronous motor is established, and the discrete state space prediction model is constructed;S2, establish hyperlocal model ULM, and design extended state observer ESO;The control gain parameters of hyperlocal model and the observer bandwidth of ESO are updated recursively online, and adaptive model-free predictive control AMFPC is formed;S3, construct the virtual voltage vector set for inhibiting harmonic current;The current of motor future time is predicted using updated AMFPC, and the optimal virtual voltage vector is selected from the virtual voltage vector set;The optimized vector is generated through the center symmetrical pulse width modulation mode to generate switching signal, to drive six-phase voltage source inverter, to control double three-phase permanent magnet synchronous motor.The application provides a promising solution for high-performance double three-phase permanent magnet synchronous motor drive system under complex working conditions.

The application discloses a high-speed permanent magnet synchronous motor position identification method, samples motor a, b, c three-phase currents, carries out Clarke transformation on the obtained currents to obtain the currents of alpha axis and beta axis on a two-phase static coordinate system, estimates the output voltage of alpha axis and beta axis according to the SVPWM conduction time calculated in the last control period, obtains a position estimation reference quantity by directly processing the current voltage, and uses a phase-locked loop to calculate the angle and speed of the position estimation reference quantity and thereby calculates motor position information, the application uses the output characteristics of a voltage source inverter to obtain a calculation formula not influenced by discretization errors, and improves the position identification precision under a low load frequency ratio.

The invention relates to a self-adaptive prediction control method and system for an LCL type active power filter, and the method comprises the following steps: introducing a self-adaptive weight, dynamically fusing a power supply current frequency domain detection component and a load current time domain detection component, and fusing frequency domain high-precision detection and time domain quick response detection through the self-adaptive weight. The limitation of a single detection mode is overcome, and the compensation precision and the response speed can be improved respectively under the steady-state and transient-state working conditions; the reference current is predicted in advance according to the digital control delay step size, an inverter voltage instruction is calculated in a reverse recursive mode according to the reference current, the inverter voltage instruction is corrected to obtain a final instruction, and the final instruction drives a voltage source inverter to output compensation current; according to the compensation current tracking error and the load power change rate, the self-adaptive weight, the outer ring prediction step length and the self-adaptive virtual damping coefficient are dynamically adjusted, and the overall adaptability of the system to complex working conditions is enhanced.

A stability detection method and system for grid-connected and grid-connected converters based on impedance modeling is proposed. This method determines the impedance matrix of the voltage source inverter based on a small-signal model of the voltage source inverter, and establishes a first impedance ratio, a second impedance ratio, and a third impedance ratio with the equivalent impedance matrix of the power grid. If the first impedance ratio does not satisfy the Nyquist stability criterion, the converter is determined to be in a negatively damped state; if the first impedance ratio satisfies the Nyquist stability criterion, the converter is determined to be in a positively damped or underdamped state. The product of the second and third impedance ratios is used as the oscillation damping coefficient. If the oscillation damping coefficient is less than zero, the converter is determined to be in a negatively damped stable state; if the oscillation damping coefficient is greater than or equal to zero and less than the critical damping coefficient, the converter is determined to be in an underdamped stable state; if the oscillation damping coefficient is greater than or equal to the critical damping coefficient, the converter is determined to be in a positively damped stable state. This method accurately describes the dynamic characteristics of the converter under nonlinear and large disturbance conditions.

The invention discloses a grid-connected converter direct-current side midpoint potential balance structure, and the structure comprises a direct-current circuit structure which comprises a direct-current positive electrode, a midpoint potential and a direct-current negative electrode; the multi-winding transformer is provided with a primary side winding and a secondary side winding, and the primary side winding is electrically connected to the direct current circuit structure between the direct current positive electrode and the midpoint potential and the direct current circuit structure between the midpoint potential and the direct current negative electrode through a primary side H-bridge inversion module; and the voltage source type inverter is electrically connected to the secondary side winding, so that an energy interaction channel is formed between the voltage source type inverter and the multi-winding transformer, and when the unbalanced magnetomotive force is generated, the secondary side winding generates a compensation current for the neutral point potential through the energy interaction channel. The primary side of the multi-winding transformer is connected with two capacitors on the direct current side, the secondary side of the multi-winding transformer is connected with the voltage source type inverter, current compensation is carried out on the offset neutral-point potential, the neutral-point potential can be automatically corrected, the development difficulty and delay of a balance algorithm are eliminated, and the adjusting speed and the balance capacity are improved.

The application belongs to the technical field of electric power automation, and discloses a voltage source inverter outer loop limiting method, device, equipment and medium; the method comprises the following steps: S1, obtaining three preset parameters; S2, calculating the d-axis current component i d and the q-axis current component i q of the VSC injected current i according to the three parameters; S3, judging whether the setting of the three parameters meets a preset condition according to the d-axis current component i d and the q-axis current component i q ; if yes, entering step S4, otherwise, modifying the three parameters and entering step S2; S4, calculating the boundary constraint of the voltage source inverter outer loop limiting according to the three parameters meeting the preset condition; S5, controlling the d-axis current component i d and the q-axis current component i q of the VSC injected current i to be within the boundary constraint. The application designs an improved VSC outer loop limiting strategy, which improves the stability of the VSC grid-connected system while modifying the limiting boundary as little as possible, so as to fully utilize the power electronic equipment and improve the transient stability of the VSC grid-connected system.

The application discloses a specified harmonic compensation method of a hybrid active filter, which simulates a virtual capacitor for a voltage source inverter in a harmonic domain, and the capacitor value can be adaptively adjusted by a perturbation and observation method, so that the LC filter and the virtual capacitor can generate series resonance at a specified harmonic frequency, and the effect of a multi-tuned filter is achieved, thereby greatly improving the filtering characteristic of the LC single-tuned filter; the control method has the advantages of simple control structure, easy implementation and good filtering effect.

This invention belongs to the field of inverter technology, specifically relating to a nonlinear control method for a three-phase voltage source inverter, including detecting inductor current I. Labc Detect the output voltage V oabc ; By transforming from the abc coordinate system to the αβ coordinate system, we obtain I Lαβ V oαβ ; Set the outer voltage loop parameter K2 and the inner current loop parameter K1; obtain the filter inductor current reference value through the outer voltage loop, input the current reference value into the inner current loop control, and obtain the inverter modulation signal S in the αβ coordinate. invx(x＝α,β) The modulated signal is transformed into an abc coordinate system as S. invz(z＝a,b,c) The invention outputs PWM drive signals for the inverter's switching devices via carrier modulation to drive the inverter to output three-phase AC power. This invention effectively solves the chattering problem caused by the sliding phase term in the current inner loop control, introduces a nonlinear control term, enhances the system's robustness, and enables the inverter to compensate for both low-order and high-order harmonic voltages.

A single-phase voltage source inverter and method including a main inverter circuit connected to an active power filter circuit, the main inverter circuit comprising an H-bridge circuit comprising a first leg and a second leg, the first leg comprising a first switch, a second switch, and the second leg comprising a third switch and a fourth switch, the active power filter circuit comprising a third leg comprising a fifth switch and a sixth switch, the main inverter circuit connected to a secondary side of a high frequency transformer and a grid filter in series, and adapted to be connected to an AC load, a primary of the high frequency transformer and a capacitor connected in series to the active power filter leg and an H-bridge leg.

The application discloses a direct torque control method and system considering DC bus voltage imbalance, and relates to the field of motor control. The method comprises the following steps: determining the distribution law of voltage vectors in the fundamental wave alpha-beta subplane and the harmonic x-y subplane when the DC bus voltage is unbalanced; determining three groups of virtual vector groups according to the distribution law and a set condition; the set condition is that the distribution of three basic voltage vectors in the harmonic x-y subplane is greater than 180 degrees, and the three basic voltage vectors are composed of two large vectors and one medium vector in the fundamental wave alpha-beta subplane; obtaining the optimal virtual vector based on the three groups of virtual vector groups according to the DC bus voltage ratio, the sector K value, the system torque and the flux demand; sorting the switches in two two-level three-phase voltage source inverters according to the action time of the three basic vectors in a control period, obtaining the optimized switch sorting, and then controlling the voltage source inverters. The application can efficiently operate under the DC bus voltage imbalance.

The application provides a single-sensor phase current reconstruction three-phase voltage source inverter fault diagnosis method, solves the feasibility and diagnosis time of open-circuit fault diagnosis of the single-current sensor three-phase voltage source inverter, and comprises the following steps: firstly, analyzing the existing mechanism of the direct-current bus single-sensor current unobservable area, and the voltage vector synthesis mechanism under four types of faults, i.e. single-tube open circuit, different-phase same-side double-tube open circuit, different-phase different-side double-tube open circuit and same-phase double-tube open circuit; then, replacing the zero vector with two complementary effective voltage vectors, realizing reliable reconstruction of the fault phase current in the current unobservable area; finally, the inverter fault diagnosis method composed of three diagnosis criteria, i.e. the current vector phase angle, the average current vector modulus and the phase angle, realizes the fault diagnosis of the three-phase voltage source inverter under the single-current sensor. The application realizes the open-circuit fault diagnosis under the single-sensor phase current reconstruction, and the method can effectively and quickly locate the fault power tube.

The disclosure is directed to an island network detection method using a voltage-impressing converter, and includes determining the frequency and phase of a voltage curve of a sub-network connected to a network connection point of the converter, and generating a voltage curve using a bridge circuit of the converter with the determined frequency. The method also includes determining a correlation between a first temporal variation and a second temporal variation of an output exchanged by the converter with the sub-network, and detecting an island network if the determined correlation undershoots a specified correlation measurement.

The application discloses a multi-harmonic suppression method for a dual three-phase permanent magnet synchronous motor, and comprises the following steps: S1, a model of a dual three-phase permanent magnet synchronous motor driving system is established; a six-dimensional voltage vector is constructed through a switching state generated by a voltage source inverter, and a stator voltage vector is decomposed by adopting a vector space decomposition method to establish a voltage equation; S2, multi-source harmonic distortion characteristics are analyzed; current harmonic components caused by phase group asymmetry, non-sinusoidal distribution of counter electromotive force and nonlinearity of the inverter are respectively identified and analyzed; S3, a harmonic suppression controller based on an online neural network assisted linear extended state observer (ONN-assisted LESO) is designed; a super-local model is constructed to describe stator current dynamics; an auxiliary neural network compensator is introduced; a weight adaptive law is designed in combination with Lyapunov stability analysis, a forward Euler method is adopted to realize discretization control, and a voltage reference value is generated to realize real-time suppression of multi-harmonics. The application can effectively realize multi-harmonic suppression under different operating conditions, and meanwhile, fast dynamic response and robust current performance are maintained.

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.

The invention discloses a hybrid cascaded H-bridge static synchronous compensator and a control method thereof. The hybrid cascaded H-bridge static synchronous compensator comprises a cascaded H-bridge static synchronous compensator and a neutral point clamping type three-phase three-level voltage source inverter which is connected with the cascaded H-bridge static synchronous compensator in series. According to different operation conditions, the hybrid cascade H-bridge static synchronous compensator can work in different working states, and the H-bridge static synchronous compensator provides reactive power support in a pure reactive compensation state; active power exchange is not carried out in a steady state; the capacitor voltage source is charged in the charging state; in a low inertia support state, inertia power support is provided by energy stored by a direct current capacitor in the cascaded H-bridge static synchronous compensator; and in a high inertia support state, inertia power support is provided by the midpoint clamping type three-phase three-level voltage source inverter. According to the invention, while the excellent reactive compensation capability of the H-bridge static synchronous compensator is inherited, the inertial support capability of the H-bridge static synchronous compensator is enhanced, and more reliable dynamic frequency support is provided for a low-inertia power grid.

The invention provides a robust model prediction control method and system suitable for a coreless motor under parameter variation, and relates to the field of motor control, and the system comprises a signal collection module which is used for collecting the three-phase current and DC bus voltage of the coreless motor; the on-line parameter identifier is used for identifying estimated values of stator resistance, inductance and flux linkage based on the three-phase current and the direct-current bus voltage of the coreless motor and the on-off state of the last period; the model prediction controller is used for updating a prediction model according to the estimated values of the stator resistance, inductance and flux linkage, and determining the optimal switching state of the next period through the updated prediction model based on an enhanced cost function and robust constraint processing; and the voltage source inverter is used for driving the coreless motor to operate based on the optimal on-off state of the next period, and has the advantage of improving the operation stability and the dynamic performance of the coreless motor under the complex working condition.

A system can include a direct current (DC) voltage source (104) and a hybrid-level five phase voltage source inverter. The hybrid-level five phase voltage source inverter can include an input side, an output side, and a DC link. The input side can be coupled to the voltage source (104) and configured to store a charge (106a, 106b). The output side can be configured to provide a five-phase alternating current (AC) output. The DC link can couple the input side and a first AC phase output of the five-phase AC output. The DC link can include a bidirectional switch (112a, 112b) between the input side and the first AC phase.

The application discloses a static reactive power compensation device based on ZYNQ, which comprises a main controller, a voltage source inverter, a reactor, a power module and a ZYNQ module; a microprocessor, a ZYNQ chip and a first FPGA chip are arranged in the ZYNQ module; a driving board and a first turn-off semiconductor device are arranged in the power module; the driving board is connected with the main controller; the driving board is internally provided with a second FPGA chip; the first turn-off semiconductor device is internally provided with a switch tube S1, a switch tube S2, a switch tube S3 and a switch tube S4; the driving board is used for sending PWM waves; the switch tube S1, the switch tube S2, the switch tube S3 and the switch tube S4 are used for receiving the PWM waves; the first FPGA chip is connected with the second FPGA chip; the first FPGA chip is used for processing analog quantity zero drift; the second FPGA chip is connected with a fiber board through backboard LVDS wiring; and the fiber board is connected with a unit driving board through a transceiving optical fiber. The device can realize efficient real-time dynamic reactive power compensation, guarantee the stability of data transmission and realize high integration of the chip.

This invention provides a sensorless virtual vector quasi-sliding mode predictive control method for T-type inverters. For three-phase, three-level T-type voltage source inverters, it directly embeds the discrete sliding mode surface into the cost function of model predictive control, combining the strong robustness of sliding mode control with the fast dynamic response of predictive control. By synthesizing a set of virtual voltage vectors composed of multiple basic voltage vectors with a zero algebraic sum of midpoint currents, it achieves unweighted factor-free autonomous balancing of the midpoint potential. A full-dimensional state observer is designed to estimate the capacitor current, enabling sensorless operation. A three-step screening strategy is proposed, significantly reducing the number of candidate virtual voltage vectors from 69 to 14, substantially reducing computational complexity. This invention solves the problems of insufficient robustness, significant chattering, cumbersome weighting factor tuning, high sensor dependence, and heavy computational burden in existing technologies, improving the inverter's output waveform quality, dynamic response, parameter robustness, and engineering feasibility.

The invention provides a voltage source inverter open-circuit fault diagnosis method. The method comprises the following steps: in each PWM interruption period, obtaining a three-phase stator current and a PWM modulated reference voltage signal, and determining a stator voltage vector required by a voltage model; utilizing the deviation between the current model flux linkage and the voltage model flux linkage to obtain a compensation voltage vector; converting the compensation voltage vector into a three-phase compensation voltage through inverse Clark transformation; the periodic integral average feature of a certain phase is converted from time domain integral to phase angle domain integral, and periodic features of the three-phase compensation voltage are extracted in a phase angle domain; constructing a three-phase absolute periodic characteristic according to the periodic characteristic, and comparing the three-phase absolute periodic characteristic with a first fault detection threshold value to obtain a fault mark; and constructing a fault variable vector, mapping the fault variable vector to 1, 0 or-1 according to a second fault detection threshold value, and positioning a fault switch tube according to a table look-up rule. Under the conditions of variable speed, variable load and parameter mismatch, rapid and low-calculation-amount online diagnosis and positioning can be realized.

The invention relates to the technical field of voltage source type inverters, particularly discloses a harmonic voltage compensation controller and a harmonic voltage compensation control method of a three-phase voltage source type inverter, and aims to solve the problem that the harmonic voltage compensation of the three-phase voltage source type inverter cannot be realized under the condition of filter parameter perturbation and nonlinear load. The technical problem of how to ensure the global bounded stability of the system and effectively compensate the harmonic voltage under the condition of simplifying the sensor configuration is solved. According to the invention, a nonlinear double-closed-loop control structure only needing a filter inductance current sensor and a capacitor voltage sensor is designed, an improved passive control equation is adopted in a voltage outer loop, and a nonlinear control item combining a voltage error absolute value item and a sign function is introduced in a current inner loop; therefore, under the condition that only two control parameters are used, effective suppression of the harmonic voltage is achieved, low total harmonic distortion of the output voltage is still kept when parameter perturbation is large, meanwhile, high robustness to load sudden change, reference voltage switching and frequency change is achieved, and system cost and control complexity are remarkably reduced.

The invention discloses a parallel power quality control method, system and equipment based on a transformer-VSI coupling structure, and a storage medium, and relates to the technical field of power electronics and power quality control, the method comprises the following steps: detecting the primary current of a transformer, extracting a fundamental component, and generating two paths of orthogonal fundamental reference signals; the synthesized signal controls the voltage source inverter to output controllable fundamental wave voltage to the secondary side of the transformer; continuously adjustable four-quadrant equivalent impedance is formed on a primary side through interaction of voltage and current, and reactive compensation, harmonic suppression and fault current limiting are synchronously realized by combining the harmonic low-resistance characteristic of the transformer; according to the invention, reactive, harmonic and current-limiting integrated treatment can be realized, and the number and cost of equipment are reduced; stable operation of the sensitive load is guaranteed, and complex detection hardware is omitted.

This invention discloses a low-voltage standby automatic transfer control method and device compatible with photovoltaic (PV) and energy storage, applied to a primary / standby power switching system. The method includes: at the moment of a mains power failure, utilizing an integrated hybrid inverter module, before the ATS physically disconnects the mains power, dynamically buffering the load through energy storage batteries to compensate for the difference between the power required by the load and the actual output power of the PV, thereby maintaining the stability of the load-side voltage and frequency; seamlessly switching from mains power to a combined PV and energy storage power supply mode without affecting the power quality on the load side; and after the switch is completed, dynamically adjusting the discharge depth and rate of the energy storage based on real-time light intensity and load changes using an adaptive impedance matching algorithm. This invention, by setting up a hybrid inverter integrating a high-speed DSP controller and a voltage source inverter topology, enables smooth, efficient, and seamless switching and coordinated power supply between the grid, PV, energy storage, and load during automatic grid switching.

A system is provided that includes multiple motors, each respective motor comprising three phases; a voltage source inverter circuit comprising multiple respective inverter legs; each respective inverter leg coupled to drive at least one phase of at least one of the respective of the respective motors; wherein a first shared inverter leg is coupled to drive a first phase of a first motor and drive third phase of a second motor; and wherein a second shared inverter leg is coupled to drive a third phase of the second motor and a first phase of a third motor.

This invention discloses a model-free predictive control method and device for an LC-filtered voltage source inverter (VSI). The method includes establishing a mathematical model of the VSI in an αβ stationary coordinate system, obtaining its eight basic vectors; reconstructing the state-space equations of the LC-filtered VSI to achieve real-time updates of voltage and current gradients; predicting future voltage and current based on the updated voltage and current gradients and sampled voltage and current, and calculating voltage and current references; applying the calculated algebraic value functions of the predicted voltage and current, selecting weighting factors to eliminate coupling effects caused by the LC filter; and substituting the predicted voltage and current corresponding to the eight vectors into the value functions for evaluation, selecting the vector with the smallest value function value as the optimal vector for application in the next control cycle. This invention uses measured voltage and current dual gradients to eliminate the dependence of predictive control on system parameters, improving parameter robustness.

The present application relates to a kind of voltage source inverter model predictive control method based on trajectory tracking, comprising the following steps: S1, establish voltage source inverter LC filter prediction model, the LC filter prediction model is calculated next control period output reference voltage by given current output reference voltage reference angular frequency and amplitude;S2, multiple target output reference voltage points are set in single control period based on trajectory tracking's model predictive control module, voltage trajectory tracking is carried out, and the optimal next control period output reference voltage is obtained, to replace LC filter prediction model next control period output reference voltage;S3, the duty ratio of three-phase full-bridge upper and lower bridge arm switch is calculated based on carrier's space vector adjustment module, and three-phase full-bridge upper and lower bridge arm switch tube of voltage source inverter is sequentially controlled, the synthesis of output reference voltage is realized.Affirmative effect is that it has good steady state and dynamic performance, and the required computing power is less.