30 results about "Pwm converter" patented technology

The present invention provides a topology, method and system for bi-directional power conversion of excitation power supply for power battery testing, wherein the topology comprises a three-phase PWM (pulse width modulation) converter, a high-frequency isolation three-level LLC (logical link control) resonant converter and a DC-DC (direct current) converter forming a topology structure for a three-stage power conversion; an input end of the three-phase PWM converter is connected to a power grid side; the high-frequency isolation three-level LLC resonant converter is connected between the three-phase PWM converter and the DC-DC converter in series and is configured for realizing bi-directional DC voltage conversion and isolation, and to raise a busbar voltage between the high-frequency isolation three-level LLC resonant converter and the DC-DC converter; and, the DC-DC converter is configured to generate charging and discharging excitation currents for a power battery testing.

The utility model relates to the technical field of power supply circuits, in particular to a bipolar output circuit for a photoresist constant-temperature power supply, which comprises a bipolar inverter circuit, a driving control circuit and an auxiliary power supply circuit. The isolation driving circuit uses a simple optical coupler device, a special digital driver or a high-speed driving optical coupler is not needed, an upper tube driving auxiliary power supply directly couples to generate two paths of driving power supplies through a mode of adding an auxiliary winding on an inductor of a conventional PWM converter, an additional independent auxiliary power supply is not needed, a bipolar voltage output function is realized, and the voltage output is realized. The circuit has the advantages of no physical contact, long service life, simple circuit and low cost.

To further improve a suppression function in a three-phase inverter apparatus in which a common mode voltage is suppressed using a transformer.SOLUTION: A three-phase inverter apparatus 14 includes an input-side transformer device 18, a three-phase PWM converter 20, and an output-side transformer device 22 in this order from an input side to an output side. The input-side transformer 18 and the output-side transformer device 22 respectively suppress a common mode voltage at the input side and the output side in accordance with input-side and output-side secondary voltages generated from input-side and output-side primary voltages corresponding to the common mode voltage.SELECTED DRAWING: Figure 1

The invention discloses a wide-gain ZVS hybrid direct-current converter based on double transformers, which belongs to the technical field of DC / DC direct-current converters and comprises an LLC resonant converter and a PWM full-bridge converter. The LLC resonant converter comprises a first full-bridge inverter, an LLC resonant cavity, a first transformer and a first full-bridge rectifier; the PWM full-bridge converter comprises a second full-bridge inverter, a second transformer and a second full-bridge rectifier; the primary side of the LLC resonant converter and the primary side of the PWM full-bridge converter share one inverter bridge arm, and the secondary side of the LLC resonant converter and the secondary side of the PWM full-bridge converter share one rectifier bridge arm. The hybrid direct-current converter provided by the invention can give full play to the advantages of high efficiency of the LLC resonant converter and wide output regulation capability of the PWM converter so as to realize advantage complementation of the two converters, so that when a converter system has a wide gain range, the loss of the system can be reduced, and the overall efficiency can be improved.

A controller for an AC-DC converter including a rectifier circuit that converts AC input voltage into DC output voltage uses control logic to control the rectifier circuit according to two or more operating modes. Each operating mode determines a gain of the rectifier circuit. The controller selects an operating mode from the two or more operating modes based on at least one of an AC input voltage value and a required DC output voltage value. The AC-DC converter provides a wide range of DC output voltage with power factor correction. The controller may be used with AC-DC converter topologies such as boost converter, isolated boost converter, PWM converter, LLC resonant converter, and LCC resonant converter.

The invention discloses a position-sensorless control method and system for a doubly-fed induction wind generator, and the method comprises the steps: collecting a three-phase stator current value and a three-phase rotor current value, obtaining a stator current vector and a rotor current vector under a static coordinate system, inputting the two vectors into a phase-locked loop, and obtaining a phase-locked loop; obtaining an included angle between the stator current vector and the rotor current vector; removing the power grid voltage from the closed-loop control loop, and only taking the power grid voltage as a feed-forward item to carry out feed-forward compensation on the included angle; the voltage of the direct current bus is kept stable through the grid-side PWM converter; giving an active instruction according to the rotor speed; and the active instruction and the reactive instruction are converted into an instruction of a rotor current quadrature-direct axis component through a rotor side PWM converter so as to realize decoupling control. The method is mainly used for position-sensorless control of a DFIG wind driven generator or a similar topological structure, does not need traditional position sensor structures such as an encoder and a rotary transformer, and has better power grid fault ride-through capability and robustness.

This invention proposes a design method for a full-band compact hybrid EMI filter circuit based on current feedback. The method includes: constructing an electromagnetic interference test circuit to obtain the common-mode EMI spectrum required for attenuation by the PWM converter, and establishing a high-frequency equivalent circuit for the PWM converter; obtaining the optimal hybrid EMI filter topology based on the high-frequency equivalent models of active and passive EMI filter circuits and the noise attenuation characteristics of the hybrid EMI filter circuit topology; designing the active EMI filter topology and its high-frequency equivalent model based on the noise cancellation principle of the active EMI filter and the common-mode EMI spectrum; designing the active EMI filter topology based on the noise cancellation principle of the active EMI filter and the common-mode EMI spectrum; designing the passive EMI filter structure based on the common-mode EMI noise spectrum after adding the active EMI filter; and designing the hybrid EMI filter circuit based on the hybrid EMI filter topology, the active EMI filter topology, the passive EMI filter structure, and the high-frequency equivalent models of the active and passive EMI filter circuits.

The present invention proposes a three-phase active APFC high-frequency control method based on the impulse equivalent principle, including the following steps: 1. Obtaining the voltage amplitude, frequency and phase information of the power grid; 2. Performing DQ rotation coordinate transformation on the three-phase input current; 3. Obtaining the output DC voltage information; 4. Performing closed-loop feedback control in the DQ coordinate system to calculate the three-phase modulation signal; 5. Multiplying the three-phase modulation signal and the carrier signal by the same proportional coefficient K (K≤1) to obtain a high-frequency pulse equivalent to the initial pulse impulse; 6. Using the regular sampling method to calculate the PWM drive signal to drive the main switch tube. The high-frequency control method proposed by the present invention is applicable to all PWM converters, can greatly reduce the volume and weight of the converter, and the system works stably and reliably.

The invention belongs to the technical field of control of three-phase parallel PWM converters. The invention discloses a laser ranging and predictive synchronous control method for a three-phase parallel PWM (Pulse Width Modulation) converter fused with anti-interference correction. The method is characterized by comprising the following steps: 1) dynamic zero-sequence circulating current suppression: constructing a self-adaptive adjustment mechanism based on real-time characteristics of zero-sequence current; according to the method, efficient, stable and reliable operation of a converter system can be achieved, the circulating current suppression precision can be improved, the signal synchronization reliability can be improved, and the environment adaptability can be enhanced.

The present disclosure relates to dynamically enhancing loop response after recovery from a fault condition. A method for dynamically enhancing loop response after recovery from a fault condition includes detecting a fault condition in response to a programmed output voltage of a pulse width modulation (PWM) converter decreasing below an input voltage of the PWM converter. In response to detecting the fault condition, sampling a peak voltage at an end of at least one clock cycle of a plurality of clock cycles of the PWM converter, wherein the peak voltage is proportional to a sensed current conducted through a transistor. Pre-setting an error output of an error amplifier to an error value determined from the peak voltage. Controlling a PWM driver with the error value to drive the transistor. In response to the input voltage increasing above the programmed output voltage, charging an output load to the programmed output voltage with the transistor.

The utility model discloses a power supply output voltage maintaining and extending circuit which comprises an AC input module, an EMI filtering module, an input rectification filtering module, a PWM converter module, an output rectification filtering module and a power supply and battery output module which are connected in sequence, the PWM control module is connected to the PWM converter module; the output rectification filtering module is also connected with a battery charging module and is connected to the power supply and battery output module through a control circuit module, and the control circuit module is provided with a battery unit. A battery charging module and a control circuit module are additionally arranged at an output rectifying and filtering module to charge and store power of a battery unit, the battery unit is used for storing electric energy when a power supply normally supplies power, and the battery unit is switched to supply power through the control circuit module after the power supply is cut off; therefore, the power supply can still be provided for more than ten seconds after power failure, so that the industrial computer has enough time to store data.

The techniques and circuits described herein include a solution for multi-mode current control of pulse width modulation (PWM) converters. In some aspects, a slope control circuit (116) is used to simulate a current through an inductor (102) as a voltage across a switched capacitor (144) during a discharge phase. A slope control voltage (134) is used to modify a slope of the simulated current waveform relative to the actual inductor current waveform. The converter may selectively operate in a continuous conduction mode (CCM), a discontinuous conduction mode (DCM), or a transition mode (TM), respectively, depending on whether the magnitude of the modified slope is greater than, less than, or equal to the actual slope.

The invention discloses a gearbox dynamic loading test system and method based on energy feedback, and the system is used for carrying out a multi-working-condition dynamic simulation loading test on a tested gearbox. Comprising a main driving module, a composite loading module, an intelligent energy management unit, a multi-dimensional sensor array and a central cooperative controller. And the composite loading module comprises a multi-degree-of-freedom loading mechanism and a load motor, and can apply a non-rotating acting force to the gearbox body and apply a rotating acting force to the output shaft respectively, so that multi-degree-of-freedom composite loading is realized. The intelligent energy management unit realizes efficient bidirectional energy flow between system internal direct current and power grid alternating current through a super capacitor module and a four-quadrant PWM converter, power fluctuation is effectively stabilized, and energy feedback efficiency is improved. And the central cooperative controller performs cooperative control on the main driving module, the composite loading module and the energy management unit according to real-time monitoring data of the multi-dimensional sensor array, so that the loading precision is remarkably improved.

An apparatus includes a converter circuit (e.g., a buck / boost converter) comprising at least one transistor and a pulse width modulated (PWM) signal generator circuit configured to receive a duty command signal, to generate at least one PWM signal for the at least one transistor responsive to the duty command signal, and to selectively disable the at least one PWM signal responsive to at least one gating signal. The apparatus further includes a gating circuit configured to generate the at least one gating signal responsive to a current sense signal representing a current through the converter circuit.

The invention belongs to the technical field of large iron rail transit power supply, and particularly relates to a working condition judgment method suitable for an alternating current traction network and a PWM converter feedback control method and system. The method comprises the following steps: respectively determining a traction network voltage change value U1pu and an alternating current line voltage change value U2pu corresponding to the PWM converter in a current time window under the conditions that an alternating current single-phase side of the PWM converter is connected to a traction network corresponding to the PWM converter and an alternating current three-phase side is connected to an alternating current line for power supply and electric quantity feedback; the AC line comprises an adjacent AC traction network of the traction network; if the absolute value of U1pu-U2pu is less than or equal to a first set positive value, judging that the voltage fluctuation of the alternating-current line causes the voltage fluctuation of the traction network; if U1pu-U2pu is less than 0 and the absolute value is greater than a first set positive value and is less than a second set positive value at the same time, determining that the locomotive is started or passes to cause voltage fluctuation of the traction network; if U1pu-U2pu is larger than the second set positive value and smaller than the third set positive value, it is judged that locomotive braking causes traction network voltage fluctuation.

The application discloses a gear box dynamic loading test system and method based on energy feedback, which is used for dynamic simulation loading test of a measured gear box under multiple working conditions. The system comprises a main driving module, a composite loading module, an intelligent energy management unit, a multi-dimensional sensor array and a central cooperative controller. The composite loading module comprises a multi-degree-of-freedom loading mechanism and a load motor, which can respectively exert non-rotating force on the gear box body and rotating force on the output shaft, thereby realizing multi-degree-of-freedom composite loading. The intelligent energy management unit realizes efficient bidirectional energy flow between the system internal direct current and the power grid alternating current through a super capacitor module and a four-quadrant PWM converter, thereby effectively suppressing power fluctuation and improving energy feedback efficiency. The central cooperative controller cooperatively controls the main driving module, the composite loading module and the energy management unit according to real-time monitoring data of the multi-dimensional sensor array, thereby significantly improving loading accuracy.

The invention discloses a two-level PWM converter switching waveform determination method for electromagnetic interference prediction, and belongs to the field of power electronic electromagnetic compatibility. According to the method, based on steady-state quantity and transient quantity solution of a state equation set, a switching waveform containing a nonlinear transient state can be efficiently obtained, and then through conversion and detection processing of an equivalent interference source, the switching waveform containing the nonlinear transient state can be obtained; a broadband high-precision switch waveform frequency spectrum for electromagnetic interference prediction can be obtained; benefited from the specified initial value of the state variable, the nonlinear device model, the simplified calculation of the steady-state value of the state variable and the parallel calculation of the transient value, the method has the advantages of good convergence, high precision and high calculation efficiency at the same time, and realizes the calculation of the switching waveform spectrum for the electromagnetic interference prediction from the physical parameters of the switching device; the spectral range covers 0-1GHz, and the calculation time is only within hundred seconds; therefore, the electromagnetic interference modeling speed can be increased, the prediction precision can be improved, and finally the electromagnetic interference suppression design of the two-level PWM converter can be accurately guided.

The utility model discloses an analog voltage signal isolation acquisition circuit. The circuit comprises an APC unit, a digital isolation unit, a shaping filtering unit, an operational amplifier output unit and an MCU acquisition unit. The APC unit comprises a filter circuit, a voltage signal to PWM converter U1 and a decoupling capacitor C2. The digital isolation unit comprises a third capacitor C3, a fourth capacitor C4 and a digital isolator U2; the shaping filtering unit comprises a second resistor R2, a fifth capacitor C5, a third resistor R3 and a sixth capacitor C6; the operational amplifier output unit comprises an operational amplifier U3, and the MCU acquisition unit comprises a chip U4. According to the utility model, the acquired analog voltage signals are more complete and stable, are not easy to be influenced by interference signals, have a fast response rate and a simple circuit structure, and have a great practical value.

This PWM converter comprises: a power conversion circuit comprising a three-phase bridge circuit in which a switching element is provided in each of the high potential side upper arm and low potential side lower arm of each of three phases and converting AC power of a three-phase AC power supply into DC power by turning on and off the switching element; a generation circuit which generates a switching command including an on command for turning on the switching element and an off command having an inverse relationship with the on command and turning off the switching element; and an adjustment circuit which generates a switching command for prohibiting all the three-phase switching elements of the upper arms from being turned on at the same time and prohibiting all the three-phase switching elements of the lower arms from being turned on at the same time.

The application discloses a wide-gain ZVS hybrid DC converter based on double transformers, and belongs to the technical field of DC / DC DC converters. The wide-gain ZVS hybrid DC converter comprises an LLC resonant converter and a PWM full-bridge converter. The LLC resonant converter comprises a first full-bridge inverter, an LLC resonant cavity, a first transformer and a first full-bridge rectifier. The PWM full-bridge converter comprises a second full-bridge inverter, a second transformer and a second full-bridge rectifier. The LLC resonant converter and the PWM full-bridge converter share a common inverter bridge arm on the primary side and share a common rectifier bridge arm on the secondary side. The hybrid DC converter can fully exert the advantages of high efficiency of the LLC resonant converter and wide output regulation capability of the PWM converter, so as to realize complementary advantages of the two converters, reduce the system loss and improve the overall efficiency when the converter system has a wide gain range.

The utility model relates to the technical field of switching power supplies, and provides a multi-point monitoring feedback switching power supply, which comprises a PWM (Pulse Width Modulation) converter U1, a power switch U3, a fast charge protocol chip U4, and an inductor LFI, a rectifier BD1, an inductor LF2, a transformer T1A and an MOS (Metal Oxide Semiconductor) tube Q1 which are sequentially connected from a power supply input to a power supply output interface J1, the first output end of the rectifier BD1 is connected with the CSS end of the PWM converter U1 through the resistor R2 and the resistor R3, the Drain end of the PWM converter U1 is connected with the second input end of the transformer T1A, the first output end of the transformer T1A is connected with the drain electrode of the MOS tube Q1, the source electrode of the MOS tube Q1 is connected with the power supply output interface J1, the grid electrode of the MOS tube Q1 is connected with the GATE end of the fast charge protocol chip U4, and the second output end of the transformer T1A is connected with the Drain end of the power switch U3. According to the technical scheme, efficient and stable power supply voltage output is realized.

The application discloses a kind of for doubly-fed induction wind-driven generator's position sensorless control method and system, comprising: acquisition three-phase stator current value and rotor current value, obtain in stationary coordinate system under stator current vector and rotor current vector, two vectors are input phase-locked loop, obtain the included angle between stator current vector and rotor current vector;Remove grid voltage from closed loop control loop, only grid voltage is as feedforward item to the included angle and is feedforward compensation;Through net side PWM converter, maintain DC bus voltage stability;According to rotor speed, give active instruction;Through rotor side PWM converter, active instruction and reactive instruction are converted into the instruction of rotor current cross-axis component, to realize decoupling control.The application is mainly used for DFIG wind-driven generator or similar topology position sensorless control, without the position sensor structure of traditional encoder, rotating transformer etc., with better grid fault ride-through capability and robustness.

The present invention discloses a method for determining a switching waveform of a two-level PWM converter for electromagnetic interference prediction, which belongs to the field of electromagnetic compatibility of power electronics. The method is based on solving steady-state and transient quantities of a state equation group, and can efficiently obtain a switching waveform containing nonlinear transients. After conversion and detection processing of an equivalent interference source, a wideband, high-precision switching waveform spectrum for electromagnetic interference prediction can be obtained. Thanks to the specified initial values ​​of state variables, nonlinear device models, simplified calculation of steady-state values ​​of state variables, and parallel calculation of transient values, the method has the advantages of good convergence, high precision, and high computational efficiency. It realizes the calculation of the switching waveform spectrum for electromagnetic interference prediction from the physical-level parameters of the switching device, with a spectrum range covering 0-1 GHz and a calculation time of only one hundred seconds. This can improve the speed of electromagnetic interference modeling, enhance prediction accuracy, and ultimately accurately guide the electromagnetic interference suppression design of the two-level PWM converter.

The invention discloses a direct-driven wind driven generator side and grid side decoupling prediction control method, and relates to the technical field of wind turbine generators, and the method comprises the steps: building a dual-PWM converter topological structure; collecting a machine side control signal and a network side control signal, and designing a generalized predictive controller; establishing a generalized virtual prediction model; outputting a control signal to a switching mechanism by using the generalized predictive controller, and selecting an actual control signal of an optimal controller output system according to an error switching strategy; outputting a corresponding generalized virtual prediction model output value according to the actual control signal, and calculating an output error as the input of a generalized prediction controller by using the set expected prediction value and the prediction model output value; the MPC control modules are arranged, the output errors, the machine side control signals and the grid side control signals are input to the corresponding MPC control modules, torque control is carried out on the motor side PWM converter, impedance control is carried out on the grid side PWM converter, and therefore the transient performance and the steady-state performance of the system are improved.

The present invention discloses a DC converter topology with adjustable output voltage within a wide input range, which belongs to the technical field of DC-DC converter topology structures, and specifically includes two transmission paths for transferring energy from an input port to an output port. The main channel is a DCX based on LLC. The auxiliary channel includes two stages, the first stage adopts a non-isolated PWM DC converter, and then a small DCX based on LLC is cascaded with it to achieve efficient isolation conversion, and the output voltage is adjusted by adjusting the PWM DC converter. The main channel and the auxiliary channel are connected in series at the input port and in parallel at the output port. The present invention performs triangular wave current mode (TCM) modulation on the PWM converter to achieve zero voltage opening of its switch tube, which significantly reduces the switching loss of the energy transmission auxiliary channel. Therefore, the proposed converter topology can achieve high transmission efficiency within a wide input voltage range.

The application provides an AC-DC converter and a controller thereof, and relates to the technical field of AC-DC converters. The controller for the AC-DC converter comprises a rectifier circuit for converting an AC input voltage into a DC output voltage, and the controller uses control logic to control the rectifier circuit according to two or more operating modes. Each operating mode of the rectifier circuit has a voltage gain, and each operating mode determines the gain of the rectifier circuit. The controller selects one operating mode from the two or more operating modes based on at least one of an AC input voltage value and a required DC output voltage value. The AC-DC converter provides a wide range of DC output voltage and power factor correction. The controller can be used with AC-DC converter topologies such as boost converters, isolated boost converters, PWM converters, LLC resonant converters and LCC resonant converters. Through the controller, the AC-DC converter can achieve optimal performance within a wide voltage variation range.

The invention discloses a primary frequency modulation control method, system and medium of a doubly-fed wind turbine, belonging to the field of wind power generation, and the method comprises: based on the mapping relationship between wind turbine power, pitch angle, wind turbine speed and wind speed, calculating the equivalent wind speed to further calculate the pitch angle compensation signal; calculating the pitch angle reference signal to control the pitch angle of the wind turbine according to the pitch angle compensation signal, wind turbine power and wind turbine speed, and calculating the electromagnetic torque reference signal; calculating the first drive signal to drive the rotor side PWM converter according to the electromagnetic power, output reactive power, three-phase voltage and electromagnetic torque reference signal of the wind turbine; calculating the second drive signal to drive the grid side PWM converter according to the collected wind turbine DC bus capacitor voltage and grid side q-axis current. In the case of inaccurate wind speed measurement, the maximum wind turbine power that should be obtained at the current wind speed can be accurately predicted, and on this basis, the wind turbine can be precisely adjusted to reduce the load.

The invention is suitable for the technical field of electric power, and provides a PWM converter, a control method and a PWM converter grid-connected system, output power adjustment values are added in the integration process of an outer ring PI controller, output power weighted distribution of PWM converters of different models and different capacities is achieved, outer ring parameters and inner ring control do not need to be modified, and the overall performance of the PWM converter is improved. Weighted distribution of the output power of the PWM converter can be achieved only by adjusting the PI control process of the PWM converter, the expandability of the system is guaranteed, and the system adapts to complex and changeable application requirements.

The invention provides a programmable slope compensation circuit applied to a PWM (Pulse Width Modulation) converter. The programmable slope compensation circuit specifically comprises a PWM converter U in a current mode; the device comprises a frequency resistor R1, a frequency resistor R4, a frequency capacitor C2, a slow charging and quick discharging circuit, a compensation depth circuit, a first output signal end U1 and a second output signal end U2, and the compensation depth circuit is composed of a first-stage attenuation network and a second-stage attenuation network. According to the programmable slope compensation circuit applied to the PWM converter, the compensation function can be achieved under various working conditions, the stability of the converter during working is improved, and when the converter works at a light load or a small duty ratio, due to the fact that the amplitude of a sampled current signal is low or the width is narrow, the stability of the converter is improved. Excessive noise picked up at a current sampling or voltage feedback input port is particularly prominent, the noise easily causes irregular pulse width jitter, and the jitter also causes instability of a system. The slope compensation of one depth is used as a bias superposition signal, so that jitter can be effectively suppressed, and meanwhile, the duty ratio precision of output PWM is not influenced.

A PWM converter sensorless control method based on model reference self-adaption belongs to the technical field of power electronic converter control, inductance parameter predictive control is added in the model predictive control of a PWM converter, even if the value of the grid-side input inductance is inaccurate or fluctuates due to the influence of parameters, accurate real-time inductance can be obtained, and the accuracy of the grid-side input inductance is improved. Therefore, the accurate direct-current side voltage is obtained, and the output effect of the post-stage is ensured. Therefore, the method has robustness for the power grid change and the parameter uncertainty of the inductor at the converter side, meanwhile, the number of grid-side voltage sensors required in converter control can be reduced, and the system cost is reduced.