51 results about "Modulation index" patented technology

The invention provides a solid-state transformer. The solid-state transformer comprises a first-stage circuit, a first direct-current bus and a second-stage circuit, the first-stage circuit structure is used for receiving alternating-current electric energy and converting the alternating-current electric energy into first direct-current electric energy. The first DC bus is electrically connected to first DC electric energy. The second-stage circuit is electrically connected to the first-stage circuit through a first DC bus, and is configured to perform isolated step-down DC / DC conversion on the first DC electric energy to generate second DC electric energy. The first stage circuit is configured to operate with a modulation index greater than 1, and the modulation index is defined as a ratio of twice an AC voltage provided by the AC power to a voltage on the first DC bus.

This invention discloses an adaptive fault-tolerant control method for a three-level ANPC inverter. Specifically, based on the influence of a faulty switching transistor on the output voltage vector, the inverter's fault-tolerant modes are classified into zero-level loss and zero-level retention fault-tolerant modes. The maximum modulation index of the inverter's output voltage vector is calculated under both fault-tolerant modes to determine whether the inverter system needs derating. For the zero-level retention fault-tolerant mode, a model predictive current control strategy with duty cycle modulation is adopted, utilizing a virtual zero-voltage vector synthesis method to solve the inverter's midpoint voltage imbalance problem. For the zero-level loss fault-tolerant mode, a cost function representing the fault-tolerant control performance index is designed, and a neural network is used to optimize the weight factors of the cost function. This invention achieves adaptive fault-tolerant control for open-circuit faults in inverters by adopting corresponding model predictive control optimization methods for different fault-tolerant modes, thereby improving the reliability of the inverter system.

An apparatus includes an unfolder with three input terminals connected to a three-phase AC power source and three output terminals, p-terminal, o-terminal, and n-terminal, and a three-port converter connected to the unfolder and feeding a direct current (“DC”) load. The three-port converter includes input capacitors. A feedback control loop includes outputs of a p-terminal modulation index derived from a difference between p-terminal current and a p-terminal reference current and an n-terminal modulation index derived from a difference between n-terminal current and an n-terminal reference current. A feedforward control loop outputs an emulated p-terminal current and an emulated n-terminal current derived from differences between DC-link voltages and ideal DC-link voltages. A duty cycle controller is configured to generate duty cycles controlling switches of the three-port converter derived from the modulation indexes and the emulated currents.

A method is provided for reducing common mode voltages in a system that includes an inverter connected to a motor by a long cable by controlling switches of the inverter to generate voltage vectors that emulate a three-phase sinusoidal waveform by switching between adjacent active vectors and active vectors that are separated by 180 degrees, determining whether a phase angle of the vectors is increasing or decreasing, determining a decision angle within the sector which is a function of a duty cycle offset and a modulation index; and applying duty cycle manipulation rules, including: responding to an increasing phase angle that is less than the decision angle by setting a duty cycle of the adjacent active vectors to a duty cycle high value; and responding to an increasing phase angle that is greater than 60 degrees minus the decision angle by setting the duty cycle to a low value.

Methods, systems, and devices for wireless communications are described. A first wireless device may receive a signal including multiple sets of bits, where each set of bits of the multiple sets of bits is associated with either a first group or a second group based on a respective modulation index for each set of bits. Each set of bits may map to one or more additional bits based on an association of each set of bits with the first group, the second group, or both. The first wireless device may decode either or both of a first message formed at least partially by the one or more additional bits or a second message formed at least partially by respective sets of bits associated with the second group. Each of the first and second messages may be for different channels or for different wireless devices.

A technique for recursively determining the modulation index for controlling a DC-AC inverter is disclosed. The modulation index can first be selected. The input voltage to the power inverter can be measured. Based on the input voltage and the selected modulation index, the output voltage of the power inverter may be estimated. The output current of the power inverter can be measured. Using the estimated output voltage and the measured output current, the active power and reactive power can be determined. Using the active power and reactive power, the updated modulation index can be determined. The updated modulation index coefficient can be used to generate a pulse-width modulated signal used to control the power inverter.

The application provides a control system and a control method of an LLC resonant induction heating power supply. The LLC resonant induction heating power supply heats a load through a half-bridge inverter circuit. The control system comprises a modulation unit and an odd harmonic control unit. The modulation unit is used to determine a target modulation index and a fundamental frequency, and to realize an output frequency adjustable high-frequency alternating square wave by controlling the switching of each power device of the half-bridge inverter circuit. The waveform of the high-frequency alternating square wave has a half-wave symmetric structure with a fundamental period as a cycle. The odd harmonic control unit is used to predict an optimal switching angle combination of each power device under the condition of meeting an odd harmonic suppression target. The modulation unit generates a modulation signal for controlling the switching of each power device based on the optimal switching angle combination. The application can significantly improve the harmonic suppression effect of a high-frequency induction heating power supply under a dynamic load.

Control system (24) for controlling the operation of a multiphase electrical machine (19), comprising: a signal generator (210) configured to generate a number n of duty cycle signals of a pulse width modulation (PWM) scheme as a combination of a continuous PWM scheme and a non-continuous PWM scheme, the combination being based on a value of a mixing coefficient Σ; wherein the signal generator (210) is configured to use each of the duty cycle signals to control the switching of a DC power to a corresponding phase of the multiphase electrical machine (19); wherein the signal generator (210) is configured to use a mixing function to determine a relative weighting of both the continuous PWM scheme and the non-continuous PWM scheme to generate the number n of duty cycle signals;wherein the mixing function is calculated on the basis of a difference between the value of the mixing coefficient γ and two thresholds a1, a2; and wherein the duty cycle signals are generated via the combination of the continuous PWM scheme and the discontinuous PWM scheme, based on the fact that the value of the mixing coefficient γ is greater than or equal to a first threshold a1 and less than a second threshold a2, where the second threshold a2 is greater than the first threshold a1; characterized in that n is an integer greater than 3 and that the mixing function determines the mixing coefficient γ as a function of the modulation index mi and a phase current Is using the following formula: γ(mi,Is)={0.50≤γ; <a10.5×(1−&lgr;−a1a2−a1)a1≤&lgr;<a20a2≤&lgr;<1wobei &lgr; eine Zwischenvariable ist, die definiert ist durch:&lgr;(mi,Is)=b⋅IsIsmax+(1−b)⋅mi,0≤b≤1 where b is a tunable constant and Ismax is the maximum current of the multiphase electric machine (19).;

A common-mode voltage generation method is provided and comprises: obtaining a DC voltage, AC voltages, and a modulation index of a DC / AC converter; generating an injection instruction of a common mode voltage for pulse width modulation based on the DC voltage, the AC voltages, the modulation index, and an adjustable modulation control factor; and providing the injection instruction to the converter, in which the injection instruction is used to instruct the converter to adjust the common mode voltage variably in accordance with changes in the modulation index and the modulation control factor. This disclosure enables the automatic adjustment of the common-mode-voltage according to the DC voltage and the AC voltages, based on pre-defined performance of the converter in terms of switching losses, CMV, and harmonics. With this automatic adaption, the modulation of the converter is changed between discontinuous mode to continuous mode.

Embodiments disclose methods for enabling an unequal modulation in a wireless local area network. The method determines a number of spatial streams (NSS) per UE associated with a user. The method determines a type of unequal modulation to be enabled at the UE. The method identifies a primary spatial stream, based on the type of unequal modulation to be enabled at the UE (102). The method enables assignment of the at least one unequal modulation index to all the spatial streams based on at least one of the NSS, the maximum difference in the modulation index allowed across different spatial streams per user, the type of unequal modulation to be enabled at the UE (102) and the identification of the primary spatial stream.

The present invention discloses a control method, device, three-level converter, storage medium, and processor for a three-level converter. The method includes: transforming the space vector of the three-level converter from a rectangular coordinate system to a 60° coordinate system; re-dividing the sectors of the space vector of the three-level converter under a virtual space vector modulation strategy in the 60° coordinate system; re-synthesizing the space vector of the three-level converter based on the re-divided sectors; calculating the action times of adjacent re-synthesized vectors; and allocating the vector action times of the three-level converter based on the calculated action times of adjacent vectors to control switches in the three-level converter and achieve midpoint potential balance control of the three-level converter. This solution, by re-dividing the sectors and re-synthesizing the vectors using the 60° coordinate system, achieves midpoint potential balance under high modulation index, which is beneficial for improving the output performance of the three-level converter.

The application belongs to the technical field of rectifiers, and proposes a sector division-based optimization control method and system for DC link current ripple in a three-phase current source rectifier, the main scheme of which is as follows: firstly, a dual-variable operating region judgment mechanism based on modulation index and sector angle is used to identify the operating region of the current three-phase current source rectifier; secondly, a corresponding modulation strategy is selected based on the operating region of the current three-phase current source rectifier, so that each modulation strategy operates in its optimal interval; finally, according to the selected modulation strategy, the action time of each reference vector is integrated to finally generate a drive signal sequence of the three-phase current source rectifier. The application can ensure the power quality output by the three-phase current source rectifier.

An electrified vehicle includes a motor having a plurality of windings, a first inverter, a main battery, and a controller configured to perform linearization control on a voltage modulation index, so as to limit a change rate of the voltage modulation index during switching between a first driving mode and a second driving mode while an auxiliary battery is mounted.

The invention discloses a high-bit-rate multi-index continuous phase modulation signal receiver which comprises a frequency conversion and conditioning module, an AD daughter card module, a frequency synthesis module, an FPGA chip 1 and an FPGA chip 2. Wherein the frequency conversion and conditioning module is configured to complete down-conversion and AGC (Automatic Gain Control) of an S-band radio frequency signal and output an S-band intermediate frequency signal; the AD daughter card module is configured to convert a received S-band intermediate frequency signal into an intermediate frequency digital signal; the frequency synthesis module is configured to complete system work clock generation; the FPGA chip 1 is configured to complete Doppler frequency capture of a received intermediate frequency digital signal, send the captured signal to the FPGA chip 2, receive a demodulation information sequence fed back by the FPGA chip 2 to complete LDPC decoding, descrambling and frame synchronization of corresponding data, and output telemetry data; the FPGA chip 2 is configured to perform carrier phase tracking, modulation index synchronization, timing synchronization and sequence detection on received data.

This invention relates to a low-complexity demodulation method and system for multi-exponential CPFSK signals. The method includes the following steps: Based on the characteristics of multi-exponential CPFSK signals, data features are extracted by processing the signals, including in-phase I-path sampling, quadrature Q-path sampling, and first-order phase difference. A signal dataset is generated based on the data features, modulation index, and labels, and preprocessed. A demodulation model based on a convolutional neural network and a demodulation model based on convolution and attention mechanisms are designed, using data features and modulation index as inputs and the demodulation result as output. A loss function is constructed based on the error between the predicted demodulation result and the labels, and the demodulation model is trained. The trained demodulation model is tested and post-processed. Based on the post-processing result, one of the demodulation models is selected for demodulating the CPFSK signal. Compared with existing technologies, this invention has advantages such as reducing demodulation complexity and improving the real-time performance of the demodulation process.

The present disclosure relates to a method, system, device and medium for hybrid modulation of a Doppler omnidirectional beacon signal, and relates to the field of antenna or signal and system technology. The method comprises: respectively configuring a first preset additional odd modulation function and a first preset additional even modulation function on one side of a preset odd mixing function and a preset even mixing function, to obtain a first upper sideband carrier signal and a first lower sideband carrier signal corresponding to the Doppler omnidirectional beacon; respectively configuring a second preset additional odd modulation function and a second preset additional even modulation function on the other side of the preset odd mixing function and the preset even mixing function, and respectively performing anti-phase modulation on the second preset additional odd modulation function and the second preset additional even modulation function according to a set modulation index, to obtain a second upper sideband carrier signal and a second lower sideband carrier signal corresponding to the Doppler omnidirectional beacon. The embodiment of the present disclosure can realize hybrid modulation of the Doppler omnidirectional beacon signal.

A method for motor control includes receiving a plurality of data points associated with operation of a motor, determining a phase angle of the motor, and obtaining a seven-phase pulse width modulation equation from a lookup table based on the phase angle of the motor. The method further includes determining a result of the seven-phase pulse width modulation equation, receiving a modulation index value, and selectively controlling the motor based on the result of the seven-phase pulse width modulation equation in response to the modulation index value being less than or equal to a first threshold value.

The present disclosure relates to adaptive DC bus voltage systems and methods using a fixed modulation index. One method includes setting a modulation index to a predetermined value for a motor. The method also includes calculating a bridge voltage for an output voltage command based on the predetermined value of the modulation index, and selectively controlling the motor based on the bridge voltage.

The invention discloses a non-contact characterization method and measurement system for bolt cross-elastoplastic stage relaxation based on third-order perturbation sound modulation, a storage medium and a program product, and the method comprises the steps: sequentially applying low-frequency pumping signals with different amplitudes and high-frequency detection signals with a constant amplitude through an incremental pumping excitation strategy; third-order nonlinear vibration sound modulation response of the bolt connection structure is excited; collecting a vibration response signal of the bolt connection structure by using a non-contact laser vibration meter, performing spectral analysis, extracting amplitudes of a fundamental wave and a first-order sideband signal, calculating a nonlinear index beta, and analyzing the concave-convex characteristic of the beta along with the change of the pumping excitation voltage; distinguishing an elastic relaxation stage and an elastic-plastic relaxation stage of the bolt according to the concave-convex characteristics of the beta curve; a correction modulation index gamma is constructed based on changes of the beta curve under different excitation voltages, and monotonous quantitative characterization of the bolt pre-tightening force in the relaxation process from the elastic-plastic stage to the elastic stage is achieved. The method has the advantage that the continuous, monotonous and quantitative characterization of the whole process from elastoplasticity to elastic relaxation of the bolt is realized.

The invention provides a multi-level power converter fault tolerance method, which comprises the following steps of: acquiring an output voltage, an inverter side current and a direct current side voltage, performing conversion, and performing PI modulation to obtain a modulation wave of a system; judging whether the system has a fault or not, and judging a specific fault-tolerant scheme according to the modulation degree of the modulation wave if the system has the fault; based on a fault-tolerant scheme, selecting an output state of a redundant vector of a non-fault phase; and based on the selected output state, generating a corresponding driving signal through carrier phase-shifting PWM (Pulse-Width Modulation). The multi-level hybrid topology can keep the same working state before and after the fault, the floating capacitor voltage and the direct current side capacitor voltage are stable, the fault response is rapid, the large-range fluctuation of the output voltage and the output current is avoided, the smooth switching of the working modes is ensured, and the fault tolerance of the system is improved.

A phase modulation signal generating device for a fiber-optic gyroscope includes a sine wave generating part and a superimposing part. The sine wave generating part generates a fundamental sine wave of an odd-order frequency (v=(2n+1)Ve, where n=0, 1, 2, . . . ) of the eigenfrequency (Ve) of the fiber-optic coil and a higher-order sine wave of an odd-order harmonic frequency ((2m+1) v, where m=1, 2, 3, . . . ) of the odd-order frequency (v). The superimposing part superimposes the fundamental sine wave and higher-order sine wave generated by the sine wave generating part at a ratio using a modulation index optimized according to a noise target to be minimized and outputs the resultant signal as a phase modulation signal.

The invention discloses a BLE modulation frequency automatic calibration method for backscatter communication. A digital Gaussian filter, a modulation voltage-controlled oscillator in signal connection with the digital Gaussian filter and a voltage-controlled oscillator in signal connection with the modulation voltage-controlled oscillator are included. Wherein the voltage-controlled oscillator comprises a phase-locked loop, and the phase-locked loop locks the frequency to fIF through a reference clock input by a crystal oscillator; the voltage of the voltage-controlled oscillator is a first control voltage, the voltage of the modulation voltage-controlled oscillator is a second control voltage, and the first control voltage is connected with the second control voltage. According to the invention, the problem that the BLE modulation center frequency and the modulation index are unstable in the backscattering technology is solved.

One method involves setting a modulation index for a motor to a predetermined value. The method also includes calculating a bridge voltage for an output voltage command based on the predetermined modulation index value and selectively controlling the motor based on the bridge voltage.

The invention belongs to the technical field of rectifiers, and provides an optimal control method and system for direct-current link current ripples in a three-phase current source rectifier based on sector division, and the main scheme is as follows: firstly, recognizing an operation region of the current three-phase current source rectifier based on a double-variable operation region judgment mechanism of a modulation index and a sector angle; secondly, corresponding modulation strategies are selected based on the operation area of the current three-phase current source rectifier, so that each modulation strategy operates in the optimal interval; and finally, according to the selected modulation strategy, integrating the action time of each reference vector, and finally generating a driving signal sequence of the three-phase current source rectifier. The quality of electric energy output by the three-phase current source rectifier can be ensured.

An apparatus includes an unfolder with three input terminals connected to a three-phase AC power source and three output terminals, p-terminal, o-terminal, and n-terminal, and a three-port converter connected to the unfolder and feeding a direct current (“DC”) load. The three-port converter includes input capacitors. A feedback control loop includes outputs of a p-terminal modulation index derived from a difference between p-terminal current and a p-terminal reference current and an n-terminal modulation index derived from a difference between n-terminal current and an n-terminal reference current. A feedforward control loop outputs an emulated p-terminal current and an emulated n-terminal current derived from differences between DC-link voltages and ideal DC-link voltages. A duty cycle controller is configured to generate duty cycles controlling switches of the three-port converter derived from the modulation indexes and the emulated currents.

Methods for controlling an electric motor using an inverter and optimal pulse patterns (OPPs) are provided. The method includes pre-generating a plurality of optimal switching angles corresponding to voltage waveforms for a range of modulation indices; storing the pre-generated optimal switching angles; generating a voltage command using a model-free predictive controller based on a flux error signal of the electric motor; selecting optimal switching angles from stored pre-generated optimal switching angles based on the voltage command; modifying the selected optimal switching angles using a pulse pattern modifier to compensate for dynamic changes in motor operating conditions; and generating gating signals for the inverter based on the modified switching angles to drive the electric motor.

A system, a method and an apparatus (200) are provided for detecting leakage-current detection in a two-stage AC / AC power converter A controlled low-impedance (202) leakage path is established using a capacitor connected in parallel with a high-value bleed resistor Rg (304) that prevents charge buildup while introducing negligible influence at switching frequencies. A single Hall- effect current sensor H (204) is connected in series within this path to capture the total high- frequency leakage current. A ADC (208) samples the sensor (204) output and applies two dedicated digital band-pass filters. Using RMS values of the respective filtered signals, a microcontroller (206) calculates stage-specific fundamental-frequency RMS leakage currents by applying a modulation-index-dependent proportionality factor derived from the pole-voltage harmonic spectrum, thus achieving precise identification and differentiation of rectifier-side and inverter- side leakage faults using only one current sensor (204).

The invention relates to a method for detecting a defect (DEF) in at least one gear of an aircraft turbomachine based on a vibratory signal (s(n)) of the gear, each gear having a determined meshing frequency (fc) corresponding to a carrier frequency, the method comprising steps consisting in estimating (E3) a target signal (x(n)) comprising a set of characteristic spectral lines based on a whitened vibratory spectrum (y(n)) obtained from a vibratory signal, the method comprising steps of determining, in the whitened vibratory spectrum (y(n)), a plurality of modulation blocks having a modulation index, each modulation block having a carrier coefficient that is dependent on a predetermined carrier frequency (fc) and on the modulation index and a plurality of modulation coefficients that are symmetric about the carrier coefficient.

The application discloses a kind of amplitude-phase difference modulation and demodulation method for MIMO system.The method is mapped in amplitude and the phase difference of adjacent symbol on source bit data at transmitting end, then according to known CSI information, SVD decomposition is carried out to channel matrix, and the optimal channel capacity power distribution is carried out using singular value matrix control signal amplitude, so that all effective channels in the same symbol period transmit the same symbol, finally, all transmitting symbols are obtained according to precoding scheme and transmitted through radio frequency chain.After synchronization is carried out to the received signal at receiving end, amplitude and phase difference value are obtained and phase wrap is demodulated, signal power of different receiving antennas is estimated, MRC is combined to amplitude and phase difference, and finally, source bit data is obtained by reflection mapping.The method combines the advantages of traditional DPSK modulation and ASK modulation, can flexibly adjust modulation index to adapt to different conditions, and the optimal energy efficiency can be obtained at transmitting end, and the complexity can also be reduced at receiving end.

A system is provided to analyze distortion in an electronic or electromechanical device, which may include testing with one or more modulated signals and / or with one or more demodulators. In one embodiment a change in pitch (or frequency) is measured at an output of the device. One or more signals from a demodulator output may be measured for an amplitude, noise, phase, aliasing, spurious signal, and / or frequency modulation effect. In another embodiment a musical signal may be used as a test signal. Providing additional test signals to the device can induce a cross-modulation distortion signal (or time varying cross-modulation distortion signal) from an output of the device. Also utilizing at least one additional filter, filter bank, demodulator and or frequency converter and or frequency multiplier provides extra examination of distortion. Also frequency and / or phase response can be measured with the presence of a de-sensing signal and or another signal that induce near slew rate limiting or near overload condition of the device under test. Another system is provided to analyze modulation index differences between input and output signals for a test signal including modulation. Another system includes providing a nested or layered modulated signal and / or a nested or layered demodulation apparatus or method. Yet another system provides for evaluating for spurious sideband signals via an un-modulated test signal.