87 results about "Modulation index" patented technology

Examples of the disclosure include a power-conditioning system comprising a load output configured to be coupled to a load, a power-factor-correction circuit (PFC) comprising a first switching leg and a second switching leg, wherein the first switching leg and the second switching leg are configured to be controlled based on a first modulation index, an inverter comprising the second switching leg and a third switching leg, wherein the third switching leg is configured to be controlled based on a second modulation index, and a capacitor coupled to an inverter output of the inverter and being coupled in series with the load output.

A method for controlling an electrical converter comprises determining an actual modulation index (m) and an actual pulse number (d); determining a neutral point voltage (vnp) of the neutral point (NP); determining an actual neutral point balancing value from the neutral point voltage (vnp); determining an optimized pulse pattern to be applied to the electrical converter from a table of optimized pulse patterns stored in a controller of the electrical converter; and applying the determined optimized pulse pattern to the electrical converter. The table of optimized pulse patterns is indexed with respect to a set of modulation indices (m) and a set of pulse numbers (d) and the optimized pulse pattern is determined based on the actual modulation index (m) and the actual pulse number (d). For a modulation index (m) and a pulse number (d), an optimized pulse pattern stored in the table comprises switching angles and at least one of a switching state and switching transition of the at least one phase leg for each switching angle. For at least some modulation indices (m) and some pulse numbers (d), an optimized pulse pattern stored in the table with respect to a modulation index (m) and a pulse number (d) comprises switching angles, which correspond to different neutral point balancing values. The switching angles of the optimized pulse pattern to be applied to the electrical converter are determined from the switching angles, which correspond to different neutral point balancing values, as a function of the actual neutral point balancing value.

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.

The invention discloses a modulation index adjusting method and device of NFC (Near Field Communication) equipment and the NFC equipment, which are used for improving the adjustment efficiency of a modulation index and enabling the modulation index to be within a protocol requirement range. The method comprises the following steps: acquiring an electrical parameter reflecting the load effect of the NFC chip; according to the electrical parameter, calculating an equivalent conduction resistance value which needs to be configured for the power amplifier; and configuring the equivalent conduction resistance value of the power amplifier according to the equivalent conduction resistance value needing to be configured, so that the modulation index of the carrier envelope transmitted by the signal transmitting circuit after configuration is within a protocol requirement range.

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.

The utility model discloses a radio frequency signal jig for a non-radio frequency test seat, which is characterized in that a tunable coupling plate is correspondingly arranged on the surface of an upper cover of the jig and at the projection position of an onboard antenna, and the area of the tunable coupling plate is adjusted to be the same as the projection area of the onboard antenna. And the distance between the tunable coupling plate and the onboard antenna is adjusted to be within a set distance range, and the load impedance of the radio frequency link is adjusted to be close to an impedance point by 50 ohms, so that the frequency response characteristic of the radio frequency signal is changed, impedance matching is realized, the anti-interference capability of the onboard measurement radio frequency signal is improved, and the mismeasurement proportion of a radio frequency modulation index is reduced. Besides, the tunable coupling plate is also connected with the impedance matching circuit, the inductance value or capacitance value of a tuning element in the impedance matching circuit is adjusted, the matching tuning impedance is replaced to enable the tunable coupling plate to be coupled and parasitic, and the impedance track of the radio frequency signal jig is moved to a 50-ohm matching point, so that better impedance matching is realized, and the impedance matching precision is improved. And the test precision and efficiency are further improved.

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).;

The present application provides a commutation ratio determination method, a power converter, an electronic device and a storage medium. The commutation ratio determination method is used for determining the commutation ratio of a three-level active neutral-point-clamped (ANPC) structure, and comprises: acquiring a thermal equilibrium mapping relationship, wherein the thermal equilibrium mapping relationship is used for indicating a mapping relationship among a power factor, a modulation index and a thermal equilibrium factor, and the thermal equilibrium factor is used for indicating the thermal equilibrium of an external half-bridge module in the three-level ANPC structure; acquiring a first power factor and a first modulation index; on the basis of the thermal equilibrium mapping relationship, determining a first thermal equilibrium factor mapped to the first power factor and the first modulation index; and on the basis of the first thermal equilibrium factor, determining the commutation ratio of the three-level ANPC structure, wherein the commutation ratio is used for indicating the number ratio of a short commutation path to a long commutation path in the working process of the three-level ANPC structure. The present solution can reduce the local hot spot temperature of a device in a three-level ANPC structure.

The invention discloses a pulse width modulation control module and system for an inverter. The system comprises an energy storage device; an inverter electrically coupled with the energy storage device; and a pulse width modulation module. The pulse width modulation module is configured to determine a modulation index according to the voltage of the energy storage device and the target output voltage of the inverter; selecting one of a plurality of pulse width modulation (PWM) methods according to the modulation index; and determining a switching instruction of the inverter according to the target output voltage and one of the selected PWM modulation methods.

In one aspect, a power converter includes: an energy storage device; an inverter electrically coupled to the energy storage device; and a boost system configured to: determine a modulation index based on a DC voltage of the energy storage device and a target output voltage of the inverter; determining whether the target output voltage is in a boost region based on the modulation index; if the target output voltage is in the boost region, determining an adjustment value based on the modulation index; and adjust one or more of the target output voltage and the associated output voltage phase angle based on the adjustment value.

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.

In one aspect, a power converter includes: an energy storage apparatus; an inverter electrically coupled to the energy storage apparatus; and a voltage boost system configured to: determine a modulation index based on a DC voltage of the energy storage apparatus and a target output voltage of the inverter; and determine whether the target output voltage is in a voltage boost region based on the modulation index; if the target output voltage is in the voltage boost region: determine an adjustment value based on the modulation index; and adjust one or more of the target output voltage and an associated output voltage phase angle based on the adjustment value.

A system for monitoring thin film deposition is described. The system includes a quartz crystal and a synthesizer to generate a modulated signal. The modulated signal is to be grounded through the quartz crystal. The system also includes a phase detector to determine a phase of the modulated signal from the quartz crystal in order to monitor thin film deposition. A modulation index can be selected so that, at resonance, high frequency of the signal matches the crystal frequency.

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 present invention provides a modulation index compensation method based on synchronous SVPWM, comprising: presetting a theoretical modulation index, and determining a sampling angle according to a frequency division number and a preset modulation strategy; calculating a comparison value at the sampling angle according to the theoretical modulation index; calculating a U-phase voltage pulse switching angle according to the comparison value; calculating an actual phase voltage fundamental peak value according to the U-phase voltage pulse switching angle; calculating an actual output line voltage effective value according to the actual phase voltage fundamental peak value; calculating an actual modulation index according to a ratio of the actual output line voltage effective value to a DC bus voltage; determining a formula for calculating the theoretical modulation index through the actual modulation index, obtaining a theoretical modulation index corresponding to each actual modulation index under each frequency division number, and storing a corresponding relationship between the actual modulation index and the theoretical modulation index when the frequency division number is greater than 3; in application, querying the corresponding relationship through the current demand modulation index to obtain the corresponding current theoretical modulation index, so as to compensate for the current demand modulation index.

A capacitor has a known capacitance value for filtering the ripple current of the DC voltage bus. A first modulation index estimator is configured to estimate a first modulation index of the first inverter. A second modulation index estimator configured to estimate a second modulation index of the second inverter. A current estimator is configured to estimate an interleaving phase shift angle associated with a respective one of a set of inverters based on the known capacitance value of the capacitor, the estimated first modulation index, the estimated second modulation index, the first control input and the second control input.

A voltage source converter includes first and second DC terminals which have at least one converter limb extending therebetween. Each limb portion includes a chain-link converter that extends between an associated AC terminal and a corresponding one of the first or the second DC terminal. Each chain-link converter also includes a chain-link converter controller which is programmed to control a series of connected chain-link modules. The voltage source converter additionally includes a voltage source converter controller which is arranged in operative communication with each chain-link converter controller to coordinate operation of the chain-link converters. Each chain-link converter controller is further programmed to reconstruct from a received modulation index demand the chain-link converter voltage reference, which the chain-link converter it is controlling is required to produce, by multiplying the received modulation index demand by a total voltage sum established at a first time instant.

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 present application discloses an optical frequency comb generation system based on an optoelectronic modulator, comprising: a signal generating unit, a radio frequency unit, a modulator unit, a power supply unit and an observation unit; the signal generating unit is used to generate an optoelectronic signal; the radio frequency unit is used to preprocess the optoelectronic signal; the modulator unit is used to modulate the optoelectronic signal; the power supply unit is used to provide a modulation voltage to the modulator unit; the observation unit is used to observe the optoelectronic signal information. By accurately adjusting the harmonic modulation index, phase and deviation of the DPMZM, a flat optical frequency comb can be generated. The solution using a single modulator is compact and easy to implement.

The present invention discloses a method, system and medium for estimating parameters of a sinusoidal frequency modulation signal. The method includes the following steps: obtaining a sinusoidal frequency modulation signal, calculating the instantaneous frequency after performing differential calculation on the sinusoidal frequency modulation signal, downsampling the instantaneous frequency according to a preset maximum number of periods, and then obtaining the spectrum of the downsampled instantaneous frequency; calculating the frequency estimation value f of the sinusoidal signal in the sinusoidal frequency modulation signal according to the maximum value in the spectrum me , calculating the period of the sinusoidal signal in the sinusoidal frequency modulation signal according to the frequency estimation value f me , calculating the weighted cumulative value y of the instantaneous phase according to the period of the sinusoidal signal, the instantaneous frequency and the frequency estimation value f me , calculating the modulation index estimation value m according to the weighted cumulative value y of the instantaneous phase f and the bandwidth estimation value Bw of the sinusoidal frequency modulation signal, and calculating the carrier frequency estimation value f0 of the sinusoidal frequency modulation signal according to the modulation index estimation value m f and the frequency estimation value f me . The algorithm logic of the present invention is simple and can better estimate various parameters of the sinusoidal frequency modulation signal.

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.

A method includes voltage vector command values for an electric motor implemented on a vehicle and operating in a linear region. The method also includes receiving system state information of the vehicle and determining that an overmodulation threshold is satisfied based on the system state information of the vehicle. Based on determining that the overmodulation threshold is satisfied, the method includes determining a modulation factor from a modulation index, generating a three-phase output based on the voltage vector command values and the modulation factor, and determining a plurality of control signals based on the three-phase output. Each respective control signal of the plurality of control signals corresponds to a respective switch among a plurality of switches of an inverter. The method also includes instructing the plurality of switches of the inverter to control operation of the electric motor in the overmodulation region based on the plurality of control signals.