872 results about "Total harmonic distortion" patented technology

The Electric Power Converter has the qualifications for an uninterruptable power supply, battery management, energy conversion, micro-grid formation, Power Factor Correction including Total Harmonic Distortion correction in real time. Uninterruptable power supply's use is for always-on, real-time, all-time, reduced distortion with functions of load reduction and management during peak load events. The Electric Power Converter as well has the ability to provide maintenance for most types of batteries including charging and discharge regiments to increase the overall lifetime of a battery, the maintenance, incorporating restorative functions that can refurbish dead batteries or can further increase the overall efficiency and useful function of weaker / aged / defective batteries. Energy conversion capabilities allow for the conversion of AC or DC to AC or DC with high efficiency and ability to actively vary the frequency in accordance to the required parameters. The Electric Power Converter is able to establish and sustain a micro-grid with multiple and varying sources of power generation and load conditions. The Electric Power Converter is achieving dynamic, real-time, interactive Power Factor Correction (PFC) function with advanced voltage harmonic distortion correction with a high efficiency ratio. The Electric Power converter is designed to function with the emerging Smart Grid technologies and provide an overall higher level of operating efficiency and higher quality of electrical power.

Distortion modeling produces distortion models for use by a distortion synthesizer to synthesize the harmonic distortion effects of audio distortion devices. A sinusoidal waveform is distorted by an audio distortion device and analyzed using a Fourier transform to produce a distortion model comprising harmonic amplitude and phase parameters. A phase correction process compensates for phase shifts induced by the audio distortion device. The distortion synthesizer uses a distortion function that distorts a digital audio signal according to the distortion model. The distortion model can be modified to alter the distortion effect and can be stored in a data-storage device for later retrieval. A frequency bandsplitter and signal mixer allow the distortion effect to be applied only to the low frequency content of the digital audio signal, thus providing spectral headroom to suppress the production of aliasing noise. Aliasing-noise suppression is provided for a full-bandwidth signal by up-converting the sampling rate of the signal before applying the distortion function and down-converting the sampling rate afterwards. A process is provided to remove the direct-current component that may be induced into the signal by the distortion function.

A single stage, single switch, input-output isolated converter configuration which uses a hybrid combination of forward and flyback converters is disclosed. The converter operates at a high input power factor with a regulated DC output voltage. It makes use of a novel control scheme utilizing duty cycle control at two discrete operating frequencies. Although the invention employs two frequencies, it does not use a continuous frequency variation. This configuration has the advantage of reduced peak current stresses on the components and is specifically suited for ‘buck’ applications where low DC output voltages (e.g. 24V, 48V) are needed. This configuration will be of specific interest to industries associated with battery charging and uninterruptible power supply (UPS) systems. Apart from having several competitive features compared with prior art techniques, the dual frequency operation scheme reduces the amplitude of its noise spectrum by spreading it over a wider frequency range thus making it more electromagnetic compatible.

A controller for determining the duty-ratio for a pulse width modulator of a converter includes an inner current loop, an outer voltage loop and a multiplier with an input voltage feed forward to connect both loops. A prediction unit determines a correction signal icor that is added to the reference current iref by means of an adder and it further determines a sample correction signal to correct the current samples in the current loop. This error-controlled duty-ratio prediction with sample correction results in an improved total harmonic distortion as well as in an improved power factor of the converter.

The invention discloses a green power converter which omits the pulse width modulation (PWM) technique in the traditional power converter, does not have high-frequency power device, does not generate EMI interference, simultaneously adopts the symmetry basic primitive (SBP) technique, the amplitude high modulate (AHM) technique and the dynamic rectification (DR) technique, and only needs to perform traditional power conversion on a small part of the input power so as to acquire the whole output power, namely that a large part of the output power neither need traditional power conversion nor need to pass through a magnetic core transformer. The input AC voltage neither needs to be rectified and filtered nor has large inductance and large capacitance, thus the power factor is 1, and the total harmonic distortion (THD) is 0. A transformer secondary side adopts dynamic rectification, can acquire a DC circuit, and can also acquire an AC voltage. The circuit complexity, the power consumption and the failure rate of the whole green power converter are greatly lowered, and the power converter can be applied in all the fields to replace the traditional power converter.

The present invention relates to a control system for a vibrator system capable of generating and applying a reciprocating force to an object, such as the underlying ground or water. The control system is generally provided with a means for outputting a drive signal having a fundamental frequency to the vibrator system to activate the reciprocating of the base plate of the vibrating system and a means for receiving a vibrator output signal indicative of the force applied to the object. The vibrator output signal includes at least one harmonic frequency signal and is delayed with respect to the phase of the initial drive signal. To increase the signal-to-noise ratio of the vibrator system, the control system includes a harmonic distortion reduction means receiving the vibrator output signal for outputting at least one harmonic drive signal to the vibrator system. The harmonic drive signal has a proper phase, amplitude, polarity, and frequency which are adjusted to minimize at least one of the harmonic frequency signals being produced by the vibrator system.

An improved micro-inverter apparatus is disclosed for intelligently controlling energy harvest from photovoltaic solar panels based on one or more adjustable, user-defined variables. The improved micro-inverter apparatus may include a microcontroller configured to monitor the operating temperature of its micro-inverter and control the power harvested from associated solar panels in order to ensure the operating temperature of the micro-inverter does not approach a level that would damage the micro-inverter's circuitry or other components. Similarly, the micro-inverter apparatuses' microcontroller may be configured to monitor the total harmonic distortion of the micro-inverter's AC power output and control the power harvested from associated solar panels in order to ensure the total harmonic distortion of the AC power output does not exceed a threshold level.

A superconducting quantum interference devices (SQUID) comprises a superconducting inductive loop with at least two Josephson junction, whereby a magnetic flux coupled into the inductive loop produces a modulated response up through radio frequencies. Series and parallel arrays of SQUIDs can increase the dynamic range, output, and linearity, while maintaining bandwidth. Several approaches to achieving a linear triangle-wave transfer function are presented, including harmonic superposition of SQUID cells, differential serial arrays with magnetic frustration, and a novel bi-SQUID cell comprised of a nonlinear Josephson inductance shunting the linear coupling inductance. Total harmonic distortion of less than −120 dB can be achieved in optimum cases.

An integrated circuit provides a complete electronic ballast control with power factor correction for fluorescent lamps. The integrated circuit contains a simplified power factor correction (PFC) circuit to reduce component count and supply voltage requirements to reduce manufacturing costs while providing a robust control. The PFC circuit has a variable gain for fast response at high gain and optimized power factor control at low gain. An increased on time for the PFC switch when the input line voltage approaches zero dynamically reduces crossover distortion, thereby reducing total harmonic distortion. The integrated circuit incorporates a number of fault protections.

A method and system of power factor optimization and total harmonic distortion are provided under the premise of efficient power management and distribution on an electrical grid. The method and system include a novel optimization technique based on a novel current profiling methodology enabling real-time power management with power factor correction as a function of the optimization. The optimization can be performed under dynamic current constraints. When deployed on an electrical grid, the method and system can provide a new technique for power management targeting an efficiency of the electrical grid. The method and system can thus provide for reduced costs of energy production and reduced carbon emissions into the atmosphere.

In terms of achieving a reduction in the cost of an antenna switch, there is provided a technology capable of minimizing harmonic distortion generated in the antenna switch even when the antenna switch is particularly formed of field effect transistors formed over a silicon substrate. Between the source region and the drain region of each of a plurality of MISFETs coupled in series, a distortion compensating capacitance circuit is coupled which has a voltage dependency such that, in either of the cases where a positive voltage is applied to the drain region based on the potential of the source region and where a negative voltage is applied to the drain region based on the potential of the source region, the capacitance decreases to a value smaller than that in a state where the potential of the source region and the potential of the drain region are at the same level.

Systems and methods disclosed herein monitor and control input to a converter in one or more of a UPS, a frequency converter, or a line conditioner. Distortion due at least in part to ripple voltage can be removed from a control signal that controls input current to the converter. The systems and methods described herein afford a simple and effective way to reduce or eliminate one or more of subharmonic oscillation and total harmonic distortion from a converter input current during synchronous and asynchronous modes of operation. The converter may include one or more of a rectifier and an inverter.

A Three-phase Power Signal Processor (TPSP) is disclosed for general three-phase power system applications. The TPSP is developed based on the concepts from adaptive filter and dynamical systems theories. The structure of the TPSP is unified as it provides a multiplicity of the signals and pieces of information without the need to change, modify, or enhance the structure or to impose excessive computational time or resource requirements. The presented TPSP receives a set of three-phase measured signals, which can be voltage, current, magnetic flux, etc, and provides (1) the instantaneous and steady-state symmetrical components, (2) the fundamental components, (3) the peak values (magnitudes) of the symmetrical components, (4) the frequency and its rate of change, (5) the synchronization signal(s) and zero-crossing instants, (6) the phase-angles of the symmetrical components, and (7) the disturbance signatures. Two or more TPSP units, when properly augmented, further provide (8) the individual harmonic components, (9) the inter-harmonics, (10) the instantaneous real and reactive current components, (11) the total harmonic distortion, dc-offset, and power factor. The TPSP can serve as the building block for various signal processing requirements encountered in the context of power system applications including power systems control, protection, monitoring, and power quality.

Two versions of an isolated single stage converter AC / DC Power Factor Corrected (PFC) converter topology have been invented. One is with a full bridge rectifier at its input and the other is a True Bridgeless version. The two versions of the topology feature new configurations and circuitry including a simplified damper circuit and a clamp capacitor flipping circuit and control methods that allow them to realize improved single stage isolated power factor converters which are suitable for high power operation, features Zero Voltage Switching to maximize conversion efficiency and to minimize Electro-Magnetic Interference generation, does not need an additional circuit to limit the inrush current, achieves reasonably low input current Total Harmonic Distortion (THD), and is easy to control. The second version provides a true bridgeless single stage isolated power factor converter with even higher efficiency and lower input current THD.

An LED illuminator configured to further reduce total harmonic distortion is provided. The LED illuminator has: a first LED string including a first partial LED string and a second partial LED string; a second LED string including a third partial LED string and a fourth partial LED string; a first switching circuit configured to switch between a state where only the first partial LED string is connected to a rectifier and a state where the first partial LED string and the second partial LED string connected in series are connected to the rectifier as a full-wave rectified voltage waveform that is output from the rectifier increases / decreases; and a second switching circuit configured to switch between a state where only the third partial LED string is connected to the rectifier and a state where the third partial LED string and the fourth partial LED string connected in series are connected to the rectifier, and the switching timing by the first switching circuit and the switching timing by the second switching circuit are set so as to differ from each other.

The invention provides a method,device, system and apparatus for testing a microphone array and a storage medium. The method comprises the following steps: receiving an audio signal obtained by collecting test audio by the microphone array; processing the audio signal to obtain a single channel designation parameter of each microphone and a channel-to-channel designation parameter between the microphones; determining the performance of the microphone array according to the single channel designated parameter and the channel-to-channel designated parameter, and outputting a performance test result; wherein, the single-channel specified parameters include sensitivity level, sensitivity level curve, total harmonic distortion parameter, total harmonic distortion curve, noise level, signal-to-noise ratio, tolerance of frequency response, tightness parameter and truncation parameter; the specified parameters among the channels include frequency response consistency parameters, time delay consistency parameters and correlation parameters. Thus, the present disclosure improves the accuracy of performance test results and reduces the difficulty of performance testing of microphone arrays.

The present invention, which aims at providing a semiconductor switch capable of reducing harmonic distortion, is made up of: an input terminal 101; an output terminal 102; a through FET 106 that is connected serially to the signal path between the input terminal 101 and the output terminal 102; a shunt FET 107 that is connected in between the output terminal 102 and the ground; and a distortion reducing circuit 120 that is connected in parallel with the through FET 106. In this semiconductor switch, the distortion reducing circuit 120 includes: a first diode 109 and a second diode 110 that are placed in parallel with each other; a first constant voltage source 111 and a second constant voltage source 112 that are placed in parallel with each other; and a FET 108.

A system, method and product for modifying the volt-ampere reactive (VARs) in a power distribution system is provided. In one embodiment, the method includes determining the VARs at a location on the power distribution system and based on the determined VARs, determining whether to modify the VARs. If it is determined to modify the VARs the method includes identifying a plurality a capacitor banks connected to a power line and from the identified plurality of capacitor banks, generating a list of eligible capacitor banks that satisfy inclusion criteria. If the list of eligible capacitor banks includes at least one capacitor bank the method includes selecting a capacitor bank from the list of eligible capacitor banks and transmitting a switching command for the selected capacitor bank. Generating the list of eligible capacitor banks may include one or more of ensuring the voltage at each capacitor bank is not beyond a threshold, ensuring the total harmonic distortion at each capacitor bank is not beyond a threshold, ensuring the capacitor bank has not been switched within a recent predetermined time period, ensuring the capacitor bank has not been switched more than a predetermined number of times within a recent time period, ensuring that communications with each capacitor bank are viable, and other criteria.

The invention provides a photovoltaic grid connected inverter island detection method based on negative sequence current injection, belonging to the technical field of power system relay protection and automatic control. According to the method, an inverter is started to inject negative sequence current when a voltage harmonic distortion rate is larger than a fixed value, common connection point voltage unbalanced degree and voltage harmonic distortion rate are detected, when both the common connection point voltage unbalanced degree and the voltage harmonic distortion rate are larger than the respective fixed value and the duration time exceeds a set time, the generation of island is determined, and the rapid detection of the island is realized. According to the method, the setting difficulty of a criterion is reduced, the improvement of the detection speed is facilitated, the interference on a power grid is reduced as much as possible in the condition that the normal operation is ensured, the influence of a power grid asymmetrical fault is avoided, and there is no detection blind area. The simulation verification is carried out in the condition that the island detection is most not facilitated, and an island operation state still can be rapidly and accurately detected according to the method. A good method is provided for the operation withdrawal of a distributed power supply in the island or the turning of power grid connected operation into island operation control mode power system safe operation and the detection.

A controller (130) for compensating reactive power and selected current load harmonics in an unbalanced multi-phase power distribution system. Control current is injected from a multi-phase voltage source inverter (118) into the multi-phase power distribution system as a function of the voltage and current provided by the source inverter 118. The injected current is operative to balance the load seen by the power distribution system including non-linear / distorted and unbalanced loads in each phase. The controller includes an inner loop control processor (216), an outer loop control processor, and an adaptation processor. The adaptation processor (238) is operative to estimate a selected set of predetermined harmonic components in the periodic disturbance which is a function of the unknown system parameters, the source current, the source voltage, and their time derivatives in stationary coordinates.

The invention provides a switching power supply controller and a switching power supply containing the same. The switching power supply controller comprises a zero-cross detection circuit for performing zero-cross detection on input feedback signals and generating zero-cross signals, an input voltage detection circuit for detecting input voltage, an output voltage detection circuit for detecting input voltage, a connection time length control module and a radio station (RS) trigger. The connection time length control module generates turn-off signals according to the input voltage, the output voltage and offset voltage so as to enable connection time of a switching tube to be relevant to the input voltage and the output voltage, and the connection time is prolonged when the input voltage rises and shortened when the output voltage rises. The setting input end of the RS trigger receives the zero-cross signals, the resetting input end of the RS trigger receives the turn-off signals, and the output end of the RS trigger generates driving signals to control connection and disconnection of the switching tube of the switching power supply. The switching power supply controller and the switching power supply containing the switching power supply controller can optimize power factors of the switching power supply controlled by a critical connection mode and reduce total harmonic distortion.

A system for transmitting communication signals, the system comprising an injector circuit connected to a powered circuit conductor and configured to modulate a power signal with a direct current voltage offset, the direct current voltage offset being within a range that causes approximately 1 percent or less total harmonic distortion of the power signal; and a decoder connected to the powered circuit conductor and a load, the decoder configured to demodulate the direct current voltage offset to control the load. A method for transmitting communication signals, the method comprising modulating a power signal on a powered circuit conductor with a direct current voltage offset, the direct current voltage offset being within a range that causes approximately 1 percent or less total harmonic distortion of the power signal; and demodulating the direct current voltage offset to control a load.

A system and method for predicting and limiting distortion of an amplified signal is described. The system includes a variable total harmonic distortion (“THD”) clipping predictor, a comparator in communication with the variable THD clipping predictor and a distortion limiter in communication with the comparator. As for the method, a reference power supply value, a maximum desired total harmonic distortion value and a preamplified signal value is provided. A THD output threshold value is calculated based on the reference power supply value and the maximum desired THD value and is then compared to the preamplified signal value. Depending on if the preamplified signal value is greater than or less than the THD output threshold value, the amplitude of the preamplified signal may be increased or decreased.

The invention relates to an island detection method of a photovoltaic grid-connected system. In views of the problems that independently-adopted passive detection mode is effective only when effective when mismatching degrees of source and load are large and a large non-detection zone (NDZ) can be accordingly provided; and when an active detection mode is independently-adopted, the system is disturbed, and therefore the disturbance results in instability of the system, and accordingly over-voltage / under-voltage is provided. An over-frequency / under-frequency detection method is combined with an improved impedance detection method to conduct island detection to the system, and therefore the NDZ is reduced to a minimum, quality of electric energy is improved and total harmonic distortion (THD) is reduced.

The invention discloses a switching power supply with a function of correcting a power factor and a control device thereof. The control device of the switching power supply comprises a power factor corrector and a total harmonic distortion optimizer. An output end of the power factor corrector is connected with a power tube and the power factor corrector is used for determining turnon time and turnoff time of the power tube. An AC (alternate current) input voltage is input through an input end of the total harmonic distortion optimizer. An output end of the total harmonic distortion optimizer is connected with the power factor corrector. An AC input signal can be dynamically tracked by the total harmonic distortion optimizer. When the AC input voltage is increased, a peak current of an inductance of the switching power supply is reduced and a current that an AC power system charges a filter capacitor of the switching power supply is compensated; and when the AC input voltage is reduced, the peak current of the inductance of the switching power supply is increased and a current that the AC power system discharges the filter capacitor of the switching power supply is compensated. By utilizing the control device disclosed by the invention, the total harmonic distortion of the AC input current caused by the filter capacitor can be reduced and the power factor of the switching power supply is improved.