129 results about "Harmonic energy" patented technology

The invention discloses a phase-locked loop frequency synthesizer which comprises a phase detection discriminator, a charge pump, a low-pass loop filter, a voltage controlled oscillator with a switched capacitor array, a frequency divider, an automatic frequency controller, a voltage comparison circuit and a relock control circuit, wherein the voltage comparison circuit judges whether tuning voltage Vtune output to the voltage controlled oscillator by the low-pass loop filter is in the preset voltage range in real time when the phase-locked loop frequency synthesizer is at the phase-locked loop loss lock detection stage; and the relock control circuit dynamically adjusts a value of a control word of the switched capacitor array of the voltage controlled oscillator according to the comparison result of the voltage comparison circuit. The invention also discloses a corresponding phase-locked loop loss lock detecting and adjusting method. By the phase-locked loop frequency synthesizer and the phase-locked loop loss lock detecting and adjusting method, increase of reference harmonic energy can be avoided; interference is reduced, and the coarse tuning time is shortened.

A method of processing seismic data obtained using a seismic vibrator that includes estimating travel times of direct wave arrivals between the seismic vibrator and an array of seismic receiver locations and wavefield deconvolving the seismic data using the direct wave arrival travel times. Also a related method of producing a high-frequency geological subsurface image that includes acquiring seismic data having significant harmonic energy using a seismic vibrator, estimating direct wave arrival travel times between the seismic vibrator and an array of seismic receiver locations, wavefield deconvolving the seismic data using the estimated direct wave arrival travel times, and using the wavefield deconvolved seismic data to produce a high-frequency geological subsurface image. A further related computer useable medium having computer readable program code means embodied therein practicing the inventive method.

The invention relates to a harmonic energy metering method of Nuttall self-convolution weighted Fourier transform. The method comprises the following steps that: a discrete Nuttall window sequence with a length of N is constructed; convolution operation is carried out on the discrete Nuttall window so as to obtain a convolution sequence; zero filling is carried out on the head or the tail of the convolution sequence so as to obtain a discrete Nuttall self-convolution window; the Nuttall self-convolution window sequence is utilized to carry out weighted operation on a discrete power signal; Fourier transform is employed to obtain a discrete frequency spectrum of the power signal; spectral lines with a greatest amplitude and a second great amplitude are searched nearby a harmonic frequency corresponded to the discrete frequency spectrum; fitting is carried out on a peak value spectral line by utilizing a least square method so as to obtain an amplitude, a frequency and an initial phase angle of a power harmonic wave, so that integral harmonic energy metering in a complex power signal is realized.

A method and apparatus for routing harmonic energy within a plasma to ground in a plasma enhanced semiconductor wafer processing reactor. A model of the chamber is used to determine the pathway for RF power and the harmonic energy of that RF power through the chamber. From this model, the placement and design of a harmonic routing circuit is determined to shunt the harmonic energy to ground.

The invention discloses an arc light grounding fault distinguishing method based on harmonic wave energy and waveform distortion characteristics. Firstly, waveforms and their harmonic amplitude valuesof three-phase voltage and zero-sequence current of a system are obtained through a power distribution network miniature PMU; the harmonic amplitude values of the waveforms of the three-phase voltageand zero-sequence current are utilized to calculate dimension-unified harmonic energy of each period, and whether the system has suspected arc light grounding faults or not is judged; randomness analysis is conducted on the harmonic energy of each period in a detection window to obtain randomness indexes of the harmonic energy, and it is determined whether identified suspected arc light groundingfaults are mistakenly judged or not; waveform distortion characteristics of stable arcing are extracted by conducting time-frequency domain analysis on the waveforms of the three-phase voltage and zero-sequence current, the influence of the stable arcing process on randomness analysis is avoided, and accordingly mistaken judgement is avoided. The arc light grounding fault distinguishing method accurately extracts arc light grounding fault characteristics and achieves the technical basis of a reliable, safe and quick fault distinguishing algorithm.

The present invention provides a harmonic electric energy measuring method, and belongs to the electric energy measuring technology filed. The method separates the basic wave coming from the signal of the voltage and the current of the power grid by a low-pass filter, separates the harmonic signal by a high-pass filter, then gets basic wave current and basic wave voltage as well as total harmonic current and total harmonic voltage; separates the total harmonic current and the total harmonic voltage to obtain a sub-harmonic current and a sub-harmonic voltage which need to be measured by an infinite impulse responding belt passing filter method; obtains different sub-harmonic current and sub-harmonic voltage of different times according to different harmonic frequencies to be measured; calculates various date of the power grid according to the basic wave current signal and the basic wave voltage signal. The spending of the present invention is less than that of the traditional rapid Fourier transform method.

A harmonic energy metering error analytic device comprises a harmonic data collection part used for inputting the harmonic data collected by power network into an electric energy data analytic part, an electric energy metering error data analytic part comprising a model storage module and an error analysis module and an error analytic result output part used for outputting or storing the error data analytic result acquired from the electric energy metering error data analytic part; wherein the model storage module is used for storing metering error models and model functions corresponding to the models of electric energy meters; the error analysis module is used for deriving the theoretical error data to be analyzed of the input harmonic data and deriving the error of each harmonic measurement and the total error. The harmonic energy metering error analytic device can provide quantitative data basis for power supply department to retrieve electric energy metering error loss and control harmonic pollution.

The invention relates to a recovery-type harmonic suppression system at the DC side of a multi-pulse rectification system and a method, belonging to the technical field of power electronics and solving the problems of system size and capacity increase of a traditional multi-pulse rectification system which adopts an active filter at the AC side for harmonic suppression. The invention is used for connecting the harmonic suppression system to the DC side of an original multi-pulse rectification system by utilizing the relation of current harmonics at the AC side and the DC side aiming at a parallel multi-pulse rectification system. The harmonic energy of the original parallel multi-pulse rectification system is extracted through the secondary side of a balance reactor with the secondary side to generate a small-capacity power supply source to influence the current of the AC side and suppress the current harmonics at the DC side, wherein the current harmonics are input at the AC side. The secondary current is rectified through a half-bridge or full-bridge controllable rectification circuit connected with the secondary side of the balance reactor with the secondary side, and the rectified output current is directly provided to a load to recycle the harmonic energy. The invention is used for the harmonic suppression of the multi-pulse rectification system.

The invention discloses a specific harmonic eliminated wireless electric energy transmission system and a design method of the specific harmonic eliminated wireless electric energy transmission system, and belongs to the wireless electric energy transmission system and design method. The system comprises a direct current power supply, a high frequency inverter, a primary side energy conversion and transmission link, a secondary side energy receiving and conversion link, a primary side harmonic energy reverse injection link and a load. After the primary side energy conversion and transmission link and the primary side harmonic energy reverse injection link respectively form a fundamental wave channel and a third harmonic extraction channel and then are reversely connected with the high frequency inverter in parallel, the third harmonic energy extracted in the primary side harmonic energy reverse injection link is reversely injected in the primary side energy conversion and transmission link through a tightly coupling transformer, thus generating superposed effects with the high frequency alternating current signals generated by the direct current power supply through the high frequency inverter. According to the system, the third harmonic content in the alternating current power supply input in the fundamental wave channel is eliminated; the design of a fundamental wave resonant network is simpler; and the system frequency stability and waveform distortion influences resulting from load or system structure change are reduced.

The invention relates to a multimode frequency division type injection locking frequency divider comprising a negative resistance unit, a tuning unit, a signal injection unit and a differential output buffer, wherein the negative resistance unit is a complementary cross coupling geminate transistor negative resistance unit composed of four MOS tubes M1, M2, M3, M4; the tuning unit constitutes a resonant cavity with variable tuning frequency by a peak inductor L1, a voltage controlled variable capacitor Cvar and a 2bit switched capacitor array in a parallel manner; the signal injection unit is composed of double MOS tubes Ms1, Ms2 connected in parallel and a multimode switching unit; and a frequency division signal is injected into an oscillator in a parallel double-MOS tube direct injection mode, the tuning frequency of the resonant cavity is changed by the voltage controlled variable capacitor and the switched capacitor array, the frequency division ratio is changed, the harmonic energy is reinforced by the serially connected peak inductor L1, and the locking range is expanded.

The invention belongs to the field of digital speech signal processing, and discloses a polyphony multi-pitch estimation method and application of pseudo bispectra to multi-pitch estimation to solve the problem of multi-pitch estimation of polyphony. The method is technically characterized by comprising the steps of framing input audio frequency; solving the pseudo bispectrum of each frame of signals, ranking the values of the matching cross-correlation function between a two-dimensional template and pseudo bispectra from large to small, and taking the first several frequencies as candidate pitches; calculating the weighting harmonic energy sum of each candidate pitch, and selecting the candidate pitch with the largest weighting harmonic energy sum as the most significantly estimated pitch output by this time of iteration. The method has the advantages that normal work can be conducted when the number of harmonic components is small, notes with overlapped harmonic frequency components can be distinguished, calculation amount is small, and the method is easy to realize and can also be used for base frequency extraction of harmonic signals besides polyphony.

The invention relates to a safe operation method of a photovoltaic power generation system. The safe operation method comprises a training method for an artificial neural network for detecting a direct current failure arc of the photovoltaic power generation system, and a real-time detection method of the direct current failure arc of the photovoltaic power generation system, wherein the steps in the real-time detection method can be completed by establishing a functional module frame and using a computer program instruction to control a computer system. In order to accurately, simply and conveniently test the direct current failure arc in the photovoltaic power generation system, direct current obtained by sampling is converted into a frequency domain, the harmonic energy of the frequency domain within a set frequency band is computed, and then the artificial neural network judges whether the direct current failure arc happens according to the harmonic energy.

The invention discloses a wide-range power adjustable wireless electric energy transmission system and a control method thereof. The system comprises a DC power supply, a high-frequency inversion unit, a fundamental wave energy path, a harmonic wave energy path, a rectification and filtering unit, a primary side control unit and a secondary side control unit. The load needs different output power of the system, the power transmission characteristic of the fundamental wave energy path is different from that of the harmonic wave energy path, and the switching modes of a fundamental wave bidirectional switch S1 in the fundamental wave energy path and a harmonic wave bidirectional switch S2 in the harmonic wave energy channel are controlled; and thus, the system works in a mode that the fundamental wave energy path supplies power independently, a mode that the harmonic wave energy path supplies power independently, and a mode that the fundamental wave energy path and the harmonic wave energy path supply power in parallel, and the output power can be adjusted in a wide range. The system and control method thereof have the advantages that the fundamental wave energy path and the harmonic wave energy path can work in a coordinated manner, the utilization rate of power energy is improved, and the output power can be adjusted in the wide range on the premise that no complex control circuit is arranged additionally.

A compressor drive system startup control method, device, apparatus, and a refrigerator are disclosed. The control method includes that a random carry frequency and an initial positioning current areobtained. According to the random carrier frequency and the initial positioning current, the positioning operation of the compressor driving system is controlled, the positioning current is controlledto increase, and the updated positioning current is detected. The bus voltage value is obtained when the positioning current updated within the preset positioning time length is detected to reach thepreset threshold value; According to the bus voltage value and the preset DC bus voltage waveform, the compressor drive system is controlled to switch to the open loop operation and the oil supply closed loop fixed frequency operation successively. The random carrier frequency reduces the amplitude of harmonic energy in the vicinity of the carrier frequency and integer multiples thereof, The starting control method enables the controller to output enough voltage when switching to the closed loop fixed frequency operation of the oil speed, and the driving system obtains the maximum starting torque of the motor, the starting speed is fast, the starting ability is strong, and the starting vibration noise is small.

The invention discloses a current control method for an active power filter. The current control method comprises the following steps of: comparing a compensating current command signal ic* with a practical compensating current signal ic; generating a PWM (Pulse Width Modulation) signal for controlling the switch-on / off of a main circuit by the hysteresis comparator by taking a difference delta ic of the two signals as an input of a hysteresis comparator; and controlling the switch-on / off of a switch by the PWM signal through a driving circuit, thereby controlling the change in the compensating current ic, wherein the width H of the hysteresis comparator is designed to be capable of automatically adjusting following the magnitude of ic; the hysteresis comparator is replaced by a comparator under timing control of a clock; the delta ic is judged for one time within each clock period; and the PWM signal changes for one time within at least one clock period. The hysteresis current control is the control based on the transient state of current and has the advantages of high dynamic response speed and excellent robustness; the hysteresis current control essentially is a frequency conversion SPWM (Sinusoidal Pulse Width Modulation) modulation mode for implied carrier wave; in a three-phase high-power factor rectifier, the wave frequency of the implied carrier wave under hysteresis control periodically changes following the voltage of a power grid; the change frequency is two times of the power frequency; the hysteresis current control is wide in output spectral range and is better in filtering property; and harmonic energy is uniformly distributed in a wider frequency band scope.

The invention discloses a low-zero-sequence-resistance slow-harmonic energy-saving transformer. Primary side windings of the transformer are connected by adopting a triangle, secondary side windings of the transformer are connected by adopting a dual-output curve; each secondary side winding comprises a first group of windings and a second group of windings, wherein the first group of windings comprises a first phase output winding, a second phase output winding and a third phase output winding; and the second group of windings comprises a fourth phase output winding, a fifth phase output winding and a sixth phase output winding. The invention has the advantages of inhibiting distortion of output voltages on the basis of an electromagnetic filtering principle, reducing zero sequence resistance and operation loss of the transformer, ensuring that harmonics are inhibited, eliminating 3 times, 5 times, 7 times, 17 times and 19 times of harmonics, greatly improving influence of secondary side harmonics to a primary side power grid, weakening primary side and secondary side winding coupling fluxes and primary side winding circulation caused by harmonic currents, and reducing operation loss of the transformer.

An electrical network harmonic administration method and equipment, is charactered in that it uses a harmonic transmitter to separate from system a harmonic three-phase voltage or the sum of the three-phase current signal; the secondary side loop of the harmonic transmitter formed by the impedance disposed on the secondary side of the harmonic transmitter, is used to consume the harmonic energy; or the secondary side loop of the harmonic transmitter carry out the phase inversion to the harmonic signals, and then again the phase inversion signal is feedback to the system to counteract the system harmonic quantity through a first side of the harmonic transmitter, and the said harmonic is the three-phase asymmetric harmonic; a symmetrical harmonic release path is disposed in the first phase or second phase of the system, located on first side of the system, or located on the secondary side of the harmonic transmitter, which converts the systema three-phase symmetrical harmonic into a three-phase asymmetric harmonic. The invention method is reliable; has a simple equipment structure; has a convenience of operating and maintenance; and the investment of the invention is only one of or even one of tens of the investment of other harmonics administration methods.

The invention discloses a femtosecond pulse measuring method and device. The femtosecond pulse measuring method comprises the steps that higher harmonics of two channels are generated through interaction of a pulse laser driving field and rare gas; higher harmonics of the two channels interfere with each other; a femtosecond pulse to be measured is introduced into the process of interaction between the pulse laser and the rare gas so as to change the accumulated phases of the generated higher harmonics of the two channels, so that the higher harmonics of each channel generate energy drift; through energy drift information generated by higher harmonics of the two channels respectively, a function that the higher harmonic energy drift of each channel changes along with time delay is determined, and structure information of a first component of the femtosecond pulse to be measured is determined according to the function; and the first component is the component with the same polarizationdirection of the femtosecond pulse to be measured and the pulse laser driving field. According to the method, the frequency drift amount of higher harmonic spectrum perturbation along with time delayis extracted, and the femtosecond pulse is reconstructed from the drift amount changing along with time delay.

The invention discloses a motor control system and a noise reduction control method and device for a frequency converter of the motor control system. The frequency converter outputs a space vector pulse width modulation (SVPWM) wave to a motor in the motor control system. The method comprises the following steps: acquiring a preset central carrier frequency, a preset frequency band constant and a preset random distribution function; acquiring a current frequency band constant according to the preset frequency band constant and the preset random distribution function, and acquiring a current carrier frequency according to the preset central carrier frequency and the current frequency band constant; generating an SVPWM wave of a current period according to the current carrier frequency, so as to reduce noise of the frequency converter. Therefore, random change of the carrier frequency of the SVPWM wave based on a certain rule can change a harmonic spectrum of voltage output by the frequency converter, so as to enable the harmonic spectrum to be distributed on a relatively wide frequency band; furthermore, under a condition of not changing total harmonic energy, a harmonic amplitude value can be reduced, so that the noise of the frequency converter is decreased and suppressed.

The invention discloses a combined local frequency multiplication sampling algorithm for generating SPWM waves. A symmetrical region is obtained with the zero point of a sine curve as the midpoint, and virtual sampling points are constructed in the region according to a linear combination mode in mathematics so that the effect of frequency multiplication can be achieved; under the situation that the number of the actual sampling points is definite, harmonic energy will gradually move in the direction of a high frequency along with the increase of the width of the region of frequency multiplication or the increase of number of frequency multiplication, and thus the energy of low-order harmonic components is reduced. According to the combined local frequency multiplication sampling algorithm for generating the SPWM waves, harmonic energy is transferred to a high-order harmonic region, the low-order harmonic components can be filtered out easily, and control signals more close to sine waves can be obtained; the algorithm is simple and easy to realize in a programming mode, and is mainly applied to rectifiers and inverters.

This invention converts inertial impulses into electric currents. Specifically, it converts impulses created by the impacts of high-energy particles from the Sun and other cosmic sources into the Earth's Magnetosphere and the varying D, E, F1 and F2 layers of its Ionosphere to controlled electric currents. This invention presents a new method of utilizing energy from the Sun and other sources of high energy articles as a virtually, inexhaustible, alternative-energy source for the world.

The invention relates to the technical field of artificial intelligence, and discloses a voice endpoint detection method. The method comprises the following steps of: obtaining input voice to be detected and a preset voice frame detection model; performing framing processing on the input voice to obtain a plurality of voice frames with time sequences; sequentially inputting each voice frame of theinput voice into the voice frame detection model for detection, and outputting a first detection result corresponding to each voice frame; sequentially performing harmonic energy detection on each voice frame of the input voice to obtain a second detection result corresponding to each voice frame; determining a frame type corresponding to each voice frame based on the first detection result and the second detection result; and determining a voice starting endpoint and a voice ending endpoint of the input voice based on the frame type corresponding to each voice frame. The invention further discloses a voice endpoint detection device and equipment and a computer readable storage medium. According to the invention, the accuracy of voice endpoint detection is improved.

Differential processing systems are provided that reduce even-order harmonic energy. The reduction may be selectively converted to, for example, random noise. This effects a tradeoff for processing systems that can afford to accept some increase in noise to thereby gain the benefits of reduction in even-order harmonic energy. In one system embodiment, first and second signal portions of a differential signal are respectively processed along first and second signal paths in a first processing mode and along the second and first signal paths in a second processing mode. The modes are selected to perform the desired conversion of even-order harmonic energy. In another system embodiment, first and second signal portions of a differential signal are processed along first and second signal paths in a first processing mode and inverted versions of these signals are processed along the first and second signal paths in a second processing mode. In addition, output signals are inverted in the second processing mode.

The invention relates to an atom-decomposition-method-based detection method for an arc-resistance ground fault of a small-current grounding system so that an arc-resistance ground fault of a system can be detected quickly and effectively. A fault current is analyzed and an arc-resistance ground fault of the system is detected; when an arc-resistance ground fault occurs at the small-current grounding system, a fault current harmonic generates a certain amount of distortion because of the nonlinearity of the fault resistance; in harmonic energy distribution, the proportion of the energy of thethird harmonic and nearby harmonic components is high relatively; and on the basis of the characteristic of the arc-resistance ground fault, calculation is carried out to obtain a harmonic energy ratio and then a criterion is compared to detect the fault. According to the invention, the atomic decomposition method is used as a fault current signal analysis tool; the high-redundancy atomic libraryis able to capture natural features of the signal well to realize sparse signal decomposition; and the signal expression result is simple and reliable.

The invention provides an antenna adjusting method and an antenna system terminal, the antenna adjusting method is applied to the antenna system terminal, and the antenna system terminal comprises a diversity antenna and a positioning antenna; The antenna adjusting method comprises the steps of obtaining communication parameters of the antenna system terminal, wherein the communication parametersat least comprise an impedance value, a low-frequency resonance point and an intermediate-frequency resonance point; Regulating and controlling a low-frequency resonance point of the antenna system terminal so as to reduce the bandwidth of the low-frequency resonance point; Adjusting and controlling an impedance value of a low-frequency resonance point of the antenna system terminal so as to reduce the frequency point efficiency of the positioning antenna; Wherein by controlling the impedance value of the antenna system terminal, the bandwidth of the low-frequency resonance point is regulatedand controlled, and the second harmonic energy generated by a communication channel is reduced; Through the antenna control method, the interference of second harmonic energy on the positioning systemcan be reduced, the sensitivity of the positioning system is improved, and the accuracy of the positioning system is improved.

A method of processing seismic data obtained using a seismic vibrator that includes estimating travel times of direct wave arrivals between the seismic vibrator and an array of seismic receiver locations and wavefield deconvolving the seismic data using the direct wave arrival travel times. Also a related method of producing a high-frequency geological subsurface image that includes acquiring seismic data having significant harmonic energy using a seismic vibrator, estimating direct wave arrival travel times between the seismic vibrator and an array of seismic receiver locations, wavefield deconvolving the seismic data using the estimated direct wave arrival travel times, and using the wavefield deconvolved seismic data to produce a high-frequency geological subsurface image. A further related computer useable medium having computer readable program code means embodied therein practicing the inventive method.

The invention discloses a power amplifier based on comb filtering. The power amplifier comprises an input port, an input matching circuit, a biasing circuit, a transistor, an output matching circuit,a harmonic suppression circuit and an output port which are sequentially connected; a signal to be amplified is connected to the input port and is transmitted to the input matching circuit, and the signal is amplified through the biasing circuit and the transistor; and the amplified signal is filtered by the output matching circuit and the harmonic suppression circuit, and the filtered signal is transmitted to a signal receiving device through the output port. According to the invention, higher harmonics of the power amplifier are mainly suppressed; harmonic energy generated by the power amplifier is recovered through combination of the comb-shaped harmonic suppression circuit and the output matching network. The power amplifier is simple in structure, suppresses harmonic components at a load, guarantees the efficiency of the power amplifier, enables the power amplifier to be easy to realize, achieves the purpose of high efficiency, facilitates miniaturization and integration of a communication system, and has very good practical value.

The invention belongs to the field of radio monitoring, and particularly relates to a radio direction finding method based on time modulation array harmonic energy detection. The method includes thata time modulation array method is adopted, N antennas in an antenna array are controlled through N different control clock signals input with one Tm time duration to enable working state of the antenna controlled by each clock in the antenna array to change along with the corresponding control signal, and direction finding of an unknown target signal is realized by analyzing a drawing result of adirectional diagram of the antenna array. The method is comparatively low in complexity, and a system is relatively simple in physical realization, easy in subsequent optimization, small in physical size, suitable for various complex environments and lower in time delay. Only one radio frequency receiving link is used, so that power consumption of the system is minimized, and better energy savingeffect is realized.

The invention discloses a high-efficiency five-order class F power amplifier. A circuit comprises an input fundamental wave matching network, a transistor, a parasitic parameter adjusting network, a class F higher harmonic matching network, an output fundamental wave matching network and a power supply decoupling bias network. According to the invention, the mutual independent accurate control ofthe fundamental wave load impedance to the fifth harmonic wave load impedance of the transistor is realized by adopting the class F higher harmonic wave matching network, and the compact network structure greatly saves the area occupied by the microstrip line circuit, thereby remarkably reducing the design cost of the circuit board. According to the high-efficiency five-order class F power amplifier, the harmonic energy loss of a transistor is reduced by utilizing a five-order class F amplification principle, the power amplification efficiency is improved, and each harmonic impedance is independently designed, so that each harmonic impedance control circuit does not influence each other, the later optimization debugging is not needed, and the design complexity is reduced.

The invention relates to a brushless generator in automatic voltage regulation state. The brushless generator comprises a generator principal winding (WA) embedded in a stator (3) and is characterized by also comprising a harmonic winding (WS) embedded in the stator (3), wherein harmonic energy is taken out from the harmonic winding (WS), is rectified by an external circuit, and is sent to an exciter exciting winding (WE1); and when the states of the generator are changed, the harmonic energy is used for regulating excitation so as to stabilize the voltage of the generator. The electrode distance (tau1) of a coil (V2) of the principal winding (WA) corresponds to three electrode distances of coils (V1) of the harmonic winding (WS). A connection method for the three coils (V1) of the harmonic winding comprises the following steps of: forming a serial circuit by connecting the tail end of the coil (1) with the tail end of the coil (2), and connecting the head end of the coil (2) with the head end of the coil (3). The brushless generator can automatically regulate the voltage for stably generating power in various states, a conventional automatic voltage regulator (AVR) module is omitted, circuits of measurement devices, amplification devices, comparison devices and power controllers are saved, and the brushless generator has a simple structure, shorter required time for stabilizing voltage, high reliability and low cost.