Shenzhen Invt Electrical Co.

Shenzhen, China

Shenzhen Invt Electrical Co.

Shenzhen, China
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Zhao Z.,Nanjing Southeast University | Zhao J.,Nanjing Southeast University | Shen K.,Nanjing Southeast University | Peng Z.,Shenzhen Invt Electrical Co. | Zhang B.,Shenzhen Invt Electrical Co.
Diangong Jishu Xuebao/Transactions of China Electrotechnical Society | Year: 2014

Due to the various advantages compared with three-level converter, the five-level diode-clamped converter (5L-DCC) is widely studied. This paper focuses on the DC-capacitor voltage balancing and vector sequences switch mechanism of a space vector modulation (SVM) modulated 5L-DCC as modulation index is less 0.5. The 5L-DCC voltage balancing strategy based on objective function optimization is analyzed. On the basis of seven segment and five segment vector sequences, this paper comes to two vector sequences selection rules according to reference vector location. The DC-capacitor voltage balancing and narrow pulse problems are solved. The simulation and experimental results show that the proposed method is effective and capacitor voltage ripple is low.


Zhao Z.,Nanjing Southeast University | Zhao J.,Nanjing Southeast University | Shen K.,Nanjing Southeast University | Peng Z.,Shenzhen Invt Electrical Co. | Zhang B.,Shenzhen Invt Electrical Co.
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2014

The multilevel converter has been widely studied due to its excellent performances, but a diode-clamped converter suffers DC-capacitor voltage imbalance problem. The effect of nearest three vector SVM method based on objective function optimization is restricted by modulation index and power factor. A DC-capacitor voltage balancing method for a five-level diode-clamped converter (5L-DCC) with high modulation index and high power factor was proposed, the algorithm took advantage of the six effective vectors of the inner hexagon, and the problem of DC-capacitor voltage balancing is restricted by power factor of 5L-DCC was resolved, the simulation and experimental results show that the method proposed is effective and has good performance. © 2014 Chin. Soc. for Elec. Eng.


Patent
Shenzhen Invt Electrical Co. | Date: 2013-04-17

A method for adjusting a PV inverter, a method for driving a PV inverter, and apparatuses thereof are provided, which are applicable in the filed of electronic and information technology. The method for adjusting a PV inverter includes: detecting a first output current of a main module in the PV inverter and a second output current of a controlled module in the PV inverter; regulating pulse widths of switching of a power component in the controlled module according to the first output current and the second output current, so that a peak amplitude of the second output current is substantially equal to that of the first output current when the power component in the controlled module is driven according to the regulated pulse widths; and storing difference information between the regulated pulse widths and present pulse widths of switching of a power component in the main module in the PV inverter. It is ensured that the total output current is distributed evenly among the multiple power modules in the PV inverter, thus achieving current balancing.


The present invention discloses an inductance parameter identification method for a synchronous motor and an implementation system thereof, The method includes: determining the position of the rotor magnetic pole axis of the synchronous motor and obtaining direct-quadrature (d-q) axes; injecting a high-frequency voltage or current signal having a predetermined amplitude to the d-axis of the synchronous motor; obtaining the amplitude of a feedback high-frequency current or voltage component that has the same frequency as the injected high-frequency voltage or current of a feedback high-frequency current or voltage at the d-axis; and calculating d-axis inductance L according to the amplitude of the feedback high-frequency current or voltage component at the d-axis. The present invention is easy to implement. It imposes no high requirements on the accuracy of the sampling of the feedback current from the synchronous motor. The frequency and amplitude of the high-frequency voltage signal injected to the synchronous motor are easy to control. Moreover, the d-axis inductance and q-axis inductance of the synchronous motor can be directly identified, whether the shaft of the synchronous motor is free or braked, without affecting the accuracy of identification.


The present invention discloses an inductance parameter identification method for a synchronous motor and an implementation system thereof. The method comprises: injecting a balanced three-phase high-frequency voltage or current signal to the synchronous motor; obtaining amplitudes of a positive sequence component and a negative sequence component that have the same frequency as the injected voltage or current of a feedback high-frequency current or voltage; and calculating d-axis inductance L_(d) and q-axis inductance Lq of the synchronous motor. The present invention can achieve accurate identification of the d-axis inductance and q-axis inductance of a synchronous motor using a general-purpose frequency-variable device without hardware cost increase. The present invention is easy to implement. It imposes no high requirements on the accuracy of the sampling of the feedback current from the motor. The frequency and amplitude of the high-frequency voltage signal injected to the motor are easy to control. Moreover, the d-axis inductance and q-axis inductance of the motor can be directly identified, whether the shaft of the motor is free or braked, without affecting the accuracy of identification.


Patent
Shenzhen Invt Electrical Co. | Date: 2012-12-26

The present invention discloses a frequency converter in which the main devices are modularly mounted, including a housing and three main device units, wherein a support frame is provided inside the housing; three main device units are supported on the support frame side by side. Each of the main device units includes a mounting frame on which a rectifier bridge, an inverter module and a plurality of capacitors are arranged. The rectifier bridge, the inverter module and the capacitors of the frequency converter are separately arranged on three mounting frames to form three main device units, such that the ratio of the length to the width of each of the main device units is relative coordinate, and each of the main device units may be cooperated and arranged with other auxiliary devices inside the housing compactly. Therefore, the space utilization rate inside the housing is enhanced, the total volume of the frequency converter is reduced and the space cost is effectively cut down. Furthermore, each of the main device units is an interchangeable modular unit. Therefore, by adopting modularly mounting method, the complexity of the mounting process is reduced and the working efficiency of mounting is improved.


Patent
Shenzhen INVT Electrical Co. | Date: 2015-03-25

A phase current reconstruction method and apparatus. In this method, PWM phase shift is performed firstly, and when a modulation vector is in an observable region, phase difference compensation is performed on a second sampling value in a PWM carrier cycle, thereby obtaining three-phase current of a motor, reducing an error caused by phase difference of sampling points, and improving accuracy of phase current reconstruction. Further, a power factor angle of the motor and an amplitude value of a current vector are calculated by using the obtained three-phase current, and when the modulation vector is in an unobservable region, initial three-phase current of the motor is obtained according to a voltage space vector angle, the power factor angle, and the amplitude value of the current vector, and the initial three-phase current is modified through one-phase current measured in the unobservable region, thereby effectively obtaining the phase current of the motor, solving the problem that single current sampling is limited in a high modulation region, and enabling the single current sampling to be better applied in an alternating current motor speed adjustment system.


Trademark
Shenzhen INVT Electrical Co. | Date: 2012-10-24

Kitchen machines, electric; agricultural machines; sewing machines; washing machines; food preparation machines, electromechanical; elevators (lifts); metalworking machines; hand-held tools, other than hand-operated; electron industry equipment; machine transmission device; power engines (not for land vehicles); gear boxes other than for land vehicles; control devices for machine engines; starters for motors and engines; generators of electricity; driving motors other than for land vehicles; propulsion mechanisms other than for land vehicles; exhausts for motors and engines; gears, other than for land vehicles; pumps (parts of machines, engines or motors); servomotor; dynamo belts; couplings other than for land vehicles; electric spindles (machine parts); spindle motors; elevator operating apparatus; threading machines; lathes (machine tools); cutting machines; finishing machines; notchers (machine tools); machine tools; crushing machines; machines and apparatus for polishing (electric); drill presses; boring lathes; electric planers; electroplating machines; electric welding apparatus; electric door openers. Data processing apparatus; computer programs (downloadable software); electronic tags for goods; bells (signal); telephone apparatus; optical communication instrument; measuring instruments; radiological apparatus for industrial purposes; protection devices for personal use against accidents; theft prevention installations, electric; punch clocks; television apparatus; cameras (photography); material for electricity mains (wires, cables); integrated circuits; eyeglasses; electrolysers; power battery; accumulator boxes; chargers for electric batteries; variometers; capacitors; resistances, electric; rheostats; transformers (electricity); inverters (electricity); switches, electric; lightning arresters. Vehicles for locomotion by land, air, water or rail; cars; cycle cars; bicycle stands; cable transport apparatus and installations; baby carriages; omnibuses; vehicle tyres; air vehicles; boats; traction engines; gearing for land vehicles; driving motors for land vehicles; propulsion mechanisms for land vehicles; land vehicle power engines; buffers for railway rolling stock; gear boxes for land vehicles; electric tail plates (land vehicle parts); motor vehicles.


Trademark
SHENZHEN INVT Electrical CO. | Date: 2012-04-30

Battery charge devices; Battery chargers; Commutators; Computer software to maintain and operate computer system; Converters; Data processors; Electrical distribution boxes; Electricity distribution consoles; Industrial automation controls; Inverters; Lightning arresters; Meteorological instruments; Photovoltaic inverters; Solar batteries.


Trademark
Shenzhen INVT Electrical Co. | Date: 2011-06-28

Automated process control system, namely, micro-processor based hardware and software used to monitor the status of power generation and electrical distribution in power stations; explosion-proof frequency converters for use in high voltage environments; electric control panels; electric distribution boxes and consoles; commutators; electric converters; electric switches; inverters; voltage stabilizing power supply; low-voltage electrical power supplies; autotransformers.

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