Showing papers on "Synchronous frame published in 2010"
14 Mar 2010
TL;DR: In this article, a new medium voltage drive has been developed based on the active neutral-point clamped 5-level (ANPC-5L) topology, which can be used to increase the efficiency of standard, low cost direct online (DOL) machines.
Abstract: A new medium voltage drive has been developed based on the active neutral-point clamped 5-level (ANPC-5L) topology. In the last decade three-level neutral-point clamped (NPC) converters have become the industry standard in MV Drives. This configuration has proved very successful for applications where high power and high performance requirements necessitated the use of inverter grade motors and the associated costs. On the other hand, there is an increasing demand by industry for drives which can be used to increase the efficiency of standard, low cost direct online (DOL) machines. The problems of high harmonic content, high dv/dt and common mode voltage have been significantly improved in this new drive solution. The structure of the converter will be described with explanation of the multiple levels of redundancy available. The necessary conditions for regulating the neutral-point and phase (or floating) capacitor voltages will be illustrated. The highly dynamic direct torque control (DTC) method has been chosen the inverter control. The synchronous frame current regulator used for rectifier control allows for full four-quadrant operation on the network side. The mechanical design philosophy will be displayed along with the salient technical features: rectifier and inverter operating waveforms, protection concept, and ride through behavior. Finally experience in pilot installations will be reviewed.
179 citations
TL;DR: This paper derives a stationary frame controller that is the exact equivalent of the commonly used synchronous frame controller with L decoupling, the new stationary frame “PRX2” controller, which consists of a proportional, a resonant, and two cross-coupling components.
Abstract: Within power systems, high-power pulsewidth-modulated ac-dc converters are used in flexible ac transmission systems controllers and for interfacing renewable energy sources to the grid. These converters traditionally employed PI controllers designed in the synchronous dq-frame with decoupling of d and q axes. Recently, stationary -frame proportional-resonant (PR) controllers have been proposed. Though both types of control are suitable for the regulation of three-phase converters, the PR controller displays steady-state and dynamic behavior that differs significantly from that of decoupled dq-frame controllers. This paper derives a stationary frame controller that is the exact equivalent of the commonly used synchronous frame controller with L decoupling. The new stationary frame “PRX2” controller consists of a proportional (P), a resonant (R), and two cross-coupling components. The PRX2 controller offers identical transient and steady-state performance and has the same frequency response as the decoupled synchronous frame PI controller. Unlike other stationary frame controllers containing resonant components, the PRX2 controller is unique because it contains a cross-coupling feedback component, which accounts for the behavior of the L decoupling branches present in synchronous frame controllers. It is shown that ignoring this decoupling component greatly increases the controller's sensitivity to frequency variation. Numerous stationary frame controllers, including the common PR controller, may be derived from the general PRX2 controller.
107 citations
Patent•
10 Feb 2010
TL;DR: In this article, matching feature points are extracted from at least two pairs of synchronous frames, and the synchronous frame pairs are provided with an image overlapping region obtained by two different angles.
Abstract: The embodiment of the invention provides an image splicing method and a system thereof; the image splicing method comprises the following steps: matching feature points are extracted from at least twopairs of synchronous frames, and the synchronous frame pairs are provided with an image overlapping region obtained by two different angles; homography matrix is solved according to the matching feature points; the homography matrix is applied to carry out image splicing to the synchronous frame pairs obtained by two different angles. In the embodiment of the invention, the matching feature points are extracted from a plurality of the synchronous frame pairs, so as to obtain a plurality of matching feature points, compared with the prior art, the matching feature points are extracted from a pair of the synchronous frame pairs, the method in the invention has representativeness, and the obtained homography matrix is reliable and accurate, thereby obtaining better image splicing effect.
11 citations
Patent•
15 Sep 2010
TL;DR: In this paper, a 3GPP (3rd Generation Partnership Project) downlink initial master synchronization detection method is presented, in which a low-pass filter is used at the receiving end to filter out a spectrum occupied by a synchronous signal, avoid the interference of other signals and improve the detection performance.
Abstract: The invention belongs to the technical field of wireless communication, in particular a 3GPP (3rd Generation Partnership Project) LET (Long Term Evolution) downlink initial master synchronization detection method. The synchronization method comprises the following steps of: using a Zadoff-Chu sequence as a synchronous marker sequence; mapping the synchronous marker sequence into a spectrum according to an LTE standard to form a synchronous frame; correlating a standard Zadoff-Chu sequence locally generated at a receiving end with a receiving sequence to confirm a district in-group marker number and a time synchronization position which are sent by a sending end, wherein a low-pass filter is used at the receiving end to filter out a spectrum occupied by a synchronous signal, avoid the interference of other signals and improve the detection performance; down sampling the filtered signal to be detected; and then mutually correlating with a local standard synchronous sequence; and differentiating and processing signal detection; averaging many times and carrying out relative detection under the condition of a low signal-to-noise ratio. The invention can rapidly and accurately provide master synchronization service for initial LET synchronization and has extremely high anti-interference performance.
11 citations
Patent•
17 Mar 2010
TL;DR: In this paper, a ring-shape synchronous network is considered, where the master station transmits synchronization frames which consist of predetermined bit patterns through two clockwise and counterclockwise routes to the slave stations.
Abstract: PROBLEM TO BE SOLVED: To obtain a ring-shape synchronous network system which can appropriately execute synchronization correction in a slave station even when a communication fault or the like occurs.SOLUTION: In a synchronous network in which a master station 001 and a plurality of slave stations 101 are connected in a ring-shape, the master station 001 synchronously transmits synchronization frames which consist of respective predetermined bit patterns through two clockwise and counterclockwise routes to the slave stations 101, and the slave station 101 is provided with: a slave clock 102, a synchronous effective section setting unit 108 which establishes a synchronous effective section for every two routes; and synchronous correction unit 107 which corrects the slave clock 102 by the synchronous frame only when a reception finish time of the synchronous frame is included in the synchronous effective section.
7 citations
19 Apr 2010
TL;DR: A new synchronous frame single-phase PLL algorithm with a decoupling network that can detect the amplitude of the input signal while has simple structures compared to the conventional synchronousframe PLLs.
Abstract: A new synchronous frame single-phase PLL algorithm with a decoupling network is presented. It applies the synchronous frame transformation but omits the effort to generate the orthogonal component. The β axis signal is set directly to zero. A decoupling network is employed to eliminate the cross couplings in the dq axis. This algorithm can detect the amplitude of the input signal while has simple structures compared to the conventional synchronous frame PLLs.
6 citations
Patent•
15 Dec 2010
TL;DR: In this article, an error detecting and correcting method for a synchronous frame is presented. But the error detection and correction method is not suitable for the case of the synchronous frames.
Abstract: The embodiment of the invention provides an error detecting and correcting method for a synchronous frame. The method uses a sending end to get a send end information sequence according to the frame structure of the own synchronous frame sequence, and to get a sending end verification sequence according to the sending end information sequence and a created polynomial; then the method uses a receiving end to get a receiving end information sequence which is relevant to the verification sequence. During error detecting, the receiving end obtains the receiving end verification sequence accordingto the receiving end information sequence and the created polynomial, and then determines the transmission correction of the synchronous frame according to the receiving end verification sequence andthe sending end verification sequence. During error correcting, the receiving end obtains a companion sequence according to the receiving end information sequence, obtains an error style according tothe companion sequence, and obtains an error correction result according to the error style and the receiving end information sequence. The embodiment of the invention also discloses an error detecting and correcting device for the synchronous frame. The error detecting and correcting method and a device for the synchronous frame of the embodiment of the invention can implement error detection and error correction for the synchronous frame simultaneously, and can improve the customer satisfaction degree.
4 citations
04 Nov 2010
TL;DR: In this paper, a synchronous rotating control strategy based on the decomposition sequence is proposed, and the forward-feed decouple method is adopted in the control system; the proposed control method is verified valid and is superior to proportion-integration control strategy on traditional synchronous frame.
Abstract: The four-leg inverter is able to provide simultaneous power supply for three-phase or single-phase load with symmetrical voltage and constant frequency. The prerequisite is that the four-leg inverter must be controlled appropriately, so the synchronous rotating control strategy based on the decomposition sequence is proposed in this paper. Firstly, the inverter's mathematical model was given. Based on the model, control variables are decomposed in the novel decomposition sequence algorithm, and the forward-feed decouple method is adopted in the control system; Secondly, control system parameters are determined. Finally, by experimental results and comparatively analysis, the proposed control method is verified valid and is superior to Proportion-Integration control strategy on traditional synchronous frame.
4 citations
21 Jun 2010
TL;DR: In this article, the transient operation of a grid connected power converter designed for microgrid applications is studied and a control system consisting of an improved droop characteristic control using synchronous frame PI regulators including a feed-forward disturbance decoupling controller is developed and tested.
Abstract: The proposed paper studies the transient operation of a grid connected power converter designed for microgrid applications. A control system consisting of an improved droop characteristic control using synchronous frame PI regulators including a feed-forward disturbance decoupling controller is developed and tested. The proposed control system can operate in two main operating modes: islanded and grid connected. When the converter works in islanded mode, it offers three different operating sub-modes: conventional droop, power quality and sync modes. In grid connected mode two different sub-modes can be used: grid feeding mode and grid supporting mode. The latter allows the converter to provide ancillary services to the main grid (i.e. frequency and voltage control). A converter prototype was built to verify the proposed control strategies.
4 citations
Patent•
29 Sep 2010
TL;DR: In this paper, the authors proposed a method to lower interference on down-going synchronization acquisition from up/down-going service channels to implement synchronization of initial frame under TDD mode rapidly, and selection for sub zone.
Abstract: In the system, each base station is synchronous strictly. There are L+1 pieces of orthogonal to each other code words of down going synchronous spread spectrum codes. Front P/2 pieces of time slot in down going synchronous frame use identical code word for all sub zones to carry out synchronization of time slot. Then, within range of P/2 pieces of time slot plus a radial time delay, using L pieceof code word carries out searching and selecting code word of sub zone, and meanwhile accomplishes frame synchronization of sub zone. The invention can lower interference on down going synchronization acquisition from up / down going service channels to implement synchronization of initial frame in down going link under TDD mode rapidly, and selection for sub zone. Features are: high synchronizing precision, small amount of calculation, simple method and easy of implementation.
3 citations
Patent•
01 Apr 2010
TL;DR: In this paper, a 3GPP (3rd Generation Partnership Project) downlink initial master synchronization detection method is presented, where a low-pass filter is used at the receiving end to filter out a spectrum occupied by a synchronous signal, avoid the interference of other signals and improve the detection performance.
Abstract: The invention belongs to the technical field of wireless communication, in particular a 3GPP (3rd Generation Partnership Project) LET (Long Term Evolution) downlink initial master synchronization detection method The synchronization method comprises the following steps of: using a Zadoff-Chu sequence as a synchronous marker sequence; mapping the synchronous marker sequence into a spectrum according to an LTE standard to form a synchronous frame; correlating a standard Zadoff-Chu sequence locally generated at a receiving end with a receiving sequence to confirm a district in-group marker number and a time synchronization position which are sent by a sending end, wherein a low-pass filter is used at the receiving end to filter out a spectrum occupied by a synchronous signal, avoid the interference of other signals and improve the detection performance; down sampling the filtered signal to be detected; and then mutually correlating with a local standard synchronous sequence; and differentiating and processing signal detection; averaging many times and carrying out relative detection under the condition of a low signal-to-noise ratio The invention can rapidly and accurately provide master synchronization service for initial LET synchronization and has extremely high anti-interference performance
Patent•
12 Jul 2010
TL;DR: In this article, a method and an apparatus for full-duplex relaying based on tree topology are provided to allow all local terminals to transmit and receive data with other terminals freely in a local area.
Abstract: PURPOSE: A method and an apparatus for full-duplex relaying based on tree topology are provided to allow all local terminals to transmit and receive data with other terminals freely in a local area. CONSTITUTION: A control unit(1204) sets up a synchronous frame and the n number of channel frames as one frame set. The control unit maintains a super frame including plural frame sets, and judges whether or not the synchronous signal is received from the first terminal located in the local area. The control unit maintains the synchronization with the first terminal which transmits the synchronous signal, and selects one of the n number of channel frames. The control unit sets up a call channel with the first terminal.
11 May 2010
TL;DR: In this article, a hybrid sensorless speed method for interior permanent magnet synchronous motors (IPMSM) is proposed, where an adaptive full-order observer has been implemented in medium and high speeds using fictitious permanent magnet model.
Abstract: In this paper a hybrid sensorless speed method for Interior Permanent-Magnet Synchronous Motors (IPMSM) is proposed. This method works efficiently at very low up to rated speed. An adaptive full-order observer has been implemented in medium and high speeds using fictitious permanent-magnet model. At standstill and low speeds a signal injection method is augmented to an adaptive observer for better estimation. Adopted signal injection method superimposes a pulsating voltage on the voltage reference in the stator reference frame. In order to achieve good performance, a Maximum Torque Per Ampere (MTPA) vector controller is incorporated with a synchronous frame decoupling scheme. Since in applied control method the motor parameters are widely utilized, a Recursive Least Square algorithm (RLS) has been applied to online parameter identification. Finally, in order to evaluate the performance of the proposed method, a comprehensive set of simulations were performed.