Abstract: The disclosure discloses a simplified space vector modulation method for multi-lever converters, and relates to the field of space vector modulation methods for multilevel converters, which solves problems that a redundant on-off state is greatly increased along with increase of a number of levels in a traditional SVM technology, and SVM is difficult to realize due to calculation of the redundant on-off state and selection of a proper on-off state. The method includes the following steps of: step 1: establishing a vector expression; step 2: establishing a reference vector trajectory model; step 3: respectively representing reference signals and level signals by coordinate components of a reference vector and a basic vector and corresponding component sums; step 4: constructing a star-connected multilevel converter; step 5: sampling a phase voltage reference vector trajectory model of the star-connected multilevel converter, and synthesizing the reference vector.

Abstract: A fault ride-through circuit with a variable frequency transformer (VFT) and a control method thereof are provided, and the control method comprises: pretreating acquired voltages of grids, a voltage of a stator interface and a voltage of a rotor interface to obtain a rotor voltage DC component and a rotor voltage DC component; testing and treating a voltage frequency of a first grid and a voltage frequency of a second grid; carrying out a reference voltage calculation for a stator voltage DC component, a rotor voltage DC component, the voltage frequencies of the first grid and the second grid to obtain a positive voltage reference value of the first PWM convertor and the second PWM convertor; and processing the voltage reference values to obtain the switch signals for controlling the first PWM convertor and the second PWM convertor.

Abstract: The disclosure discloses a simplified space vector modulation method for multi-lever converters, and relates to the field of space vector modulation methods for multilevel converters, which solves problems that a redundant on-off state is greatly increased along with increase of a number of levels in a traditional SVM technology, and SVM is difficult to realize due to calculation of the redundant on-off state and selection of a proper on-off state. The method comprises the following steps of: step 1: establishing a vector expression; step 2: establishing a reference vector trajectory model; step 3: respectively representing reference signals and level signals by coordinate components of a reference vector and a basic vector and corresponding component sums; step 4: constructing a star-connected multilevel converter; step 5: sampling a phase voltage reference vector trajectory model of the star-connected multilevel converter, and synthesizing the reference vector.

Abstract: A water conservation system for use in a building comprises a water supply pipe, water-consuming equipment, a water-consuming equipment outlet pipe, an intermediate water inlet pipe, an intermediate water collection pipe, an intermediate water outlet pipe, an intermediate water outlet valve, an intermediate water overflow pipe, and a sewage pipe. The intermediate water collection pipe is installed in the building, and a water inlet and outlet of the intermediate water collection pipe is pre-arranged at every floor. The intermediate water outlet pipe and the intermediate water inlet pipe communicates with the water inlets and outlets of the intermediate water collection pipe, respectively. The intermediate water outlet pipe communicates with a toilet water tank. A first check valve is disposed on the intermediate water inlet pipe.

Abstract: A social networking system notifies its users of different events and actions taking place inside the social networking system. To present notifications that are most likely to be of interest to the user, the social networking system observes the interactions of the user with notifications presented to the user and suggests an option to opt-out of notifications associated with a source based on the observed interactions. The option to opt-out of notifications associated with the source may be presented if the users interactions with the notifications presented are below a threshold. Notifications associated with a social group are presented to the user based on factors describing the group and the relation between the user and other users of the social group, for example, seniority of the user, size of the group, and the rate at which user actions associated with the group are received.

Abstract: A fault ride-through circuit with a variable frequency transformer (VFT) and a control method thereof are provided, and the control method comprises: pretreating acquired voltages of grids, a voltage of a stator interface and a voltage of a rotor interface to obtain a rotor voltage DC component and a rotor voltage DC component; testing and treating a voltage frequency of a first grid and a voltage frequency of a second grid; carrying out a reference voltage calculation for a stator voltage DC component, a rotor voltage DC component, the voltage frequencies of the first grid and the second grid to obtain a positive voltage reference value of the first PWM convertor and the second PWM convertor, and processing the voltage reference values to obtain the switch signals for controlling the first PWM convertor and the second PWM convertor.

Abstract: A water conservation system for use in a building comprises a water supply pipe, water-consuming equipment, a water-consuming equipment outlet pipe, an intermediate water inlet pipe, an intermediate water collection pipe, an intermediate water outlet pipe, an intermediate water outlet valve, an intermediate water overflow pipe, and a sewage pipe. The intermediate water collection pipe is installed in the building, and a water inlet and outlet of the intermediate water collection pipe is pre-arranged at every floor. The intermediate water outlet pipe and the intermediate water inlet pipe communicates with the water inlets and outlets of the intermediate water collection pipe, respectively. The intermediate water outlet pipe communicates with a toilet water tank. A first check valve is disposed on the intermediate water inlet pipe.

Abstract: An alternating current/direct current home smart micro-grid coordination system is provided, which includes an alternating current power quality screening modulator, a direct current power quality screening modulator and a power coordination module, where the power coordination module is configured to receive parameters of buses detected by the alternating current power quality screening modulator and the direct current power quality screening modulator, perform optimization calculation to obtain optimal solutions of a voltage on the power quality-insensitive load alternating current bus and a voltage on the power quality-insensitive load direct current bus, and issue an instruction to control the alternating current power quality screening modulator and the direct current power quality screening modulator to adjust the voltage on the power quality-insensitive load alternating current bus and the voltage on the power quality-insensitive load direct current bus.

Abstract: Techniques to promote messages in a social networking services to increase communication opportunities while throttling unsolicited messages are described. In one embodiment, an apparatus may have a message generation component and a message delivery component. The message generation component may be operative to receive a request from a first member of a social networking service (SNS) to send a message for a second member of the SNS. The message delivery component may be operative to deliver the message to one of multiple mailboxes for the second member based on a tiered payment schedule. The tiered payment schedule may include a first parameter to represent a relationship type between the first and second members, a second parameter to represent a subscriber tier for the second member, and a third parameter to represent a promotional cost associated with the subscriber tier. Other embodiments are described and claimed.

Abstract: Exemplary methods, apparatuses, and systems receive a request from a user to access content for a group of users of a social networking system, and send the content to the user including an interface to a third party system. The interface is to enable the user to retrieve information related to a third party service from the third party system to share with the group. The user sends the information related to the third party service to share with the group to the social networking system. The social networking system sends the shared information related to the third party service to a group member based on the group member requesting access to the content. In one embodiment, the third party service stores a file or folder on a third party server and the shared information includes a link to the shared file or folder.

Abstract: Exemplary methods, apparatuses, and systems receive a request from a user to access content for a group of users of a social networking system, and send the content to the user including an interface to a third party system. The interface is to enable the user to retrieve information related to a third party service from the third party system to share with the group. The user sends the information related to the third party service to share with the group to the social networking system. The social networking system sends the shared information related to the third party service to a group member based on the group member requesting access to the content. In one embodiment, the third party service stores a file or folder on a third party server and the shared information includes a link to the shared file or folder.

Abstract: A social networking system notifies its users of different events and actions taking place inside the social networking system. To present notifications that are most likely to be of interest to the user, the social networking system observes the interactions of the user with notifications presented to the user and suggests an option to opt-out of notifications associated with a source based on the observed interactions. The option to opt-out of notifications associated with the source may be presented if the users interactions with the notifications presented are below a threshold. Notifications associated with a social group are presented to the user based on factors describing the group and the relation between the user and other users of the social group, for example, seniority of the user, size of the group, and the rate at which user actions associated with the group are received.