Abstract: Disclosed herein is a dual-active bridge converter and methods of operating the same. The dual-active bridge converter can include a transformer, a DC-AC converter, an AC-DC converter, and/or a control device. The DC-AC converter can be coupled to a first DC bus and a primary side of the transformer. The AC-DC converter can be coupled to a secondary side of the transformer and a second DC bus. The control device can send a first PWM signal to the DC-AC converter and a second PWM signal to the AC-DC converter. The first and second PWM signals can initiate the output voltage at zero, add jump edges at odd-numbered current harmonics, or make a phase of the input voltage trail a phase of the output voltage of the DC-AC converter. The control device can adjust the PWM signals for transformer current regulation or pulse overlap control.

Abstract: A ripple control method for a modular cascaded power conversion device is provided. The method obtains, according to a grid voltage vector of three-phase AC power, a second-order fluctuating voltage superposition vector representing the total amount of second-order fluctuating voltages on respective floating DC sides of the three phases; determines a single-phase power control amount of each phase to be transferred from the floating DC sides to a low-voltage DC side; determines a single-module power control amount of each power module to be transferred to a low-voltage DC side thereof; and generates a single-module control signal for controlling the power module, so as to transfer a second-order fluctuating voltage on a floating DC side of the power module to the low-voltage DC side thereof. A modular cascaded power conversion device is also provided.

Abstract: An epoxy resin composition, a transparent composite material including the same, and a laminated board. The epoxy resin composition includes an epoxy resin A and an epoxy resin B. The refractive index of the epoxy resin A is 1.54-1.8 and the light transmittance of the epoxy resin A is 90%. The refractive index of the epoxy resin B is 1.54-1.8 and the light transmittance of the epoxy resin B is greater than 90%. The epoxy resin A is an organosilicon modified epoxy resin. The epoxy resin B is another type of epoxy resin. The organosilicon modified epoxy resin satisfying a specific condition and another type of epoxy resin also satisfying the specific condition are combined to form a specific epoxy resin composition. The composite material prepared from the epoxy resin composition, a curing agent, and a curing accelerator has the advantages of having high light transmittance and high bending strength, and also has high bonding strength.

Abstract: The present invention provides a Pulse Width Modulation (PWM) method for a Cascaded H-bridge (CHB) converter. Each phase of the converter is provided with n Cascaded H-bridge rectifier circuits, or may also be provided with n Cascaded H-bridge rectifier circuits+1 redundant H-bridge rectifier circuit. The method includes following steps of: S1, generating groups of sinusoidal signals as reference waveforms, and generating n carrier signals having sequentially decreasing levels and equal amplitudes to correspond to the H-bridge rectifier circuit at the first to the nth levels, where the levels of the n carrier signals are cascaded to fill the voltage amplitude of a unipolar half cycle of the reference waveform; and S2, determining PWM signals for controlling power transistors of the corresponding H-bridge rectifier circuits based on each reference waveform and each carrier signal.

Abstract: The present disclosure provides a distributed phase-shifting transforming apparatus, including N transformer rectifier units, where each transformer rectifier unit includes two three-phase three-winding transformers and four rectifier circuits, each three-phase three-winding transformer includes first windings on the primary side and second windings and third windings on the secondary side, AC power output by the second windings and the third windings on the secondary side is output after being rectified by the rectifier circuits. Each transformer rectifier unit is configured such that: one set of the two first windings on the primary side and the two second windings on the secondary side is phase-shifted by 150 from each other, and the other set has the same phase angle; and the second windings and the third windings of each three-phase three-winding transformer are phase-shifted by 300 from each other.

Abstract: The present invention provides a multi-active bridge converter.

Abstract: The present invention provides a Pulse Width Modulation (PWM) method for a Cascaded H-bridge (CHB) converter. Each phase of the converter is provided with n Cascaded H-bridge rectifier circuits, or may also be provided with n Cascaded H-bridge rectifier circuits+1 redundant H-bridge rectifier circuit. The method includes following steps of: S1, generating groups of sinusoidal signals as reference waveforms, and generating n carrier signals having sequentially decreasing levels and equal amplitudes to correspond to the H-bridge rectifier circuit at the first to the nth levels, where the levels of the n carrier signals are cascaded to fill the voltage amplitude of a unipolar half cycle of the reference waveform; and S2, determining PWM signals for controlling power transistors of the corresponding H-bridge rectifier circuits based on each reference waveform and each carrier signal.

Abstract: An optical fiber sub-assembly includes: a handle, a rear retainer, an optical cable, a field mountable connector (FMC) assembly, a spindle, and a protection hood fixedly connected to the spindle. An end of the optical cable is connected to the FMC assembly, the optical cable protrudes from a first end of the FMC assembly. The FMC assembly includes a ferrule provided at a second end of the FMC assembly. The spindle is sleeved outside the first end of the FMC assembly, and the protection hood is sleeved outside the second end of the FMC assembly. An end of the spindle that is away from the protection hood is connected to the rear retainer and is used to fasten the optical cable. The handle is sleeved outside the protection hood and the spindle.

Abstract: The present invention provides an auxiliary pre-charging device for a power converter. The power converter includes at least one power unit with an input end being connected to a medium and high voltage AC power source, and an output end being connected to a low voltage DC bus, wherein the auxiliary pre-charging device includes a switch, a transformer, a pre-charging resistor, and a rectifier sequentially connected in series, one end of the switch is connected to the medium and high voltage AC power source, and an output end of the rectifier is connected to the low voltage DC bus. The present invention also provides a pre-charging method for a power converter, which uses the aforementioned auxiliary pre-charging device to start pre-charging at the low-voltage output end of the power converter.

Abstract: This application provides a pre-connector and a communications device. The pre-connector includes a connector component and an outdoor component. The connector component includes a ferrule base and a ferrule that is slidable relative to the ferrule base. The ferrule base is configured to fasten the optical cable, and the ferrule is connected to an optical fiber that is of the optical cable and that is inserted into the ferrule base. In this way, the optical fiber can be connected to the communications device by using the ferrule. The outdoor component includes: a spindle that is sleeved on the ferrule base and that is fastened to the ferrule base; and a handle sleeve sleeved on the spindle. The outdoor component is used as a connecting piece to be detachably fastened and connected to the communications device, so as to provide a locking force used when the communications device is connected.

Abstract: An optical fiber sub-assembly and an optical fiber connector, where the optical fiber sub-assembly includes a connector component, where a first end of the connector component is used to connect an optical cable, and where a ferrule is disposed at a second end of the connector component. Additionally, a protection tube is disposed around the ferrule, where an end surface of the ferrule protrudes from an end surface of the protection tube or an end surface of the ferrule is level with an end surface of the protection tube. Further, the protection tube has a notch, and a beveled edge is formed at an outer end of the notch.

Abstract: An optical fiber sub-assembly includes: a handle, a rear retainer, an optical cable, a field mountable connector (FMC) assembly, a spindle, and a protection hood fixedly connected to the spindle. An end of the optical cable is connected to the FMC assembly, the optical cable protrudes from a first end of the FMC assembly. The FMC assembly includes a ferrule provided at a second end of the FMC assembly. The spindle is sleeved outside the first end of the FMC assembly, and the protection hood is sleeved outside the second end of the FMC assembly. An end of the spindle that is away from the protection hood is connected to the rear retainer and is used to fasten the optical cable. The handle is sleeved outside the protection hood and the spindle.

Abstract: A fiber access terminal including a first assembly and a second assembly. The first assembly includes a first box body and an optical fiber adapter. The second assembly includes a second box body, an optical splitter, an optical fiber connector, and a plurality of optical fiber adapters. The optical fiber adapter of the first assembly is disposed outside the first box body. The optical splitter is disposed inside the second box body, and the optical fiber connector and the plurality of optical fiber adapters of the second assembly are disposed outside the second box body. A first end of the optical fiber connector is detachably connected to the optical fiber adapter of the first assembly, a second end of the optical fiber connector is connected to an input port of the optical splitter, and each output port is connected to one optical fiber adapter of the second assembly.

Abstract: An optical fiber sub-assembly and an optical fiber connector, where the optical fiber sub-assembly includes a connector component, where a first end of the connector component is used to connect an optical cable, and where a ferrule is disposed at a second end of the connector component. Additionally, a protection tube is disposed around the ferrule, where an end surface of the ferrule protrudes from an end surface of the protection tube or an end surface of the ferrule is level with an end surface of the protection tube. Further, the protection tube has a notch, and a beveled edge is formed at an outer end of the notch.

Abstract: A fiber access terminal including a first assembly and a second assembly. The first assembly includes a first box body and an optical fiber adapter. The second assembly includes a second box body, an optical splitter, an optical fiber connector, and a plurality of optical fiber adapters. The optical fiber adapter of the first assembly is disposed outside the first box body. The optical splitter is disposed inside the second box body, and the optical fiber connector and the plurality of optical fiber adapters of the second assembly are disposed outside the second box body. A first end of the optical fiber connector is detachably connected to the optical fiber adapter of the first assembly, a second end of the optical fiber connector is connected to an input port of the optical splitter, and each output port is connected to one optical fiber adapter of the second assembly.