Abstract: A control method of an off-grid master-slave solar inverter system includes powering on the off-grid master-slave solar inverter system; a controller controlling a first inverter and a second inverter to prepare to output pulses corresponding to a first series number and pulses corresponding to a second series number, respectively; only the first inverter outputting a pulse corresponding to a first number of the first series number; and the controller controlling the first inverter to output a first alternating current voltage and the second inverter to output a second alternating current voltage with a frequency of the first alternating current voltage after a first predetermined time.

Abstract: A solar inverter system includes a first inverter, a second inverter, and a controller. The first inverter has a first input terminal, and a first output terminal. The first input terminal is coupled to a solar panel. The second inverter has a second input terminal, and a second output terminal. The second input terminal is coupled to the solar panel. The first output terminal and the second output terminal are parallel with a utility grid. The controller is coupled to the first inverter and the second inverter for controlling the first inverter and the second inverter to output total output power in turn, or controlling the first inverter and the second inverter to output the total output power simultaneously.

Abstract: A control method of a solar inverter system includes calculating total output power outputted by a first inverter and a second inverter; determining whether the total output power is less than a threshold value; and executing a corresponding operation according to a determination result.

Abstract: A battery free off-grid solar inverter system includes an inverter and a controller. The inverter is used for converting a direct current voltage provided by a solar panel into an alternating current voltage. The inverter has an input terminal, an output terminal, and a control terminal. The input terminal is used for coupling to the solar panel for receiving the direct current voltage, and the output terminal is used for coupling to a load for coupling the alternating current voltage. The controller is coupled to the control terminal for gradually increasing the alternating current voltage to make the direct current voltage be gradually decreased when the battery free off-grid solar inverter system is turned on. The controller stops increasing the alternating current voltage when the direct current voltage is lower than a predetermined direct current voltage value.

Abstract: A keyboard is disclosed and includes a base plate, a plurality of key structures, a plurality of switches, and a capacitive touch sensing device. Each of the key structures is disposed above the bottom plate and includes a keycap capable of moving up and down relative to the base plate. Each of the switches corresponds to one of the keycaps and is disposed under the corresponding keycap. Each of the keycaps is capable of moving toward the base plate to trigger the corresponding switch. The capacitive touch sensing device is disposed under the key structures, for sensing a touch operation performed on the keycaps. The functionality of the keyboard of the invention therefore improves. The keyboard uses an identical projection area to perform keying and touch operation, which avoids the inconvenience for a user when using both a keyboard and a touchpad in the prior art.

Abstract: A keyboard includes a base and a plurality of keyswitches. The keyswitches are disposed on the base. One of the keyswitches includes a key cap, a first support member and a second support member. The first support member is Z-shaped and has a first sliding portion and a first rotating portion, wherein the first sliding portion is selectively disposed on one of the base and the key cap and the first rotating portion is selectively disposed on the other one of the base and the key cap. The second support member is Z-shaped and has a second sliding portion and a second rotating portion, wherein the second sliding portion is selectively disposed on one of the base and the key cap and the second rotating portion is selectively disposed on the other one of the base and the key cap.