33results about How to "Increase the voltage amplitude" patented technology

A wireless communication device includes a speaker grille, a built-in speaker provided behind the speaker grille, and an output amplifier connected to the built-in speaker. A voltage applied to the output amplifier is increased to a level higher than the level of voltage applied to the output amplifier while audio signals are being produced, and instead of the audio signals, low-frequency continuous signals are applied to the output amplifier. By increasing the voltage applied to the output amplifier to a level higher than the level of voltage applied to the output amplifier while audio signals are being produced, the amplitude of the voltage applied to the speaker is increased. Also, instead of the audio signals, low-frequency continuous signals are applied to the output amplifier so that the speaker produces a higher sound pressure than while audio signals are being produced to discharge water in the speaker grille under the sound pressure.

The invention discloses an output current-limiting control method for an inversion type distributed power supply. The maximum of output active power of the inversion type distributed power supply under symmetrical faults and under unsymmetrical faults can be ensured; meanwhile, the positive sequence voltage amplitude value output by the inversion type distributed power supply is improved, the negative sequence voltage amplitude value is reduced, and the degree of asymmetry of output voltage of the inversion type distributed power supply is reduced; specific to different current-limiting methods, a relatively high voltage output level of the inversion type distributed power supply is ensured under unsymmetrical faults, so that a low voltage protection action is not triggered easily; specific to the negative sequence overcurrent protection, the negative sequence current output is limited by the current-limiting method provided by the invention, so that the negative sequence overcurrent protection is relatively not triggered easily; and compared with a non-current-limiting control method and other two current-limiting control methods, the output current-limiting control method provided by the invention can both better ensure the stable operation of the inversion type distributed power supply without logging out under symmetrical faults and under unsymmetrical faults, so that the system stability is improved.

The invention provides a lightning arrester operation analog simulation system. The lightning arrester operation analog simulation system mainly comprises a data processing center, a data interactive processing interface module, a human-computer interface, an optical fiber data communication module, a power supply control measurement module, a harmonic wave power module, a power frequency high-voltage power module, a voltage divider, a high-voltage lightning arrester, a temperature and humidity measuring module, a lightning arrester resistive current precision measurement module and a SO2 environmental testing module. The data processing center, the human-computer interface and the data interactive processing interface module perform operation through a computing control platform, a host machine of the computing control platform is an industrial control computer and is provided with an optical fiber conversion module, and the host machine of the computing control platform is respectively connected with the power supply control measurement module, the lightning arrester resistive current precision measurement module and the SO2 environmental testing module through the optical fiber conversion module. In functional roles, the system can simulate joint effects of double factors including an electrical characteristic and a natural environment to simulate operation condition of an actual electric power system lightning arrester.

An insulation ageing test device of frequency conversion high voltage pulse equipment is prepared as connecting output end of pulse generator to primary edge of high voltage boosting transformer with its secondary edge being connected to wire in insulation sleeve, applying 300H2 to lkH2, 1kH2 to 5kH2 , 5kH2 to 10k H2 and 10k H2 to 20k H2 as operation frequency of high voltage boosting transformer alternately, connecting said boosting transformer to output of pulse generator for outputting square wave to meet requirements of insulation ageing test.

The invention discloses a resistance measuring circuit, a temperature detecting circuit and a charging gun. Among them, the resistance measurement circuit includes a current-limiting resistance module, a switch module and a sampling module. The switch module is turned on and off according to a preset cycle. When the switch module is turned on, the current-limiting resistance module is connected to the ground, and a current flows through the measured resistance. ; When the switch module is disconnected, the current-limiting resistor module is disconnected from the ground, and no current flows through the measured resistance; in one on-off cycle of the switch module, by adjusting the on-off time, the change The time that the current flows through the resistance under test keeps the power of the resistance under test within a preset range. The sampling module is used to sample the voltage of the current-limiting resistor module and output a sampling voltage; the sampling voltage is used to calculate the resistance value of the measured resistance. The present invention adopts a non-continuous sampling method, which can increase the current flowing through the measured resistance in a short time and increase the divided voltage on the measured resistance under the condition that the power of the measured resistance is not increased, thereby increasing the signal-to-noise ratio , which improves the measurement accuracy.