47results about How to "Wide voltage regulation range" patented technology

The invention discloses a self-excitation mixed-excitation brushless direct current (DC) power-generating system and a control method thereof, belonging to the category of brushless DC power-generating systems. The power-generating system comprises a mixed-excitation brushless DC generator, a filtering capacitor, two current transformers, an excitation current detecting and regulating circuit, anoutput current detecting and regulating circuit, an output voltage detecting and regulating circuit and a digital voltage-regulating controller. The control method comprises three steps of control, i.e., voltage feedback control, load current feedback control and excitation current feedback control. The DC power-generating system does not need an external auxiliary power supply and can realize constant-voltage output within a wide rotating speed and large load range. The digital control leads to easy realization of parameter adjustment and modularization design. The DC power-generating systemhas an important application value in an independent-power-supply DC power-generating system of an airplane, a ship, an automobile, and the like.

The invention relates to the technical field of electric appliance detection and discloses a testing device for a high-capacity direct-current electric appliance. The testing device for the high-capacity direct-current electric appliance comprises a rectifier transformer T1, a rectifier D, an accompany test sample breaker QF2, an accompany test sample contactor KM1, a tested object X1 and a direct-current speed regulator A. According to the testing device for the high-capacity direct-current electric appliance, thyristors are adopted by the rectifier D to serve as rectification devices, voltage can be smoothly regulated to the maximum value from zero, and the voltage regulation range of the testing device for the high-capacity direct-current electric appliance is widened; control and protection are achieved according to the current of each thyristor, both the safety and the reliability of the testing device are improved, and the service life of the testing device is prolonged; due to the fact that the direct-current speed regulator A is adopted, digital control over a direct-current power supply is achieved, regulation can be conducted on site through a potential regulator B3, regulation can also be conducted through a remote computer, and thus voltage regulation can be achieved rapidly and conveniently through the testing device; the testing device can be used for detection testing of electric appliances on the voltage grade of 2KV-4KV.

The invention discloses an overvoltage and overcurrent protection circuit with the state holding function, comprising an overcurrent detection circuit and an overvoltage detection circuit. The overvoltage and overcurrent protection circuit with the state holding function is characterized by further comprising a triggering circuit, a state holding circuit and a switching circuit; the triggering circuit receives the control signals outputted by the overcurrent detection circuit and the overvoltage detection circuit; when the overvoltage signal appears, the overvoltage detection circuit outputs the control signal to control the switching circuit to switch off, and when the overcurrent signal appears, the overcurrent detection circuit outputs the control signal to control the switching circuit to switch off; the switching circuit is connected between the power output and the protection circuit output; the control end of the switching circuit receives the control signals outputted by the triggering circuit and the state holding circuit; the switching circuit is started by the state holding function to switch on; and when the overvoltage and overcurrent signal appears, the triggering circuit controls the switching circuit to switch off, and the state holding circuit keeps the switching circuit in the switching-off state.