53results about How to "Improve current control accuracy" patented technology

The invention relates to an inductive current detecting circuit in a switch power supply and an LED (light emitting diode) driving circuit using the inductive current detecting circuit. According to the inductive current detecting circuit provided by the embodiment of the invention, an inductive current ending time in an interrupted working mode of the inductive current can be detected precisely through a voltage sampling and holding circuit so that inductive current duration time can be obtained precisely. According to the LED driving circuit provided by the embodiment of the invention, with the adoption of the inductive current detecting circuit, an inductive current average value can be obtained precisely, i.e. output current information of the LED driving circuit can be obtained precisely, so that the current control precision is improved; furthermore, the power factor calibration is realized; and a higher power factor is obtained.

The invention provides a driving circuit and method for providing power to an LED light source, and a power converter. The driving circuit comprises a voltage filter, a transformer and a controller. The voltage filter receives and filters an input voltage to provide a stable voltage. The transformer converts the stable voltage into an output voltage to provide power to a light source. The controller generates a driving signal to make a switch work alternatively between a first state and a second state. The controller controls time durations of the first state and the second state, such that an input current decreases to a predetermined level during the second state and increases to a peak level proportional to the input voltage during the first state. The controller controls the ratio of time in the first state to time in the second state to adjust an output current flowing through the light source to a target level. According to the invention, the current control precision is improved, power factors of the driving circuit are corrected, the quality of power supply is improved, and line frequency interference of lighting of the light source is minimized.

The circuit contains a single processing circuit, it receives the control pulse. A from the electronic control unit of the motor and output high voltage driving pulse Ah and low voltage driving pulse Al to higher extreme driving circuit separately and receive the feedback sampling current signal from lower extreme driving circuit, after processing, the low voltage driving pulse Al adjust the higher extreme driving circuit to adjust the driving circuit of the electromagnetic valve. Lower extreme driving circuit receive pulse signal B from electronic control unit of the motor, this pulse signal is same with the control signal A.

A power converter includes a plurality of power conversion units connected to one another in parallel, each including an AC / DC converter (rectifier) that converts AC power from an AC input power supply (commercial power supply) into DC power, a DC / DC converter (DC power converter) that converts the DC power from the AC / DC converter, and a current detector that detects charge current flowing from the DC / DC converter as well as discharge current flowing to the DC / DC converter. The power converter further includes a battery (electrical storage unit) that is charged by a subset of DC / DC converters among the DC / DC converters of the plurality of power conversion units, as well as a CPU (controller) that controls the DC / DC converters of the plurality of power conversion units.

The present invention relates to a chain type converter-based power distribution network electric energy quality comprehensive control method and system. The method includes a system-level control strategy and a device-level control strategy, wherein the system-level control strategy realizes load reactive power, harmonic and unbalanced current detection, power distribution network PCC fundamental wave positive sequence voltage control, and power distribution network PCC fundamental wave negative sequence voltage control, and comprehensively generates chain type converter current control instruction signals, and the device-level control strategy realizes sub-module direct-current side capacitor voltage control of chain type converter control, realizes three-phase conversion chain current control of a chain type converter according to a current control instruction from the system level, and generates chain type converter switching tube duty cycle signals. With the method and system provided by the technical scheme provided by the invention adopted, electric energy quality problems such as harmonic, flicker and imbalance in a power distribution network can be comprehensively controlled.

In order to solve the technical problem that an existing driving scheme cannot work normally in a high-frequency chopping occasion or cannot obtain high-precision LED current, the invention provides adriving circuit for plant illumination. The driving circuit comprises a constant voltage source and an adjustable circuit, and the first end of the constant voltage source is used for being connectedwith the first end of a load. The adjustable circuit comprises: an adjustable voltage source, wherein the first end of the adjustable voltage source is connected with the second end of the constant voltage source; a chopper switch, wherein the first end of the chopper switch is connected with the second end of the adjustable voltage source, and the second end of the chopper switch is used for being connected with the second end of the load; and a control circuit, wherein the first end of the control circuit is used for being connected with the first end of the load, the second end of the control circuit is connected with the third end of the chopper switch, the third end of the control circuit is connected with the third end of the adjustable voltage source, and the control circuit is used for controlling the chopper switch and controlling the voltage of the adjustable voltage source according to a load current signal in order to match the sum of the voltage of the adjustable voltagesource and the voltage of the constant voltage source with a target voltage.

The invention provides a driving circuit, a method and a power converter for powering a light emitting diode light source. The driving circuit includes: a voltage filter, a transformer and a controller. The voltage filter receives and filters the input voltage to provide a stable voltage; the transformer converts the stable voltage into an output voltage to supply power to the light source; the controller generates a driving signal to make the switch work alternately in the first state and the second state, and the controller controls the the duration of the first state and the duration of the second state such that the input current decreases to a preset value in the second state and increases from the preset value to a peak value proportional to the input voltage in the first state, The controller controls the ratio between the duration of the first state and the duration of the second state to adjust the output current flowing through the light source to a target value. The invention improves the current control accuracy, corrects the power factor of the driving circuit, improves the power supply quality, and reduces the horizontal frequency interference of the light source.

The invention relates to a driving piezoelectric injector device. A current feedback module monitors the current of a piezoelectric actuator in charging and discharging; a voltage feedback module monitors the voltage of the piezoelectric actuator in charging and is capable of regulating and controlling the high charging voltage and the discharging voltage of the piezoelectric actuator; an actuator medium consumption feedback control circuit regulates a charging threshold voltage; a capacitance gating compensation circuit compensates the capacitance of the piezoelectric actuator to prevent the medium consumption of the piezoelectric actuator influencing the work of the injector; an energy recycling circuit module recycles voltage from the voltage of the piezoelectric actuator and the transient high-voltage electric potential of an oil pump and is capable of pre-charging the piezoelectric actuator. The driving piezoelectric injector device is compact in structure, high in current control precision and capable of lowering the system consumption and improving the working stability and reliability of the injector under a complex working condition.

The invention relates to a high-power linear electromagnetic acceleration system and belongs to the field of motors. The driving system of a conventional high-power linear electromagnetic accelerationsystem has a great difficulty in dynamic current-sharing control and does not have a fault-tolerant function. The high-power linear electromagnetic acceleration system is characterized in that coilsin a primary starting region has a large number of series turns, a coil driver has a small output current, a purpose of driving the low-speed section of a linear motor by using a driver with a small current and a high chopping frequency is achieved; coils in a primary terminal region has a small number of series turns and the coil driver has a large output current. When the high-speed section is driven, multiple parallel unit coils are connected in parallel, and each parallel unit coil is driven separately, thereby realizing a purpose of driving a high-power motor in parallel by using small and medium power drivers, avoiding the great difficulty in dynamic current-sharing control caused by parallel connection of multiple power switching devices and achieving the fault tolerance of the driving system.