7 results about "Filter capacitor" patented technology

The invention discloses a temperature acquisition circuit of a thermistor and a self-checking method of the temperature acquisition circuit. The acquisition circuit comprises an MCU, a voltage dividing branch, a self-checking branch and a sampling filter capacitor. After the MCU controls the self-checking branch to be conducted, the acquisition circuit begins to execute a self-checking function; and when the condition that a difference value between actual sampling voltage and theoretical sampling voltage output by the voltage dividing branch is not in a preset difference value range is determined, a failure of the acquisition circuit is judged. Compared with a traditional acquisition circuit, the self-checking function is added to the acquisition circuit disclosed by the invention, and the failure of a sampling circuit can be timely found out through self-checking of the acquisition circuit, so that a technician can timely take effective measures, and the sampling error caused by the failure of the sampling circuit is avoided.

The invention discloses an LED drive device with stable performance. The LED drive device comprises an input protection circuit, a step-down circuit, a rectifier and filter circuit and a voltage-dividing and current-limiting resistor, which are electrically connected, wherein the voltage-dividing and current-limiting resistor is used for carrying out current limiting on an LED light source circuit and carrying out current limiting protection on an LED, so that the LED works under the drive of stable voltage and current; and the service lifetime of the LED is ensured. A filter capacitor in the rectifier and filter circuit is a tantalum electrolytic capacitor; and the filter capacitor is relatively small in volume and stable in performance under the conditions of the same withstand voltage and electric capacity, can still keep good electrical performance after long-time working and can prolong the service lifetime of an LED drive circuit. A discharge chip resistor is arranged in the filter capacitor; and after a power supply is cut off, the chip resistor can discharge the electricity stored in a capacitor core within a short period of time, and reduces the voltage of the capacitor core to zero, so that bleeder resistors do not need to be connected with two ends of the filter capacitor in parallel; and the circuit for driving the power supply is relatively simple.

The invention discloses a single-phase electromagnetic deceleration type permanent magnet low-speed synchronous motor fast braking circuit. The circuit of the invention comprises a control circuit and a fast braking type driving circuit. The circuit of the invention specifically includes a voltage-stabilized power source module U0, a clock oscillator U5, a processor IC1, a left solid-state relay U1, a middle solid-state relay U2, a right solid-state relay U3, a diode D1, a resistor R1, a phase-splitting capacitor C1, a filtering capacitor C2, a single-phase electromagnetic deceleration type permanent magnet low-speed synchronous motor M and the like. According to the single-phase electromagnetic deceleration type permanent magnet low-speed synchronous motor fast braking circuit of the invention, in the mutual conversion and transition processes of parking, forward rotation and reverse rotation of the single-phase electromagnetic deceleration type permanent magnet low-speed synchronous motor, the diode and the alternating current solid-state relays are utilized to simultaneously apply half-wave rectifying voltage to windings of two phases so as to shorten parking and braking time, and therefore, positioning control performance of the single-phase electromagnetic deceleration type permanent magnet low-speed synchronous motor can be greatly improved. The single-phase electromagnetic deceleration type permanent magnet low-speed synchronous motor fast braking circuit of the invention has the advantages of being simple and reliable, and high cost performance, and is especially suitable for positioning control and reciprocating control of a small-power motion mechanism.

The invention relates to a current source converter driven asynchronous motor torque control method and system, and the method is characterized in that the method comprises the steps: adding the output filtering capacitor voltage of a current source converter into a cost function used for predicting torque control on a pre-constructed current source converter driven asynchronous motor model; and determining an optimal switching vector which minimizes the cost function so as to control the output filter capacitor voltage and the output torque of the current source type converter, and carrying out resonance suppression on an LC network formed by the output filter capacitor of the current source type converter and the stator inductance of the asynchronous motor. According to the method, energy oscillation between the filter capacitor and the stator inductor can be effectively suppressed, electromagnetic torque pulsation is reduced, meanwhile, the method has excellent steady-state performance and rapid torque dynamic response, and the method can be widely applied to the field of asynchronous motor torque control.