Controlled silicon zero-voltage turn-on module of temperature control electric blanket and implementation method thereof

Abstract

The invention relates to a controlled silicon zero-voltage turn-on module of a temperature control electric blanket and an implementation method thereof. The turn-on module consists of a shaping circuit, an MCU (microprocessor control unit) and a controlled silicon peripheral circuit. By introducing the MCU for intelligent control, the turn-on module can easily realize the detection of an alternating current zero crossing point, the control of a time point after the synchronization with a power supply electric network, and the generation of PWM (pulse width modulation) waveform, thereby realizing that controlled silicon of the electric blanket is turned on at a voltage zero-crossing point; and compared with the turn-on of the controlled silicon of the conventional electric blanket at any point of alternating voltage, the controlled silicon zero-crossing turn-on module ensures that the voltage is reduced to zero before the turn-on of the controlled silicon to eliminate the overlapping of voltage and current in the turn-on process and reduce the change rate of the voltage and the current, thereby greatly reducing even eliminating losses and switching noises, and ensuring that the temperature control electric blanket is developed in a green direction while prolonging the service life of a product.

Description

technical field [0001] The invention relates to a thyristor zero-voltage opening module, in particular to a temperature-controlled electric blanket thyristor zero-voltage opening module and a realization method thereof. Background technique [0002] Temperature-controlled electric blankets generally use thyristor as the power output switching device. The thyristor has three connection terminals: anode A, cathode K and gate (control terminal) G, such as figure 1 As shown, the cathode is the common terminal of the thyristor main circuit and the control circuit. The activation of its normal work needs to meet the following two conditions at the same time: [0003] (1) Withstand forward voltage, that is, the anode A voltage is greater than the cathode K voltage; [0004] (2) There is a trigger current at the gate; [0005] In the previous electric blanket controller, because the power switching device - the thyristor gate trigger signal did not have any time point control, it...

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Problems solved by technology

[0005] In the previous electric blanket controller, because the power switching device - the thyristor gate trigger signal did not have any time point control, its power output was carried out at any point (often the peak value) of the AC half wave, and the thyristor was at Under the condition of high voltage or current between the anode and the cathode, it is turned on under the control of the gate. Since the voltage and current are not zero during the turn-on process, there is overlap, which leads to switching loss and the temperature of the thyristor rises. , which affects the life of the device, and the voltage and current change rapidly, and the waveform has obvious overshoot, which leads to the generation of switching noise. The typical turn-on process is as follows figure 2 As shown, such a SCR turn-on process brings serious electromagnetic interference problems to the circuit, and the electromagnetic radiation is large, which affects the normal operation of peripheral electronic equipment. More importantly, it seriously affects the service life of the product and hinders the control. The process of the development of warm and electric blankets in the direction of green environmental protection

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