Thermal memory circuit for breaker and charging adjusting method thereof

Abstract

The invention relates to a thermal memory circuit for a breaker and a charging adjusting method thereof for independently adjusting the charging according to the current. The charging control for a capacitor is completely realized by using a simulating circuit. The circuit comprises a microprocessor, a current sampling circuit, a PWM (Pulse-Width Modulation) comparison generating circuit, a charging and discharging circuit and a voltage sampling circuit. When a circuit current does not exceed a preset threshold value, a reference voltage is more than a current sampling signal all the time and the PWM comparison generating circuit does not drive the capacitor charging and discharging circuit to charge the energy-storing capacitor. When the circuit current exceeds the preset threshold value, the charging and discharging circuit is driven to charge the energy-storing capacitor by the PWM comparison generating circuit. A duty cycle of a driving signal generated by the PWM comparison generating circuit is determined by the magnitude of the circuit current; the bigger the circuit current is, the bigger the duty cycle of the driving signal is and the quicker the charging of the capacitor is; voltage information of the charged and discharged capacitor is fed to the microprocessor by a voltage feedback circuit; and when the breaker is repeatedly electrified, an energy residue equivalent value is supplied to the microprocessor and is processed.

Description

technical field [0001] The invention relates to an intelligent circuit breaker, in particular to a thermal memory circuit of the circuit breaker, which is used to protect circuits and motor loads, etc., and belongs to the technical field of circuit breakers. Background technique [0002] The thermal memory function of the circuit breaker refers to the function that the circuit breaker records and saves the energy (heat, mainly related to the current of the main circuit) information of the main circuit, so as to provide a basis for energy accumulation when the main circuit is overloaded next time. It includes two types of electric thermal memory and power-off thermal memory. At present, electrified thermal memory is relatively easy to implement, but it needs to rely on an external power supply. Power-off thermal memory can save energy information when the system is completely powered off, and simulate energy decay after the system is powered off, which requires the use of ex...

AI Technical Summary

Problems solved by technology

An electronic release with thermal memory is disclosed, but its improvement method for the release is similar to the Chinese patent (application number: 200820185417.X), and it cannot overcome the complexity of the microprocessor software and low product reliability Defects

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