Focusing on the research and
manufacturing of cookers27year
manufacturing of cookers27year
Service Hotline
86-757-28987796
What is the working principle of an induction cooker? Simply put, an induction cooker utilizes the principle of electromagnetic induction to achieve heating.
Induction cookers utilize the principle of electromagnetic induction (Law of) Electromagnetic Induction is an electrical appliance that converts electrical energy into thermal energy. Inside the induction cooker, the rectifier circuit will The 50Hz 220V AC voltage is converted into pulsating DC voltage, which is filtered by a capacitor and then converted into a frequency of 20KHz~40KHz by a control circuit The high-frequency voltage and rapidly changing current flowing through the coil will generate a rapidly changing magnetic field (electromagnetic generation). When the magnetic lines in the magnetic field pass through the metal container (magnetic and conductive material) at the bottom of the metal body, a large amount of strong eddy currents (magnetic generation) are generated. When the eddy currents are obstructed by the resistance of the material, a large amount of heat (electric heating) is emitted, thereby heating the food.
The main circuit of the induction cooker is an AC-DC-AC (AC-DC-AC) converter, consisting of a bridge rectifier and a voltage resonant converter. The voltage resonant converter is the core of the main circuit, which functions to invert DC power into high-frequency AC power to meet the requirements of induction heating. The induction cooker is connected to the power grid through a socket and obtains 220V mains power, which is the energy source of the induction cooker; Then, the induction cooker converts the mains electricity into direct current through a bridge rectifier circuit; Then, the DC power is converted into high-frequency AC power with a frequency of 20-40kHz through a voltage resonant converter; High frequency alternating current establishes a high-frequency magnetic field through a heating coil disk wound on a circular plane.
Induction cookers transmit power to cookware through heating coils. According to the principle of electromagnetic induction, when an alternating high-frequency current flows through the heating coil of the coil disk, closed magnetic field lines will be generated along the radius direction of the coil disk. The magnetic field lines penetrate the stove surface through the magnetic circuit formed by the coil and the bottom of the pot, and are coupled to the bottom of the pot (similar to a hollow transformer), forming eddy currents at the bottom of the pot and generating heat, playing a role in heating the food in the pot. Due to the skin effect and proximity effect of high-frequency current, the bottom of the pot is close to the surface of the coil disk, and the current density is the highest. When the surface of the pot moves inward from the coil disk, the current density decreases exponentially. Therefore, the heating current is mainly located on the surface of the heating coil and pot, thus better utilizing high-frequency heating current.
Firepower control, also known as power control, corresponds to an output power for each firepower level. Therefore, when users choose different firepower, they are selecting different power levels. Due to P=V * I, in order to achieve power control, it is necessary to first detect the voltage of the mains power, and then determine the heating current based on the selected firepower. The specific process is as follows: select the firepower level, that is, determine the working power P of the induction cooker; Detecting the mains voltage, i.e. determining the operating voltage V; Obtain the heating current I of the induction cooker based on P=V * I; For induction cookers, the control of heating current is achieved through the switch in the resonant converter: the on-time of the switch is determined based on the magnitude of the current, that is, the duty cycle of the PWM signal; The magnitude of the load current generated by PWM signals with different output duty cycles varies: the higher the duty cycle, the greater the load current; The lower the duty cycle, the smaller the load current.
