KR100550162B1 - Induction heating apparatus using digital signal processor - Google Patents

Abstract

The present invention provides a induction heating cooking apparatus using a DSP that implements a control algorithm using a DSP for a detection method and a driving method required for driving an induction heating cooking apparatus, the rectifying unit for rectifying the input commercial AC power; An input current detector which detects a current from the input commercial AC power supply using a current transformer and inputs a corresponding voltage level to the DSP; An input voltage detector detecting a voltage from a commercial power source input through the rectifier and inputting the voltage to a DSP; LC resonance and induction heating unit for induction heating of cookware by repeating switching of IGBT and energy charging and discharging by time constant of LC resonance circuit; A resonance voltage detector for detecting an LC resonance voltage; An IGBT driver which drives the IGBT according to the IGBT drive control signal supplied from the DSP; A resonant voltage phase detector for detecting a zero phase of the LC resonant voltage detected by the resonant voltage detector to be used as a conduction start signal of the IGBT; An overvoltage detector and an overcurrent detector for protecting the IGBT from overvoltage and overcurrent; And a DSP for driving the IGBT appropriately based on the output of each unit.

Induction Heating Cooker, DSP, LC Resonance, IGBT

Description

Induction heating cooking device using DSP {INDUCTION HEATING APPARATUS USING DIGITAL SIGNAL PROCESSOR}

1 is a block diagram of an induction heating cooking apparatus using a DSP according to the present invention.

<Description of the symbols for the main parts of the drawings>

10: rectifier 20: input current detector

30: input voltage detector 40: LC resonance and induction heating unit

50: temperature detector 60: resonance voltage detector

70: IGBT driver 80: resonant voltage phase detector

90: overvoltage detector 100: overcurrent detector

110: DSP

The present invention relates to an induction heating cooking apparatus, and more particularly, to an induction heating cooking apparatus using a DSP that implements a driving control algorithm, a protection operation, a detection operation, and a power device driving using a DSP (Digital Signal Processor). It is about.

In general, induction heating device uses Eddy Current Loss and alternating magnetic field by causing an induction magnetic field generated when switching induction heating coil at high speed to flow Eddy Current to the surface of magnetic heating object adjacent to induction heating coil. Induction heating cooking device is a device to heat the cooking vessel by using it, and the induction heating cooking device has been implemented to control the output using most analog circuits. Has been.

Therefore, the number of circuit components is large, the control characteristics change due to temperature fluctuation factors of circuit components, the user interface is small, the signal connection line with the main controller is difficult, and it is difficult to construct various protection circuits. There was no solution for this.

In addition, there is a possibility that the output power due to the fluctuation of the input power is large, the current distortion occurs due to the voltage waveform of the input power, and there is no instantaneous power failure detection method, thereby causing a malfunction in the power failure. In particular, functions that require nonlinear control characteristics have many limitations and have limited performance.

The present invention is to solve this problem, the present invention can implement the drive control algorithm of the induction heating cooking apparatus using a DSP to reduce the number of components, as well as to reduce the fluctuation factors according to the temperature, Reduces the number of inputs, detects the input power fluctuations in the DSP so that constant power can be supplied regardless of the input power fluctuations, and reduces the output distortion due to the current waveform distortion by calculating and controlling the current waveform distortions according to the input voltage waveforms Its purpose is to provide the induction heating cooking device using DSP that memorizes the state of power failure before instantaneous power failure and can drive it to the state before power recovery, and acquires precise and high performance control and copes with various situations. have.

Induction heating cooking apparatus using a DSP according to the present invention for achieving the object of the present invention, rectification unit for rectifying the commercial power input through the over-current protection fuse and the EMI filter for removing the conductive noise through the bridge diode; An input current detector for detecting a current using a current transformer from a commercial power source input through the overcurrent prevention fuse and an EMI filter for removing conductive noise and inputting a voltage level according to the DSP; An input voltage detector converting an output of the rectifier input through the rectifier into a voltage level through a resistance voltage divider circuit and inputting the same to a DSP; LC resonance and induction heating unit for induction heating of cookware by repeating switching of IGBT and energy charging and discharging by time constant of LC resonance circuit; A resonance voltage detector for detecting an LC resonance voltage; An IGBT driver which drives the IGBT according to an IGBT drive control signal supplied from a DSP; A resonant voltage phase detector for detecting a zero phase of the LC resonant voltage detected by the resonant voltage detector to be used as a conduction start signal of the IGBT; An overvoltage detector connected to the resonance voltage detector and configured to detect an overvoltage greater than an allowable breakdown voltage of the IGBT to stop driving of the IGBT; An overcurrent detecting unit connected to the IGBT driving unit and detecting an overcurrent exceeding an allowable current of the IGBT to stop driving of the IGBT; The output of the LC resonance and the induction heating unit are controlled to be constant based on the output of the input current detector and the input voltage detector, and the switching of the IGBT when the resonance voltage is zero phase based on the signal detected by the resonance voltage phase detector. And a DSP for preventing burnout by overvoltage and overcurrent of the IGBT based on outputs of the overvoltage detector and the overcurrent detector.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

Figure 1 shows the configuration of the induction heating cooking apparatus using a DSP according to the present invention.

As shown, the rectifier 10 for full-wave rectifying the commercial power (AC) input via the overcurrent protection fuse (F1) and the EMI filter (L1) for removing the conductive noise through the bridge diode 11, the overcurrent protection An input for detecting current from a commercial power source (AC) input through a fuse (F1) and an EMI filter (L1) for removing conductive noise, using a current transformer (T1), and inputting the voltage level to the DSP 110 accordingly. Switching and LC resonant circuit 42 of the input voltage detector 30 and IGBT 41 for converting the current detector 20 and the output of the rectifier 10 into voltage levels through a resistance voltage divider circuit and inputting them to the DSP 110. The temperature of LC resonance and induction heating unit 40 which induces heating of the cooking appliance 43 by repeating the energy charging and discharging by the time constant of the C) and the operating temperature of the IGBT 41 and inputs it to the DSP 110. Detection unit 50 is connected to the LC resonant circuit 42 to detect the LC resonant voltage Is composed of a resonance voltage detector (60), DSP IGBT drive 70 for driving the IGBT (41) based on the IGBT drive control signal supplied from the unit 110.

In addition, the resonance voltage phase detector 80 and the resonance voltage detector 60 detect the zero phase of the LC resonant voltage detected by the resonance voltage detector 60 and use the same as the conduction start signal of the IGBT 41. It is connected to the overvoltage detector 90 for stopping the driving of the IGBT 41 by detecting an overvoltage greater than the allowable breakdown voltage of the IGBT 41, and is connected to the IGBT driver 70, and the IGBT 41 The overcurrent detector 100 and the input current detector 20, the input voltage detector 30, the temperature detector 50, and the resonant voltage phase to detect the overcurrent of the allowable current or more and stop the driving of the IGBT 41. The IGBT 41 outputs an IGBT drive control signal for driving control of the IGBT 41 based on the outputs of the detector 80, the overvoltage detector 90, and the overcurrent detector 100 to the IGBT driver 70. It is composed of a DSP (110) to be properly driven.

The rectifier 10 has an EMI filter L1 for removing conductive noise in parallel to an overcurrent protection fuse F1 connected to a commercial power input, and a bridge diode 11 connected to the EMI filter L1. In the structure, the capacitor C1 connected in parallel to the overcurrent protection fuse F1 is for preventing surge voltage.

The input current detector 20 detects a current from the commercial power source AC input through the rectifier 10 to the current transformer T1, and the current value detected by the current transformer T1 is a resistor R3. R4 is configured to be input to the A / D converter of the DSP 110 as a voltage level.

The input voltage detector 30 is configured to be input to the A / D converter of the DSP 110 as a corresponding voltage level by using a resistor voltage divider circuit consisting of resistors R5-R8 from the output of the rectifier 10. Capacitor C3, which is not described, is for circuit protection.

In addition, the LC resonator and induction heating unit 40 includes an LC resonant circuit 42 and a capacitor (C5) and a capacitor (C5) and an induction heating coil (L3) connected in parallel to each other in a coil (L2) connected to the rectifier (10). The collector is connected to C5), the base is connected to the IGBT driver 70, and the emitter is composed of an IGBT 41 connected to the ground, and the temperature detector 50 detects an operating temperature of the IGBT 41. The sensor 51 is comprised.

The resonance voltage detector 60 is connected to the LC resonance circuit 42 and includes a plurality of resistors R10 to R14 and a capacitor C6 for detecting the LC resonance voltage, and the IGBT driver 70 is the DSP. And an IGBT switching control IC 71 for driving the IGBT 41 in accordance with the IGBT drive control signal from the 110.

The resonant voltage phase detector 80 has a (+) terminal connected to the resonant voltage detector 60, and a reference voltage formed by the resistors R17, R18 and the capacitor C8 is connected to the (-) terminal. The comparator 81 is input, and the overvoltage detector 90 has a positive terminal connected to the resonance voltage detector 60, and is formed by resistors R20, R21, and a capacitor C9. Comprising a comparator 91 is a reference voltage is input to the (-) terminal, the over-current detection unit 100 is a (+) terminal is connected to the IGBT switching control IC 71, the (-) terminal reference Comparator 101 to which a voltage is input.

Commercial power (AC) input in the present invention configured as described above is rectified by the rectifier 10, is supplied to the LC resonant circuit 42, the supplied power is the IGBT drive control signal provided from the DSP (110) By the switching of the IGBT 41 according to the transfer from the induction heating coil (L3) to the cooking utensil 43, the cooking utensil 43 can be heated.

At this time, the DSP 110 based on the amount of current and voltage detected by the input current detector 20 and the input voltage detector 30 to maintain a constant power supplied to the cooking appliance 43 IGBT (41) It determines the switching operation time of to control this.

Also, in order to switch when the resonant voltage is zero phase, the DSP 110 supplies a conduction start signal of the IGBT 41 based on a signal detected by the resonant voltage phase detector 80 from the output of the resonant voltage detector 60. Will be provided.

In addition, the present invention detects the temperature of the IGBT 41 in the temperature detector 50 to protect the IGBT 41, which is a switching element, and the DSP 110 protects the IGBT 41 from overheating based thereon. You can do it.

The DSP 110 protects the IGBT 41 from burnout according to the overvoltage based on the output of the overvoltage detector 90 which detects the overvoltage from the output of the resonance voltage detector 60, and the overcurrent detector 100. Based on the output of the IGBT 41 is protected from burnout due to overcurrent.

In particular, the DSP 110 detects the instantaneous power failure from the output of the input current detector 20 or the input voltage detector 30 to store the state before the power failure at the time of power failure, and to be driven to the state before power failure.

As described above, although described with reference to a preferred embodiment of the present invention, those skilled in the art various modifications of the present invention without departing from the spirit and scope of the invention described in the claims below Or it may be modified.

As described above, the present invention can implement the driving control algorithm of the induction heating cooking apparatus using a DSP to reduce the number of circuit components, reduce the variation factor due to temperature, reduce the number of control signal lines, input power The change can be detected by the DSP to supply a constant amount of power regardless of changes in the input supply.

In addition, the operation of the current waveform distortion according to the input voltage waveform in the DSP to reduce the output distortion caused by the current waveform distortion, and to remember the state before the power failure during instantaneous power failure to drive the previous state when restoring to improve the product quality It becomes possible.

Claims (3)

 A rectifier for rectifying the commercial power input through an over current prevention fuse and an EMI filter for removing conductive noise through a bridge diode; An input current detector for detecting a current using a current transformer from a commercial power source input through the overcurrent prevention fuse and an EMI filter for removing conductive noise and inputting a voltage level according to the DSP; An input voltage detector converting an output of the rectifier into a voltage level through a resistance voltage divider circuit and inputting the same to a DSP; LC resonance and induction heating unit for induction heating of cookware by repeating switching of IGBT and energy charging and discharging by time constant of LC resonance circuit; A resonance voltage detector for detecting an LC resonance voltage; An IGBT driver which drives the IGBT according to an IGBT drive control signal supplied from a DSP; A resonant voltage phase detector for detecting a zero phase of the LC resonant voltage detected by the resonant voltage detector to be used as a conduction start signal of the IGBT; An overvoltage detector connected to the resonance voltage detector and configured to detect an overvoltage greater than an allowable breakdown voltage of the IGBT to stop driving of the IGBT; An overcurrent detecting unit connected to the IGBT driving unit and detecting an overcurrent exceeding an allowable current of the IGBT to stop driving of the IGBT; The output of the LC resonance and the induction heating unit are controlled to be constant based on the output of the input current detector and the input voltage detector, and the switching of the IGBT when the resonance voltage is zero phase based on the signal detected by the resonance voltage phase detector. And controlling a DSP to prevent burnout due to overvoltage, overcurrent, and overheating of the IGBT based on the output of the overvoltage detector and the overcurrent detector. The DSP of claim 1, wherein the DSP detects a power failure based on an output of the input current detector or the input voltage detector, stores a previous state at the time of power failure, and operates the previous state at the time of power recovery. Induction heating cooker. The induction heating cooking apparatus using a DSP of claim 1, further comprising a temperature detector configured to detect the temperature of the IGBT and input the DSP to protect the IGBT in an overheated state.

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