JPS58176891A - Induction heater - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to an induction heating device.

More specifically, the present invention relates to an induction heating apparatus equipped with means for appropriately controlling static heating of an object to be inductively heated.

Conventionally, there has been a device of this type as shown in FIG.

In the figure, an inductively heated object 3 is housed in an induction heating coil λ connected to a power source 1 for the induction heating device, and a capacitor is connected to the input side of the induction heating coil λ to improve its power factor. A transformer S for an output power detection meter and a current transformer 6 are connected to the output side of the 7 power supply/.

A power converter 7 is provided which combines these output signals and extracts the resultant signal as a power signal. The output of the self-excitation time/power setting device, which sets the relationship between the energization time to the induction heating coil and the power value, is output by the power regulator along with the output of the power converter 7. Here, the output signals of both are matched and the power is adjusted. The controller /θ connected to the power supply 7 is for adjusting the power of the power supply #, /, and is a power regulator? and a manual setting device for manually setting power settings via a switch. With this configuration, the automatic operation of the device is such that the output is first increased from the power source/in accordance with the output of the automatic time/power setting device t, and the resulting voltage and current are transferred to the transformer S,
It is detected by the current transformer 4, and the power converter 7 combines the two and outputs it as a power signal, which is compared with the signal of the automatic time Φ power setting device r, and controlled by the controller /θ to reduce the difference. are doing. On the other hand, the 1 manual setting device // functions to control the output of the power source / via the controller lθ according to its output.

Because the automatic control means of conventional induction heating equipment was configured as described above, it lacked the ultimate purpose of detecting and monitoring the heating temperature, and it also failed to detect and monitor the heating temperature target value at a predetermined time. or cause a temperature difference.

There were problems such as over or under heating temperature due to slight fluctuations in load.

This invention was made in view of the above circumstances, and adds time and temperature control to the conventional automatic time and power control circuit.
The object of the present invention is to provide an induction heating device equipped with automatic time/temperature control and power control means that can always minimize the difference between heating temperature and target temperature.

The present invention will be described below with reference to an embodiment shown in FIG. In the figure, numerals 1 to 12 are the same as in FIG. 1, and their explanation will be omitted.

The temperature detector/3 measures the heating temperature of the heated object 3, and its output temperature signal is sent to the automatic time/a degree setting device/
The signal is input to the Kg degree regulator /j together with the reference signal, and the two signals are compared here.

The output is input to the temperature/power ratio setter/6. The output of the power regulator 9 described above is also added to the temperature/power ratio setting device 1B, and the output of the temperature/power ratio setting device 1B is inputted to the controller 10 via the switch 12.

With the configuration shown below, the outputs of the power regulator D and temperature regulator S 15 are input to the temperature/power ratio setter/men.

By adjusting the ratio between temperature and power here.

By calculating the optimal sharing ratio through actual measurements, the input signal for setting the output power of the power source 1 can be obtained.In this way, by adding 1 hour and temperature control to the conventional time and power control, temperature correction is performed and the specified output power is set. heating temperature can be maintained. In addition, by accumulating a large number of actual measurements (therefore, improving the pattern of the automatic time and power setting device to reduce the burden of time and temperature control, and preventing hunting due to temperature lag and improving the time and temperature control functions) be able to.

In addition, if it is difficult to install a current transformer base for a transformer for output power detection, for example, if an inverter is used as an induction heating power source, the output waveform will be distorted and there will be many measurement errors. Instead of a signal, as shown in Figure 3,
Install transformer A and transformer A 4 at the input terminal of power supply l,
input voltage.

The current may also be detected. However, it is necessary to consider induction heating power supply loss.

Further, as shown in the diagram, a plurality of induction heating coils 2 correspond to a single power source 1, and the power source and load are always used in pairs. In other words, it may be used in a load switching type. In such a case, it is necessary to compensate for the characteristics unique to each load circuit. As this compensation means, a load circuit compensator/7 is inserted between the automatic time/power setting device t and the power regulator D in FIG. 1, and the load circuit compensator/7 is inserted at the same time as the load circuit is switched. By switching, the above characteristic compensation can be achieved.

As described above, the present invention can maintain the heating temperature at the target m degrees by adding simple elements to the conventional control system.

[Brief explanation of the drawing]

Figure Is1 is a wiring diagram of a conventional device, Figure 1 is a wiring diagram of an embodiment of the present invention, and Figures 3 and 3 are partially modified wiring diagrams. K...Induction heating coil, 3...Heated object,! ...Transformer, 6..Current transformer, /7..Load circuit compensation device. In each figure, the same reference numerals indicate the same or corresponding parts. Agent Shin Kuzuno - Rod 1 figure Tomari 4 figure

Claims (1)

[Claims] (/) A power converter that outputs a power signal of a power supply that supplies power to an induction heating coil, and an output of an automatic time/power setting device that sets the relationship between the energization time and power value of the induction heating coil. and a power regulator to which the output of the power converter is applied, and an automatic time controller that sets the relationship between the output of the temperature detector that detects the heating temperature of the heated object, the energization time of the induction heating coil, and the temperature.
A temperature controller to which the output of the temperature setting device is input, a temperature/power ratio setting device to which one output of this temperature controller and the output of the predistribution power controller are input and adjust the ratio of temperature and power, and this temperature/power ratio setting device. An induction heating device comprising: a controller that controls the power source in accordance with the output of the power ratio setter. (2) The induction heating device according to claim 1, wherein the power converter is connected to the input side of a power source. (3) In a device in which a plurality of induction heating coils are switched and connected to a single power source, a switching means is inserted and connected between an automatic time/power setting device and a power regulator and synchronizes with switching of the induction heating coils. An induction heating device according to claim 1, comprising a load circuit compensator.