INDUCTION HEATING DEVICE AND LOAD DETECTION METHOD IN INDUCTION HEATING DEVICE
FIG3 is a view illustrating sections A and B included in left heating zone Lh, right heating zone Rh, and central heating zone Ch, respectively
FIG3 is a view illustrating two sections (sections A and B) included in left heating zone Lh, right heating zone Rh, and central heating zone Ch, respectively. As illustrated in FIG3, in left heating zone Lh and right heating zone Rh, section A has two heating coils 3 which are heating coil A1 and heating coil A2 arranged behind heating coil A1. Section B has two heating coils 3 which are heating coil B1 and heating coil B2 arranged behind heating coil B1.
view
8
switching unit switching units
23
output current detector
4
driver drivers
50
controller
10
detector
3
heating coils heating coil
['1. An induction heating device comprising: a top panel (2) on which a load is placeble; a plurality of heating coils (3, 31, 32, 33, 34, A1, A2, B1, B2) provided below the top panel (2); a driver (4) configured to supply a high frequency power to the plurality of heating coils (3, 31, 32, 33, 34, A1, A2, B1, B2); an electric signal detector (10) configured to detect an electric signal relating to an element included in the driver (4); and a controller (50) configured to receive the electric signal and control the driver (4),  characterized in that the controller (50) is configured to cause the driver (4) to supply a first detection current which is a high frequency power to the plurality of heating coils (3, 31, 32, 33, 34, A1, A2, B1, B2), and determine whether the load is placed above the plurality of heating coils (3, 31, 32, 33, 34, A1, A2, B1, B2) based on an electric signal in response to the first detection current, and when determining that the load is not placed above the plurality of heating coils (3, 31, 32, 33, 34, A1, A2, B1, B2) based on the first detection current, the controller (50) is configured to cause the driver (4) to supply a second detection current which is a high frequency power and has a larger current value than the current value of the first detection current to the plurality of heating coils (3, 31, 32, 33, 34, A1, A2, B1, B2), and determine whether the load is placed above the plurality of heating coils (3, 31, 32, 33, 34, A1, A2, B1,  B2) based on an electric signal in response to the second detection current.', '2. The induction heating device according to claim 1, further comprising a switching unit (8) configured to connect or disconnect each of the plurality of heating coils (3, 31, 32, 33, 34, A1, A2, B1, B2) to or from the driver (4) under control of the controller (50), wherein, when the first detection current or the second detection current is supplied, the controller (50) causes the switching unit (8) to connect all of the plurality of heating coils (3, 31, 32, 33, 34, A1, A2, B1, B2) to the driver (4), when determining that the load is placed above the plurality of heating coils (3, 31, 32, 33, 34, A1, A2, B1, B2) based on the electric signal in response to the first detection current or the second detection current, the controller (50) controls the driver (4) and the switching unit (8) such that a third detection current which is a high frequency power is sequentially and independently supplied to each of the plurality of heating coils (3, 31, 32, 33, 34, A1, A2, B1, B2), and the controller (50) determines whether the load is placed above each of the plurality of heating coils (3, 31, 32, 33, 34, A1, A2, B1, B2) based on an electric signal in response to the third detection current.']