Cooking apparatus and method of controlling the same
The present disclosure relates to a cooking apparatus and a method of controlling the same, and more particularly, to a technology for reducing stress caused by a current flowing through a diode included in the cooking apparatus. The cooking apparatus includes a coil on which a vessel is mounted, configured to form a magnetic field upon application of a current; a first switch and a second switch configured to change a direction of the current flowing through the coil; a first diode connected in parallel to the first switch or a second diode connected in parallel to the second switch; and a controller configured to alternately control a turn-on operation of the first switch and the second switch, and when a maximum value of the current flowing through the first diode or a maximum value of the current flowing through the second diode exceeds a predetermined value, to increase an operating frequency of turning on the first switch and the second switch to limit the maximum value of the current flowing through the first diode or the second diode to less than or equal to the predetermined value.
1. A cooking apparatus comprising:
a coil on which a vessel is mounted, configured to form a magnetic field upon application of a current;
a first switch and a second switch configured to change a direction of the current flowing through the coil;
a first diode connected in parallel to the first switch and a second diode connected in parallel to the second switch; and
a controller configured to:
alternately control a turn-on operation of the first switch and the second switch, and
when a maximum value of the current flowing through the first diode or a maximum value of the current flowing through the second diode exceeds a predetermined value, limiting the maximum value of the current flowing through the first diode or the second diode to less than or equal to the predetermined value by increasing an operating frequency of alternately turning on the first switch and the second switch.
2. The cooking apparatus according to claim 1 , wherein the controller is configured to determine a zero cross point (ZCP) of the current flowing through the coil.
3. The cooking apparatus according to claim 2 , wherein the controller is configured to determine a free-wheeling section in which the current flows in the first diode or the second diode based on a point at which the first switch and the second switch alternately turn on and the determined ZCP.
4. The cooking apparatus according to claim 3 , wherein the controller is configured to determine from a turn-off point of the first switch to an end point of the ZCP as the free-wheeling section in which the current flows in the second diode based on a current phase at the turn-off point of the first switch and a current phase at the end point of the ZCP.
5. The cooking apparatus according to claim 3 , wherein the controller is configured to determine from a turn-off point of the second switch to a start point of the ZCP as the free-wheeling section in which the current flows in the first diode based on a current phase at the turn-off point of the second switch and a current phase at the start point of the ZCP.
6. The cooking apparatus according to claim 3 , wherein the controller is configured to determine the maximum value of the current flowing through the first diode or the maximum value of the current flowing through the second diode in the free-wheeling section, and to compare the maximum value of the determined current with the predetermined value.
7. The cooking apparatus according to claim 6 , further comprising:
a current detector configured to detect the current flowing in the coil,
wherein the current detector is configured to detect the maximum value of the current flowing through the first diode or the maximum value of the current flowing through the second diode in the free-wheeling section.
8. The cooking apparatus according to claim 1 , further comprising:
a signal generator configured to generate an operating frequency for operating the first switch and the second switch.
9. The cooking apparatus according to claim 8 , wherein the signal generator is configured to generate an increased operating frequency at a preset frequency under the control of the controller, and to apply the increased operating frequency to a gate end of the first switch and a gate end of the second switch.
10. The apparatus of claim 1 , further comprising:
a current detector configured to detect the current flowing in the coil,
wherein the current detector includes:
a current transformer that decreases in proportion to a magnitude of current supplied to the first coil, and
an ampere meter that detects the magnitude of a proportionally reduced current.
11. A method of controlling a cooking apparatus, the cooking apparatus including a coil configured to form a magnetic field according to an application of a current, the method comprising:
alternately controlling, by a controller, a turn-on operation of a first switch and a second switch;
determining, by the controller, a maximum value of the current flowing through a first diode connected in parallel to the first switch or a maximum value of the current flowing through a second diode connected in parallel to the second switch; and
when the maximum value of the determined current exceeds a predetermined value, limiting the maximum value of the current flowing through the first diode or the second diode to less than or equal to the predetermined value by increasing, via the controller, an operating frequency of alternately turning on the first switch and the second switch.
12. The method according to claim 11 , further comprising:
determining, by the controller, a zero cross point (ZCP) of the current flowing through the coil.
13. The method according to claim 12 , further comprising:
determining, by the controller, a free-wheeling section in which the current flows in the first diode or the second diode based on a point at which the first switch and the second switch alternately turn on and the determined ZCP.
14. The method according to claim 13 , wherein the determining of the free-wheeling section comprises:
determining from a turn-off point of the first switch to an end point of the ZCP as the free-wheeling section in which the current flows in the second diode based on a current phase at the turn-off point of the first switch and a current phase at the end point of the ZCP; and
determining from a turn-off point of the second switch to a start point of the ZCP as the free-wheeling section in which the current flows in the first diode based on a current phase at the turn-off point of the second switch and a current phase at the start point of the ZCP.
15. The method according to claim 13 , wherein the determining of the maximum value of the current comprises:
determining the maximum value of the current flowing through the first diode or the maximum value of the current flowing through the second diode in the free-wheeling section; and
comparing the maximum value of the determined current with the predetermined value.
16. The method according to claim 15 , further comprising:
detecting, by a current detector, the current flowing in the coil,
wherein the detecting of the current comprises detecting the maximum value of the current flowing through the first diode or the maximum value of the current flowing through the second diode in the free-wheeling section.