Plasma reactor

1. A plasma reactor comprising:

a reactor body having a gas inlet at a side thereof, a gas outlet at another side thereof, and an annular loop space therein;

a magnetic core provided in a shape surrounding a portion of the reactor body, and wound with a primary coil for receiving power from a power generator, so as to generate plasma by exciting a gas in the annular loop space;

a controller for determining whether the plasma is in an off state, by comparing, to a reference value, an electrical parameter related to an output of the primary coil; and

a sensor for measuring an electrical signal for obtaining the electrical parameter,

wherein the electrical parameter comprises a phase difference between a current and a voltage through the primary coil,

wherein the controller obtains the electrical parameter based on the electrical signal,

wherein the reference value is set as a range including the electrical parameter of a case when the plasma is in an on state, and

wherein the controller determines that the plasma in the reactor body is in the off state, when the phase difference is greater than the reference value.

2. The plasma reactor of claim 1 , wherein the controller controls the power generator to cut off or reduce supply of the power from the power generator to the primary coil when it is determined that the plasma in the reactor body is in the off state.

3. The plasma reactor of claim 2 , wherein the power generator comprises an inverter for switching the power, and

wherein the controller turns off the inverter when it is determined that the plasma in the reactor body is in the off state.

4. The plasma reactor of claim 1 , wherein the sensor comprises:

a first sensor mounted on the primary coil to measure the current; and

a second sensor for measuring the voltage through a secondary coil wound around the magnetic core,

wherein the electrical signal comprises the current and the voltage.

5. The plasma reactor of claim 4 , wherein the sensor further comprises a third sensor for measuring active power transferred through the primary coil,

wherein the electrical signal further comprises the active power, and

wherein the controller obtains apparent power based on a root mean square (RMS) value of the voltage and an RMS value of the current, and obtains the phase difference based on the active power and the apparent power.

6. The plasma reactor of claim 4 , wherein the controller presets a reference voltage for arc detection, and detects whether an arc is generated in the reactor body, by comparing, to the reference voltage, the voltage measured by the second sensor.

7. The plasma reactor of claim 6 , wherein the controller detects that the arc is generated in the reactor body, when the voltage is less than or equal to the reference voltage.

8. The plasma reactor of claim 4 , wherein the controller presets a reference current for arc detection, and detects whether an arc is generated in the reactor body, by comparing, to the reference current, the current measured by the first sensor.

9. The plasma reactor of claim 8 , wherein the controller detects that the arc is generated in the reactor body, when the current measured by the first sensor is greater than or equal to the reference current.