JP2019127933A - Plasma reactor power supply system - Google Patents

Abstract

To provide a plasma reactor power supply system which can stop the plasma reactor in an early stage when a further abnormal discharge is suspected while capable of surely detecting the abnormal discharge.SOLUTION: In a plasma reactor power supply system 1 having a power supply device 2 for supplying power to a plasma reactor 101, and a control device 4 for controlling the power supply device 2, the control device 4 reduces the number of determinations to nfrom n(S4) on condition that a difference value A2 between a current peak value A1 which is measured at this time (a peak value of a current flowing between the power supply device 2 and the plasma reactor 101) and a current peak value A0 which has been measured last time exceeds a second threshold N2 (S2: YES), and stops power supply to the plasma reactor 101 when the number P of times that the current peak value A1 exceeds a first threshold N1 in the prescribed number of measurements reaches the reduced number of the determinations n(S8: YES).SELECTED DRAWING: Figure 3

Description

  The present invention relates to a power supply system for a plasma reactor.

  BACKGROUND Conventionally, a plasma reactor is known as an apparatus for decomposing harmful components such as particulate matter (PM) contained in exhaust gas.

  Further, as a method of detecting abnormal discharge of the plasma reactor, a method of judging that there is a leak when the current value to the plasma reactor is equal to or more than a predetermined threshold has been proposed (see, for example, Patent Document 1).

JP 2017-152341 A

  However, in the method described in Patent Document 1, if the threshold value is set to a value close to a normal current peak value, abnormal discharge may be erroneously detected due to noise or the like.

  Also, if the threshold value is set to a value far from the normal current peak value, abnormal discharge can not be detected.

  Accordingly, an object of the present invention is to provide a power supply system for a plasma reactor that can detect an abnormal discharge reliably but can stop the plasma reactor at an early stage when an abnormal discharge is suspected.

  The present invention is a power supply device that supplies power to a plasma reactor and a control device that controls the power supply device, wherein the number of times that the peak value of the current supplied to the plasma reactor exceeds a first threshold is a predetermined value. And a controller for stopping power supply to the plasma reactor when the number of determinations has been reached, wherein the controller determines the difference between the peak value of the current measured this time and the peak value of the current measured previously. The power supply system for plasma reactors which reduces the number of times of judgment when the 2nd threshold is exceeded is included.

  According to such a configuration, power supply to the plasma reactor is stopped when the number of times that the peak value of the current supplied to the plasma reactor exceeds the first threshold (the number of abnormal discharges) reaches a predetermined number of times of determination. To do.

  Therefore, false detection of abnormal discharge due to noise or the like can be suppressed, and abnormal discharge can be reliably detected.

  Furthermore, when the difference between the peak value of the current measured this time and the peak value of the current measured last time exceeds the second threshold, the number of determinations is reduced.

  That is, when the difference between the peak value of the current measured this time and the peak value of the current measured last time exceeds the second threshold value, the power supply to the plasma reactor is stopped when the reduced number of determinations is reached. .

  Thereby, when abnormal discharge is suspected more, that is, the peak value of the current supplied to the plasma reactor exceeds the first threshold, and the difference between the peak value of the current measured this time and the peak value of the current measured last time If the second threshold value is exceeded, the power supply to the plasma reactor can be stopped with a small number of determinations.

  Therefore, when abnormal discharge is suspected, the plasma reactor can be stopped early to reduce the influence on peripheral equipment.

  In summary, while the abnormal discharge can be reliably detected, the plasma reactor can be shut down earlier if abnormal discharge is suspected.

  According to the present invention, the abnormal discharge can be reliably detected, and the plasma reactor can be stopped early if abnormal discharge is suspected.

FIG. 1 is a circuit diagram showing an embodiment of a power supply system for a plasma reactor according to the present invention. FIG. 2 is a schematic configuration diagram of the plasma reactor. FIG. 3 is a flowchart showing control of the plasma reactor power supply system. FIG. 4 is an explanatory diagram for explaining the control of the power supply system for plasma reactor together with FIG. 3, and is a graph showing a change in peak current value.

1. Plasma Reactor Power Supply System A plasma reactor power supply system 1 shown in FIG. 1 is mounted on a vehicle, for example, and supplies power to a plasma reactor 101 (see FIG. 2) from a power supply 100 such as a battery. The plasma reactor power supply system 1 includes a power supply 2, a current sensor 3, and a controller 4.

(1) Power Supply Device The power supply device 2 supplies power to the plasma reactor 101. The power supply device 2 includes a booster circuit 5 such as a flyback converter and a switching element 6 such as a MOSFET. The control device 4 controls the switching element 6 so that the power supply device 2 supplies power to the plasma reactor 101. Specifically, when the booster circuit 5 is a flyback converter, when the control device 4 turns on the switching element 6, a current flows through the primary coil 7 and the core is magnetized. Thereafter, when the control device 4 turns off the switching element 6, an induced electromotive force is generated in the secondary coil 8. The secondary coil 8 is electrically connected to the positive electrode panel of the plasma reactor 1011 via the plus wiring 102 and is electrically connected to the negative electrode panel of the plasma reactor 101 via the minus wiring 103. Therefore, power is supplied to the plasma reactor 101 by the induced electromotive force generated in the secondary coil 8.

(2) Current sensor The current sensor 3 measures the peak value (current peak value) of the current flowing between the plasma reactor 101 and the power supply device 2 as a value representing the intensity of discharge in the plasma reactor 101. Note that the value representing the intensity of discharge in the plasma reactor 101 may be a voltage value or an integrated current value. The current sensor 3 outputs an electrical signal corresponding to the measured current value. The electrical signal output from the current sensor 3 is input to the control device 4.

(3) Control device The control device 4 controls the switching element 6 of the power supply device 2 as described above. The control device 4 is, for example, an ECU (Electronic Control Unit) that executes electrical control in a vehicle.

2. Plasma Reactor The plasma reactor 101 is interposed, for example, in the middle of the exhaust pipe of a vehicle. As shown in FIG. 2, the plasma reactor 101 includes a plurality of electrode panels 104 and a casing 105 that houses the plurality of electrode panels 104.

  Each of the plurality of electrode panels 104 extends in a predetermined direction. The plurality of electrode panels 104 are arranged at intervals in the direction intersecting the predetermined direction. Among the plurality of electrode panels 104, the electrode panel 104 electrically connected to the plus wiring 102 is a positive electrode panel, and the electrode panel 104 electrically connected to the minus wiring 103 is a negative electrode panel. When power is supplied to the plasma reactor 101, discharge (dielectric barrier discharge) occurs between the positive electrode panel and the negative electrode panel. Thereby, the gas between the positive electrode panel and the negative electrode panel is in a plasma state. That is, plasma is generated in the plasma reactor 101. Then, harmful components (for example, hydrocarbon (HC), nitrogen oxide (NOx), particulate matter (PM) and the like) flowing into the plasma reactor 101 are decomposed by the plasma in the plasma reactor 101.

  Here, for example, when a dielectric breakdown occurs in a part of the plasma reactor 101, such as when moisture adheres to the terminal part of the electrode panel 104, an abnormal discharge may occur in the part where the dielectric breakdown has occurred.

3. Control of Plasma Reactor Power Supply System 1 Control of the plasma reactor power supply system 1 will be described with reference to FIG.

In the plasma reactor power system 1, the control device 4, the current peak value A1 measured by the current sensor 3 times (abnormal discharge number) P exceeds the first threshold value N1, reaches a predetermined number of determinations n ₁ If it is determined (S9: YES), the power supply to the plasma reactor 101 is stopped (S10).

  Specifically, the control device 4 calculates and acquires a difference value A2 between the current peak value A1 of this time and the current peak value A0 of last time (S1).

  Next, it is determined whether the difference value A2 exceeds the second threshold N2 (S2).

When the difference value A2 does not exceed the second threshold value N2 (S2: NO), thereby the number of judgments is increased from _{n 0} to _{n 1} (S3). The initial determination number n ₀ is, for example, two, and the increased determination number n ₁ is, for example, five.

On the other hand, if the difference value A2 is greater than the second threshold value N2 (S2: YES), the determination count is reduced from _{n 0} to _{n 1} (S4). The reduced determination number n ₁ may be one.

Note that the initial number of determinations n ₀ is the number of determinations previously calculated stored in the control device 4, and the number x of increasing or decreasing the number of determinations may be increased in proportion to the magnitude of the difference value A 2 Good.

  Next, the control device 4 determines whether the current peak value A1 exceeds the first threshold N1 (S5).

Here, when the power supply to the plasma reactor 101 is stopped immediately when the current peak value A1 exceeds the first threshold value N1, abnormal discharge may be erroneously detected due to noise or the like. However, by detecting the abnormal discharge in the predetermined determination number of times n _1, it is possible to suppress such erroneous detection.

When the current peak value A1 does not exceed the first threshold value N1 (S5: NO), the determination value p _{0 is set to} 0 (S6).

On the other hand, when the current peak value A1 exceeds the first threshold value N1 (S5: YES), the determination value p _{0 is set to} 1 (S7).

The control device 4 includes past determination values p ₋₁ (previous determination value), p ₋₂ (second determination value), p ₋₃ (third determination value), p ₋₄ (4 The judgment value before the operation) is stored.

Here, the number of times the current peak value A1 exceeds the first threshold value N1 (the number of abnormal discharges) P is calculated within a predetermined number of times of measurement (in this embodiment, including the current time of 5) (S8). . The abnormal discharge count P is the sum of all judgment values acquired during a predetermined measurement count (ie, P = p ₀ + p ₋₁ + p ₋₂ + p ₋₃ + p ₋₄ ).

If abnormal discharge count P has not exceeded the number of judgments _{n 1} (S9: NO), the control device 4, the number of judgments _{n 1} that is currently set, is stored as the initial determination count _{n 0} in the next (S11).

Further, the control device 4 sets the current p ₀ as the next p ₋₁ (previous determination value), the current p ₋₁ as the next p ₋₂ (second determination value), and the current p _{−. 2} is stored as the next p ₋₃ (determination value three times before), and the current p ₋₃ is stored as the next p ₋₄ (determination value four times before) (S12).

  Thereafter, the difference value A2 is acquired again.

On the other hand, if the abnormal discharge count P has exceeded the number of judgments _{n 1} (S9: YES), it stops the supply of power to the plasma reactor 101 (S10).

Thus, without erroneous detection of abnormal discharge or noise, a smaller number of determinations n _1, the power supply to the plasma reactor 101 can be stopped (S10).

  Therefore, when abnormal discharge is suspected, the plasma reactor 101 can be stopped early to reduce the influence on peripheral devices.

4. Action Effect According to the power supply system 1 for the plasma reactor, as shown in FIG. 3, when the abnormal discharge count P reaches the predetermined determination count n ₁ (S9: YES), the power supply to the plasma reactor 101 is stopped. To do (S10).

  As a result, erroneous detection of abnormal discharge due to noise or the like can be suppressed, and abnormal discharge can be reliably detected.

Further, when the difference value A2 exceeds the second threshold value N2 (S2: YES), when the abnormal discharge count P reaches the reduced determination count n ₁ (S4) (S9: YES), The power supply to the plasma reactor 101 is stopped (S10).

Thereby, when abnormal discharge is suspected more, specifically, the current peak value A1 exceeds the first threshold N1 (S5: YES), and the difference between the current peak value A1 measured this time and the current peak value A0 measured last time If the value A2 is greater than the second threshold value N2 (S2: YES), a small number of determinations _{n 1,} the power supply to the plasma reactor 101 can be stopped (S10).

  Therefore, when abnormal discharge is suspected, the plasma reactor 101 can be stopped early to reduce the influence on peripheral devices.

  In summary, while the abnormal discharge can be detected reliably, the plasma reactor 101 can be stopped early if abnormal discharge is suspected.

DESCRIPTION OF SYMBOLS 1 Power supply system for plasma reactors 2 Power supply apparatus 4 Control apparatus 101 Plasma reactor

Claims (1)

A power supply for supplying power to the plasma reactor;
A control device for controlling the power supply device, wherein power supply to the plasma reactor is performed when the number of times the peak value of the current supplied to the plasma reactor exceeds a first threshold reaches a predetermined number of times of determination. Control device to stop the
The control device reduces the number of determinations when the difference between the current peak value measured this time and the current peak value measured last time exceeds a second threshold value. .

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