Electrostatic spraying device
An electrostatic spraying device includes: a high-voltage generation device for applying a voltage between a spray electrode and a reference electrode; and a controller that controls an output power of the high-voltage generation device based on operation environment information indicating at least one of (i) a surrounding environment of the device and (ii) an operation state of a power supply that supplies power to the device, independently of a current value and a voltage value at the spray electrode and the reference electrode.
1. An electrostatic spraying device that, by applying a voltage between a first electrode and a second electrode, sprays liquid from a tip of the first electrode, the electrostatic spraying device comprising:
a voltage applicator for applying the voltage between the first electrode and the second electrode; and
a controller that controls an output power of the voltage applicator based on operation environment information indicating at least one of (i) a surrounding environment of the device and (ii) an operation state of a power supply that supplies power to the device, wherein the controller is configured to control the output independently from a current value and a voltage value at the first electrode and the second electrode.
2. The electrostatic spraying device according to claim 1 , wherein:
the voltage applicator comprises:
an oscillator for converting a direct current supplied from the power supply into an alternating current;
a transformer connected to the oscillator and converting a magnitude of a voltage; and
a converter circuit connected to the transformer and converting an alternating current into a direct current, wherein the controller outputs to the oscillator a PWM signal (pulse width modulation signal) of which a duty cycle is set to be constant.
3. The electrostatic spraying device according to claim 1 , wherein the controller controls the output power according to a duty cycle of a PWM signal (Pulse Width Modulation signal).
4. The electrostatic spraying device according to claim 1 , wherein the operation environment information includes information indicating at least one of air temperature, humidity and pressure around the device, and viscosity of the liquid, as information indicating the surrounding environment.
5. The electrostatic spraying device according to claim 4 , wherein:
the operation environment information includes information indicating the air temperature around the device; and
the controller controls the output power according to a duty cycle of a PWM signal,
increases the duty cycle of the PWM signal in response to rising of the air temperature, and
reduces the duty cycle of the PWM signal in response to dropping of the air temperature.
6. The electrostatic spraying device according to claim 5 , wherein:
the controller determines a spray interval for which a period of time during which the device sprays the liquid and a period of time during which it stops spraying are one cycle, based on a following formula (1),
[
Math
.
1
]
Sprayperiod
(
T
)
=
(
1
+
T
-
T
0
100
*
Sprayperiod_compensation
_rate
)
*
Sprayperiod
(
T
0
)
(
1
)
where,
Sprayperiod(T): Spray interval (s) for which the period of time during which the device sprays the liquid and the period of time during which it stops spraying at temperature T are one cycle
T: Air temperature (° C.)
T 0 : Initial setting temperature (° C.)
Sprayperiod_compensation_rate: Spray time compensation rate (-)
Sprayperiod(To): Spray interval (s) for which the period of time during which the device sprays the liquid and the period of time during which it stops spraying at the initial setting temperature T 0 are one cycle.
7. The electrostatic spraying device according to claim 5 , wherein:
the controller determines a period of time for turning on the PWM signal based on a following formula (2),
[
Math
.
2
]
PWM_ON
_time
(
T
)
=
(
1
+
T
-
T
0
100
*
PWM_compensation
_rate
)
*
PWM_ON
_time
(
T
0
)
(
2
)
where,
PWM_ON_time(T): ON time (μs) of the PWM signal
T: Air temperature (° C.)
PWM_compensation rate: PWM compensation factor (/° C.)
PWM_ON_time(T 0 ): ON time (μs) of the PWM signal at initial setting temperature T 0 .
8. The electrostatic spraying device according to claim 5 , wherein:
the controller
increases a spray interval for which a period of time during which the device sprays the liquid and a period of time during which it stops spraying are one cycle and increases the duty cycle of the PWM signal in response to rising of the air temperature, and
reduces the spray interval for which the period of time during which the device sprays the liquid and the period of time during which it stops spraying are one cycle and reduces the duty cycle of the PWM signal in response to dropping of the air temperature.
9. The electrostatic spraying device according to claim 1 , wherein the operation environment information includes information indicating a magnitude of at least one of a voltage and a current supplied from the power supply to the voltage applicator, as information indicating the operation state of the power supply.
10. The electrostatic spraying device according to claim 1 , further comprising:
a conversion circuit for converting a magnitude of a voltage supplied from the power supply to the voltage applicator, wherein:
the conversion circuit is provided between the power supply and the voltage applicator, and
the controller controls the output power by giving, to the conversion circuit, a command to increase or decrease a conversion magnification of the voltage in the conversion circuit.