Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
  • F16K31/00—Actuating devices; Operating means; Releasing devices
  • F16K31/02—Actuating devices; Operating means; Releasing devices electric; magnetic
  • F16K31/06—Actuating devices; Operating means; Releasing devices electric; magnetic using a magnet, e.g. diaphragm valves, cutting off by means of a liquid
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F7/00—Magnets
  • H01F7/06—Electromagnets; Actuators including electromagnets
  • H01F7/064—Circuit arrangements for actuating electromagnets
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F7/00—Magnets
  • H01F7/06—Electromagnets; Actuators including electromagnets
  • H01F7/08—Electromagnets; Actuators including electromagnets with armatures
  • H01F7/18—Circuit arrangements for obtaining desired operating characteristics, e.g. for slow operation, for sequential energisation of windings, for high-speed energisation of windings
  • H01F7/1844—Monitoring or fail-safe circuits
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F7/00—Magnets
  • H01F7/06—Electromagnets; Actuators including electromagnets
  • H01F7/08—Electromagnets; Actuators including electromagnets with armatures
  • H01F7/18—Circuit arrangements for obtaining desired operating characteristics, e.g. for slow operation, for sequential energisation of windings, for high-speed energisation of windings
  • H01F2007/1888—Circuit arrangements for obtaining desired operating characteristics, e.g. for slow operation, for sequential energisation of windings, for high-speed energisation of windings using pulse width modulation

Definitions

• the present disclosure relates to a solenoid control method, and more particularly, to a solenoid control apparatus and a solenoid control method for preventing over-energizing of a solenoid in which, when a duty ratio is reset in a PWM (Pulse Width Modulation) control process of a solenoid actuator, the initial cycle for the reset duty ratio is corrected in consideration of an already progressed duty cycle in the current cycle, so as to minimize an over-energizing of the solenoid.
• PWM Pulse Width Modulation
• an ECU Electronic Control Unit
• a solenoid configured to drive, for example, a hydraulic unit valve, is equivalent to a connection of a resistor (R) having a resistance and a coil (L) having an inductance, and a magnetic field generated in the solenoid is proportional to an electric current that flows in the solenoid. Accordingly, the magnetic field applied to the valve is also proportional to the current.
• FIG. 1 is a PWM drive circuit of a conventional solenoid current control apparatus.
• the solenoid current control apparatus includes a solenoid 10, a protection-purpose field effect transistor FET1, a control-purpose field effect tran ⁇ sistors FET2, a controller 20, a driver 30, a reference power supply unit 40, a current measurement unit 50, and a flyback diode D2.
• the same components will be assigned the same reference numerals .
• the solenoid 10 is configured to drive a hydraulic valve and is configured by a resistor R c and a coil L c in an equivalent viewpoint.
• the flyback diode D2 is connected to the solenoid 10 in parallel and configures a protection circuit in consideration of a PWM operation characteristic for current-control of the solenoid 10.
• the control-purpose field effect transistor FET2 is connected to the solenoid 10 in series.
• the control-purpose field effect transistor FET2 is configured to be turned ON/OFF so as to obtain a desired power according to a PWM drive signal output from the controller 20.
• the control-purpose field effect transistor FET2 controls a current flowing in the solenoid 10 in proportion to a PWM duty ratio.
• the protection-purpose field effect transistor FET 1 is connected to the solenoid 10 in series so as to protect the circuit when the control-purpose field effect transistor FET2 malfunctions.
• the protection-purpose field effect transistor FET1 is configured to be turned ON/OFF by receiving a drive signal output from the controller 20 through the driver 30, and receives a battery power V B AT supplied thereto.
• the solenoid 10 is connected with the reference power supply unit 40 which is configured by a reference resistance R ref and a reverse output prevention diode Dl to receive a reference power V cc (5V) supplied thereto.
• the current measurement unit 50 configured to measure the current flowing in the coil L c of the solenoid 10 in real time is connected between the protection-purpose field effect transistor FET1 and the solenoid 10.
• the current measurement unit 50 includes a shunt resistor R s configured to detect a current, condensers CI and C2 configured to remove a noise component included in a value detected by the shunt resistor R s , divider resistors Rl and R2 ; R3 and R4 configured to divide the value detected by the shunt resistor R s by a smoothened DC voltage, and Zener diodes ZD1 and ZD2 configured to bypass only a yield voltage of the DC voltage smoothened by the divider voltages Rl and R2 ; R3 and R4 so as to input a predetermined voltage to ADC terminals ADC2 and ADC3 of the controller 20.
• the controller 20 compensates for an error of the resistance values in a software manner so as to control the PWM duty ratio. As a result, a more precise current measurement exhibits a more precise control performance.
• the above-described conventional duty ratio control for a solenoid may induce a precise solenoid control.
• the control signal of the solenoid is extended at a variable timing of the duty, thereby increasing an energizing time and thus deteriorating the endurance of the solenoid . That is, because a new control is initiated after a duty cycle which has previously progressed is terminated or a new control is applied instantly at a time point where a new duty cycle is required according to a solenoid control pattern, the control cycle which has previously progressed is broken so that excessive current flows in the solenoid, thereby causing a over-energizing state. As a result, noise occurs when driving the solenoid and the endurance of the solenoid may be reduced.
• the present disclosure has been made in order to solve the problems as described above and an object of the present disclosure is to provide a solenoid control apparatus and method for preventing over-energizing of a solenoid, which can prevent an over-energizing state in advance at the time of controlling a solenoid actuator that requires a rapid response, thereby suppressing occurrence of unnecessary noise caused by an over-energizing state and preventing the fracture of the so ⁇ lenoid .
• Another object of the present disclosure is to provide a solenoid control apparatus and method for preventing over-energizing of a solenoid which, when a new duty cycle request for the solenoid control occurs, apply a newly requested duty cycle in con ⁇ sideration of a solenoid ON time and a solenoid OFF time of a control signal which has previously progressed, thereby in- creasing a response performance of a solenoid and preventing over-energizing of the solenoid.
• a solenoid control apparatus for preventing over-energizing of a solenoid prevents the over-energizing of the solenoid at the time of changing a duty for a solenoid control.
• the solenoid control apparatus includes: an ECU configured to modify and output a duty ratio in such a manner that a change-requested duty ratio is applied within a solenoid control period in consideration of a currently elapsed solenoid ON time and OFF time at a duty control time point for changing a solenoid duty ratio; and an interface box configured to supply a rating signal for driving an actuator equipped with the solenoid in response to a duty control signal provided from the ECU.
• a solenoid control method includes: a) determining whether the level of the current duty cycle is in an ON state when the duty change is requested; b) when it is determined in step a) that the level of the current duty cycle is in the ON state, comparing the currently elapsed ON time and the maximum ON time of the change-requested duty cycle; c) when it is determined that the currently elapsed ON time is shorter than the maximum ON time of the
• step b) maintaining the current ON state by the ON time of the change-requested duty cycle, and when it is determined that the currently elapsed ON time is longer than the maximum ON time of the change-requested duty cycle, converting the level of the duty cycle into an OFF state during the remaining control period; d) when it is determined in step a) that the level of the current duty cycle is in the OFF state, comparing the currently elapsed OFF time and the minimum OFF time of the change-requested duty cycle; e) when it is determined in step d) that the currently elapsed OFF time is shorter than the minimum OFF time of the change-requested duty cycle, converting the level of the duty cycle into the ON state during the remaining control period, and when it is determined that the currently elapsed OFF time is longer than the minimum OFF time of the change-requested duty cycle, maintaining the current duty level only by the minimum OFF time; and f) when the current control period is terminated, controlling
• the solenoid control apparatus and method according to the present disclosure apply the newly requested duty cycle in consideration of the solenoid ON time and OFF time of the control signal which has previously progressed, thereby enhancing the responding ability of the solenoid and preventing over-energizing of the solenoid to enhance the endurance of the solenoid.
• FIG. 1 is a circuit diagram for describing a conventional solenoid control apparatus
• FIG. 2 is a configuration view for describing a solenoid control apparatus according to the present disclosure
• FIG. 3 is a flowchart for describing the operations of the solenoid control apparatus of FIG. 2;
• FIG. 4 illustrates PWM graphs for exemplifying the execution of the operation of FIG. 3.
• the solenoid control proposed by the present disclosure may be applied to, for example, an injector of a vehicle fuel injector.
• the present disclosure is not limited to the vehicle fuel injector. This is because the solenoid applied to the vehicle fuel injector requires a rapid operation according to a PWM method.
• a pumping apparatus configured to generate a predetermined pressure may employ such a solenoid.
• a PWM control is performed so as to variably control the pumping pressure according to a set program.
• the solenoid control exemplified in the present disclosure may be applied to any field in which a PWM control and a duty ratio control are enabled, other than the application to a vehicle.
• FIG. 2 illustrates an example of a solenoid control apparatus according to the present disclosure.
• the solenoid control apparatus includes an ECU 201 configured to modify and output a duty ratio in such a manner that a change-requested duty ratio may be applied within a solenoid control period in consideration of the currently elapsed solenoid ON time and OFF time at the duty control time point for solenoid duty ratio change, and an interface box 203 configured to supply a rated signal for driving an actuator 211 equipped with the solenoid in response to the duty control signal provided from the ECU 201.
• the solenoid control period refers to the sum of the solenoid ON time and the solenoid OFF time. In the present disclosure, the control period is not modified even when the solenoid duty ratio is modified, thereby preventing the over-energizing state of the solenoid .
• the ECU 201 stores the solenoid ON time and the solenoid OFF time in an internal memory in each cycle unit and when duty change is requested, calculates a duty cycle progress state at the current time point with reference to the solenoid operation time stored in the memory.
• the interface box 203 is configured to amplify the duty signal provided from the ECU 201 to the operation voltage and current of the solenoid incorporated in the actuator 211 and output the amplified voltage and current of the solenoid.
• a high power switching circuit is provided in the interface box 203.
• FIG. 3 is a flowchart for describing the operating states according to the present disclosure.
• FIG. 4 illustrates PWM control graphs exemplifying the operations of FIG. 3.
• the ECU 201 determines whether or not a new duty ratio for a solenoid duty control has been set. For example, the ECU 201 determines whether or not a PWM duty for controlling the operating speed of the actuator 211 so as to vary a fuel injection amount is changed.
• the existing duty ratio is maintained through step S311.
• step S303 it is determined whether the current duty cycle is in an ON state. This corresponds to CASE 1 of FIG. 4 in which, for example, when the current duty ratio of 50% is requested to be changed to a new duty ratio of 80%, it is determined whether the current cycle is in the ON state.
• step S305 the ECU 201 calculates the elapsed time of the ON state and the solenoid ON time according to the currently requested duty ratio using the internal counter. In addition, the ECU 201 calculates the difference between the requested duty ON time and the elapsed duty ON time.
• step S303 When it is determined in step S303 that the requested duty ON time is larger than the elapsed duty ON time in the current cycle, that is, when it is necessary to maintain the current ON state as in CASE 1 due to the increase of the duty ratio, the current state is maintained from the currently elapsed ON time to the ON time to be continued according to the duty ratio change in step 317.
• a pulse width modulation is performed with the changed duty through step S313.
• the elapsed duty ON time is larger than the currently requested duty ON time, that is, that the control time for operating the solenoid to be turned ON has already elapsed as a result of the duty ratio change.
• this case may correspond to a case in which the request duty ON time of duty ratio is changed to 10% in a cycle and the elapsed duty ratio ON time of duty ratio is maintained to 50% and the current duty ratio at the control time for operating the solenoid to be turned ON is already elapsed to 20%, as in CASE 2.
• step S313 the changed duty ratio is normally applied in the next cycle.
• the normal application of the changed duty refers to that pulse width modulation having a duty ratio of 10% is conducted in the next cycle so that the solenoid control is conducted through the corresponding duty.
• step S303 corresponds to a procedure performed when the current duty cycle is in the ON state in step 303.
• step S307 the process proceeds to step S307.
• This step implies that the solenoid is OFF state by the control signal of the current cycle in the state where duty ratio change is requested.
• the ECU 201 continuously measures and stores the timing for operation states of respective cycles, that is, the ON state and the OFF state, the elapsed time and condition of the duty cycle are stored in the internal memory.
• the current solenoid OFF state is recognized by the ECU 201. Furthermore, the ECU 201 recognizes the elapsed time of the solenoid OFF state. Based on this recognition, the ECU 201 determines whether the OFF time elapsed in the current duty cycle is smaller than the minimum OFF time of the duty cycle newly changed on the basis of the currently requested duty ratio and the previously set control period in step S307.
• step S307 When it is determined by the ECU 201 in step S307 that the currently elapsed duty OFF time is smaller than the re-set duty OFF time, that is, that the duty OFF time calculated according to the duty change is longer than the OFF time of the duty which has progressed up to now and thus, the solenoid OFF progress is effective, the ECU 201 enters step 321 so as to maintain the OFF state during the time period obtained by subtracting the already elapsed OFF time from the minimum OFF time.
• the previous duty ratio is 50% and duty ratio change occurs in the current cycle so that the duty ratio is re-set to 80%.
• the current duty cycle is in the OFF state and the already elapsed OFF time is shorter than the reset OFF time. Accordingly, the OFF state is maintained by the difference between the changed OFF time and the currently elapsed OFF time.
• a time point where the OFF state should be terminated may occur within the cor- responding control period and this may be modified to a control signal of a pulse form as illustrated. This causes the current OFF state to be maintained by the minimum OFF time according to the changed duty ratio, thereby minimizing the over-energizing state of the solenoid.
• the above-mentioned minimum OFF time is a time defined in a solenoid specification and may be varied according to the kind of the solenoid.
• the maximum ON time for solenoid ON control is also set according to the specification.
• a section where the duty ratio is set to 100% and a section where the duty ratio is set to 0% are excluded, which is directly related to the endurance of the solenoid and follows a specification required by a manufacturer.
• the maximum ON duration and the minimum OFF duration according to the operation time of a solenoid are set according to the specification of the solenoid.
• step S307 when it is determined that the elapsed OFF time is longer than the minimum OFF time of the changed duty ratio, that is, when the solenoid OFF time according to the changed duty ratio has already elapsed and thus, the minimum OFF time has elapsed, the process proceeds to step S319.
• the ECU 201 converts the remaining control period to the ON state, thereby rapidly correcting an unnecessary control pattern.
• step S313 When a duty cycle is corrected as much as possible according to a requested duty ratio in steps 319 and 321, the process proceeds to step S313 so that a pulse width control is conducted with the changed duty ratio from the next cycle.
• the processes as described above are repeatedly conducted in real time so that response to the duty ratio change may be performed in real time.

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• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Electromagnetism (AREA)
• Power Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Magnetically Actuated Valves (AREA)

Applications Claiming Priority (2)

Publications (1)

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Citations (3)

Family Cites Families (2)

• 2012
  • 2012-11-05 KR KR1020120124167A patent/KR102052954B1/ko active IP Right Grant
• 2013
  • 2013-11-04 WO PCT/EP2013/072936 patent/WO2014068111A1/en active Application Filing

Patent Citations (3)

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