Method for operating a magnetic valve device of a vehicle dynamics system having a plurality of coils

Abstract

The invention relates to a method for operating a magnetic valve device for a vehicle dynamics system, the magnetic valve device having a plurality of coils, wherein the coils are connected in parallel to one another and in series with a common measuring shunt, wherein the actual current flowing in each coil is regulated to a target current by means of a PWM specification, and wherein a resistance model is used for regulating the actual current for each individual coil, wherein the following steps are carried out to create the resistance model: a) specifying in which coil the actual current should be measured, b) switching all other coils into freewheeling, c) determining the actual current based on measuring an electrical variable at the common measuring shunt of all coils, d) calculating the resistance model based on the measured actual current, and e) repeating the steps a) to d) using another coil to determine the actual current in the other coil.

Description

Technical Field

[0001] This invention relates to a method for operating a solenoid valve device having multiple parallel coils for a driving dynamics system. Furthermore, a control device, a computer program, a machine-readable storage medium, a solenoid valve device for a vehicle, and a vehicle having such a solenoid valve device are proposed. This invention is particularly applicable to driving dynamics systems. Background Technology

[0002] A solenoid valve is a valve actuated by a magnetic assembly with an energized coil due to electromagnetic induction.

[0003] Such solenoid valves are used in hydraulic braking systems with functions such as ABS and / or ESP, and are used to control the entry or exit of hydraulic fluid and / or control and regulate its flow direction. Here, the current used to actuate the solenoid valve can be adjusted or controlled. Typically, the coils of the solenoid valves are connected in parallel with current regulators via separate channels. Here, the current flowing into each coil (called the actual current) can be individually adjusted to a preset current (called the target current) via an adjustable duty cycle of a PWM (Pulse Width Modulation) specification. For this purpose, the actual current of each coil is measured and the duty cycle is adjusted according to the PWM specification. Summary of the Invention

[0004] Based on the above, a method is described here, by which the parameters required to operate such a solenoid valve can be obtained.

[0005] To this end, a method is proposed for operating a solenoid valve device for a driving dynamics system with multiple coils, wherein the coils are connected in parallel with each other and in series with a common current measuring device (hereinafter also referred to as a measuring shunt), wherein the actual current flowing in each coil is regulated to a target current by means of a PWM specification, and wherein a resistance model for each individual coil is used for regulating the actual current, wherein the following steps are performed to create the resistance model:

[0006] a) Specify in which coil the actual current should be measured.

[0007] b) Switch all other coils to freewheeling.

[0008] c) Determine the actual current based on the electrical variables measured at the common measuring shunt across all coils.

[0009] d) Calculate the resistance model based on the measured actual current, and

[0010] e) Repeat steps a) to d) using another coil to determine the actual current in the other coil.

[0011] The method described herein is characterized in particular by using exactly one measuring shunt to measure the actual current passing through all the coils. Furthermore, the ohmic resistance of the coils can be determined from this, for example, by means of the supply voltage.

[0012] Using a single measuring shunt is particularly aimed at reducing the design and equipment costs associated with generating resistance models. Instead of using a separate measuring shunt for each coil to measure the actual current flowing in the coil, which incurs significant hardware overhead and associated costs, this paper proposes using a common measuring shunt for all coils and performing the actual current measurement for each coil sequentially.

[0013] The measuring shunt can determine the actual current flowing through it. Because the measuring shunt is connected in series with the coil to be checked during the measurement in step c), the current through the coil can be determined using the measuring shunt.

[0014] Also to consider is the duty cycle to be set for pulse width modulation, for example, by software preset. Of course, if the coil is controlled entirely in software via the PWM specification, it is very costly to determine information about the actual current in real time so that this information can be evaluated in the software and used in the PWM specification.

[0015] Using the described method, instead of relying on costly direct measurements, the real-time actual current of each coil is essentially estimated indirectly by means of a resistance model, which is then adapted by occasional measurements of the current in each coil.

[0016] Furthermore, the described method uses only a single common measuring shunt to measure the actual current of each coil, whereas in the prior art multiple separate measuring shunts associated with each coil are required. With the common measuring shunt, current measurement of each coil can be performed cost-effectively and practically while the coil is energized.

[0017] The described method is particularly suitable for controlling solenoid valve devices used in driving kinematic systems. Here, the solenoid valve device is used to control the flow of hydraulic fluid in a hydraulic braking system, and to control the flow of that hydraulic fluid.

[0018] Such a solenoid valve device may include multiple coils that, by applying a suitable current, can generate the magnetic force desired for the normal operation of the actuator. Here, for example, the desired magnetic force is generated by applying an adjustable current to move the solenoid valve piston to a desired position at a desired speed. This allows control of the flow of hydraulic fluid. The actual current flowing in the coils can be adjusted by a current regulator, through adapting the duty cycle of the PWM (Pulse Width Modulation) specification.

[0019] Duty cycle describes the ratio of pulse duration to period duration for a periodic pulse sequence. Duty cycle is described as a numerical scale, ranging from 0 to 1 or 0% to 100%. Duty cycle should be understood as the actual, derived duty cycle. Here, the duty cycle can be preset based on a resistance model and the target current in response to control.

[0020] The current regulator can be designed as a hardware current regulator, such as in the form of an electronic circuit, or as a software current regulator. Here, the current regulator can be configured or designed to adjust the actual current value to the target current value by adapting the duty cycle of the pulse width modulation.

[0021] Preferably, each coil has an associated switch, which is connected downstream of the coil, for example, as a low-voltage side switch. Thus, the coil current for each coil can be increased or decreased by activating or deactivating the switch. Each coil preferably has an associated protection diode connected in parallel with the coil. Therefore, overvoltage can be avoided, especially when deactivating the switch associated with the coil, while the current can continue to circulate through the coil.

[0022] Each coil, its associated switch, and its associated protection diode thus constitute a channel that can be controlled individually. Each channel has a specific resistance, which can also be called a channel-specific resistance. This resistance is determined in particular by the ohmic resistance and inductive resistance of the coil (i.e., the coil's impedance).

[0023] The term "coils in parallel" here specifically means that each coil, along with its associated electronics, is connected in channels to a separate current regulator. Thus, each coil can be individually controlled by the current regulator, with individual energization of the respective coil achieved by means of pulse width modulation.

[0024] All channels of all coils pass through a common measuring shunt, allowing all currents flowing into the coils to also flow through this common measuring shunt. This enables the measurement of all currents flowing into the coils based on the electrical variables measured at the common measuring shunt. The common measuring shunt can be designed as an ohmic resistor. Current can also be calculated by measuring the voltage at the common measuring shunt.

[0025] To associate the measured current with the coil to be measured by means of voltage measurement at a common measuring shunt, first, according to step a), select in which coil the actual current flowing is to be measured. Then, according to step b), switch all other coils to freewheeling. This means that the corresponding channel is cut off, so that the channel that does not need to be measured is switched to freewheeling. Here, the switch associated with the coil to be measured may remain active or must be activated. All other switches are deactivated, thereby (actively or passively) running the channel or coil in freewheeling mode. Therefore, only the current of the channel to be measured flows through the common measuring shunt or through the coil to be checked. If it cannot be lower than the minimum current of the channel that does not need to be measured, the coil current can be increased before measurement so that it does not fall below the minimum current during measurement due to possible delays in freewheeling if the current drops.

[0026] According to step c), the actual current is determined based on the measured electrical variables at the common measuring shunt. Here, the electrical variables specifically represent the voltage at the common measuring shunt. The voltage drop at a 100% duty cycle or the average voltage at a constant duty cycle can be measured.

[0027] The actual current determined in step c) is incorporated into the resistance model, so the resistance model can be adapted according to step d) based on the incorporated actual current. In particular, possible deviations between the resistance model and the actual channel-specific resistance can be adjusted. Therefore, the real-time actual current of each coil can be estimated more accurately using a resistance model adapted based on occasional current measurements.

[0028] According to step e), the actual current flowing in other channels or coils can be determined sequentially by repeating steps a) to d), and the resistance model can be adapted based on the determined actual current.

[0029] The described method can be implemented, for example, in software or hardware or a hybrid of software and hardware, such as in a control device.

[0030] Using the described method, the current through a given coil can be measured based on changes in electrical characteristics (e.g., voltage drop at a common measuring shunt). To consider only the current through the coil to be measured, all coils not to be measured can be briefly switched to freewheeling. Thus, essentially only the current of the coil to be measured flows through the common measuring shunt, allowing the measurement results to be specifically associated with the corresponding coil.

[0031] The described method allows for sequential, cyclic current measurement of all coils, either within or outside control, using a common measuring shunt. In contrast, in the prior art, the current of each coil can only be measured at any given time using a specific measuring shunt associated with that coil. Compared to the prior art, the method described herein can be implemented cost-effectively and practically.

[0032] Furthermore, the described method can also be used to determine the channel-specific resistance by measuring the current during control, which is only feasible in the prior art outside of control or with the aid of a separate current measuring device.

[0033] The measured current can be directly used for readjustment and / or further calculations, such as channel-specific resistance values. Channel-specific resistances can be calculated based on the measured current and supply voltage. The calculated channel-specific resistance can be input into a resistance model, thereby allowing the calculation and setting of the duty cycle for the PWM specification.

[0034] Preferably, in step c), the actual current is measured as follows: the duty cycle of the PWM specification is set to 100%, such that the actual current is measured based on the voltage drop at a common measuring shunt. With a 100% duty cycle, essentially a DC current flows into the coil, making the inductive component of the channel impedance zero, and the ohmic portion of the channel impedance, combined with the voltage drop at the common measuring shunt, determines the actual current flowing into the coil.

[0035] Preferably, in step c), the actual current is measured as follows: the duty cycle of the PWM specification is set to a constant value, such that the actual current is measured based on the average voltage at the common measurement shunt. Instead of a 100% duty cycle, the duty cycle for current measurement can also be set to a constant value, such that the frequency-dependent inductive component of the channel impedance is no longer zero, and the voltage measured at the common measurement shunt is the average voltage. The current flowing through the coil can be determined taking into account the duty cycle and the measured average voltage. Alternatively, the current flowing through the coil can be determined by taking into account the inductance through a single voltage measurement at a defined time point during the current rise.

[0036] Preferably, the voltage is detected by means of a sample-and-hold circuit, and the average voltage is formed by means of software. Alternatively, the average voltage can be formed, for example, by means of a low-pass circuit, and the average voltage can be measured by means of a sample-and-hold circuit.

[0037] Preferably, using the described method, the current has already started oscillating before the measurement begins, prior to step c). Therefore, the measurement time can be shortened.

[0038] Preferably, each coil is associated with a low-side switch, such that in step b), the coil switches to freewheeling by deactivating its associated low-side switch. The low-side switch may be designed as a field-effect transistor, such as a MOSFET, and the ohmic and inductive loads may be grounded.

[0039] Preferably, each coil is controlled by a duty cycle adapted to the PWM specification, determined based on the actual current flowing into the coil and a coil-specific resistance derived from that actual current. Here, a channel-specific resistance can be calculated based on the measured actual current and the applied supply voltage. This resistance can then, for example, be used in a resistance model to calculate the target value to be set for the duty cycle.

[0040] Preferably, the control device is designed to perform the described method. The control device can be understood as any type of electronic device, such as an application-specific integrated circuit (ASIC), a computer core (CPU), or other device capable of performing data processing, control, and / or regulation.

[0041] It is also preferred that a computer program be used to perform the methods described herein. In other words, this particularly relates to a computer program (product) comprising instructions that, when executed by a computer, cause the computer to perform the methods described herein.

[0042] Furthermore, it is preferable to use a machine-readable storage medium on which the computer program presented herein is stored. A machine-readable storage medium is typically a computer-readable data carrier.

[0043] Furthermore, a solenoid valve device with at least two parallel coils is proposed, which operates according to the described method.

[0044] Furthermore, a vehicle having at least one of the described solenoid valve devices is proposed. Attached Figure Description

[0045] The solutions presented herein and their technical context are explained in more detail below with reference to the accompanying drawings. It should be noted that the invention should not be limited to the embodiments shown. In particular, unless explicitly stated otherwise, certain aspects of the facts explained in the drawings may be extracted and combined with other parts and / or understandings from other drawings and / or other parts of this specification. Illustratively:

[0046] Figure 1 The method described herein for operating a solenoid valve device for a driving kinematic system is shown.

[0047] Figure 2 The equivalent circuit of a known solenoid valve device with multiple coils is shown.

[0048] Figure 3 Showing the method of measurement in a known manner Figure 2 The equivalent circuit of the coil current shown is shown.

[0049] Figure 4 Showing a method for measuring according to the invention Figure 2 The equivalent circuit diagram of the coil current shown is shown, and

[0050] Figure 5 This illustrates the method used for measurement according to the invention during the execution of measurements. Figure 2 The equivalent circuit diagram of the current in the coil shown is illustrated. Detailed Implementation

[0051] To provide an overview of the basic ideas and advantages of the described method, firstly, based on... Figure 1 An exemplary method for operating a solenoid valve device 12 having, for example, three coils 13 is explained.

[0052] Furthermore, compared to the existing technology that uses multiple individual measurement shunts 5, the advantages of using a common measurement shunt 6 are as follows: Figures 2 to 5 The diagram is shown. Here, the known equivalent circuit and known measurement methods are as follows: Figure 2 and Figure 3 As shown, the equivalent circuit according to the invention and the measurement method according to the invention are in Figure 4 and Figure 5 As shown in the image.

[0053] Figure 1 The method described herein for operating a solenoid device 12 having three coils 13 operating in parallel, each connected to a common measuring shunt 6, is illustrated schematically and exemplary.

[0054] Each coil 13 is controlled by a PWM specification 14 with a certain duty cycle, which is set based on the resistor model 15 and the target current (i.e., the target current).

[0055] To adjust the resistance model 15 due to possible deviations from the actual resistance of coil 13, the actual current of each coil 13 is occasionally measured via a common measuring shunt 6. While measuring the actual current of a particular coil 13, all other coils 13 can be switched to freewheeling mode. The measured actual current is incorporated into the resistance model 15, thus allowing the resistance model 15 to be adapted based on the incorporated actual current.

[0056] By means of the method described herein, the real-time actual current of each coil 13 is indirectly estimated by means of a resistance model 15 instead of the costly direct measurement, wherein the resistance model 15 is adapted in terms of its accuracy by occasionally measuring the current of the coil 13.

[0057] Using the described method, the current of all coils 13 can be measured only via a common measuring shunt 6, as will be explained below. Figure 4 and Figure 5 As shown in the image. In contrast, Figure 3 A known method is shown for measuring the current of all coils 13 via a measuring shunt 5 connected to the individual channels associated with coil 13.

[0058] Figure 2 The equivalent circuit of a known solenoid device 12 with multiple coils 13 is schematically shown. The impedance of each coil 13 is shown by an ohmic resistor 1 and an inductor 2. The ohmic resistor 1 and the inductor 2 are connected in series with a low-voltage side switch 4. The low-voltage side switch 4 is typically designed as a transistor and connected downstream of the load, i.e., downstream of the coils 13. By activating or deactivating the low-voltage side switch 4, the coils 13 are energized or de-energized. To protect against overvoltage, especially when deactivating the low-voltage side switch 4, a protection diode 3 is connected in parallel with the ohmic resistor 1 and the inductor 2.

[0059] A series connection of an ohmic resistor 1, an inductor 2, and a low-voltage side switch 4, along with a protection diode 3 connected in parallel with the ohmic resistor 1 and the inductor 2, constitutes channel 10, which is connected to a current regulator (not shown). To control the coil 13 in channel 10, the current regulator outputs a PWM specification 14 with a set duty cycle.

[0060] Figure 2 Two channels 10 are shown in parallel, and multiple channels (not shown) can be extended between them. Figures 2 to 5 The ellipsis between the two channels 10 shown indicates an extended channel 10 (not shown). Channels 10 can be structurally identical but with different parameters (e.g., different ohmic resistances and / or inductances). According to... Figures 2 to 5 The coils 13 in channel 10 can be controlled via PWM specification 14.

[0061] Figure 3 Showing based on Figure 2 An extension for measuring the current in all channels 10 in a known manner. Figure 3 It can be identified that: a channel-specific measuring shunt 5 is connected downstream of the corresponding low-voltage side switch 4 in each channel 10. The current flowing in that channel can be measured based on the voltage 7 at the channel-specific measuring shunt. (Using...) Figure 3 The measurement method shown requires multiple channels of separate measurement shunts 5 for multiple coils 13.

[0062] replace Figure 3 The channel shown is a separate measurement shunt 5. Figure 4A common measuring shunt 6 is shown, which is connected in series downstream of the low-voltage side switch 4 of all channels 10, such that the current 10 flowing in each channel also flows through the common measuring shunt 6.

[0063] To measure only the actual current 9 flowing in the channel 10 to be measured, the low-voltage side switches 4 of all channels that do not need to be measured can be temporarily deactivated, such as... Figure 5 As shown, all coils 13 that do not require measurement can be temporarily switched to freewheeling. Thus, essentially only the actual current 9 to be measured flows through the common measuring shunt 6, allowing the measurement result to be specifically associated with the corresponding coil 13. Here, the actual current 9 to be measured can be measured based on the voltage 8 at the common measuring shunt. With a duty cycle of 100% and no freewheeling current 11, the actual current 9 to be measured can be measured based on the voltage drop across the ohmic resistor 1 and the common measuring shunt 6. Under another constant duty cycle with freewheeling current 11, the actual current 9 to be measured can be measured based on the average voltage across the common measuring shunt 6 and the inductor resistor 2. The currents in other channels can be measured sequentially in the same manner.

[0064] With the help of Figure 4 and Figure 5 The proposed method allows the current in all channels 10 to be measured cost-effectively, and more precisely, under control, using a common measuring shunt 6. Figure 1 and Figure 2 The known methods require the use of individual channel measuring shunts 5 to measure the current of all channels 10 at high cost.

Claims

1. A method for operating a solenoid valve device for a driving dynamics system having multiple coils, wherein the coils (13) are connected in parallel with each other and in series with a common measuring shunt (6), wherein an actual current (9) flowing in each coil (13) is regulated to a target current by means of a PWM specification (14), and wherein a resistance model (15) for each individual coil (13) is used for regulating the actual current (9), wherein the following steps are performed to create the resistance model (15): a) Specify in which coil (13) the actual current (9) should be measured. b) Switch all other coils (13) to freewheeling. c) Determine the actual current (9) based on the electrical variables measured at the common measuring shunt (6) of all coils (13). d) Calculate the resistance model (15) based on the measured actual current (9), and e) Repeat steps a) to d) using another coil (13) to determine the actual current (9) in the other coil (13) and create a resistance model (15).

2. The method according to claim 1, wherein the actual current (9) is measured in step c) by setting the duty cycle of the PWM specification (14) to 100% such that the actual current (9) is measured based on the voltage drop as an electrical variable at the common measuring shunt (6).

3. The method according to claim 1, wherein the actual current (9) is determined in step c) by setting the duty cycle of the PWM specification (14) to a constant value such that the actual current (9) is measured based on the adjusted average voltage as an electrical variable at the common measuring shunt (6).

4. The method of claim 3, wherein the average voltage is detected by means of a sample-and-hold circuit and subsequently by forming an average value.

5. The method of claim 3, wherein the average voltage is formed by means of a low-pass circuit and the average voltage is detected by means of a sample-and-hold circuit.

6. The method according to any one of claims 1 to 5, wherein the ohmic resistance (1) of each coil (13) is determined by means of the method, and the ohmic resistance is taken into account when determining the actual current (9) in step c).

7. The method according to any one of claims 1 to 5, wherein each coil (13) is associated with a switch (4) such that in step b), the coil (13) is switched to freewheeling by deactivating the switch (4) associated with the coil.

8. The method according to any one of claims 1 to 5, wherein each coil (13) is controlled by adapting the duty cycle of the PWM specification (14), and the duty cycle is determined based on the actual current (9) flowing in the coil (13) and the coil-specific resistance derived from the actual current (9).

9. A control device designed to perform the method according to any one of claims 1 to 8.

10. A computer program product comprising instructions that, when executed by a computer, cause the computer to perform the method according to any one of claims 1 to 8.

11. A machine-readable storage medium having a computer program stored thereon, the computer program being used to perform the method according to any one of claims 1 to 8.

12. A solenoid valve device (12) having at least two coils (13) connected in parallel, the solenoid valve device operating according to any one of claims 1 to 8.

13. A vehicle having at least one solenoid valve device (12) according to claim 12.

Images