Control device for electrically controlling a solenoid valve

Abstract

Control device (1) for electrically controlling a solenoid valve (104), the control device (1) comprising: an actual current detector (40) that detects an actual current value flowing through the solenoid valve (104); a primary command generator (20) receiving a current command value and the actual current value detected by the actual current detector (40) and generating a primary command voltage value while feeding back the current command value based on the actual current value; a fluctuation command calculator (83) that calculates a fluctuation command voltage value for causing a periodic voltage oscillation; a fluctuation command superimposer (31) which generates a secondary command voltage value by superimposing the fluctuation command voltage value generated by the fluctuation command calculator (83) on the primary command voltage value generated by the primary command generator (20); and a PWM signal generator (32) which converts the secondary command voltage value generated by the fluctuation command superimposed (31) into a PWM signal, characterized by: a filter processor (50) that filters the actual current value detected by the actual current detector (40) to eliminate a frequency corresponding to a period of the fluctuating command voltage value and outputs the filtered actual current value to the primary command generator (20); an application voltage generator (60) which generates an application voltage to be applied to the solenoid valve (104) based on the PWM signal generated by the PWM signal generator (32); and a power supply voltage calculator (82) that calculates a power supply voltage, wherein the fluctuation command voltage value calculated by the fluctuation command calculator (83) has an amplitude not greater than half the power supply voltage.

Description

TECHNICAL FIELD

[0001] This technology relates to a control device for electrically controlling a solenoid valve. BACKGROUND TECHNOLOGY

[0002] In automatic transmissions, for example, installed in vehicles, shift speeds are achieved by establishing transmission gears according to the engagement state of frictional engagement elements, such as clutches and brakes. The engagement state of the frictional engagement elements is controlled by hydraulic pressure supplied therefrom to hydraulic servos. The hydraulic pressure is usually regulated by a linear solenoid valve provided in a hydraulic control device. The linear solenoid valve has a coil, and a current supplied to the coil drives a plunger (a movable iron part) to control the position of a piston, which regulates the hydraulic pressure, thereby regulating the hydraulic pressure.

[0003] The current supplied to the linear solenoid valve is controlled by a control unit (ECU). Specifically, the control unit determines switching based on, for example, vehicle speed and accelerator pedal depression, calculates a current value supplied to the linear solenoid valve based on the determination, generates a PWM signal by PWM modulating the current value, and controls an applied voltage by driving switching elements with the PWM signal, thereby controlling the current flowing through the linear solenoid valve.

[0004] In the linear solenoid valve described above, when the current flowing through the coil reaches a steady state, the plunger and the spool become stationary accordingly. If the current is varied to move the spool, especially after sliding friction is applied to the spool by the static friction coefficient, a delay in response may occur and hydraulic response may be deteriorated. In one known approach to preventing the steady state and improving hydraulic response, the current is periodically oscillated with a fluctuation period, that is, the position of the spool is oscillated with the fluctuation period (see JP 2014-197655 A).

[0005] Furthermore, it is difficult to accurately control a linear solenoid valve using a current command value without feedback control of the target current command value by detecting the actual current flowing through the linear solenoid valve. In this regard, according to Japanese Patent Application Publication No. 2014-197655, in order to cause the current supplied to the linear solenoid valve to oscillate with the fluctuation period, a current value of a fluctuation superimposed modulation amount that achieves the fluctuation period is calculated and superimposed on the target current command value.

[0006] After the fluctuation current value is added to the command value, feedback control is performed using the actual current value flowing through the coil. However, since the actual current value has a phase lag of 90 degrees relative to a PWM signal and is superimposed on the fluctuation current value, feedback control is performed under conditions where there is a deviation between the command current and the actual current value with the phase lag. Therefore, it is difficult to achieve a target fluctuation amplitude. This prevents the coil body from vibrating at a target amplitude, making it difficult to improve hydraulic response and impossible to effectively prevent the stationary state described above.

[0007] To achieve a target fluctuation amplitude, a complicated calculation of a current value of a fluctuation amplitude that achieves / achieves the fluctuation period must be performed by considering the phase delay in the feedback control, and the current value must be added to the command current value. This increases the computational load and requires an increase in the size of a chip such as a CPU, making it difficult to reduce the cost of a control device.

[0008] The document US 2009 / 0 005 913 A1, which represents the generic prior art, discloses a generic control device according to the preamble of the independent patent claim.

[0009] Further prior art is known from the documents DE 39 39 857 A1 and JP 2007- 40 361 A. SUMMARY OF THE INVENTION

[0010] In view of the foregoing, a purpose of the invention is to provide a control device that reduces the computational amount so as to eliminate the need to increase the size of a chip, thereby achieving cost reduction.

[0011] According to the invention, a control device is provided as defined by independent claim 1. Advantageous embodiments or further developments of the control devices according to the invention are defined by the dependent claims.

[0012] By the control device recited in claim 1, conversion into the primary command voltage value is performed by feeding back the current command value based on the actual current value flowing through a coil, and the fluctuation command voltage value having the fluctuation superimposed modulation amount that achieves the fluctuation period is superimposed on the primary command voltage value. This allows the fluctuation command voltage value to be calculated without considering that the actual current value is fed back while accurately controlling the linear solenoid valve. As such, this reduces computational load and eliminates the need to increase the size of a chip such as a CPU, thereby making it possible to achieve cost reduction. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a block diagram illustrating a control device according to an embodiment. Fig. 2 is a timing diagram illustrating a current signal and a voltage signal on which a fluctuation period is superimposed. Fig. 3 is a timing chart illustrating a fluctuation command voltage value. EMBODIMENTS OF THE INVENTION

[0013] With reference to Fig. 1 to Fig. 3, an embodiment will be described. First, the schematic structure of an automatic transmission 100 and the schematic structure of a control device 1 (hereinafter referred to as "control unit") of the automatic transmission 100 will be described with reference to Fig. 1 described.

[0014] As it is in Fig. 1, the automatic transmission 100 includes the following: a torque converter (T / C) 101 drivingly coupled to an engine (E / G) 200 serving as a drive source; an automatic speed change mechanism (T / M) 102 that outputs a rotational output of the torque converter 101 to wheels 300 while changing the speed of the rotational output; a hydraulic control device (V / B) 103 that controls hydraulic pressure including circulating hydraulic pressure in the torque converter 101, working hydraulic pressure supplied to a non-illustrated lockup pressure provided in the torque converter 101, and a clutch control device (C / D) 104.Lock-up / lock-up clutch, working hydraulic pressure supplied to non-illustrated friction engagement elements (such as clutches and brakes) in the automatic speed change mechanism 102, and lubricating hydraulic pressure for supplying lubricating oil to the automatic speed change mechanism 102; and the control unit (ECU) 1, which implements a control device described in detail below.

[0015] The hydraulic control device 103 includes a plurality of linear solenoid valves, including, for example, the following: a linear solenoid valve that regulates control pressure for controlling a regulator valve that regulates hydraulic pressure of an oil pump (or an electrically driven oil pump) driven by the engine 200 to line pressure; a linear solenoid valve that regulates working hydraulic pressure supplied to the lockup clutch; and a linear solenoid valve that regulates working hydraulic pressure supplied to hydraulic servos of the friction engagement elements. To simplify the description, the embodiment describes an example in which a linear solenoid valve 104 is controlled, which is one of these. The linear solenoid valve 104 has axially movable driven components including a plunger (not illustrated).Plunger in a solenoid section and a (not-illustrated) plunger in a valve section. The plunger is driven by being excited by a current flowing through a coil. The plunger is driven by being pushed by the plunger, thus changing an amount by which each port is opened or closed. The purpose of the embodiment is to reduce sliding friction on the moving components (the plunger and the plunger), particularly to reduce sliding friction on the plunger.

[0016] The automatic speed change mechanism 102 may be any type of speed change mechanism, and may be a multi-stage speed change mechanism using a planetary gear or the like to achieve multiple speeds, or may be a continuously variable speed change mechanism using a band-type or ring-type continuously variable speed change mechanism. Although the example described in the embodiment includes the automatic transmission 100, the automatic transmission 100 may be replaced by a hybrid drive device including a rotating electrical machine such as a motor / generator serving as a drive source. Furthermore, in each case of the automatic transmission 100 or the hybrid drive device, an idle stop function may be allowed to stop the engine 200.

[0017] An alternator (AL) 410, driven by the engine 200, is disposed near the engine 200, and electricity generated by the alternator 410 is supplied to a battery 400 to charge the battery 400. Although the battery 400 has a nominal voltage of, for example, 12 volts, the voltage of the battery 400 may rise to, for example, approximately 16 volts when the alternator 410 is driven. In contrast, the voltage of the battery 400 may drop to approximately 9 volts when the amount of charge remaining in the battery 400 is low, such as when the engine 200 is stopped due to an idle-stop feature, or when the alternator 410 is stopped because the amount of battery charge is large.For example, a buck converter circuit may generate electricity to be used instead of the battery 400 by stepping down a high voltage to drive a hybrid drive device.

[0018] Next, the structure of the control unit (ECU) is described. As shown in Fig. 1, the control unit (ECU) 1 is connected to sensors such as the following to receive signals therefrom: an accelerator operation amount sensor 91 that detects the operation amount of a non-illustrated accelerator pedal (or a throttle operation amount sensor that detects the operation amount of a throttle valve); an output speed sensor 92 that detects the speed of a rotational output of the automatic speed change mechanism 102 (or a vehicle sensor that detects the speed of a vehicle); and a battery voltage sensor 93 that detects the voltage of the battery 400.

[0019] The control unit 1 generally includes a switching controller (a current command value generator) 81, a power supply voltage calculator 82, a fluctuation amplitude command value calculator (a fluctuation command calculator) 83, and a driver 10. The driver 10 includes a primary command generator 20, a fluctuation command superimposed 31, a PWM signal generator 32, an actual current detector 40, a filter processor 50, and a drive circuit 60 including switching elements 61 and 62. Of these, the switching controller 81, the power supply voltage calculator 82, and the fluctuation amplitude command value calculator 83 are implemented by programs stored in a ROM or the like and executed by a CPU or the like.

[0020] On the other hand, the driver 10 is constructed in one set as a so-called driver assembly or card. In the control unit 1, a plurality of drivers are configured to correspond one-to-one to the plurality of linear solenoid valves, and a fluctuation amplitude command value calculator outputs signals to the plurality of drivers. To simplify the description, a driver 10 will be taken as an example and described. According to the embodiment, the primary command generator 20, the fluctuation command superimposed 31, the PWM signal generator 32, the actual current detector 40, the filter processor 50, and the drive circuit 60 are implemented by physical electrical circuits (hardware) that achieve their respective functions.Alternatively, they may be implemented by software if they can be implemented, without physical electrical circuits, by programs stored in a ROM or the like and executed by a CPU or the like.

[0021] Next, the function of each part of the control unit 1 will be described. The switching controller 81 generates a current command value Icmd for a current supplied to each of the linear solenoid valves by making a switching determination based on the accelerator pedal operation amount sensor 91 and the vehicle speed detected by the output speed sensor 92, that is, by determining which of the frictional engagement elements to engage or whether to switch between engagement and disengagement of the frictional engagement elements. Note that an update period of the current command value Icmd generated by the switching controller 81 is longer than a period (a fluctuation period) of a fluctuation command voltage value Vdiz, which will be described later.

[0022] Based on a voltage detection value Vbd of the battery (a power supply) 400 detected by the battery voltage sensor 93, the power supply voltage calculator 82 calculates a power supply voltage as a power supply voltage value Vbac, which is a digital value. When calculating the power supply voltage value Vbac, the power supply voltage calculator 82 may recalculate the power supply voltage value Vbac to correct the voltage detection value Vbd of the battery 400 according to the rotational speed of the engine 200 and the operating state of the alternator 410.

[0023] The fluctuation amplitude command value calculator 83 receives the power supply voltage value Vbac calculated by the power supply voltage calculator 82 and calculates an amplitude (hereinafter referred to as fluctuation amplitude) based on the power supply voltage value Vbac while calculating its period (hereinafter referred to as fluctuation period), thereby generating a fluctuation command voltage value Vdiz for causing a periodic voltage oscillation. The fluctuation amplitude and fluctuation period of the fluctuation command voltage value Vdiz are described in detail below.

[0024] On the other hand, the primary command generator 20 includes the following: an FB controller 22 that subjects the current command value Icmd received from the switching controller 81 to feedback control based on an actual current value Ir detected by the actual current detector 40 and representing the actual value of a current flowing through the linear solenoid valve 104; an FF controller 21 that performs feedforward control based on the current command value Icmd received from the switching controller 81. According to the embodiment, the FB controller 22 uses a PID controller, calculates a sum of a proportional term (P) by a proportional function, an integral term (I) by an integral function, and a derivative term (D) by a derivative function.-process, it estimates a resistance value Ra of the linear solenoid valve 104 by dividing a primary command voltage value Vc1 calculated in a previous control cycle by the current command value Icmd, and outputs a feedback voltage value Vfb by multiplying the sum by the resistance value Ra. On the other hand, the FF controller 21 outputs a feedforward voltage value Vff by multiplying the current command value Icmd received from the switching controller 81 by the estimated resistance value Ra of the linear solenoid valve 104. The primary command generator 20 combines the feedback voltage value Vfb and the feedforward voltage value Vff to generate and output a primary command voltage value Vc1. The primary command voltage value Vc1 is a command voltage value based on which the linear solenoid valve 104 can be operated or controlled as intended.

[0025] The fluctuation command superimposer 31 generates a secondary command voltage value Vc2 by superimposing the primary command voltage value Vc1 generated by the primary command generator 20 and the fluctuation command voltage value Vdiz calculated by the fluctuation amplitude command value calculator 83, that is, by modulating the primary command voltage value Vc1 with the fluctuation amplitude and the fluctuation period.

[0026] Based on the secondary command voltage value Vc2 generated by the fluctuation command superimposed 31, the PWM signal generator 32 generates a PWM signal with a modulated pulse width to be output at a predetermined period and outputs the PWM signal to the gate electrodes of the switching elements 61 and 62 of the drive circuit 60, which will be described below. According to the embodiment, the period of the PWM signal is set smaller than the fluctuation period. Since the PWM signal has a smaller period, the linear solenoid valve 104 receives a command at a smaller interval. Accordingly, control accuracy is improved and response is enhanced.

[0027] The drive circuit (an application voltage generator) 60 includes the following: a current path 63 connected to the battery 400; the switching element 61, such as a MOSFET element, inserted in the current path 63; a current path 71 connecting the PWM signal generator 32 and a gate electrode of the switching element 61; a current path 65 connected to a ground side of the current path 63; the switching element 62, such as a MOSFET element, inserted in the current path 65; a current path 72 connecting the PWM signal generator 32 and a gate electrode of the switching element 62; a current path 66 connecting the current path 65 and ground; a current path 64 connected at a node.A junction between the current path 63 and the current path 65 branches off and is connected to one end of an unillustrated coil of the linear solenoid valve 104 to supply an applied voltage to the coil; and a current path 67 branches off at a junction between the current path 65 and the current path 66 and is connected to the other end of the unillustrated coil of the linear solenoid valve 104 to ground the coil. Furthermore, a shunt resistor 68 is interposed in the current path 66. The switching elements 61 and 62 may each be a bipolar transistor instead of a MOSFET, or may be an IGBT element, which is a combination of these.

[0028] In the drive circuit 60, when the switching element 61 is turned ON (connected) and the switching element 62 is turned OFF (disconnected) by the PWM signal from the PWM signal generator 32, a voltage Vb of the battery 400 is applied to the coil of the linear solenoid valve 104 via the current paths 63 and 64, while the coil of the linear solenoid valve 104 is grounded via the current paths 67 and 66, so that an electromotive current flows according to an application voltage Va and the resistance value Ra of the linear solenoid valve 104. In contrast, when the switching element 62 is turned ON (connected) and the switching element 61 is turned OFF (disconnected) by the PWM signal from the PWM signal generator 32, the coil of the linear solenoid valve 104 is grounded via the current paths 66, 65, and 64, so that a counter electromotive current flows.

[0029] The actual current detector 40 detects the actual current value Ir flowing through the linear solenoid valve 104. Specifically, the actual current detector 40 includes the following: current paths 48 and 49 connected to different ends of the shunt resistor 68 interposed in the grounded current path 66; an operational amplifier 41 that detects a voltage difference between the current paths 48 and 49; and an A / D converter 42 that receives the voltage difference detected by the operational amplifier 41 as an analog value, calculates the actual current value Ir flowing through the linear solenoid valve 104 from a resistance value Rs of the shunt resistor 68, converts the actual current value Ir into a digital value, and outputs the digital value.

[0030] The filter processor 50 is a band-stop filter that cuts off a frequency corresponding to the fluctuation period. The filter processor 50 filters the actual current value Ir received from the A / D converter 42, thereby outputting the actual current value Ir, which has no fluctuation superimposed modulation frequency, to the FB controller 22. The filter processor 50 is configured to cut off at least the frequency of the fluctuation command voltage value (hereinafter referred to as the fluctuation frequency), and can also cut off noise components.As long as these functions are achieved, the filter processor 50 may be any type of filter, including a notch filter that cuts / cuts the fluctuation frequency, a high-pass filter that passes only frequencies higher than the fluctuation frequency, and a band-pass filter that cuts / cuts the fluctuation frequency while passing frequencies within a necessary band.

[0031] Next, it will be described how the fluctuation amplitude command value calculator 83 calculates the fluctuation command voltage value Vdiz. According to the embodiment shown in Fig. 3, the fluctuation amplitude command value calculator 83 calculates a limiting amount VdizLim to which the amplitude of the fluctuation command voltage value Vdiz is limited by dividing the power supply voltage Vb by two, that is, setting the amplitude of the fluctuation command voltage value Vdiz (hereinafter referred to as fluctuation amplitude) to half of the power supply voltage Vb. Thus, a fluctuation superimposition modulation amount of the fluctuation command voltage value Vdiz has the same range as the power supply voltage Vb. The fluctuation command voltage value Vdiz, as an application voltage to be applied to the linear solenoid valve 104, is superimposed on a command voltage value (that is, the primary command voltage value Vc1) based on the current command value Icmd. Thus, as shown in Fig. 3, a voltage actually applied to the linear solenoid valve 104 is a superimposed voltage having the fluctuation amplitude equal to the limiting amount VdizLim (power supply voltage Vb / 2) with respect to a value calculated by multiplying the resistance value Ra of the linear solenoid valve 104 and the actual current value Ir.

[0032] In this case, for example, when the fluctuation superposition modulation amount of the fluctuation command voltage value Vdiz is not less than half of the power supply voltage Vb, the application voltage command value Va cannot become less than the power supply voltage or less than 0 volts, such as when the primary command voltage value Vc1 becomes half of the power supply voltage Vb. Changing the primary command voltage value Vc by changing the current command value Icmd under such conditions only causes the application voltage command value Va to change within a range not less than the power supply voltage Vb or within a range less than 0 volts, without causing the actual application voltage to change within the range not less than the power supply voltage Vb or within the range not less than 0 volts.As a result, the average voltage remains unchanged, so the actual current cannot change. Therefore, the feedback control cannot regulate the hydraulic pressure as intended. As described above, the range of the command value for the applied voltage Va exceeding the range of the power supply voltage Vb makes it impossible to perform satisfactory control. For this reason, according to the embodiment, the fluctuation amplitude is set to half of the power supply voltage Vb by dividing the power supply voltage value Vbac, which is an accurately calculated value of the voltage Vb of the battery 400, by two.

[0033] When the fluctuation amplitude is half of the power supply voltage Vb, for example, when the primary command voltage value Vc1 rises above half of the power supply voltage Vb, the command value for the application voltage Va cannot become less than the power supply voltage Vb; or conversely, when the primary command voltage value Vc1 falls below half of the power supply voltage Vb, the command value for the application voltage Va cannot become less than 0 volts. However, one of the upper and lower sides of the amplitude of the command value for the application voltage Va is within the range from 0 volts to the power supply voltage Vb. Changing the primary command voltage value Vc by changing the current command value Icmd under such conditions causes one of the upper and lower sides of the amplitude to change, thereby causing the actual average voltage to change.At this time, since the other side of the amplitude does not change, the amount of change in the average applied voltage Va is small. However, the actual average voltage is subjected to feedback control after temporarily deviating from a target average voltage, so that the actual average applied voltage Va is adjusted to the target average voltage. Thus, the hydraulic pressure is regulated as intended.

[0034] As described above, when the fluctuation amplitude is not greater than half of the power supply voltage Vb, the applied voltage Va is calculated as desired through feedback control. Nevertheless, in order to achieve stability, it may be considered that the fluctuation amplitude is made smaller to reduce voltage oscillation. However, this approach may reduce the current supplied to the linear solenoid valve 104 and accordingly reduce the movement of the piston, making it difficult to achieve the effect of reducing sliding friction on the piston. Although it is applicable to calculate a voltage value that achieves the effect of reducing sliding friction each time, this calculation becomes complicated when the piston is moved.The coil bobbin position and the oil viscosity, which depends on the oil temperature, are taken into account. Therefore, according to the embodiment, the fluctuation amplitude is set to half of the power supply voltage Vb, thus achieving the effect of reducing sliding friction and stabilizing the calculation in the feedback control.

[0035] In addition, according to the embodiment, as shown in Fig. 3, the fluctuation amplitude command value calculator 83 calculates and sets the period (hereinafter referred to as the fluctuation period) of the fluctuation command voltage value Vdiz such that the fluctuation period is a predetermined multiple of the period of the PWM signal, specifically, for example, eight times longer than the period of the PWM signal, as described in detail below. Furthermore, the fluctuation period is set shorter than the update period of the current command value Icmd generated by the switching controller 81. In other words, the update period of the current command value Icmd is set longer than the fluctuation period.

[0036] Assuming that the period of the PWM signal is approximately eight times longer than in the prior art, the period of the PWM signal is substantially equal to the fluctuation period. In this case, even if no fluctuation superimposed modulation amount is superimposed, the spool of the linear solenoid valve 104 is driven as if with the fluctuation period, thus reducing sliding friction. However, improving the response of the linear solenoid valve 104, that is, improving the hydraulic response, requires making the period of the PWM signal smaller. If the period of the PWM signal is smaller, the drive period of the spool is smaller. Therefore, the effect of reducing sliding friction will not be achieved unless measures are taken.Therefore, according to the embodiment, the period of the PWM signal is reduced so that the fluctuation period is accordingly set to a predetermined multiplication of the period of the PWM signal.

[0037] In addition, the update period of the current command value Icmd is set longer than the fluctuation period. This allows the current command value Icmd to change while the plunger and spool of the linear solenoid valve 104 move slightly, thereby improving the responsiveness.

[0038] As described above, the fluctuation command voltage value Vdiz is calculated by the fluctuation amplitude command value calculator 83, superimposed on the primary command voltage value Vc1 calculated based on the received current command value Icmd, and generated as the PWM signal. The voltage applied to the linear solenoid valve 104 based on the PWM signal has a pulse-width modulated voltage waveform (a linear solenoid voltage waveform) as shown in Fig. 2. Thus, as shown in Fig.2, the actual current value Ir flowing through the linear solenoid valve 104 has a waveform (a linear solenoid current waveform) that oscillates with the fluctuation period in the range of the fluctuation superimposed modulation amount with an average of (with respect to) the current command value Icmd and fluctuates with the PWM period.

[0039] As described above, in the control unit 1 according to the embodiment, the primary command generator 20 generates the primary command voltage value Vc1 by feeding back the current command value Icmd based on the actual current value Ir, while feeding forward the current command value Icmd. The fluctuation command voltage value Vdiz calculated by the fluctuation amplitude command value calculator 83 is then superimposed on the primary command voltage value Vc1 as a voltage value, not a current value. This eliminates, for example, the need for the switching controller 81 to calculate the current command value by considering the fluctuation superimposed modulation amount, making it possible to reduce the bit width (the number of bits) of the current command value.Furthermore, this eliminates, for example, the need for the switching controller 81 to calculate the current command value by considering whether the current command value is subjected to feedback or feedforward, making it possible to reduce the computational effort. As such, this eliminates the need to increase the size of a chip such as a CPU, making it possible to achieve cost reduction. [Summary of the implementation example]

[0040] A control device (1) according to the embodiment electrically controls a solenoid valve (104) and comprises: an actual current detector (40) that detects an actual current value flowing through the solenoid valve (104); a primary command generator (40) that receives a current command value and the actual current value detected by the actual current detector (40) and generates a primary command voltage value while feeding back the current command value based on the actual current value; a fluctuation command calculator (83) that calculates a fluctuation command voltage value for causing a periodic voltage oscillation; a filter processor (50) that filters the actual current value detected by the actual current detector (40) to eliminate a frequency corresponding to a period of the fluctuation command voltage value and outputs the filtered actual current value to the primary command generator;a fluctuation command superimposer (31) that generates a secondary command voltage value by superimposing the fluctuation command voltage value generated by the fluctuation command calculator (83) on the primary command voltage value generated by the primary command generator (20); a PWM signal generator (32) that converts the secondary command voltage value generated by the fluctuation command superimposer (31) into a PWM signal; and an application voltage generator (60) that generates an application voltage to be applied to the solenoid valve (104) based on the PWM signal generated by the PWM signal generator (32).

[0041] Thus, conversion to the primary command voltage value is performed by feedback of the current command value Icmd based on the actual current value flowing through the coil, and the fluctuation command voltage value is superimposed on the primary command voltage value with the fluctuation superposition modulation amount that achieves the fluctuation period. This allows the fluctuation command voltage value Vdiz to be calculated without considering that the actual current value Ir is being fed back while accurately controlling the linear solenoid valve. As such, this reduces a computational load and eliminates the need to increase the size of a chip, such as the CPU of the control unit 1, thereby making it possible to achieve cost reduction.

[0042] Furthermore, the control device (1) according to the embodiment includes a power supply voltage calculator (82) that calculates a voltage of a power supply (400), and the fluctuation command voltage value calculated by the fluctuation command value calculator (83) has an amplitude that is not greater than half the voltage of the power supply.

[0043] This ensures that the fluctuation command voltage value Vdiz is not greater than half of the power supply voltage Vb, thereby preventing the amplitude of the secondary command voltage value Vc2 superimposed on the primary command voltage value Vc1 from exceeding the range (0 to Vb) of the power supply voltage Vb, and stabilizing a calculation in the feedback control.

[0044] Furthermore, in the control device (1) according to the embodiment, the period of the fluctuation command voltage value calculated by the fluctuation command value calculator (83) is longer than one period of the PWM signal.

[0045] This makes it possible to achieve the effect of reducing the sliding friction on the piston or spool while reducing the period of the PWM signal to improve a response of the linear solenoid valve 104.

[0046] Specifically, in the control device (1) according to the embodiment, the period of the fluctuation command voltage value calculated by the fluctuation command value calculator (83) is a predetermined multiple of the period of the PWM signal.

[0047] Furthermore, the control device (1) according to the embodiment includes a current command value generator (81) that generates the current command value, and the current command value calculated by the current command value generator (81) has a period longer than a period with which the fluctuation command voltage value is calculated.

[0048] As such, the update time of the current command value becomes longer than the fluctuation period. This allows the current command value to change while the linear solenoid valve 104 moves slightly, thereby improving the responsiveness.

[0049] Furthermore, the control device (1) according to the embodiment comprises a drive assembly (10) having an electric circuit that implements the actual current detector (40), the primary command generator (20), the fluctuation command superimposed (31), the filter processor (50), the PWM signal generator (32) and the applied voltage generator (60), and a program that implements the fluctuation command value calculator (83) is executed to output the fluctuation command voltage value to the drive assembly (10). [Possibility of further embodiments]

[0050] Although the control device according to the above-described embodiment is used to control a linear solenoid valve in an automatic transmission, the invention is not limited to the embodiment and is applicable to any control device that controls a solenoid valve.

[0051] Although the command voltage value is generated by feeding the current command value forward according to the embodiment, only feedback can be performed without feedforward. Furthermore, although a PID controller is taken as an example to describe the feedback control, the feedback control is not limited to a PID controller and can only use a PI controller. Any type of feedback control that can feed back the actual current value to the current command value can be used. INDUSTRIAL APPLICABILITY

[0052] The control device can be used to electrically control a solenoid valve that controls hydraulic pressure, and can particularly preferably be used to eliminate the need to increase the size of a chip such as a CPU, thereby achieving cost reduction. Description of reference symbols 1 CONTROL DEVICE (CONTROL UNIT) 10 CONTROL ASSEMBLY (DRIVE CONTROL) 20 PRIMARY COMMAND GENERATOR 31 Oscillation Command Overlay 32 PWM signal generator 40 ACTUAL CURRENT DETECTOR 50 FILTER PROCESSOR 60 APPLICATION VOLTAGE GENERATOR (CONTROL CIRCUIT) 81 CURRENT COMMAND VALUE GENERATOR (SWITCH CONTROL) 82 POWER SUPPLY VOLTAGE CALCULATOR 83 SWING COMMAND CALCULATOR 104 (FLUCTUATION AMPLITUDE COMMAND VALUE CALCULATOR) SOLENOID VALVE (LINEAR SOLENOID VALVE)

Claims

[1] Control device (1) for electrically controlling a solenoid valve (104), the control device (1) comprising: an actual current detector (40) that detects an actual current value flowing through the solenoid valve (104); a primary command generator (20) receiving a current command value and the actual current value detected by the actual current detector (40) and generating a primary command voltage value while feeding back the current command value based on the actual current value; a fluctuation command calculator (83) that calculates a fluctuation command voltage value for causing a periodic voltage oscillation; a fluctuation command superimposer (31) which generates a secondary command voltage value by superimposing the fluctuation command voltage value generated by the fluctuation command calculator (83) on the primary command voltage value generated by the primary command generator (20); and a PWM signal generator (32) which converts the secondary command voltage value generated by the fluctuation command superimposed (31) into a PWM signal, characterized by : a filter processor (50) that filters the actual current value detected by the actual current detector (40) to eliminate a frequency corresponding to a period of the fluctuating command voltage value and outputs the filtered actual current value to the primary command generator (20); an application voltage generator (60) which generates an application voltage to be applied to the solenoid valve (104) based on the PWM signal generated by the PWM signal generator (32); and a power supply voltage calculator (82) that calculates a power supply voltage, wherein the fluctuation command voltage value calculated by the fluctuation command calculator (83) has an amplitude not greater than half the power supply voltage. [2] Control device (1) according to claim 1, wherein: the period of the fluctuation command voltage value calculated by the fluctuation command calculator (83) is longer than one period of the PWM signal. [3] The control device (1) according to claim 2, wherein the period of the fluctuation command voltage value calculated by the fluctuation command calculator (83) is a predetermined multiple of the period of the PWM signal. [4] Control device (1) according to one of claims 1 to 3, additionally comprising: a control module (10) with an electrical circuit that implements the actual current detector (40), the primary command generator (20), the fluctuation command superimposer (31), the filter processor (50), the PWM signal generator (32) and the application voltage generator (60), wherein a program implementing the fluctuation command calculator (83) is executed to output the fluctuation command voltage value to the drive module (10).

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