JP2007030663A - Electromagnetic suspension device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnetic suspension device capable of efficiently performing energy regeneration by a motor and improving riding comfort in a vehicle.
In an electromagnetic suspension device including one member, the other member exhibiting relative motion with respect to the one member, and a motor capable of suppressing at least the relative motion, the short-circuit characteristic T passes through the origin and is a stroke in the short-circuit characteristic. The tangent line tangent to the speed and load curve is set to pass above the point where the stroke speed is 0.1 m / s and the generated load is 1000 N, or the load in the short-circuit characteristic is the frequently used stroke speed range An electromagnetic suspension device that is set to take a maximum value within the range.
[Selection] Figure 4

Description

  The present invention relates to an improvement of an electromagnetic suspension device that is optimal for a vehicle.

  As this type of electromagnetic suspension device, for example, a cylinder connected to one of the sprung member or unsprung member of the vehicle, a rod connected to one of the sprung member or unsprung member and inserted into the cylinder, A linear motor is composed of a plurality of permanent magnets mounted on the outer periphery of the rod in an axial direction and a plurality of windings provided on the inner periphery of the cylinder and facing the permanent magnet, and the electromagnetic force of the linear motor is It is used as a load (control force) that suppresses relative movement in the axial direction with the cylinder.

And the winding in this linear motor is made into three phases of U, V, and W, and the electromagnetic suspension device configured as a linear motor is PWM (Pulse Width Modulation) controlled by an inverter, and the generated damping force is variable. In this electromagnetic suspension device, since the load generation source is a linear motor, energy regeneration for converting the kinetic energy in the relative motion between the rod and the cylinder into electric energy is performed. Is possible.
Japanese Patent Laying-Open No. 2003-104025 (Detailed Description of the Invention, FIG. 15)

  As described above, since the above-described electromagnetic suspension device can perform energy regeneration, it can be charged to a battery as a power source when mounted on a vehicle, and a load is applied according to the vehicle speed. Although it is useful in that it is intended to save power by effectively using the current generated by the motor by limiting the area where it occurs, it may be pointed out that there are the following problems .

  In other words, the regenerative region where energy regeneration can be completely performed in the conventional electromagnetic suspension device is a limited range, and is not always controlled within the region, and may not necessarily lead to power saving.

  In recent years, the development of hybrid vehicles equipped with motors and gasoline engines to improve fuel consumption and electric vehicles that are driven entirely by motors has become active. Considering the expected mounting in a vehicle, the power consumption of the electromagnetic suspension device may affect the driving of the vehicle, so that the conventional electromagnetic suspension device may not be sufficient in terms of power consumption.

  Furthermore, in the conventional electromagnetic suspension device, in order to achieve the above power saving, complicated control for determining the control range by the expansion / contraction stroke and its speed is required each time, and the behavior of the vehicle is switched between the controls. The vehicle rider may feel uncomfortable or uneasy, resulting in a loss of ride comfort in the vehicle.

  Accordingly, an electromagnetic suspension device that has been developed to improve the above-described problems, and that aims to efficiently perform energy regeneration by a motor and improve riding comfort in a vehicle. Is to provide.

  In order to achieve the above-described object, the problem-solving means of the present invention is an electromagnetic suspension device including one member, the other member that exhibits relative motion with respect to the one member, and a motor that can suppress at least the relative motion. The short-circuit characteristic, which is the relationship between the stroke speed and load when the motor winding is short-circuited, generates a tangent line that passes through the origin and touches the stroke speed-load curve in the short-circuit characteristic at a stroke speed of 0.1 m / s. The load is set so as to pass above a point where the load is 1000 N.

  According to another aspect of the present invention, there is provided an electromagnetic suspension apparatus comprising: one member; the other member that exhibits relative motion with respect to the one member; and a motor that can suppress at least the relative motion. The load in the short-circuit characteristic, which is the relationship between the stroke speed and the load when the short circuit is short-circuited, takes the maximum value within the most frequently used stroke speed range.

  According to the first aspect of the present invention, since the tangent is set to pass above the point where the stroke speed is 0.1 m / S and the load is 1000 N, the stroke speed at which the electromagnetic suspension device is frequently used. The entire load range that needs to be generated as a shock absorber within the range will be covered in the regeneration region.

  Therefore, in a scene where the electromagnetic suspension device is frequently used, the power source is always regenerated to charge the power source, so that the power source power is not consumed, so that power saving is ensured and the power source is increased. Such a situation can be prevented, and furthermore, it is optimal for a vehicle in which a drive source such as an electric vehicle uses a motor.

  According to the invention of claim 2, the short circuit characteristic of the motor is set so that the load reaches a peak at a stroke speed or less frequently used during traveling of the vehicle, that is, the load in the short circuit characteristic is a frequently used stroke. The maximum value is set within the speed range.

  Then, since the regeneration area in which the power source can be charged within the stroke speed range that frequently appears while the vehicle is running increases, the opportunity to charge the power source by regeneration can be increased, and the energy regeneration by the motor is efficiently performed. Therefore, power saving can be ensured.

  In addition, in this electromagnetic suspension device, there is no need for special control in order to perform efficient regeneration, so that the behavior of the vehicle is not switched for the purpose of power saving control, and the vehicle is boarded. It is possible to improve the riding comfort in the vehicle without causing the person to feel uncomfortable or uneasy.

  The present invention will be described below based on the embodiments shown in the drawings. FIG. 1 is a conceptual diagram of an electromagnetic suspension device according to an embodiment. FIG. 2 is a system diagram of a motor control device. FIG. 3 is a diagram illustrating the PWM circuit. FIG. 4 is a diagram showing a short-circuit characteristic that is a relationship between a stroke speed and a load of the electromagnetic suspension device in a state where the motor is short-circuited. FIG. 5 is a diagram illustrating a setting frequency state of generated loads on the expansion side and the contraction side of a shock absorber applied to light, small, and ordinary automobiles. FIG. 6 is a diagram showing the frequency of the expansion / contraction stroke speed of the shock absorber while the vehicle is running. FIG. 7 is a diagram illustrating a controllable region of the electromagnetic suspension device. FIG. 8 is a diagram illustrating the d-phase current with respect to the stroke speed during field-weakening control. FIG. 9 is a diagram illustrating the d-phase current with respect to the stroke speed during field-weakening control. FIG. 10 is a diagram illustrating the d-phase current with respect to the stroke speed during field-weakening control. FIG. 11 is a diagram illustrating the d-phase current with respect to the stroke speed during field-weakening control. FIG. 12 is a conceptual diagram of another electromagnetic suspension device.

  As shown in FIG. 1, the electromagnetic suspension device in one embodiment includes a screw shaft 1 that is one member, a ball screw nut 2 that exhibits relative motion with respect to the screw shaft 1, and a motor M. .

  Specifically, the screw shaft 1 is rotatably engaged with the ball screw nut 2, and the upper end of the screw shaft 1 in FIG. 1 is connected to the rotor R of the motor M. The other ball screw nut 2 is fixed to the upper end of a cylinder 4 into which the screw shaft 1 is inserted, and can be connected to one of the sprung member and the unsprung member of the vehicle via this cylinder 4. It is like that.

  The screw shaft 1 is rotatably connected to the other of the sprung member and the unsprung member of the vehicle. Specifically, the screw shaft 1 is provided on the other of the sprung member and the unsprung member of the vehicle. The motor M is fixed to the other of the sprung member and the unsprung member of the vehicle.

  Therefore, when the screw shaft 1 and the ball screw nut 2 exhibit a linear relative motion in the axial direction, the screw shaft 1 exhibits a rotational motion, and the rotational motion of the screw shaft 1 is transmitted to the rotor R of the motor M. It will be. Here, the rotational speed of the screw shaft 1 may be reduced through a reduction gear constituted by a gear mechanism or the like to transmit the rotational motion of the screw shaft 1 to the rotor R.

  When the screw shaft 1 and the ball screw nut 2 exhibit a linear relative motion in the axial direction, the ball screw nut 2 is used when the screw shaft 1 cannot be rotated and the ball screw nut 2 is rotated instead. The rotational motion of 2 may be transmitted to the rotor R of the motor M. Specifically, the screw shaft 1 is non-rotatably connected to one of the sprung member and unsprung member of the vehicle, and the other ball screw nut 2 is connected to the other of the sprung member and unsprung member of the vehicle with a ball bearing or the like. The rotational movement of the ball screw nut 2 may be transmitted to the rotor R of the motor M via a gear mechanism, a friction wheel mechanism, or the like.

  In this case, the motor M includes a cylindrical frame 10, a stator that is an armature provided on the inner peripheral side of the frame 10, and a rotor R that is rotatably supported by the frame 10. Specifically, the stator includes an annular stator core 11 having a plurality of teeth, and a winding 12 in each of the U, V, and W phases wound around each tooth, The rotor R includes a shaft 13 and a driving magnet 14 mounted on the outer periphery of the intermediate portion of the shaft 13.

  The drive magnet 14 is composed of a block magnet that can realize a predetermined number of poles and is embedded in the shaft 13, and the motor M is an embedded magnet type. Of course, the drive magnet 14 is blocked so that a predetermined number of poles can be realized and bonded to the outer periphery of the shaft 13, or it is formed in an annular shape and dividedly magnetized so as to be fitted to the outer periphery of the shaft 13. However, when the so-called surface magnet type is used, an eddy current loss is likely to occur on the surface of the driving magnet 14 during field weakening control, which will be described later, and therefore the embedded magnet type is preferable.

  The motor M is equipped with a rotation angle sensor 15 for detecting the rotation angle of the rotor R. Specifically, for example, the rotation angle sensor 15 is attached to the resolver core provided on the shaft 13 and the frame 10. It only has to be constituted by a resolver stator facing the provided resolver core. In addition, an optical encoder may be adopted, and when a sensing magnet is provided in the rotor R, a Hall element, MR element, etc. The magnetic sensor may be provided on the frame 10.

  As described above, in this electromagnetic suspension device, since the drive source is the motor M, when the motor M is driven by being supplied with electric energy, the screw shaft 1 is rotationally driven to rotate the screw shaft 1 and the ball. The screw nut 2 can be positively moved in a relatively linear motion, that is, can be stroked, and the function as an actuator can be exhibited.

  In addition, when a rotational motion is forcibly input from the screw shaft 1, the motor M generates a magnetic field by generating a magnetic field due to an induced electromotive force or power from the power source, thereby generating an electromagnetic force. Since the torque that suppresses the rotational movement of the shaft 1 is generated, it functions to suppress the relative linear movement of the screw shaft 1 and the ball screw nut 2. That is, in this case, the torque generated by the electric power obtained by the motor M regenerating kinetic energy input from the outside and converting it into electric energy, or by the electric power supplied from the power source in addition to this regeneration. Thus, the relative linear motion of the screw shaft 1 and the ball screw nut 2 can be suppressed.

  Therefore, this electromagnetic suspension device can cause the motor M to function as both an actuator and a generator, so that the relative linear motion of the screw shaft 1 and the ball screw nut 2 can be suppressed, and at the same time, the function as an actuator can be utilized. Thus, the posture control of the vehicle body of the vehicle can be performed at the same time, so that the function as an active suspension can be exhibited.

  In order to control the current flowing through the winding 12 of the motor M, specifically, the U, V and W phase windings 12 are connected to the control device 20, and the motor M is connected to the control device 20. Is driven and controlled.

  As shown in FIG. 2, the control device 20 basically performs dq conversion on the current flowing in two phases of the three phases of the winding 12 to calculate a d-phase current value and a q-phase current value. Proportion for calculating the d-phase voltage command value and the q-phase voltage command value based on each current target value determined by the phase current calculation means 21 and the current target value calculation unit 26 and the d-phase and q-phase current values. The integration control unit 22, the three-phase conversion calculation means 23 for converting the d-phase voltage command value and the q-phase voltage command value into voltage command values for U, V, and W phases, and U, V of the three-phase brushless motor. , W, a current detector 24 for detecting a current value flowing in two phases, and a PWM circuit 25 as a motor drive circuit.

  The control device 20 includes the d-phase and q-phase current target values determined by the current target value calculation unit 26, and the d-phase and q-phase current values obtained as the calculation results of the two-phase current calculation means 21. The motor M is proportional-integral controlled based on the respective deviations. Note that proportional differential integration control may be performed by adding an element obtained by differentiating the deviation.

  Here, the current target value calculation unit 26 outputs the d-phase and q-phase current target values as torque commands to the proportional-plus-integral control unit 22 according to a predetermined control law. Vehicle speed, steering angle, and sprung and unsprung speed / acceleration, which are necessary information, are input to the current target value calculation unit 26 as voltage signals or the like from various sensors other than the rotation angle sensor 15 as appropriate. It has come to be. The expansion / contraction amount, stroke speed and expansion / contraction acceleration of the electromagnetic suspension device may be calculated from the rotation angle θ obtained from the rotation angle sensor 15, the pitch of the screw shaft 1, and the reduction ratio, and there is no need to provide a separate sensor. . For example, when Skyhook theory is adopted as the control law, the sprung speed in the vehicle may be input to the current target value calculation unit 26. In this case, the current target value The computing unit 26 computes d-phase and q-phase target current values as torque commands from the sprung speed and outputs them to the proportional-plus-integral control unit 22.

  The current value target calculation unit 26 basically calculates the q-phase current target value with the d-phase current target value set to 0 except during field-weakening control described later.

  Further, as the current detector 24, a non-contact type using a Hall element, a winding, or the like, or a current sensor that obtains a current value from a voltage drop of a resistor connected in series to each of the three-phase windings 12 is used. Good.

  The current detector 24 only needs to detect the current value flowing in two phases of the U, V, and W phases. This is described below from the electrical angle θ of the rotor R if the current values of the two phases are known. This is because it can be converted into d-phase and q-phase current values using the equation (1).

  Further, as shown in FIG. 3, the PWM circuit 25 includes a power supply E, six switching elements 41 that supply current to the windings 12 of the three phases of the motor M, and PWM pulse signals to the switching elements 41. The PWM circuit 25 includes a pulse generator (not shown) such as a multivibrator to be provided, and the PWM circuit 25 is configured to adjust the phase to each phase with a predetermined PWM duty ratio based on each voltage command value output from the proportional integration control unit 21. Supply current. The power supply E may be a battery mounted on the vehicle.

比例積分制御部２２は、各電流目標値ｉｄ*，ｉｑ*と電流値ｉｄ，ｉｑの各偏差εｄ，εｑを算出し、算出された偏差εｄ，εｑを積分して得られた積分値に所定の積分ゲインを乗じ、さらには、各偏差εｄ，εｑに所定の比例ゲインを乗算じ、積分ゲイン乗算後の値と比例ゲイン乗算後の値を加算して、各電圧指令値Ｖｄ，Ｖｑを出力する。 Then, using the electrical angle θ, the two-phase current calculation means 21 converts the current values iv and iu into d-phase and q-phase current values id and iq as shown in the following equation (1). The converted d-phase and q-phase current values id and iq are output to the proportional-plus-integral control unit 22.

The proportional-integral control unit 22 calculates each deviation εd, εq between each current target value id *, iq * and the current value id, iq, and sets the predetermined integral value obtained by integrating the calculated deviations εd, εq. Is multiplied by the integral gain, and each deviation εd, εq is multiplied by a predetermined proportional gain, and the value after multiplication of the integral gain and the value after multiplication of the proportional gain are added to output each voltage command value Vd, Vq. To do.

また、このモータ制御装置は、リミッタ２７を備えており、このリミッタ２７は、三相変換演算手段２３が出力する上記各電圧指令値Ｖｕ，Ｖｖ，Ｖｗのうち、ＰＷＭ開度が全開、すなわち、ＰＷＭデューティ比が最大値以上となる場合に、ＰＷＭデューティ比を最大値とする値に電圧指令値Ｖｕ，Ｖｖ，Ｖｗを制限する。 Further, the d-phase voltage command value Vd and the q-phase voltage command value Vq are input to the three-phase conversion calculation means 23 that converts the voltage command values of the U, V, and W phases as described above. The conversion calculation means 23 converts the d-phase voltage command value Vd and the q-phase voltage command value Vq into actual U, V, W phase voltage command values Vu, Vv, Vw by the calculation of the following equation (2). The converted voltage command values Vu, Vv, and Vw are output to the PWM circuit 25.

Further, the motor control device includes a limiter 27. The limiter 27 has the PWM opening fully opened among the voltage command values Vu, Vv, and Vw output from the three-phase conversion calculation unit 23, that is, When the PWM duty ratio is greater than or equal to the maximum value, the voltage command values Vu, Vv, and Vw are limited to values that maximize the PWM duty ratio.

  Each unit other than the PWM circuit 25 of the control device 20 amplifies each signal output by hardware, specifically, for example, the current detector 24, the rotation angle sensor 15, and various sensors necessary for vehicle body posture control. Amplifier, converter for converting analog signal into digital signal, storage device such as CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), crystal oscillator and these It is configured as a well-known computer system (not shown) provided with a bus line that can output voltage command values Vu, Vv, Vw to the PWM circuit 25. In addition, each part other than the PWM circuit 25 of the control apparatus 20 as this hardware may be integrated into ECU mounted in a vehicle.

  In this case, the control processing procedure for calculating the target value in the current target value calculation unit 26 and the processing procedure of field weakening control to be described later are stored in advance in a ROM or other storage device as a program.

  By the way, in this electromagnetic suspension device, when the rotor R of the motor M rotates, the magnetic flux of the driving magnet 14 of the rotor R crosses the winding 12, so that an induced electromotive force is generated in the winding 12 and a regenerative current flows. The current due to the power source E provided in the PWM circuit 25 and the regenerative current due to the induced electromotive force flow through the winding 12. However, the regenerative power that can charge the power source E by the induced electromotive force of the winding 12 of the motor M The regenerative region K that can be performed is a range surrounded by the stroke speed axis and the tangent line S that passes through the origin and is in contact with the stroke speed and load curve in the short circuit characteristic T. As shown in FIG. You can decide. The rotational speed of the rotor R of the motor M is proportional to the relative speed of the screw shaft 1 and the ball screw nut 2, that is, the stroke speed of the electromagnetic suspension device, and the output torque of the motor M depends on the load of the electromagnetic suspension device. Since it is proportional, the short circuit characteristic T is obtained by converting the short circuit characteristic, which is the relationship between the rotational speed and torque of the motor M itself, into the relationship between the stroke speed and the load of the electromagnetic suspension device. In the present specification, the term “short-circuit characteristic” refers to the relationship between the stroke speed and the load of the electromagnetic suspension device when the motor is short-circuited as described above unless otherwise specified.

  The load in the short-circuit characteristic T, which is the relationship between the stroke speed and the load of the electromagnetic suspension device in a state where the windings 12 of each phase of the motor M are short-circuited, takes the maximum value within the most frequently used stroke speed range. Set to

  Here, the stroke speed is the linear relative movement speed of the ball screw nut 2 in the axial direction with respect to the screw shaft 1, and the load is the straight line between the screw shaft 1 and the ball screw nut 2 generated by the torque generated by the motor M. It is a force that suppresses or promotes relative movement.

  In FIG. 4, on the stroke speed axis, when the stroke speed in the direction in which the electromagnetic suspension device contracts is positive for convenience, the right side of the origin indicates the stroke speed in the contraction direction, and the electromagnetic suspension device extends. If the stroke speed is a negative value for convenience, the left side of the origin indicates the stroke speed in the extension direction. On the other hand, if the load in the direction of extending the electromagnetic suspension device is positive for the load axis for the sake of convenience, the portion above the origin indicates the load in the expansion direction, and the load in the direction of contracting the electromagnetic suspension device is negative for convenience. The value below the origin indicates the load in the contraction direction.

  Accordingly, in FIG. 4, the first quadrant shows a state in which the electromagnetic suspension device strokes in the contracting direction, but generates a load that suppresses the stroke, and the second quadrant shows the electromagnetic suspension device. Indicates a state in which a load is generated in a direction that promotes the stroke while a stroke is generated in the extending direction, and the third quadrant is a load that suppresses the stroke in the extending direction. The fourth quadrant shows a state in which a load that promotes the stroke is generated while the stroke is in the contracting direction.

  As described above, the regenerative region K is a range (shaded area in FIG. 4) surrounded by the stroke speed axis and the tangent line S that passes through the origin and touches the stroke speed and load curve in the short circuit characteristic T. Further, the inclination at the tangent S includes the torque constant of the motor M and the overall resistance of the winding 12 and the PWM circuit 25, that is, the internal resistance of the lead wire in addition to the resistor in the circuit. However, since the value is determined by the overall resistance, the regeneration region K can also be determined by setting the torque constant and the overall resistance. Further, the inclination of the tangent S can be adjusted by the lead of the screw shaft 1.

  Note that a horizontal line a that determines the maximum or minimum load of each quadrant in FIG. 4 is a load-generating region determined by limiting the q-phase current target value iq * calculated by the current target value calculation unit 26. The curve b is also a line that divides the area where the load can be generated from the area where the load is impossible.

  The short-circuit characteristic T described above draws a curve in which the load reaches a peak at a certain stroke speed as the stroke speed is increased, and the load gradually decreases as the stroke speed increases thereafter. . That is, until the load peak is reached, the current obtained by power generation caused by forcibly rotating the rotor R of the motor M flows through the windings 12 of each phase so as to effectively generate torque that suppresses the stroke. However, when the stroke speed is increased to the extent that the load peak is exceeded, the reactive current that does not contribute to torque increases and the load decreases. This does not affect the regeneration region K.

  Note that the overall resistance of the winding 12 and the PWM circuit 25 of the motor M, that is, the overall resistance including the internal resistance of the lead wire in addition to the resistors in the circuit, and further the lead of the screw shaft 1 are changed. The short-circuit characteristic T can be compressed and expanded along the stroke speed axis. If the resistance is decreased or the lead of the screw shaft 1 is decreased, the short-circuit characteristic T is compressed toward the origin along the stroke speed axis. On the contrary, if the resistance is increased or the lead of the screw shaft 1 is increased, the short-circuit characteristic T is extended toward the high speed side along the stroke speed axis, whereby the inclination of the tangent S can be changed. . Further, if the torque constant is increased, the inclination of the tangent line S can be increased, and conversely, if the torque constant is decreased, the inclination of the tangent line S can be decreased. In particular, by reducing the overall resistance, increasing the torque constant, reducing the lead of the screw shaft 1, or any combination thereof, the electromagnetic suspension device can achieve a stroke speed. Even if it is low, a large load is obtained, and the regenerative region K also becomes large.

  Here, in this electromagnetic suspension device, the short-circuit characteristic T is set so that the load reaches a peak in a stroke speed range that is frequently used while the vehicle is running, and the load in the short-circuit characteristic T is within the frequently used stroke speed range. Is set to take the maximum value.

  Then, since the regeneration region K within the stroke speed range that is frequently used while the vehicle is running increases, the opportunity for charging the power source E by regeneration can be increased, and energy regeneration by the motor M can be performed efficiently. It is possible to ensure power saving.

  In addition, in this electromagnetic suspension device, there is no need for special control in order to perform efficient regeneration, so that the behavior of the vehicle is not switched for the purpose of power saving control, and the vehicle is boarded. It is possible to improve the riding comfort in the vehicle without causing the person to feel uncomfortable or uneasy.

  As can be understood from the above description, the inclination of the tangent S that passes through the origin and is in contact with the stroke speed and load curve in the short-circuit characteristic T is the total resistance, torque constant, and winding of the motor M and the PWM circuit 25. Since it can be determined by the lead of the screw shaft 1, the load in the short-circuit characteristic T is maximized within a predetermined stroke speed range by setting the overall resistance, torque constant, and torque constant and lead of the screw shaft 1. It can be set to take.

  By the way, in the vehicle, a spring element is interposed between the unsprung member and the unsprung member in order to make it difficult to transmit the vibration input to the unsprung member to the unsprung member during traveling of the vehicle. In order to suppress vibration, a shock absorber is usually interposed between an unsprung member and a sprung member, and the expansion side and contraction side of the shock absorber applied to light, small, and ordinary automobiles are generated. From FIG. 5 showing the setting frequency situation of the load, on the expansion side, there are many shock absorbers that generate a load in the range of 200N to 1000N centering around 600N, and on the contraction side, there are about 0N to 600N centering around 300N. Many shock absorbers generate a load within the range, and in order to suppress the above-described vehicle body vibration, the shock absorber needs to generate a load of about 1000 N on the expansion side and about 600 N on the contraction side. .

  Moreover, from FIG. 6 which shows the frequency of the expansion / contraction stroke speed of the shock absorber during traveling of the vehicle, the shock absorber is -0.1 m / s, assuming that the contraction side stroke speed is a negative value and the expansion side stroke speed is a positive value. Is frequently used within a stroke speed range of 0.1 m / s.

  As can be understood from the above, the stroke speed frequently used in the expansion and contraction of the shock absorber is within the range of 0.1 m / s (in the case where a positive or negative sign is attached in the expansion and contraction direction, it is 0 to 0.1 m / s or more. .. Within a range of 1 m / s or less), and the required generated load is 1000 N or less.

  Therefore, specifically, the frequently used stroke speed range in which the load in the short-circuit characteristic T of the above-described electromagnetic suspension device is maximized is set to a range in which the expansion / contraction stroke speed is 0.1 m / s or less. .

  Accordingly, since the regeneration region K within the stroke speed range that frequently appears during vehicle travel increases, the opportunity for charging the power source E by regeneration can be increased, and energy regeneration by the motor M can be performed efficiently. Needless to say, the power saving can be ensured, and further, the riding comfort in the vehicle can be improved. However, the electromagnetic suspension device can be obtained by standardizing the frequently used stroke speed range in this way. This improves the versatility and reduces the manufacturing cost.

  At this time, if the tangent S is set so as to pass above a point where the stroke speed is 0.1 m / s and the load is 1000 N, the stroke in which the electromagnetic suspension device is frequently used. The entire load range that needs to be generated as a shock absorber within the speed range is covered in the regeneration region K.

  Therefore, in the case where the electromagnetic suspension device is frequently used, when the electromagnetic suspension device is frequently used, the power source E is always regenerated and the power source E is not consumed and the power of the power source E is not consumed. It is possible to reliably save power, prevent a situation where the power source E is raised, and further, it is optimal for a vehicle using a drive source such as an electric vehicle as a motor.

  In this electromagnetic suspension device, it is possible to save power, but it is necessary to increase the torque constant to some extent in order to generate a load that can control the attitude of the vehicle even if the stroke speed is low. However, as the torque constant increases, the amount of power generated by the motor M increases. Therefore, the controllable curve P that determines the controllable region W in the second and fourth quadrants becomes smaller as the stroke speed at which the induced electromotive force generated in the winding 12 of the motor M exceeds the voltage of the power source E is reduced as it is. The load that can be generated in the second and fourth quadrants is reduced, and as a result, the controllable area is reduced.

  Therefore, in this electromagnetic suspension device, field weakening control is performed in order to shift the stroke speed at which the induced electromotive force generated in the winding 12 of the motor M exceeds the voltage of the power source E to the high speed side.

  The field weakening control is performed when the induced electromotive force exceeds or exceeds the voltage of the power source E in a state where the motor M is controlled in accordance with a normal control law.

  More specifically, in this field weakening control, since a small negative current is applied to the d phase to reduce the magnetic flux, the power generation amount is also reduced.

  Then, by the field weakening control, the controllable curve P in FIG. 7 is shifted to the field weakening control curve P ′, and the controllable region W (shaded portion in FIG. 7) is expanded. Further, since the controllable curve P in FIG. 4 defines the first quadrant and the third quadrant regenerative region K, the regenerative region K is shifted by shifting to the weak field control time curve P ′ by the weak field control. Can be enlarged.

  Therefore, according to this electromagnetic suspension device, the short-circuit characteristic T and the torque constant are set so as to expand the regenerative region K within the frequently used stroke speed range, and as a result, the torque constant increases and the induced electromotive force increases. Even in the case where the stroke speed exceeding the voltage of the power supply E becomes low, it is possible to prevent the controllable area W of the second and fourth quadrants from decreasing, and at the same time, the regeneration area K is expanded and consumed. Electric power can be reduced.

  In addition, since the controllable area W in the second and fourth quadrants is originally an active control area, the electromagnetic suspension device cannot generate a sufficient load during active control. There is no invitation.

  In the field weakening control, specifically, the current value to be passed through the d phase is determined by the current target value calculation unit 26. In the current target value calculation unit 26, the rotation angle θ input from the rotation angle sensor 15 is determined. An induced electromotive force in which the expansion / contraction stroke speed of the electromagnetic suspension device obtained based on the rotational angular velocity ω obtained by differentiation and the pitch of the screw shaft 1 and the reduction ratio if the reduction gear is connected exceeds the voltage of the power source E is obtained. The field-weakening control is performed when the generated speed Z is reached or when the speed reaches a speed lower than the absolute value of the speed Z by a predetermined speed.

  When the field weakening control is performed when the speed Z is recognized, basically, as shown in FIG. 8, the current target value calculation unit 26 sets the d-phase current target value to a predetermined value of the negative current. Subsequently, the proportional-integral control unit 22 calculates the d-phase voltage command value and the q-phase voltage command value, and the three-phase conversion calculation means 23 calculates the d-phase voltage command value and the q-phase voltage command value as U, V, W. This is performed by converting the voltage command value of each phase and outputting it to the PWM circuit 25, whereby the controllable region W and the regeneration region K are expanded. The predetermined value is set such that the motor M does not cause demagnetization.

  Further, when the field weakening control is performed at the time when the speed Z is recognized, the current target value calculation unit 26 has a d-phase proportional to the magnitude at which the absolute value of the stroke speed exceeds the speed Z, as shown in FIG. When the current target value is gradually decreased to the negative side and the absolute value of the stroke speed exceeds the speed Z and reaches an arbitrary speed Z ', the d-phase current target value is set to a predetermined value of the negative current, and the absolute value of the subsequent stroke speed You may make it fix to the said predetermined value with respect to the increase in a value. The arbitrary speed Z ′ may be set to a value that is optimal for the vehicle through experiments or the like.

  In this way, by gradually increasing the degree of field weakening according to the stroke speed, the demagnetization of the motor M can be surely prevented, and the d-phase current target value is suddenly set to a predetermined value with the speed Z. Even when field-weakening control is turned on and off in the vicinity of speed Z, the d-phase current is prevented from becoming excessively vibrational and the control becomes complicated, and the practicality is improved.

  Further, when the field weakening control is performed at the time when the absolute value of the stroke speed is recognized when the speed Z ″ is smaller than the speed Z, basically, as shown in FIG. The d-phase current target value is gradually reduced to the negative side in proportion to the magnitude that exceeds the speed Z ″, and when the absolute value of the stroke speed exceeds the speed Z ″ and reaches the speed Z, the d-phase current target value is reduced to the negative current. The predetermined value is set to the predetermined value, and the predetermined value is fixed to the subsequent increase in the absolute value of the stroke speed.

  Thus, even when the stroke speed is rapidly increased in the vicinity of the speed Z by performing field-weakening control from the speed Z "whose absolute value of the stroke speed is lower than the speed Z at which the induced electromotive force exceeds the voltage of the power supply E, First, the field-weakening control is performed and the controllable area W is expanded in each quadrant, so that the situation where the load is generated by the electromagnetic suspension device is prevented from being overloaded. Riding comfort can be improved, and in particular, since there is no load shortage during active control, vehicle body posture control can be performed reliably, even when field-weakening control is turned on and off near speed Z ″. The d-phase current is excessively oscillatory and the control is prevented from becoming complicated, thereby improving the practicality.

In addition, when the field weakening control is performed when the absolute value of the stroke speed is recognized as a speed Z ″ smaller than the speed Z, the absolute value of the stroke speed is input to the current target value calculation unit 26 as shown in FIG. in proportion to the magnitude of greater than Z "is gradually decreased to d-phase current target value on the negative side, when the absolute value of the stroke speed reaches the speed Z ₃ exceeds the speed Z predetermined value of d-phase current target value minus current The absolute value of the stroke speed thereafter may be fixed to the predetermined value.

Therefore, even if the stroke speed is suddenly increased in the vicinity of the speed Z by performing field-weakening control from the speed Z ″ whose absolute value of the stroke speed is lower than the speed Z at which the induced electromotive force exceeds the voltage of the power source E, it is first Thus, the field-weakening control is performed and the controllable area W is expanded in each quadrant, so that a situation in which an excess or shortage of the load to be generated by the electromagnetic suspension device is prevented is prevented. It is possible to improve the comfort, and it is of course possible to reliably perform the vehicle body posture control since there is no load shortage during active control, but in this case as well, the speed Z ₃ exceeding the speed Z Since the field weakening level is increased until the value reaches, the d-phase current becomes excessively oscillating even when the field weakening control is turned on and off near the speed Z. The control is prevented from becoming complicated and the practicality is improved.

  9 to 11, in the field weakening control, the d-phase current is linearly changed. Of course, this may be smoothly changed in a curved line. is there.

  In addition, the electromagnetic suspension device is, like the other electromagnetic suspension devices shown in FIG. 12, a cylinder 31 that is one member, a rod 32 that is the other member that exhibits relative movement with respect to the cylinder 31, and at least suppressing the relative movement. You may make it comprise with possible motor M2.

  Specifically, the cylinder 31 is connected to one of a sprung member and an unsprung member of the vehicle, and a rod 32 connected to the other of the sprung member and the unsprung member of the vehicle is passed through the cylinder 31. .

  The motor M2 includes a driving magnet 33 that is mounted on the outer periphery of the rod 32 so that S poles and N poles appear alternately in the axial direction, and a winding 34 that faces the driving magnet 33 in the cylinder 31. The windings 34 are arranged so that the U, V, and W phases are alternately arranged along the axial direction of the cylinder 31 over a predetermined length.

  Note that the winding 34 provided in the cylinder 31 is formed in an annular shape, and at least the inner peripheral side is coated with resin or the like. The inner periphery of the winding 34 and the outer periphery of the rod 32 or the drive magnet 33 An annular bearing (not shown) is disposed between them, and the shaft 32 is prevented from shaking with respect to the cylinder 31.

  That is, in this other electromagnetic suspension device, a so-called linear motor type configuration in which the drive magnet 33 moves relative to the winding 34 when the rod 32 advances and retreats relative to the cylinder 31 and exhibits relative motion. Even in the other electromagnetic suspension devices, similarly to the electromagnetic suspension device in the above-described embodiment, the motor M2 functions as both a motor and a generator. The short-circuit characteristic T of the motor M2 is set so that the load reaches a peak below the stroke speed that is frequently used while the vehicle is running, that is, the load in the short-circuit characteristic T is within the frequently used stroke speed range. Is set to take the maximum value.

  Therefore, even in this other electromagnetic suspension device, since the regeneration region K within the stroke speed range that frequently appears during vehicle travel increases, the opportunity to charge the power source E by regeneration can be increased, and the motor Energy regeneration by M2 can be performed efficiently, and power saving can be ensured.

  In addition, in this electromagnetic suspension device, there is no need for special control in order to perform efficient regeneration, so that the behavior of the vehicle is not switched for the purpose of power saving control, and the vehicle is boarded. It is possible to improve the riding comfort in the vehicle without causing the person to feel uncomfortable or uneasy.

  This is the end of the description of the embodiment of the present invention, but the scope of the present invention is of course not limited to the details shown or described.

It is a conceptual diagram of the electromagnetic suspension apparatus in one embodiment. It is a system diagram of a motor control device. It is a figure which shows a PWM circuit. It is a figure which shows the short circuit characteristic which is the relationship between the stroke speed and load of an electromagnetic suspension apparatus in the state which short-circuited the motor. It is a figure which shows the setting frequency situation of the generation | occurrence | production load of the expansion | extension side and shrinkage | contraction side of the shock absorber applied to a light, small size, and a normal motor vehicle. It is a figure which shows the frequency of the expansion-contraction stroke speed of the buffer during driving | running | working of a vehicle. It is a figure which shows the controllable area | region of an electromagnetic suspension apparatus. It is a figure which shows d phase current with respect to the stroke speed at the time of field weakening control. It is a figure which shows d phase current with respect to the stroke speed at the time of field weakening control. It is a figure which shows d phase current with respect to the stroke speed at the time of field weakening control. It is a figure which shows d phase current with respect to the stroke speed at the time of field weakening control. It is a conceptual diagram of another electromagnetic suspension apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Screw shaft which is one member 2 Ball screw nut 10 which is the other member Frame 11 Stator core 12, 33 Winding 13 Shafts 14, 34 Driving magnet 15 Rotation angle sensor 20 Controller 21 Two-phase current calculation means 22 Proportional integral control unit 23 Phase conversion calculation means 24 Current detector 25 PWM circuit 26 Current target value calculation unit 27 Limiter 31 Tube 32 as one member Rod 41 as the other member Switching element E Power source M Motor R Rotor

Claims (10)

Relationship between stroke speed and load when a motor winding is short-circuited in an electromagnetic suspension device including one member, the other member that exhibits relative motion with respect to the one member, and a motor that can suppress at least the relative motion. The short circuit characteristic is set so that a tangent line passing through the origin and touching the curve of the stroke speed and load in the short circuit characteristic passes above a point where the stroke speed is 0.1 m / s and the generated load is 1000 N. An electromagnetic suspension device. Relationship between stroke speed and load when a motor winding is short-circuited in an electromagnetic suspension device including one member, the other member that exhibits relative motion with respect to the one member, and a motor that can suppress at least the relative motion. The electromagnetic suspension device is characterized in that the load in the short-circuit characteristic is set to take a maximum value within a frequently used stroke speed range. One or both of the motor winding and drive circuit overall resistance and motor torque constant is the relationship between stroke speed and load when the motor winding is short-circuited. The electromagnetic suspension device according to claim 1, wherein the electromagnetic suspension device is set so as to take a maximum value. The one member exhibits a rotational motion when the other member exhibits a linear relative motion with respect to the one member and the other member, and the rotational motion of the one member is transmitted to the motor. The electromagnetic suspension device described. The electromagnetic suspension device according to any one of claims 1 to 4, wherein the load in the short-circuit characteristic takes a maximum value when the stroke speed is 0.1 m / s or less. The short-circuit characteristic is set so that the tangent line passing through the origin and touching the stroke speed and load curve in the short-circuit characteristic passes above the point where the stroke speed is 0.1 m / s and the generated load is 1000 N. The electromagnetic suspension apparatus according to claim 2, wherein the electromagnetic suspension apparatus is characterized in that: The electromagnetic suspension device according to any one of claims 1 to 6, wherein the motor is subjected to field weakening control. 8. The electromagnetic suspension device according to claim 7, wherein the field weakening control is performed by controlling the d-axis current based on the expansion / contraction stroke speed. 9. The electromagnetic suspension device according to claim 7 or 8, wherein the field weakening control is started when the induced electromotive force of the winding in the motor becomes at or near the expansion / contraction stroke speed exceeding the power supply voltage. 10. The electromagnetic suspension device according to claim 7, wherein the d-phase current during field-weakening control is gradually decreased as the expansion / contraction stroke speed increases until reaching a predetermined value.

Images