DE102020209217A1 - Motor control device - Google Patents

Abstract

A motor control device for controlling a polyphase motor (21) for SBW control is provided, which is capable of reducing heat generation in circuit elements by dissipating load energy in accordance with an operating sequence of motor control, the number of elements being smaller. In the motor drive device, a control circuit (40, 90) controls electrical conduction of a drive current to respective windings (21a to 21c) of respective phases. In the electrical conduction control that is carried out while driving the polyphase motor (21), (i) the control circuit (40, 90) maintains an electrically conductive switching element (31 to 33) in an electrical conduction path to the winding of a during a driving current increase period electrically conductive phase continuously in an on state; the control circuit (40, 90) alternately turns on the electrically conductive switching element (31 to 33) and a reverse flux switching element (34 to 36) by PWM control in a drive current holding period; and (iii) the control circuit (40, 90) maintains the electrically conductive switching element (31 to 33) and the reverse flux switching element (34 to 36) in an off state in a drive current decay period.

Description

The present invention relates to a motor drive device.

Shift-by-wire control (hereinafter also referred to as SBW) is known as control of a vehicle shift mechanism by a motor drive device. In the SBW control, a drive of a switched reluctance motor (SRM) as a three-phase motor is controlled by a motor drive circuit that is included in a motor control unit, and a rotation of the motor is transmitted to a shaft via gears, whereby a Switching range change mechanism is controlled with a special angle. In this way, switching positions such as a parking position (P), a reverse position (R), a neutral position (N) and a drive position or forward position (D) are changed or switched.

In the case of such an activation control, the motor activation device, for example, keeps a switching element, which is arranged in an electrical conduction path to a coil or winding of an electrically conductive phase, which is to be made electrically conductive, in a switched-on state or at a point in time when a control current rises. Switch-on state in order to shorten the rise time of the control current. Since a sufficient torque is easily ensured at the time of starting electrical conduction, driving of the motor at high speed is realized. In the event of a drop or decay of the control current, the switching element that corresponds to the energized phase is kept in a switched-off state, and thus the current quickly disappears and the torque becomes zero.

In such a case, in a configuration in which an H-bridge circuit is used as an electric conduction circuit to the motor, freewheeling diodes are used for reversing a motor drive current. As a result, a forward voltage Vf of the diode is generated during electrical conduction to the motor coil or motor winding even when the current is reversed, and heat is continuously generated in the diodes depending on the temporal integration of the power, which is determined by “drive current x forward voltage “Is represented. For this reason, it is necessary to use a diode having a high thermal resistance in terms of reverse flux, resulting in increased cost and size.

On the other hand, there is a technique of controlling a potential difference generated in a reverse flux path at the time of reversing the drive current during electrical conduction to the motor winding to almost zero using a switching element such as a MOS transistor. In such a technique, however, the potential difference is controlled in accordance with the magnitude of the drive current in order to dissipate energy that is stored in the motor winding. That is, control according to the operational sequence of the motor drive circuit is not performed. In addition, since the H-bridge circuit is used, the number of elements constituting the circuit increases, resulting in increased cost and size. The configuration and technique described above are, for example, in FIG JP 2012 - 125 096 A and in the JP 2000 - 358 397 A described.

It is an object of the present invention to provide a motor drive apparatus for performing SBW control which is capable of reducing heat generation in circuit elements by dissipating load energy in accordance with an operation sequence of motor driving while reducing the number of elements is.

According to one aspect of the present invention, a motor control device is designed to control a multiphase motor, which has three or more phases, for shift-by-wire control (electrical switching). The motor control device contains: a plurality of electrically conductive switching elements which are arranged in electrical conduction paths to coils or windings of the respective phases of the polyphase motor; a plurality of reverse flux switching elements arranged in reverse flux paths of the coils of the respective phases; a plurality of diodes connected in parallel with the reverse flux switching elements; and a control circuit which is designed to carry out an electrical conduction control of a drive current to the respective coils or windings. In the electrical conduction control of the drive current to the respective coils or windings, which is carried out while the polyphase motor is being driven, (i) the control circuit controls the corresponding electrically conductive switching element in the electrical path to the coil in a drive current increase period or duration or winding an electrically conductive phase in such a way that it is continuously kept in a switched-on state; (ii) the control circuit controls the corresponding electrically conductive switching element and the corresponding reverse flux switching element by means of a PWM control in a drive current holding period or period of time in such a way that they are switched on alternately with one another; and (iii) the control circuit controls both the corresponding electrically conductive switching element and the corresponding reverse flux switching element in a drive current decay period or duration in such a way that they are kept in an off state.

Before describing the operations, the energy dissipation of the reverse current, which is caused in connection with the electrical line to the coil or winding, is described. The time required for the energy to dissipate the reverse current is monitored by the potential difference which is caused in the reverse flux switching element or the diode in the reverse flux path.

With the electrical line to the coil or winding described above, it is not necessary to carry out the energy dissipation during the drive current holding period. When the drive current is reversed during the drive current holding period since the reverse flux switching element is turned on in the reverse flux path, the potential difference becomes substantially zero. Therefore, the above-described switching element can be prevented from generating heat.

According to the configuration described above, in the electric conduction control of the drive current to the coils of the respective phases, the control circuit keeps the electrically conductive switching element in the electric conduction path continuously in the on state during the drive of the polyphase motor during the drive current increase period. In the drive current holding period, the control circuit switches on the electrically conductive switching element and the reverse flux switching element alternately with one another by means of PWM control. Accordingly, during the driving current holding period, heat generation in the reverse flux switching element and the diode due to the reverse current can be reduced.

In addition, the control circuit keeps both the electrically conductive switching element and the reverse flux switching element in the off state during the drive current decay period. As a result, the reverse current caused by stopping power conduction to the coil of the electrically conductive phase can flow through the reverse flux path through the diode instead of through the reverse flux switching element during the drive current decay period. As a result, the power dissipation is facilitated and the current can be brought to zero quickly.

In the case in which such a motor control device is used for the SBW control, a small operating angle of the motor in a control and the length of the interval for a respective control are operating characteristics. In the SBW control, therefore, the frequency of energy dissipation by the diode connected in parallel with the reverse flux switching element in a control performed to move or change the switching position can be lower than in other motor products. Since the interval for each drive is long, even if the switching element generates heat, the heat can be dissipated by the next drive.

• 1 ein Diagramm, das eine elektrische Konfiguration einer Motoransteuerungsvorrichtung bzw. Elektromotoransteuerungsvorrichtung gemäß einer ersten Ausführungsform darstellt;
• 2 ein Diagramm, das eine schematische Struktur eines SBW-Systems darstellt;
• 3 ein Zeitdiagramm einer Motoransteuerungssteuerung gemäß der ersten Ausführungsform;
• 4 ein Flussdiagramm der Motoransteuerungssteuerung gemäß der ersten Ausführungsform;
• 5 ein Flussdiagramm einer Motoransteuerungssteuerung gemäß einer zweiten Ausführungsform;
• 6 ein Zeitdiagramm der Motoransteuerungssteuerung gemäß der zweiten Ausführungsform;
• 7 ein Diagramm, das eine elektrische Konfiguration einer Motoransteuerungsvorrichtung gemäß einer dritten Ausführungsform darstellt;
• 8 ein Flussdiagramm einer Motoransteuerungssteuerung gemäß der dritten Ausführungsform;
• 9 ein Diagramm, das eine elektrische Konfiguration einer Motoransteuerungsvorrichtung gemäß einer vierten Ausführungsform darstellt; und
• 10 ein Diagramm, das eine elektrische Konfiguration einer Motoransteuerungsvorrichtung gemäß einer fünften Ausführungsform darstellt.

The above and other objects, features and advantages of the present invention will become apparent from the following detailed description with reference to the accompanying drawings, in which like parts are designated by the same reference numerals. Show it:

• 1 is a diagram illustrating an electrical configuration of a motor drive device according to a first embodiment;
• 2 Fig. 3 is a diagram showing a schematic structure of an SBW system;
• 3 a time chart of a motor drive control according to the first embodiment;
• 4th a flowchart of the motor drive control according to the first embodiment;
• 5 a flow chart of a motor drive control according to a second embodiment;
• 6th a timing chart of the motor drive control according to the second embodiment;
• 7th is a diagram showing an electrical configuration of a motor drive device according to a third embodiment;
• 8th a flowchart of a motor drive control according to the third embodiment;
• 9 is a diagram showing an electrical configuration of a motor drive device according to a fourth embodiment; and
• 10 is a diagram illustrating an electrical configuration of a motor drive device according to a fifth embodiment.

First embodiment

In the following, the first embodiment of the present invention will be explained with reference to FIG 1 to 4th described.

Like it in 1 shown includes a motor drive device 100 a motor unit 20th and an engine control unit 30th . The motor control device 100 receives electric power from a drive power source such as a vehicle battery 1 . The motor control device 100 controls the activation of a three-phase motor (electric motor) 21st the motor unit 20th , whereby the control of an SBW system via a drive power transmission unit 2 is controlled. A rotational force exerted by the three-phase motor 21st is outputted to a range switching mechanism (hereinafter referred to simply as a switching mechanism) 4 via a shaft 3 as an output shaft and is transmitted to the driving force transmission unit 2 transfer.

The motor unit 20th contains the three-phase motor 21st , a coding sensor 22nd and a speed reduction mechanism 23 consisting of gears. The rotational force from the three-phase motor 21st is made by the speed reduction mechanism 23 on the wave 3 transfer. The three-phase motor 21st consists of a switched reluctance motor (SRM) and has a rotor which has a magnetic body with a predetermined number of salient pole sections. The three-phase motor 21st contains coils or windings 21a , 21b and 21c of a stator corresponding to three phases, that is, a U phase, a V phase and a W phase. The rotor is rotated by attractive forces created by directing DC currents to these windings 21a , 21b and 21c caused. First ends of the windings 21a to 21c are commonly connected to a common connection point, and the common connection point is to a power supply line L1 connected. Second ends of the windings 21a to 21c selectively pass currents through the motor control unit 30th .

The coding sensor 22nd detects the rotational position of the rotor of the three-phase motor 21st . The engine control unit 30th receives a rotational position signal from the encoding sensor 22nd . The rotational force of the shaft of the three-phase motor 21st is made by the speed reduction mechanism 23 decreased and then on the wave 3 transfer.

The engine control unit 30th includes six n-channel MOS transistors 31 to 36 and a control circuit 40 . The six MOS transistors 31 to 36 have respective body diodes or body diodes (hereinafter referred to simply as diodes) 31a to 36a. The six MOS transistors 31 to 36 contain electrically conductive MOS transistors 31 to 33 and reverse flux MOS transistors 34 to 36 . The electrically conductive MOS transistors 31 to 33 are arranged in correspondence with the three phases, i.e. the U phase, the V phase and the W phase, and serve as electrically conductive switching elements for conducting control currents as motor control currents for energizing the windings 21a to 21c . The reverse flux MOS transistors 34 to 36 are arranged in correspondence with the three phases and serve as reverse flux switching elements for reversing the drive current. The electrically conductive MOS transistors 31 to 33 are referred to below simply as electrically conductive MOSs 31 to 33 and are designated in the drawings with E-MOS. The reverse flux MOS transistors 34 to 36 are hereinafter referred to simply as reverse flux MOSs 34 to 36 and are designated in the drawings by R-MOS.

The engine control unit 30th has terminals A and B that correspond to positive and negative terminals of the vehicle battery, respectively 1 are coupled and a DC voltage is applied to them. The connection A is with the power supply line L1 and the terminal B is connected to a power supply line L2 via a current detection resistor 37 connected. In a configuration where a relay or an upper ECU is connected to the vehicle battery 1 connected are the positive and negative terminals of the vehicle battery 1 via the relay or the upper ECU to port A and port B of the engine control unit 30th connected.

The electrically conductive MOS 31 and the reverse flux MOS 34 are in series between the power supply line L1 and the power supply line L2 switched. Similarly, the electrically conductive MOS 32 and the reverse flux MOS 35 in series between the power supply line L1 and the power supply line L2 switched, and the electrically conductive MOS 33 and the reverse flux MOS 36 are in series between the power supply line L1 and the power supply line L2 switched. The electrically conductive MOSs 31 to 33 are on a low side or low side or negative voltage side, and the reverse flux MOSs 34 to 36 are on a high side or a side of high or higher or positive voltage. The power supply line L1 is connected to the common connection point to which the first ends of the windings 21a to 21c of the three-phase motor 21st are connected together. A common connection point between the reverse flux MOS 34 and the electrically conductive MOS 31 , a common connection point between the reverse flux MOS 35 and the electrically conductive MOS 32 and a common connection point between the reverse flux MOS 36 and the electrically conductive MOS 33 are corresponding to the second ends of the windings 21a to 21c connected.

The control circuit 40 contains a computing circuit 41 and a drive circuit 42 . In particular, the control circuit 40 provided by a microcomputer. The control circuit 42 applies gate drive signals to gates of the MOS transistors 31 to 36 at. The computing circuit 41 controls an activation of the electrically conductive MOSs 31 to 33 and the reverse flux MOS 34 to 36 via the control circuit 42 . The computing circuit 41 uses a terminal voltage of the current detection resistor 37 to detect a motor drive current Im.

2 Fig. 10 shows a schematic structure of the range changing mechanism 4th the SBW system and a driving force transmission unit 2 a parking lock activated by the engine control device 100 are controlled, represents. The control of the motor 20th is controlled by the engine control unit 30th controlled, and the engine 20th serves as a drive source of the changing mechanism 4th .

The change mechanism 4th contains a locking plate 5 that on the shaft 3 is fixed, a locking spring 6th and similar. The change mechanism 4th transmits the rotational driving force of the shaft 3 by the speed reduction mechanism 23 is output to a manual valve 7th and a parking lock part 8th the driving force transmission unit 2 . The locking plate 5 has a tenon 5a on that in the direction along the shaft 3 protrudes and engages a groove at the top of the manual valve 7th on.

When the lock plate 5 by the engine 20th is driven in rotation, the pin 5a rotated, and the manual valve 7th is driven in its axial direction by a driving force passing through a section of the manual valve 7th that is transferred into the tenon 5a intervenes, moved back and forth. The manual valve 7th is in a valve body 9 arranged. When the manual valve 7th moved back and forth in the axial direction, the shift range or shift position range is changed.

The locking plate 5 has four recesses 5b on an outer circumference which the locking spring 6th contacted the manual valve 7th to hold at the respective positions that correspond to the switching ranges. The rotational position of the lock plate 5 is made by the force of the locking spring 6th at the position of any of the pits 5b held.

The depressions 5b correspond from the near end of the locking spring 6th from the shift ranges of D (drive or drive or D position), N (neutral), R (reverse) and P (parking). The position at which the locking plate 5 rotated furthest in the positive direction of rotation is the D position, and is the position at which the lock plate 5 rotated most in the negative direction of rotation is the P range.

The parking lock part 8th includes a parking pole 10 , a cone 11 , a parking pawl 12 , a shaft portion or shaft portion 13 and a parking gear 14th . The parking pole 10 moves the cone 11 in the direction of arrow P when the lock plate 5 pivots in the negative direction of rotation which is opposite to the positive direction of rotation. As a result, the parking pawl becomes 12 pushed up in the direction of arrow L, and the protrusion 12a and the parking gear 14th mesh with each other, causing the parking gear 14th blocked or blocked.

The following is an operation of the configuration described above with reference to FIG 3 and 4th described.

The three-phase motor 21st The present embodiment generates a magnetic force when the windings 21a , 21b and 21c of the U, V and W phases successively and selectively conduct motor drive currents in accordance with a predetermined conduction pattern. As a result, the protrusions of the magnetic body constituting the rotor are magnetically attracted and rotated one by one, thereby generating a rotational moment.

That is, for each of the windings 21a to 21c of the respective phases, the motor drive current Im is increased in a current increase period Tr to a target current value Ia which is set to a predetermined level. In a current holding period Tk after the current increasing period Tr, the motor drive current Im is controlled so as to hold the target current value Ia. In a current decay period Td after the current holding period Tk, the motor drive current Im falls to the zero level. In this case, the electrical conduction becomes the respective windings 21a to 21c of the three-phase motor 21st by driving and controlling the electrically conductive MOSs 31 to 33 and the reverse flux MOSs 34 to 36 arranged in correspondence with the three phases by means of the control circuit 40 controlled. The following are the winding 21a the U phase, the winding 21b the V phase and the winding 21c the W-phase also as a U-phase winding 21a , V-phase winding 21b and W-phase winding 21c designated. In addition, the phase, the winding of which the motor control current is supplied, is also referred to as an electrically conductive phase or phase that is energized.

3 provides an electrical line pattern for the U-phase winding 21a who have favourited V-phase winding 21b and the W-phase winding 21c Here is the electrical conduction pattern of the U-phase winding 21a described as an example. The Control circuit 40 controls the activation of the electrically conductive MOS 31 arranged in an electric conduction path and the reverse flux MOS 34 such that the motor drive current Im to the U-phase winding 21a is directed. In 3 Vg1 represents a gate voltage applied to the electrically conductive MOS, and Vg2 represents a gate voltage applied to the reverse flux MOS.

Initially, the control circuit stops 40 the reverse flux MOS in the current increasing period Tr 34 in an off state and controls the electrically conductive MOS 31 so that it is switched on at a time t0. The control circuit 40 holds the electrically conductive MOS 31 in an on-state during the current increasing period Tr. When the electrically conductive MOS 31 is or is switched on, the voltage is taken from the vehicle battery 1 via the electrically conductive MOS 31 to the winding 21a created. As a result, the motor control current Im is induced in the winding 21a flows, and the value of the motor drive current Im continues to increase during the current increasing period Tr. When the current value passing through the current sensing resistor 37 is detected, a target current value Ia is reached at a point in time t1, the control circuit ends 40 the current increasing period Tr and goes to the current holding period Tk.

During the current holding period Tk, the control circuit controls 40 the electrically conductive MOS 31 and the reverse flux MOS 34 by a PWM control in order to switch them on alternately at the time t1, at the time t2, at the time t3 ... in order to keep the motor drive current Im at the setpoint current value Ia. That is, in the current holding period Tk, the electrically conductive MOS 31 and the reverse flux MOS 34 driven such that they have turn-on and turn-off patterns with opposite phases. Thus, the electrically conductive MOS 31 and the reverse flux MOS 34 switched on alternately.

The control circuit then switches 40 the electrically conductive MOS 31 and the reverse flux MOS 34 at a time t4 at which the detection signal from the coding sensor 22nd changes to electrical conduction to the U-phase winding 21a to end. In this case the energy that is in the coil 21a stored, flowing through a reverse flux path that passes through the body diode 34a of the reverse flux MOS 34 is formed, and becomes zero at a time point t5.

Vemb in 3 represents the potential difference in the reverse flux path of the current of the winding 21a in the current holding period Tk and the current decay period Td according to the present embodiment, and Vcmp represents the potential difference of a comparative example. Since, in the present embodiment, the reverse flux MOS 34 while the current holding period Tk is on, no potential difference occurs in the current holding period Tk as shown in FIG 3 is shown. On the other hand, in a conventional method as shown in the comparative example in FIG 3 Fig. 8 shows a reverse flux path formed across the body diode. Therefore, a potential difference occurs corresponding to the forward voltage Vf of the diode during the current holding period Tk.

That is, in the current holding period Tk of the present embodiment, there is no need to power the body diode 34a of the reverse flux MOS 34 derive. The control circuit 40 switches the reverse flux MOS 34 on to set the motor control current Im of the winding 21a to reverse, and thus the potential difference in the reverse flux path can become almost zero.

4th Fig. 13 shows a flow of motor drive control by the control circuit 40 .

The control circuit 40 starts the motor drive control in response to a shift range change request from an upper level ECU or the like. First, the control circuit starts 40 in step S100 a current monitor. In this case the control circuit monitors 40 the motor drive current Im based on the terminal voltage of the current detection resistor 37 . If any of the electrically conductive MOSs 31 to 33 is or is switched on, the motor control current Im is applied to the corresponding winding 21a to 21c of the corresponding phase and flows through the current detection resistor 37 . The arithmetic circuit thus reads 41 the voltage across the current sensing resistor 37 is applied, in order to detect the motor control current Im.

The control circuit then switches 40 in step S110 for example the electrically conductive MOS 31 from the electrically conductive MOSs 31 to 33 one to provide electrical conduction to the U-phase winding 21a to effect and holds the electrically conductive MOS 31 in the on-state. In this case, electrical conduction can be started for a single phase or for multiple phases. Then the control circuit stops 40 in the next step S120 the switched-on state of the electrically conductive MOS 31 until the motor control current Im, which is in the U-phase winding 21a flows, a predetermined target value Ia is reached. When the motor drive current Im has reached the predetermined target value Ia, the control circuit proceeds 40 to step S130 .

In step S130 switches the control circuit 40 the electrically conductive MOS 31 the U phase and the reverse flux MOS 34 of the U-phase through the PWM control alternately to the motor control current Im, which is in the U-phase winding 21a flowing at a constant level. The control circuit then performs 40 repeat the steps S130 and S140 out. When the engine 20th turns and the output of the coding sensor 22nd changes, the control circuit advances 40 to step S150 .

In step S150 determines the control circuit 40 whether a motor rotation variable Mr has reached a target value Mtg, that is, whether the change mechanism 4th has rotated to the position of the target angle. When it is determined that the motor rotation amount Mr has not reached the target value Mtg, that is, when the motor rotation amount Mr is insufficient, the control circuit proceeds 40 to step S160 . In step S160 holds the control circuit 40 the electrically conductive MOS 31 and the reverse flux MOS 34 the U-phase in the switched-off state in order to start a decrease or decay of the motor drive current Im. The control circuit then returns 40 to step P. 110 back.

When the control circuit 40 to step S110 returns, the control circuit performs 40 the electrical line control described above for one of the windings 21a to 21c of the phase to be electrically conductive next, while an overlap takes place with the decay period Td of the motor drive current Im of the current phase. Note that the phase for holding the electrically conductive MOS and the reverse flux MOS in the off state in step S160 does not have to be present for all electrically conductive phases. In step S110 the next electrical conduction step can be carried out after the decay period Td of the motor drive current Im has ended.

Thereafter, the control circuit repeats 40 the steps S110 to S160 until the motor rotation variable Mr reaches (has) the setpoint Mtg. If the motor rotation quantity Mr has reached (has) reached the target value Mtg in S150, the control circuit proceeds 40 to step S170 . In step S170 controls the control circuit 40 the electrically conductive MOSs 31 to 33 and the reverse flux MOSs 34 to 36 all phases in such a way that they are kept in the switched-off state. When controlling the motor 20th is stopped, the switching range change is ended accordingly.

In the present embodiment described here, the control circuit switches 40 during electrical conduction to the windings 21a to 21c During the current holding period Tk, the electrically conductive MOS corresponding to the electrically conductive phase turns off and turns on the reverse flux MOS corresponding to the electrically conductive phase. As the diodes 34a to 36a are not used to reverse the current in the reverse flow path, with this configuration, the generation of heat can be prevented during the current holding period Tk.

In the current decay period Td, the control circuit switches 40 the electrically conductive MOS and the reverse flux MOS of the electrically conductive phase. As the diodes 34a to 36a are used to reverse the current in the reverse flux path, in this case the current can return to the zero level within a short time by dissipating the energy.

In the present embodiment, the drive circuit is used to perform electrical conduction to the three-phase motor 21st through the three electrically conductive MOSs 31 to 33 and the three reverse flux MOSs 34 to 36 educated. Therefore, the number of switching elements can be halved compared with a configuration in which an H-bridge circuit is arranged at the terminals of the respective windings of the three phases.

In the embodiment described above, the control circuit 40 for example provided by a microcomputer. The control circuit 40 however, it is not limited to the example described above, but can also be provided by an IC including logic circuits or a combination of the microcomputer and the IC.

Second embodiment

A second embodiment will now be described with reference to FIG 5 and 6th described. The configurations different from the first embodiment are mainly described below. In the present embodiment, the electrical configuration is similar to that of the first embodiment. The control at the time of stopping electrical conduction to the windings 21a to 21c however, is partially different from the control performed in the motor drive control of the first embodiment.

Like it in 5 is shown, the control circuit performs 40 of the present embodiment step S100 up step S160 in a similar manner to the first embodiment. The control circuit 40 however, performs another control at the time of stopping the Motor drive control as in the first embodiment as shown in step S170a.

If in step S150 the control circuit 40 determines that the motor rotation amount Mr has reached the target value Mtg, controls the control circuit 40 in the next step S170a, the electrically conductive MOS of the electrically conductive phase into the switched-off state and the reverse flux MOS of the electrically conductive phase into the switched-on state. As a result, there is a braking action on the rotor of the three-phase motor 21st exercised to stop the control of the motor, and the change of the switching range is ended.

6th Fig. 13 is a timing chart schematically showing a sequence of control operation by the control circuit 40 for the three-phase windings 21a to 21c of the three-phase motor 21st shows.

In this control, the control circuit leads 40 at a time t10 which is the start of electrical conduction to the three phase motor 21st is to conduct electrical conduction for two windings at the same time, e.g. for the U-phase winding 21a and the V-phase winding 21b . In this case, the electrical conduction of each phase is performed in a manner similar to that in the first embodiment. At a time point t11, the control circuit stops 40 the electrical conduction to the U-phase winding 21a and starts electrical conduction to the W-phase winding 21c . At a point in time t12, the motor drive current Imw reaches the W-phase winding 21c the setpoint current value Ia.

In this case, the control circuit controls 40 the electrically conductive MOS 31 and the reverse flux MOS 34 for the U-phase winding 21a as described above to the switch-off state. Therefore, the motor drive current Imu causes the winding 21a about the diode 34a flows as reverse current. As a result, there becomes a potential difference Vf across the diode 34a is generated in the reverse flux path, and the motor drive current Imu is derived as a reverse current so that it is substantially equal to zero at time t12.

The control circuit then controls 40 the electrically conductive MOSs 32 and 33 and the reverse flux MOSs 35 and 36 into the switched-off state in order to be electrically connected to the V-phase winding at a point in time t13 21b and the W-phase winding 21c than stop electrically conductive phases. Thus, the currents Imv and Imw of the windings become 21b and 21c vice versa so that they are over the respective diodes 35a and 36a flow. At time t13, the control circuit starts 40 also the electrical conduction to the U-phase winding 21a . As a result, a potential difference Vf occurs in the two reverse flux paths due to the diodes 35a and 36a on, and thus the reverse currents Imv and Imw are diverted to be substantially zero at a time t14 while electrically conducting to the U-phase winding 21a is carried out.

If thus the amount of rotation of the rotor of the three-phase motor 21st the setpoint by electrically conducting to the three-phase windings 21a to 21c reached in the manner described above, the control circuit stops 40 the electrical conduction to the W-phase winding 21c than the electrically conductive phase at a time point t21. At this time, the control circuit switches 40 the electrically conductive MOS 33 off and turns off the reverse flux MOS 36 on in order to keep the motor drive current Imw after time t22. Time t22 is a time when the current Imw of the winding 21c becomes zero when the reverse flux MOS 36 is brought into the off state as indicated by a dashed line in 6th is shown.

Since, in the present embodiment, the reverse flux MOS 36 is kept in the on-state at time t21, the current Imw becomes substantially zero at time t23, which is after time t22, as indicated by a thick solid line in FIG 6th is shown. Thus, the time for dissipating the energy for exerting a braking effect is extended. As a result, the rotor becomes the three-phase motor 21st stopped at a predetermined position. In this case, in order to stop the rotor more reliably, it is also possible to carry out the electrical conduction to another phase in order to cause a torque in the direction opposite to the direction of rotation of the motor.

In the above-described second embodiment, by performing the motor drive control in the manner similar to the first embodiment, effects similar to the first embodiment can be obtained. Since the reverse flux MOS is turned on when the driving of the rotor is stopped, there is the three-phase motor 21st has reached the predetermined amount of rotation, braking is applied and the rotor can be stopped quickly.

Third embodiment

A third embodiment will now be described with reference to FIG 7th and 8th described. The following mainly describes the configurations different from the first embodiment. The present embodiment has a configuration that performs control for preventing overheating when causes the reverse current to flow through the diodes 34a to 36a the reverse flux MOSs 34 to 36 flows.

That is, in the engine control unit 50 are respective temperature sensing elements 51 to 53 for sensing temperatures in the vicinity of the reverse flux MOSs 34 to 36 arranged. The temperature sensing elements 51 to 53 use, for example, thermistors or the like. The computing circuit 41 the control circuit 40 receives temperature detection signals from the temperature detection elements 51 to 53 . Since the reverse flux MOSs 34 to 36 the diodes 34a to 36 may have the temperatures of the reverse flux MOSs 34 to 36 and the diodes 34a to 36a through the temperature sensing elements 51 to 53 are recorded.

The control circuit 40 changes the pattern of motor drive control according to the temperatures of the reverse flux MOSs 34 to 36 by the temperature sensing elements 51 to 53 are recorded. 8th shows the sequence of the motor control control. When the motor drive control is started, the control circuit starts 40 monitoring of the motor drive current Im and the temperature T in step S100a . When monitoring the motor control current Im, the control circuit uses 40 the connection voltage of the current detection resistor 37 to detect the motor control current Im. When monitoring the temperature T uses the control circuit 40 the detection signals of the temperature detection elements 51 to 53 to find the respective temperatures T of the reverse flux MOSs 34 to 36 capture.

The control circuit 40 performs similar processing in steps S110 to S150 and S170 as in the first embodiment. If in step S150 it is determined that the motor rotation quantity Mr has not yet reached the target value Mtg, the control circuit proceeds 40 to step S180 . In step S180 determines the control circuit 40 whether the detected temperature of the temperature detection element 51 to 53 , which corresponds to the electrically conductive phase, is equal to or higher than a predetermined temperature. In other words, in step S180 it is determined whether the heating value Q of the temperature detecting element corresponding to the electrically conductive phase is equal to or larger than a predetermined value Qpred.

If the result of the determination in step S180 No, that is, if, for example, the electrically conductive phase is the U phase and the temperatures of the reverse flux MOS 34 and the diode 34a by the temperature sensing element 51 are detected, have not increased to equal to or greater than the predetermined temperature, the control circuit performs 40 processing in step S160 similar to the first embodiment. Therefore, the control circuit switches 40 the electrically conductive MOS 31 and the reverse flux MOS 34 corresponding to the electrically conductive phase. This causes the reverse current of the winding 21a the U phase as the electrically conductive phase across the diode 34a flows and is discharged as described above. In this way the reverse current drops.

On the other hand, if the result of the determination in step S180 Yes, that is, if, for example, the U phase is the electrically conductive phase and the temperature of the reverse flux MOS 34 by the temperature sensing element 51 the U-phase is detected, has reached or exceeded the predetermined temperature, the control circuit proceeds 40 to step S190 . In step S190 switches the control circuit 40 the electrically conductive MOS 31 , which corresponds to the electrically conductive phase, and switches the reverse flux MOS 34 corresponding to the electrically conductive phase.

As a result, the reverse current of the winding is caused 21a the U phase as the electrically conductive phase via the reverse flux MOS 34 instead of through the diode 34a flows. In this case, even if the drive current decay period is lengthened, the voltage applied to the reverse flux MOS 34 is applied, essentially zero. Thus, the generation of heat is reduced compared to the configuration in which the reverse current through the diode 34a flows.

The control circuit then returns 40 to step again S110 back and move on to the electrical conduction step for the next phase. The control circuit leads as the next electrical conduction step 40 the step S110 for one of the windings 21a to 21c of the phase to be electrically conductive next and performs the above-described electrical conduction control. The control circuit 40 repeats the steps described above S110 to S160 . If in step S150 it is determined that the motor rotation amount Mr has reached the target value Mtg, the control circuit proceeds 40 to step S170 and holds the electrically conductive MOSs 32 , 34 and 36 and the reverse flux MOSs 31 , 33 and 35 all electrically conductive phases in the switched-off state. When thus controlling the motor 20th is stopped, the switching range change is ended.

In the third embodiment described above, the temperature sensing elements are 51 to 53 in correspondence with the respective reverse flux MOSs adjacent thereto 34 to 36 arranged. In the case where the rotation amount of the three-phase motor 21st has not reached the setpoint and the electrical conduction to the winding of the electrically conductive phase is stopped, the control circuit switches 40 turns off the electrically conductive MOS and turns on the reverse flow MOS only when the detected temperature of the temperature detecting element corresponding to the electrically conductive phase is equal to or higher than the predetermined temperature.

In the operation that causes the reverse current through the diodes 34a to 36a flows in parallel to the respective reverse flux MOSs 34 to 36 are switched to dissipate the energy in a short time, if an overheating condition is expected, the reverse current is caused to flow through the reverse flux MOSs 34 to 36 flows. Thus, heat generation is reduced and the reverse flux MOSs can 34 to 36 protected from thermal destruction.

The present embodiment can vary according to the specifications, characteristics and conditions of using the three-phase motor 21st as well as the element characteristics of the reverse flux MOSs 34 to 36 be used. When the present embodiment is appropriately used depending on these conditions, the advantageous effects described above can be obtained.

Note that the present embodiment can be used for the configuration of the second embodiment.

Fourth embodiment

A fourth embodiment is described below with reference to FIG 9 described. The following mainly describes the configurations different from the first embodiment. In the present embodiment, an engine control unit 60 Current sensing resistors 61 to 63 instead of the current sensing resistor 37 on.

That is, in the present embodiment, the current detection resistors are 61 to 63 between the electrically conductive MOSs 31 to 33 and the power supply line L2 arranged in correspondence with the U, V and W phases in contrast to the first embodiment in which the current detection resistor 37 is arranged in order to collect the motor drive current Im independently of the electrically conductive phase. The recorded voltages of the current detection resistors 61 to 63 become the computing circuit 41 provided.

Therefore, in the fourth embodiment as well, effects similar to those in the first embodiment can be obtained. In addition, the motor control current Im can be recorded independently for each electrically conductive phase.

Fifth embodiment

A fifth embodiment is described below with reference to FIG 10 described. The following mainly describes the configurations different from the first embodiment. In the present embodiment, an engine control unit 70 a motor control device 101 twelve MOS transistors 71 to 82 on. The MOS transistors 71 to 82 have respective body diodes 71a to 82a on.

The MOS transistors 72 , 74 , 76 , 78 , 80 and 82 serve as the electrically conductive MOSs, and the MOS transistors 71 , 73 , 75 , 77 , 79 and 81 serve as the reverse flux MOSs. The unit of the MOS transistors 71 to 74 , the unit of MOS transistors 75 to 78 and the unit of MOS transistors 79 to 82 are each designed as an H-bridge circuit and correspond to the windings 21a to 21st c of the respective phases of the three-phase motor 21st arranged.

The control circuit 90 contains a computing circuit 91 and a drive circuit 92 and controls activation of the MOS transistors 71 to 82 in a similar manner to the control circuit described above 40 . The detection signal of the current detection resistor 37 becomes the computing circuit 91 provided.

Here, a configuration similar to that of the conventional system is used. The control circuit 90 performs motor drive control in a manner similar to that in the first embodiment. In this case the control circuit leads 90 the electrical conduction to the windings 21a to 21c of the respective phases in the following manner.

With regard to the electrical conductivity of the U-phase winding 21a in the current increasing period Tr, the control circuit switches 90 for example the reverse flux MOS 71 and the electrically conductive MOS 74 that form the H-bridge circuit to drive the motor current to the U-phase winding 21a to direct. Since in this case the SRM is independent of the direction of the current line to the winding 21a is operated, the control circuit 90 electrical conduction by turning on the reverse flux MOS 73 and the electrically conductive MOS 72 realize.

The control circuit then performs 90 in the current holding period Tk as the electrically conductive period during which the Turn-on control is alternately performed by the PWM control, alternately and repeatedly the operation for turning on the reverse flux MOS 71 and the electrically conductive MOS 74 and the operation to turn on the reverse flux MOSs 71 and 73 , while the electrically conductive MOS 74 is off, through to form the reverse flow path for the reverse current. The reverse flux path can be created by turning on the electrically conductive MOSs 72 and 74 , while the reverse flux MOS 71 is turned off, trained.

In the current decay period Td, the control circuit switches 90 the reverse flux MOS 71 and the electrically conductive MOS 74 off so that all MOSs 71 to 74 that form the H-bridge circuit are in the off state. In this case, the reverse current is caused to the U-phase winding 71a about the diodes 72a and 73a flows. Thus, a potential difference is created in the reverse flux path and the energy is dissipated.

Also in the fifth embodiment described above, the state in which the reverse current flows in the reverse flux path in which the potential difference is substantially equal to zero, and the state in which the energy dissipation is caused by the reverse currents in the reverse flow paths via the Diodes 72a and 73a flowing, suitable and distinguishable achieved and used. Therefore, an operation can be realized that heat generation of the reverse flux MOSs 71 and 73 reduced or prevented.

Other embodiments

The present invention is not limited to the above-described embodiments but can be variously modified within the scope of the invention. For example, the following modifications and extensions are possible.

The multi-phase motor is not based on the three-phase motor 21st limited, but can be a multiphase motor with four or more phases.

The electrically conductive MOSs can be on the high voltage side and the reverse flux MOSs can be on the low voltage side. In this case, first ends are the windings 21a to 21c commonly connected to a common connection point, and the common connection point may be connected to ground.

The electrically conductive switching element and the reverse flux switching element are not limited to MOS transistors, but can be provided by any switching elements such as IGBTs.

The diodes that form the reverse flux paths are not limited to body diodes. The diodes that form the reverse flux paths can be provided by external diodes. In this case, the diodes are connected at least in parallel to the reverse flux switching elements.

In summary, a motor control device is designed according to one embodiment, a multiphase motor 21st , which has three or more phases, for shift-by-wire control, with each phase having a winding 21a to 21c contains. The motor control device contains: a plurality of electrically conductive switching elements 31 , 32 , 33 , 72 , 74 , 76 , 78 , 80 , 82 that are in electrical conduction paths to the windings 21a to 21c the respective phases of the multiphase motor 21st are arranged; multiple reverse flux switching elements 34 , 35 , 36 , 71 , 73 , 75 , 77 , 79 , 81 that are in reverse flux paths of the windings 21a to 21c are arranged; multiple diodes 34a , 35a , 36a , 71a , 73a , 75a , 77a , 79a , 81a in parallel with the respective reverse flux switching elements 34 , 35 , 36 , 71 , 73 , 75 , 77 , 79 , 81 are switched; and a control circuit 40 , 90 , which is designed, an electrical line control for conducting a control current as a motor control current to the respective windings 21a to 21c perform.

In the electrical line control for the respective windings during the control of the multi-phase motor 21st is performed, (i) controls the control circuit 40 , 90 in a drive current rise period, the corresponding electrically conductive switching element in the electrical conduction path to the winding of an electrically conductive phase in such a way that it is continuously kept in a switched-on state; (ii) controls the control circuit 40 , 90 in a drive current holding period the corresponding electrically conductive switching element and the corresponding reverse flux switching element in such a way that they are switched on alternately by a PWM control; and (iii) controls the control circuit 40 , 90 in a drive current decay period, the corresponding electrically conductive switching element and the corresponding reverse flux switching element in such a way that they are kept in the switched-off state.

According to one embodiment, the control circuit controls 40 , 90 in the electric line control at a time of stopping the control of the multi-phase motor 21st is performed, the reverse flux switching element of the electrically conductive phase in the drive current decay period so as to be kept in the ON state.

According to one embodiment, the motor control device also contains a temperature detection element 51 , 52 , 53 , which is arranged, a temperature of a respective reverse flux switching element 34 , 35 , 36 , 71 , 73 , 75 , 77 , 79 , 81 capture. When the temperature measured by the temperature sensing element 51 , 52 and 53 is detected is equal to or greater than a predetermined temperature, controls the control circuit 40 the corresponding reverse flux switching element in the drive current decay period such that it is switched on.

According to one embodiment, the multi-phase motor is 21st a switched reluctance motor, and first ends of the windings 21a to 21c all phases are common with a connection of a drive power supply or drive power supply 1 connected.

While only selected exemplary embodiments and examples have been chosen to illustrate the present invention, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the scope of the invention, which is set forth in the appended claims. In addition, the above description of the exemplary embodiments and examples of the present invention is only exemplary and does not limit the invention as set out in the appended claims.

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• JP 2012125096 A [0005]
• JP 2000358397 A [0005]

Claims (4)

Motor control device which is designed to control a multiphase motor (21), which has three or more phases, for shift-by-wire control, each phase containing a winding (21a to 21c), the motor control device having: a plurality of electrically conductive switching elements (31, 32, 33, 72, 74, 76, 78, 80, 82) which are arranged in electrical conduction paths to the windings (21a to 21c) of the respective phases of the polyphase motor (21); a plurality of reverse flux switching elements (34, 35, 36, 71, 73, 75, 77, 79, 81) arranged in reverse flux paths of the windings (21a to 21c); a plurality of diodes (34a, 35a, 36a, 71a, 73a, 75a, 77a, 79a, 81a) connected in parallel to the respective reverse flux switching elements (34, 35, 36, 71, 73, 75, 77, 79, 81) are; and a control circuit (40, 90) which is designed to carry out an electrical conduction control for conducting a drive current to the respective windings (21a to 21c), wherein in the electrical line control, which is carried out for the respective windings during a control of the polyphase motor (21), the control circuit (40, 90): (i) in a drive current rise period controls the corresponding electrically conductive switching element in the electrical conduction path to the winding of an electrically conductive phase in such a way that it is continuously kept in a switched-on state; (ii) controls the corresponding electrically conductive switching element and the corresponding reverse flux switching element in a drive current holding period in such a way that they are switched on alternately with one another by a PWM control; and (iii) controls the corresponding electrically conductive switching element and the corresponding reverse flux switching element in a drive current decay period in such a way that they are kept in a switched-off state. Motor control device according to Claim 1 , wherein in the electric conduction control that is carried out at a time of stopping the drive of the polyphase motor (21), the control circuit (40, 90) controls the reverse flux switching element of the electrically conductive phase in the drive current decay period so that this in the Is kept on. Motor control device according to Claim 1 or 2 further comprising: a temperature detecting element (51, 52, 53) arranged to detect a temperature of the respective reverse flow switching element (34, 35, 36, 71, 73, 75, 77, 79, 81), where if the temperature detected by the temperature detecting element (51, 52, 53) is equal to or higher than a predetermined temperature, the control circuit (40) controls the corresponding reverse flux switching element in the drive current decay period to be on. Motor control device according to one of the Claims 1 to 3 wherein the multi-phase motor (21) is a switched reluctance motor, and first ends of the windings (21a to 21c) of all phases are commonly connected to a terminal of a drive power supply (1).

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