JP3482965B2 - Drive control device for permanent magnet type synchronous motor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive controller for controlling a permanent magnet type synchronous motor (hereinafter referred to as PM motor).

[0002]

2. Description of the Related Art There is a strong demand for miniaturization of vehicle running motors for electric vehicles. The PM motor, which is a motor using a permanent magnet as a means for generating an exciting magnetic flux,
Since the field magnetomotive force per unit volume is large and the size can be easily reduced as compared with other types of motors, various electric vehicles using PM motors as vehicle driving motors have been proposed so far.

At the same time, it is required for a vehicle running motor of an electric vehicle to be able to cover a wide speed range (rotational speed range). Field weakening control, which is a part of vector control, has been used as a method to meet this demand. Here, the vector control is a method for controlling the motor current IM separately for the torque current component Iq and the field current component Id. Of these components, Iq is a component that generates torque (magnet torque) by interlinking with the main magnetic flux, that is, the exciting magnetic flux obtained by the permanent magnet. Id is a component that generates an exciting magnetic flux that partially assists or cancels the main magnetic flux, and when the motor has a saliency, Id also generates a torque (reluctance torque) proportional to Id · Iq. When trying to extend the speed range of the motor, that is, to extend the operable range of the motor to a region of higher speed rotation, the speed electromotive force ω · E0, that is, the electromotive force proportional to the rotational angular velocity ω of the motor generated in the main magnetic flux E0. As a result, the terminal voltage of the motor generally rises as the number of revolutions N rises, and often exceeds the value corresponding to the battery voltage VB which is the power supply voltage. In order to prevent this, a method of generating an exciting magnetic flux in the direction of canceling E0 by controlling Id and extending the operable region of the motor to the field weakening region on the higher rotation side than the normal field region (see FIG. 6) is This is the above-described field weakening control, and by executing this control, even a motor with a relatively small output can cover the high-speed rotation region. It should be noted that the vector control has a mode based on the absolute value and the torque angle, but since it is equivalent to the mode based on Id and Iq, they are not distinguished in the following description.

While the field weakening control has such advantages, it also has the aspect of decreasing efficiency. For example, if the Id during field weakening control (hereinafter also referred to as the field weakening current) is too large, the loss increases due to an increase in Id that is a current component that does not contribute to torque generation or that does not contribute easily. On the contrary, if the field weakening current is too small, it will be difficult to achieve the original purpose of field weakening. That is, in order to control the motor output, stress is applied to the power converter provided between the battery that is the power source and the motor that is driven, and the required Iq
It also causes problems such as being unable to output. As a method of alleviating these, the applicant of the present application has previously proposed a method of changing the value of the field weakening current according to VB (see Japanese Patent Laid-Open No. 7-107772). According to this method, the loss generated by the field weakening control can be minimized and optimized in relation to the voltage or state of charge of the battery.

[0005]

However, as long as field weakening control is performed, it is impossible to eliminate the occurrence of loss due to the field weakening current and the resulting reduction in system efficiency. On the other hand, a technique of boosting and using a battery voltage during high speed operation is known from Japanese Patent Laid-Open No. 8-214592. One of the objects of the present invention is to eliminate the need for field weakening control by devising a booster circuit for boosting the battery voltage and its peripheral circuits, thereby achieving improvement in system efficiency, and target operation of a PM motor. In addition to performing boost control according to the position of the point, thereby maintaining and maintaining the speed range in which the PM motor can operate at a level that is equivalent to or higher than that of conventional systems, the loss in the boost circuit is suppressed, and system efficiency is improved. There is a further improvement. One of the objects of the present invention is to realize a more automated system by providing means for autonomously bypassing the booster circuit. One of the objects of the present invention is to provide a means for forcibly bypassing the booster circuit so that the booster circuit can be bypassed when the need for regenerative braking or the like arises. One of the objects of the present invention is to make it possible to eliminate the inrush prevention circuit by using the booster circuit.

[0006]

In order to achieve such an object, the present invention provides a current converter connected between a battery and a PM motor for converting VB into a motor current, a battery and a power converter. Is formed between the battery and the power converter in the drive control device that controls the PM motor by the booster circuit that boosts VB before the power is supplied to the power converter, including the booster reactor connected between the power converter and the power converter. Conduction path
And the target operating point belongs to the normal field region or regenerative region.
It is characterized in that it is provided with a conduction path which does not go through the booster circuit during the operation . In such a configuration, the booster circuit and hence the booster reactor inside the booster circuit are bypassed by issuing an appropriate command.

In the present invention, for example, by providing an autonomous gate element (for example, a diode) that forms / interrupts a conduction path that does not pass through the booster circuit between the battery and the power converter according to the voltage difference before and after the booster circuit, The booster circuit can be bypassed by the autonomous gate element when boosting is not being performed. That is, by preventing the boosting when VB is low, it is possible to suppress the occurrence of loss in the booster circuit and further improve the system efficiency. Also,
This bypass formation / blocking is carried out autonomously, i.e. automatically by the autonomous gate element, so that no control device or procedure therefor is necessary. Alternatively, a controllable gate element (for example, a thyristor) that forms / interrupts a conduction path that does not pass through the booster circuit between the battery and the power converter according to a command.
And means for forcibly forming the conduction path by giving a command to the controllable gate element when the target operating point belongs to the regenerative side, thereby providing a booster circuit as necessary for regenerative braking or the like. It becomes possible to bypass.

The present invention is not limited to the configuration in which the booster circuit is used only for boosting. For example, as a booster circuit, a booster reactor that is a passive element that stores energy discharged from a battery, and an active element (transistor, etc.) that switches and connects this passive element to the positive and negative input terminals of a power converter according to a command. If a circuit having and is used, these elements can be used for path formation during regeneration, and the current generated by charging of the inrush prevention circuit, that is, the smoothing capacitor generally provided between the DC terminals of the power converter, can be used. The circuitry to prevent can be abolished using these elements.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a system configuration of an electric vehicle according to an embodiment of the present invention. In this embodiment, the three-phase PM motor 10 is used as a vehicle traveling motor. Driving power for the motor 10 is supplied from a battery 12 through an intelligent power module (IPM) 14. That is, the discharge output of the battery 12 is smoothed by the smoothing capacitor C and then converted from direct current to three-phase alternating current by the IPM 14, and the resulting current iu,
iv and iw are supplied to each phase winding of the motor 10. The output torque of the motor 10 is controlled by the controller 16. That is, the controller generates a switching signal in response to an operation such as an accelerator, a brake, a shift, etc. by the vehicle operator, and according to the rotation speed (or rotor angular position) of the motor 10 detected by the rotation sensor 18 such as a resolver. By doing so, the switching pattern of the switching element forming the IPM 14 is controlled. By executing such control, the output torque of the motor 10 can be set to a torque according to the accelerator operation of the vehicle operator. In this control, the phase currents iu, iv, iw of the motor 10 are detected by the current sensors 20u, 20v, 20w provided corresponding to the windings of the motor 10, and the controller 16
Be fed back to.

A rush prevention circuit 22, a diode Df, a thyristor Dr and a booster circuit 24 are provided between the battery 12 and the IPM 14. Of these, the inrush prevention circuit 22 is a circuit for suppressing or preventing an inrush current that flows due to charging of the smoothing capacitor C immediately after the battery 12 is connected to the IPM 14, and is turned on / off according to the operation of the ignition (IG). 2 switches SW1 and SW2 connected in parallel, and a resistor Rs serially connected to the switch SW2. Further, the booster circuit 24 forms a part of the feature of the present invention, and controls the terminal voltage VB of the battery 12 by the controller 16.
The voltage is increased to a higher voltage VI and applied between the DC terminals of the IPM 14 under the control of. The diode Df is a booster circuit 24.
Is a means for bypassing the booster circuit 24 when a large potential difference is not generated between the input end and the output end, that is, when the booster circuit 24 is not performing the boosting operation. The thyristor Dr is turned on / off by a signal supplied from the controller 16, and generates a current path in a direction opposite to the current direction determined by the diode Df. Note that reference numerals 25 and 26 in the figure denote voltage sensors for detecting VB and VI, respectively. As an example configuration of the booster circuit 24, two transistors Tr1 and T1 connected in series in the forward direction between the DC terminals of the IPM 14 are used.
r2, diodes D1 and D2 connected in anti-parallel to these transistors, and transistors Tr1 and Tr
The structure which equips the connection point of 2 with the pressure | voltage rise reactor L by which the one end and the other end were connected to the battery 12 side is shown.

FIG. 2 shows a motor 10 according to this embodiment.
The principle of speed range extension is shown. The region represented as region A in this figure corresponds to the region represented as the normal field region in FIG. Conventionally, by increasing the field-weakening current Id in accordance with the increase in the motor rotation speed N, the motor 10 reaches the characteristic shown by the solid line in FIG. 2, that is, the region shown as the field-weakening region in FIG. The outputable area of was expanded. On the other hand, in the present embodiment, the outputtable region of the motor 10 is expanded by controlling the booster circuit 24 instead of controlling Id.
That is, the current target operating point (T, N) is the current VB
Or, when it is located on the higher rotation side than the region that can be realized by VI, in the present embodiment, for example, from region A to B, from B to C, and further from C to D, ... The step-up circuit 24 raises the step-up ratio and raises VI so that the outputable region of the motor 10 expands. Further, since the control of Id is not involved in the expansion of the output possible range or the speed range based on this principle, unlike the conventional field weakening control, the system efficiency is not impaired by such a cause.

3 and 4 show an example of a procedure executed by the controller 16 to implement such a principle. First, as shown in FIG.
Turns on the switch SW2 of the inrush prevention circuit 22 immediately after the IG is turned on, and turns on the switch SW1 after a lapse of some time (100). That is, the smoothing capacitor C is charged for a while immediately after the IG is turned on by using the resistor Rs as a charging resistor, and then SW1 is turned on to short-circuit both ends of the resistor Rs when the smoothing capacitor C can be considered to be sufficiently charged. After that, the operation of the controller 16 shifts to a series of repetitive procedures for controlling the output torque of the motor 10.

In controlling the output torque of the motor 10, the controller 16 first inputs signals from various parts of the vehicle (102). For example, accelerator opening, brake pedal force, shift lever position, motor speed N, motor currents iu, iv, iw, battery voltage VB, IPM
Input voltage VI and the like. After that, the controller 16
Is the accelerator opening, brake pedal force, shift position,
The torque command T ^*, that is, the target value of the torque to be output from the motor 10 is determined based on the information such as the motor rotation speed N (104). Based on the torque command T ^* determined in this way, the controller 16 sets the current commands (Id ^* , Iq) so that the system efficiency of the motor 10 is maximized.
^* ) To determine. Of the current commands referred to here, Id ^* is a command related to the field current component Id, and Iq ^* is a command related to the torque current component Iq. The controller 16
After adjusting the IPM input voltage VI using the current command (Id ^* , Iq ^* ) determined in this way (10
8), the signal is output to the IPM 14 and others (110).
That is, the current i corresponding to the current command (Id ^* , Iq ^* )
A signal indicating a switching pattern is output to the IPM 14 so that u, iv, and iw flow, and the torque command T
^{When *} belongs to the regeneration area (area T <0 in FIG. 2), the thyristor Dr is instructed to turn on. The above steps 102 to 110 are repeated until the IG is turned off by the vehicle operator (11
2). When the IG is turned off, the controller 16 turns off the switches SW1 and SW2 (114), and the battery 1
The power supply from 2 to the motor 10 is cut off.

The adjustment of the IPM input voltage shown in step 108 is executed by the procedure as shown in FIG. That is, the controller 16 uses, for example, the following equation

## EQU1 ## Vd = (R + pLd) .Id ^* -. Omega.Lq.Iq ^* Vq = .omega.Ld.Id ^* + (R + pLq) .Iq ^* +. Omega.E0 where R: motor winding resistance Ld, Lq: The d-axis and q-axis inductance ω of the motor winding: motor electric angular velocity E0: main magnetic flux p: (Vd ^* , Vq ^* ) is calculated according to the differential operator (200). Alternatively, instead of

[Equation 2]   Vd = Kp · ΔId + Ki · ∫ΔId−ω · Lq · Iq   Vq = Kp · ΔIq + Ki · ∫ΔIq + ω · Ld · Id + ωE0 However, ΔId = Id^*-Id ΔIq = Iq^*-Iq According to (Vd^*, Vq^*) May be sought. in this way
Obtained (Vd^*, Vq^*) Is the torque command T^*To
In order to realize the^*, Iq ^*)
It represents the voltage required to achieve it. Controller 1
6 is the following formula

## EQU3 ## V = k (Vd ² + Vq ² ) ^1/2 However, k: The voltage V is obtained according to a coefficient for converting the motor terminal voltage into the IPM input voltage. The voltage V thus obtained is a value obtained by converting the terminal voltage of the motor 10 required to realize the target operating point of the motor 10, that is, (T ^* , N), into a value on the DC terminal side of the IPM 14. The controller 16 determines whether this voltage V exceeds VB (204) and whether it exceeds VI (206). Of these judgment conditions, V> V
When the condition of B is not established, it can be considered that the target operating point (T ^* , N) can be realized when the current battery voltage VB is applied almost as it is, that is, when it is applied as VI to the IPM 14 through the diode Df. Step 11 without boosting by the booster circuit 24
Move to 0. When the condition of V> VB is satisfied, V> VI is always satisfied if the booster circuit 24 has not started its operation at that time. Therefore, the operation of the controller 16 is step 208, that is, the booster circuit 24. The operation shifts to the command operation of the step-up ratio to. In step 208, the controller 16 determines VI that satisfies V <VI.
In order to obtain, the operation of controlling the transistors Tr1 and Tr2 is started. Further, even after the boosting operation by the booster circuit 24 is started, V> VI is caused due to the insufficient boosting ratio.
The condition (1) may be satisfied, and in this case (206), step 208 is also executed.

According to the control procedure as described above, in this embodiment, the power running possible area (particularly the speed range) is secured and the motor system efficiency is improved according to the principle shown in FIG.

FIG. 5 shows the system configuration of an electric vehicle according to the second embodiment of the present invention. In this embodiment, the battery 12 is replaced by an IPM instead of the inrush prevention circuit 22.
A switch SW for switching connection between the 14 side and the booster circuit 24 side is used, and the diode Df and the thyristor Dr are abolished. Further, along with this, a change has also occurred in the procedure of the operation of the controller 16.

First, in the above-described embodiment, the time difference ON control of the switches SW1 and SW2 was performed in step 100 of FIG. 3, but in the embodiment, the switch SW is first turned to the side in step 100, and the battery is turned on. 12 is connected to the booster circuit 24. As described above, the booster reactor L is built in the booster circuit 24. The controller 16 uses the upper transistor Tr1.
Is turned on and the transistor Tr2 on the lower side is turned off, so that the battery 12 is connected to the IP via the step-up reactor L.
A state in which it is connected to the M14 side is formed, and the boost reactor L
By charging the smoothing capacitor C via the, the same function as the inrush prevention circuit 22 in the first embodiment is achieved.

Further, the controller 16 turns the switch SW to the side after a lapse of time enough to consider that the smoothing capacitor C is sufficiently charged, and the battery 12 is IPMed.
Connect to 14 side. After this, as in the first embodiment described above, the procedure of steps 102 to 110 is repeatedly executed until the vehicle operator turns off the IG. However, when the torque command T ^* belongs to the regeneration area,
Instead of the control of turning on the thyristor Dr, the control of turning on the transistor Tr1 and turning off the transistor Tr2 is executed. With such control, a current path via the boost reactor L is formed as in the case immediately after the IG is turned on, so that the braking energy can be regenerated to the battery 12. Further, as a means for regenerating braking energy, it is also possible to turn down the switch and regenerate without passing through the boost reactor L. Further, after the IG is turned off, the controller 16 pushes the switch SW to disconnect the battery 12 from the IPM 14 and the booster circuit 24.

With such a configuration and procedure, the outputable region of the motor 10 can be expanded and the system efficiency can be improved, as in the first embodiment described above. Further, in this embodiment, the inrush prevention circuit and the like can be eliminated.

[0021]

According to the present invention, by appropriately issuing a command, it is possible to bypass the booster circuit and thus the booster reactor inside the booster circuit. In particular, by providing the autonomous gate element, the occurrence of loss in the booster circuit can be suppressed and the system efficiency can be further improved without a control device or procedure therefor. Further, by providing the controllable gate element and its control means, the booster circuit can be bypassed as required for regenerative braking or the like. And passive elements such as boost reactors can be used to form a revised path and to charge the smoothing capacitor that is generally provided between the DC terminals of the power converter, thus eliminating the inrush circuit and simplifying the circuit. it can.

[0022]

[Addendum] In the above description, the present invention is expressed as an invention relating to the "drive control device", but the present invention is, for example, "drive control method""drivedevice""drivemethod""power supply device""power supply method". Can also be expressed as Further, although the application to a pure electric vehicle is assumed, the present invention can be applied to various applications for both electric vehicles and so-called hybrid vehicles, regardless of industrial or consumer use. Further, the permanent magnet type synchronous motor to be controlled is not limited to the three-phase AC motor, and it does not matter whether the reluctance torque is used or not.

Further, the description has been made on the premise that the output torque of the motor is controlled by the open loop based on the detected value of the number of revolutions. The present invention can be applied to the configuration, the configuration in which the closed loop control is performed instead of the open loop control, and the configuration in which the control is performed based on the rotation speed estimated value instead of the rotation speed detected value. in addition,
Although the operating point of the motor is expressed exclusively in the torque rotation speed space,
Other types of spaces may be used as long as the output of the motor can be expressed, such as the motor voltage / current space.

Also, an example was described in which when the battery voltage is low, it is boosted and adjusted so as to exceed the counter electromotive force of the motor. Good. Further, although an example in which the boosting (falling) pressure is not performed at the time of regeneration is shown, it may be performed. In that case, I
A switching element or the like in the PM can be used. Various modifications can be made to the specific configuration of the step-up / down circuit. Furthermore, when using a circuit that has both functions of buck-boost,
Switch for bypassing the booster circuit, diode,
Elements such as thyristors can be eliminated. Also,
Although the parallel circuit of the diode and the thyristor is used in the first embodiment described above, an element such as a bidirectional thyristor may be used instead. Although details of the operation of the booster circuit are omitted, the operation is well known to those skilled in the art.

It should be noted that modifications of the above-described embodiment, especially those having the meaning described in this section, can be easily implemented by those skilled in the art based on the disclosure of the present application.

[Brief description of drawings]

FIG. 1 is a block diagram showing a system configuration of an electric vehicle according to a first embodiment of the present invention.

FIG. 2 is a torque rotation speed space diagram showing a principle of expansion of an outputtable area and improvement of system efficiency in the present embodiment.

FIG. 3 is a flowchart showing a flow of operation of a controller in this embodiment.

FIG. 4 is a flowchart showing a flow of operations of the controller in the present embodiment.

FIG. 5 is a block diagram showing a system configuration of an electric vehicle according to a second embodiment of the present invention.

FIG. 6 is a torque rotation speed space diagram for explaining conventional field weakening control.

[Explanation of symbols]

10 motor, 12 battery, 14 IPM, 16
Controller, 18 resolver, 24 booster circuit, 25,
26 voltage sensor, Df diode, Dr thyristor, L boosting reactor, Tr1, Tr2 boosting transistor, SW switch, C smoothing capacitor.

Front page continuation (58) Fields surveyed (Int.Cl. ⁷ , DB name) H02P 6/08 B60K 1/04 B60L 7/14

Claims (3)

(57) [Claims] 1. A power converter including a current converter connected between a battery and a permanent magnet type synchronous motor to convert a battery voltage into a motor current, and a boosting reactor connected between the battery and the power converter. In a drive control device that controls a permanent magnet synchronous motor by a booster circuit that boosts the battery voltage prior to supply to the power supply, a conduction path formed between the battery and the power converter.
Therefore, the target operating point belongs to the normal field area or regenerative area.
A drive control device comprising a conduction path that does not go through a booster circuit when the power is on. 2. The drive control device according to claim 1, wherein an autonomous gate is formed / interrupted between the battery and the power converter according to a voltage difference between the booster circuit and a conduction path that does not pass through the booster circuit. A drive control device comprising an element, wherein the booster circuit is automatically bypassed by the autonomous gate element when boosting is not being performed. 3. The drive control device according to claim 1, wherein a controllable gate element that forms / interrupts a conduction path that does not pass through the booster circuit between the battery and the power converter according to a command, and the target. A drive control device comprising: means for giving a command to the controllable gate element to forcibly form the conduction path when the operating point belongs to the regeneration side.