DE102008018819A1 - Motor pump unit for motor vehicle brake control systems - Google Patents

Abstract

A motor pump assembly having an electronic drive circuit for controllably driving an electric pump motor driving the pump, wherein the motor is a brushless electric motor and a brushless DC electric motor driving circuit is provided which drives the brushless electric motor, and wherein a winding changeover is provided which enables on-demand adjustment of the engine torque and the Rated speed allowed.

Description

The The invention relates to a motor pump unit according to the preamble of claim 1.

Of the Pump drive in motor pump units for an electronic Automotive vehicle braking system is usually with a DC motor equipped, which includes a commutator, the corresponding the position of the rotor in an appropriate manner, the armature windings of the Rotor controls so that the motor performs a rotary motion.

Brushless DC motors are known per se. There are also known applications for such motors in which a load adjustment is made via the winding of the motor. From the EP 1 236 596 A1 goes out a pump motor for a refrigerator, which, in order to lower the starting current, is controlled during startup with a first, specially adapted for a high starting torque motor winding. In operation, it is then switched from the first to a second motor winding, with which the operating speed is achieved at a lower current.

The US 5,650,886 relates to a compact disc data storage drive with a brushless motor, wherein the drive circuit for the disc driving motor in addition to a commutation circuit (BEMF logic) also comprises means for winding adaptation. When starting the disk, the motor is operated in bipolar or tripolar mode to provide sufficient torque to overcome the static frictional forces of the read heads. When the disc reaches a certain speed, it switches to the unipolar mode. In unipolar mode then a higher speed of the disc can be achieved. At startup, the motor arrangement described takes due to the small size of the motor only comparatively small currents (in the range around 500 mA). A transmission of the specified drive circuit to the automotive technology is not possible because the circuit is designed for low motor currents.

The Object of the present invention is now a motor pump unit indicate which can be made more compact.

These The object is achieved by the motor pump unit according to claim 1.

The Motor pump unit according to the invention comprises a electronic brushless DC electric motor drive circuit for the controlled control of an electric, a pump driving Pump motor, which is a brushless electric motor. Preferably, a winding switch is within the unit provided that a needs-based adjustment of the engine torque and the rated speed allowed.

At the brushless DC electric motor drive circuit is preferably a brushless, multi-pole motor (BLDC motor) with permanent magnetic or electromagnetic external excitation connected. A corresponding BLDC motor usually has three motor windings, which within the engine at the so-called Star point are connected. Preferably, in operation with the Motoransteuerschaltung a BLDC motor used in which the neutral point led out for connection to the circuit.

According to the invention a winding switching provided, the needs-based adjustment of the Engine torque and the speed allowed. In principle leaves This adaptation is also due to a known field weakening control reach the engine. In field weakening can such a higher engine speed can be achieved. The disadvantage is that to achieve the same load torque in the field weakening operation a higher motor current is required. When the through achieved the winding switching according to the invention Speed should be further increased, it may be appropriate be, the winding switch according to the invention with the field weakening method described above to combine.

The Winding changeover is preferably that in one mode more windings are supplied to the pump (eg bipolar operation), than in another mode. This can be between a Mode with increased engine torque (at lower speed) and a higher speed mode (lower speed mode) Moment) (eg unipolar operation). To this Way, the power loss in the mode for the higher Speed can be kept at a reasonable low level. Advantageously, the properties can be achieved in this way of two different engines in one engine.

Preferably, the following combinations for winding drives are feasible: high speed high torque uniolar bipolar unipolar tripolar bipolar tripolar

there becomes under a tripolar control a so-called 180 ° commutation Understood. Under a bipolar control, a so-called 120 ° commutation understood. Particularly preferred the motor windings are controlled in the 120 ° commutation so that in the case of a motor with 3 windings two of the windings (first and second winding) are connected in series. Another Speed level results when in the aforementioned particularly preferred bipolar mode the third, not connected in series, winding is also controlled. In this mode you get compared to the tripolar mode an internal motor resistance from about 3/4.

Further preferred embodiments will be apparent from the dependent claims and the following description of an embodiment on the hand of figures.

It demonstrate

1 a motor pump unit with an electronic controller,

2 a circuit diagram for a motor drive circuit in bipolar operating mode,

3 the motor drive circuit according to 2 in the mode for unipolar operation and

4 two diagrams illustrating the unipolar and bipolar mode of operation.

In 1 form motor pump unit 10 and electronic controller (ECU) 11 the electronic motor vehicle brake control unit 12 , A motor pump assembly 10 is from a valve block 13 and electric motor 14 composed. The wires 15 to the motor windings are through a hole 15 of the valve block 13 guided and with one inside the regulator 11 arranged electronic board 17 connected, which among other things, the control electronics 18 for the engine 14 wearing. Motoransteuerelektronik 18 Can also be separated from the brake electronics 17 be arranged in the range of the engine.

In 2 is a circuit diagram for a motor drive circuit 18 shown. Motor drive circuit 18 is supplied by a DC voltage between terminals GND (reference potential) and V +. V + denotes a positive voltage with respect to the reference potential at terminal GND, which is usually 12 V (rated voltage) in the automotive sector. The supply voltage V + leads via semiconductor switches 4 to Motoransteuerstufe 2 , which comprises 6 semiconductor switches A +, A-, B +, B-, C +, C-, with which the motor windings A, B and C can be energized clocked independently of each other. The motor drive stage 2 and suitable control methods for controlling the semiconductor switches contained therein as well as suitable methods for sensorless commutation of the motor are known per se.

The in 2 shown current corresponds to the bipolar operation of the circuit. switch 3 is locked. Since, according to the example described here, in each case two motor windings are appropriately energized via a PWM control in accordance with the rotor position, the motor has a mode in accordance with FIG 3 higher torque. During the operating mode in 2 (bipolar) is switch 4 open, whereas switches 3 closed is. The (virtual) star point 9 of the motor is in this operating mode at the potential V + / 2. In the in 1 illustrated application of the circuit in a motor vehicle brake control system, the motor is driven predominantly in the bipolar mode described here.

3 shows the circuit according to 2 in unipolar operation mode. To switch to this mode of operation, becomes semiconductor switch 3 open. The star point 9 of the motor 1 is connected in this way to the positive potential of the battery supply V +. Current now flows, as an example for a commutation state, via switches 3 to the star point 9 and from there via windings C and switch C- to the negative terminal GND of the battery. The stored energy from the last Abkommutierung in the capacitor C1 is as long as the capacitor voltage> V +, additionally initiated via switch A + in the engine. Depending on Commutation state are alternately all switches of the bridge circuit A +, A-, B +, B- C +, C- operated switch 4 remains closed during the operating state described here. In the power supply accordingly 3 can be a factor 2 higher rated speed than the current in 1 can be achieved, however, the achievable torque of the engine is lower. This mode is described in the application example of a pump motor according to 1 chosen only for a short time to achieve a particularly high flow rate.

4a ) qualitatively shows the curve of the motor torque T versus the speed n for a motor drive in bipolar operation (solid line 5 ) and a motor control in unipolar operation 6 (solid line 6 ).

In 4 b) the torque curve T is shown as a function of the current. Curve 7 (solid line) represents the torque for bipolar operation, curve 8th (dashed line) corresponds to the torque curve in unipolar operation.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - EP 1236596 A1 [0003]
• US 5650886 [0004]

Claims (9)

A motor pump unit having an electronic drive circuit for the controlled control of an electric pump motor driving the pump, characterized in that the motor is a brushless electric motor and a brushless DC electric motor driving circuit is provided which drives the brushless electric motor, and wherein a winding changeover is provided, which provides an appropriate adjustment of the Engine torque and the speed allowed. Motor pump unit according to claim 1, characterized that by another electronics in the control electronics a first operating mode of the pump is selected in which more Motor windings are energized than in a second mode the pump, resulting in a higher engine torque in the first Operating mode results, and for temporarily increasing the speed in the second operating mode, only part of the motor windings are energized which results in a lower engine torque. Motor pump unit according to claim 1 or 2, characterized in that the motor is a multi-pole motor ( 1 ) with permanent magnetic or electromagnetic external excitation, which further comprises motor windings (A, B, C) and three motor terminals (a, b, c) which are connected to the drive circuit for electrical drive, which winding semiconductor switches (A +, A-, B +, B-, C +, C-), which are suitably controllable for a motor run, wherein the Ansteuerschal device is supplied by a DC voltage (V +). Motor pump unit according to at least one of the preceding claims, characterized in that the brushless DC electric motor drive circuit between positive supply potential (V +) and the reference potential (GND) of the circuit or before the winding semiconductor switches (A +, A-, B +, B-, C +, C-) a capacitor (C1) parallel to the voltage source, which by a semiconductor switch ( 4 ) can be separated from the operating voltage (V +), wherein the semiconductor switch ( 4 ) is preferably arranged between the capacitor and the positive supply potential (V +) and / or between the capacitor and the reference potential (GND). Motor pump unit according to at least one of the preceding claims, characterized in that the brushless DC electric motor drive circuit comprises at least one semiconductor neutral point switch ( 3 ), with which the neutral point of the motor, which is led out of the motor interior to the outside, can be temporarily connected for winding adaptation with a suitable potential. Motor pump unit according to claim 5, characterized in that that the neutral point potential to the positive supply voltage or the reference potential (GND) of a battery is placed. Motor pump unit according to at least one of the preceding Claims, characterized in that the control lines the semiconductor switch of an integrated th circuit, in particular be controlled by a microcontroller. Motor pump unit according to at least one of the preceding Claims, characterized in that the Abkommutierungsenergie one or more motor windings (A, B, C) in a capacity (C1) or inductance cached and to a later time fed to another motor winding again becomes. Use of the motor pump unit after at least one of the preceding claims in motor vehicles, in particular in a hydraulic motor vehicle brake pressure regulating unit.