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WO-2026092834-A1 - MOTOR VEHICLE DRIVE

WO2026092834A1WO 2026092834 A1WO2026092834 A1WO 2026092834A1WO-2026092834-A1

Abstract

The invention relates to a drive (10) of a motor vehicle (2), in particular of an ancillary unit (8), having a brushless DC motor (38) with three phases (40). The drive (10) further comprises a converter (26), which has a first connection (28) for a positive pole (20), a second connection (30) for a negative pole (22), and a third connection (32) for a mid-potential (24), and which has two bridge branches (34), each comprising two switching elements (36) electrically connected in series that have a centre tap (48) formed between them in each case. The two bridge branches (34) are each connected between the first connection (28) and the second connection (30), and the centre tap (48) of each bridge branch is routed towards a phase connection (44) of one of the phases (40). The third connection (32) is routed towards a phase connection (44) of the remaining phase (40). The invention also relates to a method for operating a drive (10) and to a circuit (14).

Inventors

  • KOCOWICZ, Arkadiusz

Assignees

  • Brose Fahrzeugteile SE & Co. Kommanditgesellschaft, Würzburg

Dates

Publication Date
20260507
Application Date
20241029

Claims (9)

  1. 1. Drive (10) of a motor vehicle (2), in particular of an auxiliary unit (8), with a brushless DC motor (38) having three phases (40), and with an inverter (26) having a first connection (28) for a positive pole (20), a second connection (30) for a negative pole (22) and a third connection (32) for a center potential (24), and having two bridge branches (34) each with two switching elements (36) connected in series, between which a center tap (48) is formed, wherein the two bridge branches (34) are each connected between the first connection (28) and the second connection (30) and their center tap (48) is connected to a phase connection (44) of one of the phases (40), and wherein the third connection (32) is connected to a phase connection (44) of the remaining phase (40).
  2. 2. Drive (10) according to claim 1 , characterized in that the three phases (40) are connected together in a star connection.
  3. 3. Drive (10) according to claim 1 or 2, characterized by a control circuit (50) by means of which the switching elements (36) are actuated in pulse width modulation.
  4. 4. Method for operating a drive (10) according to claim 3, wherein a duty cycle for the switching elements (36) is determined as a function of a power requirement (58), by means of which the switching elements (36) are actuated, wherein the duty cycle is extended when the phase (40) directed towards the third terminal (32) is energized. Page 19
  5. 5. Circuit (14) of a motor vehicle (2), comprising a voltage source (12) which is electrically connected to a drive (10) according to one of claims 1 to 3.
  6. 6. Circuit (14) according to claim 5, characterized in that the voltage source (12) is a battery (16) comprising two battery modules (18) connected electrically in series, wherein the series connection is between the first terminal (28) and the second terminal (30), and wherein each battery module (18) is electrically connected to the third terminal (32).
  7. 7. Circuit (14) according to claim 6, characterized in that the battery modules (18) are identical in construction to each other.
  8. 8. Circuit (14) according to claim 5, characterized in that the voltage source (12) is an AC voltage source (60) with two AC voltage connections (62) which is electrically connected to the converter (24) via a rectifier (64).
  9. 9. Circuit (14) according to claim 8, characterized in that the first terminal (28) is electrically connected to both AC terminals (62) via a diode (66) and the second terminal (30) is electrically connected to both AC terminals (62) via a diode (44), and wherein the third terminal (32) is electrically connected to one of the AC terminals (62), and wherein a capacitor (68) is connected between the first terminal (28) and the third terminal (32) and between the second terminal (30) and the third terminal (32).

Description

Page 1 2023 223 WO Description Motor vehicle drive The invention relates to a drive system for a motor vehicle. The drive system comprises a frequency converter and a three-phase brushless DC motor. The invention further relates to a method for operating a drive system and to a circuit with such a drive system. Motor vehicles have a variety of drive systems that generate movement during operation. One such drive system is a main drive, which propels the entire vehicle. Alternatively, the drive system can be a component of an auxiliary unit, which does not directly contribute to the vehicle's propulsion. Examples of such an auxiliary unit include a pump, such as an oil or water pump, or an electric air conditioning compressor. In another configuration, the auxiliary unit is an actuator, which drives an adjustable component along a defined path. This adjustable component could be, for example, a window pane, a sunroof, a seat, or part of a seat. The drive system typically consists of an electric motor that generates the movement. For this purpose, the electric motor has several electrical coils that interact with the motor's permanent magnets during operation. The electric motor is, for example, a brushed commutator motor. To increase efficiency, it is increasingly being designed as a brushless direct current (BLDC) motor. In this case, the electrical coils are connected in multiple phases, usually three phases, and a frequency converter is typically used to supply power to these phases. The frequency converter has a bridge circuit, which, according to the number of... Page 2 The inverter is designed with phases. Each phase is assigned a bridge branch, which includes two semiconductor switches. For a three-phase electric motor, a total of six semiconductor switches are therefore required, which is why the inverter's space requirements and manufacturing costs are comparatively high. The invention is based on the objective of providing a particularly suitable drive system for a motor vehicle, a particularly suitable method for operating a drive system, and a particularly suitable electrical circuit, advantageously reducing manufacturing costs and/or weight. With regard to the drive, this problem is solved according to the invention by the features of claim 1, with regard to the method by the features of claim 4, and with regard to the circuit by the features of claim 5. Advantageous further developments and embodiments are the subject of the respective dependent claims. The drive system is a component of a motor vehicle. In other words, the drive system is suitable, specifically designed and configured, to form a component of the motor vehicle in its assembled state. The motor vehicle is primarily intended for land use and preferably has multiple tracks. It is suitably possible to position the motor vehicle essentially freely, preferably on a suitable roadway. For this purpose, the motor vehicle expediently has appropriate wheels. In summary, it is preferably possible to position the motor vehicle on land essentially independently of other conditions. In other words, the motor vehicle is suitably not rail-guided. Preferably, the motor vehicle is a passenger car or a commercial vehicle, such as a truck or bus. The drive is, for example, a component of the main drive system of the motor vehicle, by means of which the motor vehicle is thus moved during operation. Particularly preferably, however, the drive is a component of an auxiliary unit of the motor vehicle, by means of which the motor vehicle is not directly propelled. Page 3 is created. In particular, the drive is a component of an adjustment mechanism, such as a seat adjustment or a window regulator. Alternatively, the drive is, for example, a component of a pump, such as a water pump or an oil pump. In another alternative, the drive is, for example, a component of a transmission actuator, and the auxiliary unit is, in particular, a transmission. In yet another alternative, the drive is, for example, a component of an air conditioning compressor. In yet another alternative, the auxiliary unit is a steering or braking system. The drive system features a three-phase brushless DC motor. In other words, the brushless DC motor (BLDC), which will also be referred to simply as a DC motor or electric motor, has several electrical coils connected to the three phases. Advantageously, each phase is assigned the same number of electrical coils. For example, each phase may have exactly one electrical coil. Preferably, however, each phase comprises at least two or more of these coils. Each phase has two phase terminals, which form the ends of each phase. Therefore, if there is a different electrical potential at the two phase terminals of the respective phase, the corresponding electrical coil(s) will be energized. Advantageously, the three phases are a component of the stator of the DC motor. The electric motor (DC motor) further comprises a rotor to which one or mor