Electric machine drive arrangement for a heavy-duty vehicle

An electric machine drive arrangement for a heavy-duty vehicle. The electric machine drive arrangement comprises an electric machine. The electric machine drive arrangement further comprises a brake arrangement connected to the electric machine. The electric machine drive arrangement further comprises a braking resistor controller configured to control the brake arrangement. The braking resistor controller has a primary power feed connection and a back-up power feed connection. The back-up power feed connection is connected to an alternating current side of the electric machine for the electric machine to supply back-up power to the braking resistor controller.

RELATED APPLICATIONS

The present application claims priority to European Patent Application No. 22159365.0, filed on Mar. 1, 2022, and entitled “ELECTRIC MACHINE DRIVE ARRANGEMENT FOR A HEAVY-DUTY VEHICLE,” which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

Embodiments presented herein relate to an electric machine drive arrangement for a heavy-duty vehicle. Embodiments presented herein further relate to a vehicle comprising such an electric machine drive arrangement.

BACKGROUND

In general terms, the purpose of a braking resistor is to quickly stop or slow down a mechanical system by producing a braking torque. Commonly, a braking resistor is connected in series with a chopper or with a circuit breaker on the direct current (DC) side of the electric motor drive system (MDS) in vehicles.

FIG.1shows an electric machine drive arrangement100according to an illustrative example. The electric machine drive arrangement100comprises an electric machine110. The electric angular speed and the alternating current (as measured by an alternating current measurement unit170) are, together with a (direct current) voltage (UDC), provided as input to an electric machine controller160. The electric machine controller160controls a switching pattern of six switches122as provided in a motor drive system inverter120. A brake arrangement130comprises a braking resistor132connected in series with a direct current chopper134and/or a circuit breaker136. The brake arrangement130is controlled by a braking resistor controller150. The brake arrangement130, and thus the braking resistor132, is provided in a parallel circuit to the motor drive system inverter120and an electric energy storage system140comprising a battery or another type of energy storage circuitry142.

In general terms, electronic drive units for power electronics are powered from low voltage (LV) power systems and controlled from the vehicle communication system (such as a controller area network (CAN). If the contactors of the electric energy storage system140open, the MDS for (propulsion) will go into DC voltage control, maintaining the DC voltage to supply the LV power system from DC/DC converters. This will help to maintain the brake performance of the braking resistor132, whilst the DC voltage control of the MDS will handle the load rejection caused by the braking resistor requesting active power from the current control of the electric motor. Consequently, the electric motor will provide brake power correspondingly to the power of the braking resistor to maintain the DC voltage.

However, consider a brake scenario where a fault occurs that shuts down the electronic control unit (ECU) of the MDS or the vehicle communication system, or where a loss of LV power to the MDS and the braking resistor controller150occurs. This will cause the brake performance of the braking resistor132to be lost.

SUMMARY

An object of the embodiments disclosed herein is to address the issues noted above.

A particular object of the embodiments disclosed herein is to provide an electric machine drive arrangement addressing the above issues

According to a first aspect, the object is achieved by an electric machine drive arrangement for a heavy-duty vehicle. The electric machine drive arrangement comprises an electric machine. The electric machine drive arrangement further comprises a brake arrangement connected to the electric machine. The electric machine drive arrangement further comprises a braking resistor controller configured to control the brake arrangement. The braking resistor controller has a primary power feed connection and a back-up power feed connection. The back-up power feed connection is connected to an alternating current side of the electric machine for the electric machine to supply back-up power to the braking resistor controller.

According to a second aspect, the object is achieved by a vehicle comprising an electric machine drive arrangement according to the first aspect.

Advantageously, the disclosed electric machine drive arrangement enables the brake performance to be maintained even if the power of the vehicle communication system is lost. This enables the brake arrangement to be controlled independently of the primary low voltage power supply and the communication over the vehicle communication system of the vehicle to maintain brake performance.

According to an embodiment, the back-up power feed connection is connected to the AC side of the electric machine via an auxiliary low voltage power supply interconnected between the AC side of the electric machine and the back-up power feed connection. The auxiliary low voltage power supply comprises a rectifier for rectifying AC voltage supplied from the AC side of the electric machine to a low voltage DC voltage that is provided to the back-up power feed connection. Advantageously, in case of loss of low voltage supply power, this auxiliary low power supply will enable the braking resistor functions to maintain vehicle brake functionality.

According to an embodiment, the electric machine drive arrangement further comprises an electric machine controller configured to control the electric machine, where the electric machine controller comprises a power feed connection connected to the AC side of the electric machine for the electric machine to supply power to the electric machine controller. Advantageously, this enables the auxiliary low power supply to enable the electric machine controller, including power electronic drivers in the inverter, or converter, to maintain its functionality in cases of lost power and/or communication within the vehicle.

Further advantages and advantageous features of the inventive concept are disclosed in the following description and in the dependent claims.

DETAILED DESCRIPTION

According to the herein disclosed embodiments there is provided an electric machine drive arrangement for a heavy-duty vehicle addressing the above issues.

FIG.2illustrates an electric machine drive arrangement200for a heavy-duty vehicle according to a first embodiment.

The electric machine drive arrangement200comprises an electric machine110, a brake arrangement130, and a braking resistor controller150. The brake arrangement130is connected to the electric machine110. The braking resistor controller150is configured to control the brake arrangement130. The braking resistor controller150has a primary power feed connection (not illustrated inFIG.2; seeFIG.3) and a back-up power feed connection (not illustrated inFIG.2; seeFIG.3). The primary power feed connection is connected to a primary low voltage power supply (not illustrated inFIG.2; seeFIG.6) for the braking resistor controller150. The back-up power feed connection is, over a connection210, connected to the AC side of the electric machine110for the electric machine110to supply back-up power to the braking resistor controller150.

By means of the back-up power feed being connected to the AC side of the electric machine110, during (electric) braking, the power generated by the electric machine110is supplied to the braking resistor controller150. According to this embodiment, the brake performance can be maintained even if the power of the vehicle communication system is lost. Hence, the brake arrangement130can be controlled independently of the primary low voltage power supply and the communication over the vehicle communication system of the vehicle to maintain brake performance.

FIG.2further illustrates additional components of the drive arrangement200. The electric angular speed and the alternating current (as measured by an alternating current measurement unit170) are, together with a DC voltage (UDC), a speed requirement and a torque requirement provided as input to an electric machine controller160. The electric machine controller160controls a switching pattern of switches as provided in a motor drive system inverter120. The motor drive system inverter120has an AC side for interfacing with the electric machine110. The brake arrangement130is connected in a parallel circuit to the motor drive system inverter120and an electric energy storage system140on the DC side of the motor drive system inverter120.

Reference is next made to the electric machine drive arrangement300ofFIG.3. The electric machine drive arrangement300shows one illustrative realization of the electric machine drive arrangement200. A repeated description of components already described is omitted for brevity.

FIG.3shows the back-up power feed connection320provided in the braking resistor controller150being connected to the connection210.FIG.3further shows the primary power feed connection330in braking resistor controller150.

Further, in the realization exemplified by the electric machine drive arrangement300, six switches122in addition to two capacitors124are provided in the motor drive system inverter120. In the realization exemplified by the electric machine drive arrangement300, the electric machine controller160controls the switching pattern of the six switches122. In this respect, the motor drive system inverter120can be realized in several ways. InFIG.3is illustrated a two-level voltage sources converter. However, the proposed electric machine drive arrangements are not limited to such a topology. The electric machine drive arrangements could be realized using any multi-level configuration and also two-phase and multi-phase electric machines110can be applied. Further, in the realization exemplified by the electric machine drive arrangement300, the energy storage system140is provided as a battery another type of energy storage circuitry142.

In the realization exemplified by the electric machine drive arrangement300, the brake arrangement130comprises a braking resistor circuit132realized as a braking resistor. The braking resistor circuit132is connected in series with a DC chopper134and/or a circuit breaker136. The braking resistor circuit132is thus connectable to a control circuit134. That is, in the realization exemplified by the electric machine drive arrangement300, the braking resistor circuit132is a braking resistor. However, in other realizations of the electric machine drive arrangement200, the braking resistor circuit132is an electrical motor. The electrical motor is connectable to a mechanical brake circuit.

In the realization exemplified by the electric machine drive arrangement300, the control circuit134is a DC chopper circuit. However, in other realizations of the electric machine drive arrangement200, the control circuit134is a thyristor switch. In further detail, when, for example, considering an electric machine drive arrangement200with an asynchronous electric machine110, the DC chopper circuit can be exchanged with a thyristor switch. The thyristor switch will stop conducting when the current is zero. This is achieved by setting the reactive current in the electric machine controller160to zero. By that, the rotor magnetic field will go to zero and the induced voltage will go to zero. By that, the current will be zero.

FIG.4illustrates an electric machine drive arrangement400for a heavy-duty vehicle according to a second embodiment. A repeated description of components already described is omitted for brevity. The electric machine drive arrangement400differs from the electric machine drive arrangement200in that the electric machine drive arrangement400further comprises a rectifier arrangement410. The rectifier arrangement410is connected in parallel between the brake arrangement130and the motor drive system inverter120on the AC side of the motor drive system inverter120. Hence, the placement of the brake arrangement130is different in the embodiment ofFIG.4compared to in the embodiment ofFIG.2.

Reference is next made to the electric machine drive arrangement500ofFIG.5. The electric machine drive arrangement500shows one illustrative realization of the electric machine drive arrangement400. A repeated description of components already described is omitted for brevity.

In the realization exemplified by the electric machine drive arrangement500, the rectifier arrangement410is a three-phase rectifier composed of diodes512.

FIG.6illustrates an electric machine drive arrangement600for a heavy-duty vehicle according to a third embodiment. A repeated description of components already described is omitted for brevity.

In the electric machine drive arrangement600(the back-up power feed connection of) the braking resistor controller150is connected to the AC side of the electric machine110via an auxiliary low voltage power supply610. The auxiliary low voltage power supply610is interconnected between the AC side of the electric machine110and (the back-up power feed connection of) the braking resistor controller150. If the operation of the MDS is blocked due to a fault, the electro-motoric force (EMF) of the electric machine110can thereby still provide the AC voltage needed during braking to power the drive units of the braking resistor controller150.

Further, inFIG.6is illustrated the primary low voltage power supply620being connected to (the primary power feed connection of) the braking resistor controller150. The primary low voltage power supply620might be connected to the braking resistor controller150over the vehicle communication system (not illustrated inFIG.6). If there is an additional (back-up) power supply from the AC side circuit that powers the ECU to the DC chopper as well as the drive units to the DC chopper, it will become fail-safe if high voltage system is shutting down during braking. Hence, the brake performance of the braking resistor will be maintained. This applies also if the vehicle completely loses low voltage power supply and all ECUs shutdown, or if loss of communication over the vehicle communication system occurs. Hence, the operation of the brake arrangement130as controlled by the braking resistor controller150is completely unaffected by this.

A DC/DC converter630is provided between a high voltage supply (i.e., the electric energy storage system140) and a low voltage power supply (i.e., the primary low voltage power supply620), and is arranged to provide power to the low voltage power supply to charge the low voltage energy storage. In addition, the DC/DC converter630will supply additional power to the low voltage loads.

Further, in the electric machine drive arrangement600the electric machine controller160comprises a power feed connection connected, over a connection210, to the auxiliary low voltage power supply610for the auxiliary low voltage power supply610to supply power to the electric machine controller160.

Reference is next made to the auxiliary low voltage power supply610ofFIG.7. The auxiliary low voltage power supply610shows one illustrative realization of the auxiliary low voltage power supply610inFIG.6.

The auxiliary low voltage power supply610comprises a rectifier for rectifying AC voltage supplied from the AC side of the electric machine110to a DC voltage that is provided to the back-up power feed connection320. In the realization of the auxiliary low voltage power supply610illustrated inFIG.7, the rectifier comprises six diodes740.

The auxiliary low voltage power supply610comprises a buck converter720for voltage control of the low voltage. The auxiliary low voltage power supply610comprises a capacitor750arranged for voltage stabilization and/or a low voltage stabilizer710as well as for short time low voltage power reserve when the machine speed is low or at stand still, also during anti-lock brake system (ABS) events. Particularly, the capacitor750is arranged for mitigating DC voltage ripple and the capacitor710is arranged for the auxiliary low voltage power supply610to have a stable low voltage supply.

The auxiliary low voltage power supply610comprises a DC/DC converter which inFIG.7is realized as a buck-converter that consists of an insulated-gate bipolar transistor (IGBT)770and diodes730,760. The duty cycle of the switching of the IGBT770in the buck-converter regulates the low voltage in the auxiliary low voltage power supply610.

The herein disclosed electric machine drive arrangements200:600are suitable for use in a vehicle800, such as a heavy-duty vehicle.FIG.8schematically illustrates a vehicle800comprising an electric machine drive arrangement200:600as herein disclosed. In some embodiments, the vehicle800is a heavy-duty vehicle. In this respect, the present inventive concept is applicable to different types of heavy-duty vehicles800, such as, but not limited to, trucks, buses and construction equipment.