Patent Description:
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> shows an electric machine drive arrangement <NUM> according to an illustrative example. The electric machine drive arrangement <NUM> comprises an electric machine <NUM>. The electric angular speed and the alternating current (as measured by an alternating current measurement unit <NUM>) are, together with a (direct current) voltage (UDC), provided as input to an electric machine controller <NUM>. The electric machine controller <NUM> controls a switching pattern of six switches <NUM> as provided in a motor drive system inverter <NUM>. A brake arrangement <NUM> comprises a braking resistor <NUM> connected in series with a direct current chopper <NUM> and/or a circuit breaker <NUM>. The brake arrangement <NUM> is controlled by a braking resistor controller <NUM>. The brake arrangement <NUM>, and thus the braking resistor <NUM>, is provided in a parallel circuit to the motor drive system inverter <NUM> and an electric energy storage system <NUM> comprising a battery or another type of energy storage circuitry <NUM>.

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 system <NUM> open, 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 resistor <NUM>, 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 controller <NUM> occurs. This will cause the brake performance of the braking resistor <NUM> to be lost.

<CIT> relates to a control system for an alternating current motor, such as an elevator hoisting induction motor.

<CIT> relates to a power system architecture for a hybrid electric vehicle that includes a power control unit including a motor inverter, a generator inverter, a DC-to-DC converter, and vehicle power management circuitry.

<CIT> relates to a power grid high-low voltage fault ride-through system based on driver with controllable rectifier bridge (in the technical field of wind power generation).

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, wherein the brake arrangement comprises a braking resistor circuit. 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, wherein the primary power feed connection (<NUM>) is connected to a primary low voltage power supply for the braking resistor controller. 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, orconverter, 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.

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

<FIG> illustrates an electric machine drive arrangement <NUM> for a heavy-duty vehicle according to a first embodiment.

The electric machine drive arrangement <NUM> comprises an electric machine <NUM>, a brake arrangement <NUM>, and a braking resistor controller <NUM>. The brake arrangement <NUM> is connected to the electric machine <NUM>. The braking resistor controller <NUM> is configured to control the brake arrangement <NUM>. The braking resistor controller <NUM> has a primary power feed connection (not illustrated in <FIG>; see <FIG>) and a back-up power feed connection (not illustrated in <FIG>; see <FIG>). The primary power feed connection is connected to a primary low voltage power supply (not illustrated in <FIG>; see <FIG>) for the braking resistor controller <NUM>. The back-up power feed connection is, over a connection <NUM>, connected to the AC side of the electric machine <NUM> for the electric machine <NUM> to supply back-up power to the braking resistor controller <NUM>.

By means of the back-up power feed being connected to the AC side of the electric machine <NUM>, during (electric) braking, the power generated by the electric electric machine <NUM> is supplied to the braking resistor controller <NUM>. According to this embodiment, the brake performance can be maintained even if the power of the vehicle communication system is lost. Hence, the brake arrangement <NUM> can 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> further illustrates additional components of the drive arrangement <NUM>. The electric angular speed and the alternating current (as measured by an alternating current measurement unit <NUM>) are, together with a DC voltage (UDC), a speed requirement and a torque requirement provided as input to an electric machine controller <NUM>. The electric machine controller <NUM> controls a switching pattern of switches as provided in a motor drive system inverter <NUM>. The motor drive system inverter <NUM> has an AC side for interfacing with the electric machine <NUM>. The brake arrangement <NUM> is connected in a parallel circuit to the motor drive system inverter <NUM> and an electric energy storage system <NUM> on the DC side of the motor drive system inverter <NUM>.

Reference is next made to the electric machine drive arrangement <NUM> of <FIG>. The electric machine drive arrangement <NUM> shows one illustrative realization of the electric machine drive arrangement <NUM>. A repeated description of components already described is omitted for brevity.

<FIG> shows the back-up power feed connection <NUM> provided in the braking resistor controller <NUM> being connected to the connection <NUM>. <FIG> further shows the primary power feed connection <NUM> in braking resistor controller <NUM>.

Further, in the realization exemplified by the electric machine drive arrangement <NUM>, six switches <NUM> in addition to two capacitors <NUM> are provided in the motor drive system inverter <NUM>. In the realization exemplified by the electric machine drive arrangement <NUM>, the electric machine controller <NUM> controls the switching pattern of the six switches <NUM>. In this respect, the motor drive system inverter <NUM> can be realized in several ways. In <FIG> is 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 machines <NUM> can be applied. Further, in the realization exemplified by the electric machine drive arrangement <NUM>, the energy storage system <NUM> is provided as a battery another type of energy storage circuitry <NUM>.

In the realization exemplified by the electric machine drive arrangement <NUM>, the brake arrangement <NUM> comprises a braking resistor circuit <NUM> realized as a braking resistor. The braking resistor circuit <NUM> is connected in series with a DC chopper <NUM> and/or a circuit breaker <NUM>. The the braking resistor circuit <NUM> is thus connectable to a control circuit <NUM>. That is, in the realization exemplified by the electric machine drive arrangement <NUM>, the braking resistor circuit <NUM> is a braking resistor. However, in other realizations of the electric machine drive arrangement <NUM>, the braking resistor circuit <NUM> is an electrical motor. The electrical motor is connectable to a mechanical brake circuit.

In the realization exemplified by the electric machine drive arrangement <NUM>, the control circuit <NUM> is a DC chopper circuit. However, in other realizations of the electric machine drive arrangement <NUM>, the control circuit <NUM> is a thyristor switch. In further detail, when, for example, considering an electric machine drive arrangement <NUM> with an asynchronous electric machine <NUM>, 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 controller <NUM> to 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> illustrates an electric machine drive arrangement <NUM> for a heavy-duty vehicle according to a second embodiment. A repeated description of components already described is omitted for brevity. The electric machine drive arrangement <NUM> differs from the electric machine drive arrangement <NUM> in that the electric machine drive arrangement <NUM> further comprises a rectifier arrangement <NUM>. The rectifier arrangement <NUM> is connected in parallel between the brake arrangement <NUM> and the motor drive system inverter <NUM> on the AC side of the motor drive system inverter <NUM>. Hence, the placement of the brake arrangement <NUM> is different in the embodiment of <FIG> compared to in the embodiment of <FIG>.

In the realization exemplified by the electric machine drive arrangement <NUM>, the rectifier arrangement <NUM> is a three-phase rectifier composed of diodes <NUM>.

<FIG> illustrates an electric machine drive arrangement <NUM> for 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 arrangement <NUM> (the back-up power feed connection of) the braking resistor controller <NUM> is connected to the AC side of the electric machine <NUM> via an auxiliary low voltage power supply <NUM>. The auxiliary low voltage power supply <NUM> is interconnected between the AC side of the electric machine <NUM> and (the back-up power feed connection of) the braking resistor controller <NUM>. If the operation of the MDS is blocked due to a fault, the electro-motoric force (EMF) of the electric machine <NUM> can thereby still provide the AC voltage needed during braking to power the drive units of the braking resistor controller <NUM>.

Further, in <FIG> is illustrated the primary low voltage power supply <NUM> being connected to (the primary power feed connection of) the braking resistor controller <NUM>. The primary low voltage power supply <NUM> might be connected to the braking resistor controller <NUM> over the vehicle communication system (not illustrated in <FIG>). 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 arrangement <NUM> as controlled by the braking resistor controller <NUM> is completely unaffected by this.

A DC/DC converter <NUM> is provided between a high voltage supply (i.e., the electric energy storage system <NUM>) and a low voltage power supply (i.e., the primary low voltage power supply <NUM>), and is arranged to provide power to the low voltage power supply to charge the low voltage energy storage. In addition, the DC/DC converter <NUM> will supply additional power to the low voltage loads.

Further, in the electric machine drive arrangement <NUM> the electric machine controller <NUM> comprises a power feed connection connected, over a connection <NUM>, to the auxiliary low voltage power supply <NUM> for the auxiliary low voltage power supply 610to supply power to the electric machine controller <NUM>.

Reference is next made to the auxiliary low voltage power supply <NUM> of <FIG>. The auxiliary low voltage power supply <NUM> shows one illustrative realization of the auxiliary low voltage power supply <NUM> in <FIG>.

The auxiliary low voltage power supply <NUM> comprises a rectifier for rectifying AC voltage supplied from the AC side of the electric machine <NUM> to a DC voltage that is provided to the back-up power feed connection <NUM>. In the realization of the auxiliary low voltage power supply <NUM> illustrated in <FIG>, the rectifier comprises six diodes <NUM>.

The auxiliary low voltage power supply <NUM> comprises a buck converter <NUM> for voltage control of the low voltage. The auxiliary low voltage power supply <NUM> comprises a capacitor <NUM> arranged for voltage stabilization and/or a low voltage stabilizer <NUM> as 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 capacitor <NUM> is arranged for mitigating DC voltage ripple and the capacitor <NUM> is arranged for the auxiliary low voltage power supply <NUM> to have a stable low voltage supply.

The auxiliary low voltage power supply <NUM> comprises a DC/DC converter which in <FIG> is realized as a buck-converter that consists of an insulated-gate bipolar transistor (IGBT) <NUM> and diodes <NUM>, <NUM>. The duty cycle of the switching of the IGBT <NUM> in the buck-converter regulates the low voltage in the auxiliary low voltage power supply <NUM>.

The herein disclosed electric machine drive arrangements <NUM>:<NUM> are suitable for use in a vehicle <NUM>, such as a heavy-duty vehicle. <FIG> schematically illustrates a vehicle <NUM> comprising an electric machine drive arrangement <NUM>:<NUM> as herein disclosed. In some embodiments, the vehicle <NUM> is a heavy-duty vehicle. In this respect, the present inventive concept is applicable to different types of heavy-duty vehicles <NUM>, such as, but not limited to, trucks, buses and construction equipment.

Claim 1:
An electric machine drive arrangement (<NUM>:<NUM>) for a heavy-duty vehicle (<NUM>), comprising:
an electric machine (<NUM>);
a brake arrangement (<NUM>) connected to the electric machine (<NUM>), wherein the brake arrangement (<NUM>) comprises a braking resistor circuit (<NUM>); and
a braking resistor controller (<NUM>) configured to control the brake arrangement (<NUM>), wherein the braking resistor controller (<NUM>) has a primary power feed connection (<NUM>) and a back-up power feed connection (<NUM>), wherein the primary power feed connection (<NUM>) is connected to a primary low voltage power supply for the braking resistor controller (<NUM>), and wherein the back-up power feed connection (<NUM>) is connected to an alternating current, AC, side of the electric machine (<NUM>) for the electric machine (<NUM>) to supply back-up power to the braking resistor controller (<NUM>).