DE102019212048A1 - Drive train for a mixer drum, control device for such a drive train and method for operating such a drive train - Google Patents

Abstract

A drive train for a mixer drum (MT) is proposed, the drive train having a generator (G) which outputs a first alternating voltage to a first converter (SR1), the first converter (SR1) being connected to a high-voltage direct voltage network (HVN) . A second converter (SR2) is also provided, which is connected to the high-voltage direct voltage network (HVN) and which supplies an electric motor (CMe) for driving the mixer drum (MT) with a second alternating voltage. The drive train also has a high-voltage battery (HV-BAT), which is connected to the high-voltage direct voltage network (HVN). In addition, an onboard charger is connected to the high-voltage DC voltage network. The onboard charger rectifies the connected external AC voltage and converts it to high-voltage DC voltage. A DC voltage connection is also connected to the high-voltage DC voltage network, the DC voltage connection converting an external DC voltage to the high-voltage DC voltage. Finally, a control device is also provided that is connected to the first and second power converters or the battery and thus controls a flow of energy via the high-voltage DC voltage network. The control unit is configured in such a way that the high-voltage battery is charged either via the generator or the onboard charger or the DC voltage connection.

Description

The invention relates to a drive train for a mixer drum, a control device for such a drive train and a method for operating such a drive train according to the preamble of the independent claims.

Out EP 2 807 007 B1 a truck mixer is known with a device for rotating the drum of the concrete mixer. The drum is driven by an electric motor. The electric motor is supplied with AC voltage via an inverter, with the inverter drawing its energy from a battery. The battery can be supplied by a generator or the mains. Appropriate rectifiers are then provided for this. Recuperation from the drive train for charging the battery is also known. Out EP 2 719 510 A1 a drive train for a concrete mixer is known. This drive train includes an electric motor, a connection to the power grid, and the drive train includes a generator for generating electrical power and a battery. Furthermore, an inverter is provided which supplies the electric motor for driving the drum.

The drive train according to the invention for a mixer drum or the control device according to the invention or the method according to the invention with the features of the independent claims have the advantage that the high-voltage battery is only charged by one energy source. The other energy sources are then used for the drum drive or other electrical applications. In particular, a control device is provided which is connected to the power converters and the battery and possibly other components and controls a flow of energy via a high-voltage DC voltage network. A converter is connected to this high-voltage DC voltage network, which then supplies the electric motor with AC voltage. This high level of flexibility via the high-voltage network and control via the control unit enable the drive train to be designed in a cost-effective and flexible manner. Conventional components can thus be used.

The control device, and thus in particular the control device software, is configured in such a way that only one energy source charges the battery.

A drive train is therefore proposed, which is provided for a mixer drum, with a generator which outputs an alternating voltage to a first converter, the first converter being connected to a high-voltage direct voltage network. The drive train also has a second converter which is also connected to the high-voltage direct voltage network and which supplies an electric motor for driving the mixer drum with a further alternating voltage. Furthermore, a high-voltage battery is provided, which is connected to the high-voltage DC voltage network. In addition, an onboard charger and a DC voltage connection are connected to the high-voltage DC voltage network, the onboard charger and the DC voltage connection converting the respective external electrical energy to the high-voltage DC voltage. In addition, the control device is provided, which is connected to the first and second power converters and / or the battery and thus controls a flow of energy via the high-voltage DC voltage network. In other words, the control unit specifies which components are to be supplied to the high-voltage DC voltage network and how much energy. The control unit can use values from the components for this. The control unit is configured in such a way that the high-voltage battery is charged either by the generator or by the onboard charger or by the DC voltage connection.

Furthermore, a corresponding control unit and method for operating this drive train are proposed.

In the present case, a drive train is understood to mean the combination of the components that are necessary for driving the mixer drum in order to understand the invention. The drive train can of course also comprise further components, but these are not necessary for the definition of the invention.

The mixer drum is a known drum in which concrete or cement or some other material is subjected to a rotation in order to mix this material accordingly. This material is then usually used on construction sites for the construction of buildings. A mixer drum is usually placed on a so-called trailer that is moved by a tractor. It can also be a one-piece mixer vehicle, a so-called fixed structure, tractor and trailer are then not separate or can be separated.

In the present case, a generator is to be understood as a device that generates alternating voltage from direct voltage. For this purpose, an asynchronous machine is used here and switched as a generator. The asynchronous machine has a simple structure and supplies the corresponding alternating voltage. This alternating voltage is usually three-phase.

A power converter is to be understood as meaning, in particular, inverters which convert AC voltage to DC voltage or vice versa. Such inverters have a DC voltage part with a so-called intermediate circuit and a further part that generates an AC voltage from the DC voltage by providing power switching elements that quasi chop the DC voltage and thus convert it into an AC voltage.

In the present case, a high-voltage DC voltage network is to be understood as an electrical connection that exists between the components and at which a voltage of preferably 650 V is applied. This voltage has proven to be very advantageous because it involves low conduction losses. This means that the components that are connected to this high-voltage DC voltage network absorb or output a voltage of 650 V.

In the present case, the electric motor is also preferably to be understood as an asynchronous machine and which is thus supplied with the corresponding three-phase alternating voltage by the second converter. Usually, when necessary, the electric motor is not connected directly to the mixer drum, but via a gear, preferably a reduction gear.

A high-voltage battery is to be understood as a battery that is designed in such a way that it emits the voltage at 650 V, for example. Such a battery has a capacity of 32 kWh, for example. During operation, for example, a continuous output of 50 kW and a short-term peak output of 80 kW can be called up. In the present case, as shown below, so-called battery management is also provided, which is ensured on the one hand on the control device of the battery itself, but also by the control device according to the claims, with which the battery control device communicates, for example via a CAN bus. In this way, the amount of energy present in the battery and the electrical parameters are checked, checked for plausibility and determined.

Furthermore, it is provided that an onboard charger is connected to the high-voltage DC voltage network, which rectifies a connected external AC voltage and converts it to the high-voltage DC voltage. In this way, when the mixer vehicle is at a standstill, for example overnight, in particular the battery can be charged or, even if the battery fails, a direct supply of the high-voltage DC voltage network can be established.

In addition, it is possible that there is a DC voltage connection which is connected to the high-voltage DC voltage network and converts an external DC voltage to the high-voltage DC voltage. A corresponding DC voltage converter is then also to be provided for this, which preferably also has galvanic isolation.

It is also advantageous that the control device is connected to the onboard charger and the DC voltage connection in order to regulate the flow of energy via the high-voltage DC voltage network.

The control device according to the invention is to be understood as a control device that is connected to the converters and / or the battery and controls the flow of energy via the high-voltage DC voltage network. The control unit achieves this by removing or connecting individual components from this high-voltage DC voltage network or by influencing the absorption or output of energy. For this purpose, the control device is technically connected to this component data, for example via a CAN bus or a direct data line or another data bus.

In the present case, the energy flow is understood to mean the flow of electrical energy via the high-voltage direct voltage network.

The control unit per se receives these signals as sensor signals, whereby these signals can be already processed sensor signals and uses them to generate control signals for the energy flow. Of course, there are also other signals present, for example an input (not shown) by the user that influences the functions of the control unit. For this purpose, the control device has a computer, preferably a microcontroller, interfaces and preferably also a housing.

The procedure runs accordingly.

Advantageous refinements of the invention are defined by the dependent claims.

It is provided that a DC voltage converter is connected to the high-voltage DC voltage network, which derives a low voltage from the high-voltage DC voltage to supply further components. Such a low voltage is, for example, 24 V and is therefore in a range from 20 to 40 V. However, other voltage ranges are also possible. The DC voltage converter is in particular galvanically separated so that there is no direct electrical connection between the low voltage and the high voltage voltage. This can be done inductively, for example, but a capacitive solution is also possible.

Furthermore, it is provided that the further components are a chute adjustment or a driven drum cover or a cooling system. The chute adjustment is intended for the drainage of the building material and this flows via a line, which is referred to here as chutes. The driven drum cover must be closed in particular when the concrete mixer is traveling downhill, for example, so that no building material escapes through the cover. The power of the tractor's electrical system is far from sufficient for these components. This solution is therefore advantageous over the additional DC voltage converter. Alternatively, it is possible to use a separate 24 V battery or another low-voltage battery.

In addition, it is provided that the control device furthermore has at least the following functions: speed control for the mixer drum, monitoring of a maximum speed of the mixing drum, further monitoring of a predetermined direction of rotation, holding of the mixer drum, compensation for an uneven distribution of a material, So the building material in the mixer drum, and a torque control for the mixer drum. These functions are provided in addition to regulating the flow of energy via the high-voltage DC voltage network.

The speed control reacts in particular to an input by a user in that the mixer drum is then adjusted to this input speed. This can also be done on the system side, depending on the constellation. The monitoring of the maximum speed is a safety function so that such a maximum speed is not exceeded. It may be necessary to hold the mixer drum in certain operating states and is then set by this control unit. Compensating for an uneven distribution of the building material in the mixer drum is also a function that can be used regularly, for example, when the mixer drum is full. Depending on the application, the control unit also has to provide torque control. The control device is connected in particular to the second converter, which itself has signal processing in order to implement such requirements. The second converter can also have such functions itself, at least in rudimentary form, in order to then implement them via the electric motor. These functions ensure that the electric motor is controlled accordingly. The speed and torque of the mixer drum are determined by the electric motor.

It is also provided that the second converter transmits data to the control unit, the data being derived from at least the following values: a first temperature value of the electric motor, which in particular reflects the temperature of the coils, and / or a second temperature value of the converter itself and / or a speed of the electric motor, from which the speed of the mixer drum can then be derived. As shown above, the converter can already preprocess these values and then transfer them to the control unit accordingly. Corresponding temperature sensors and speed sensors are provided for this purpose, which provide these values directly or indirectly.

It is also provided that the first and second power converters and the DC / DC converter are housed together in a switch cabinet. This means that the entire power electronics and also the control devices, the DC voltage converter, the high-voltage DC voltage network with appropriate fuses and the low-voltage distribution can be accommodated in a switch cabinet. This means that all electronic components are also protected from the demanding everyday work on the construction site.

Furthermore, it is provided that at least one pilot contact is provided, which connects components of the drive train on the tractor and the trailer. In this case, it is to be avoided that arcing or dangerous situations arise when the components on the tractor and trailer are physically separated. This could result in an electric arc or electric shock. This is prevented by the pilot contact. This pilot contact is intended to interrupt the control current for systems when the connection is pulled under load or to trigger a contactor in order to disconnect the circuit at a switch designed for this purpose before this happens at the plug connection. The pilot contact is there to connect the plug to the neutral conductor. This means that a contactor drive can be switched to the neutral conductor via one of the outer conductors and thus switch off the device before the plug contacts are disconnected. The contactor or contactor is an electrically or electromagnetically operated switch for a large electrical output and is similar to a relay. The contactor knows two switch positions and normally switches to monostable without special precautions.

Exemplary embodiments of the invention are shown in the drawing and are explained in more detail in the following description.

• 1 ein erstes Blockschaltbild des erfindungsgemäßen Antriebsstrangs;
• 2 ein zweites Blockschaltbild des erfindungsgemäßen Antriebsstrangs;
• 3 ein drittes Blockschaltbild des erfindungsgemäßen Antriebsstrangs;
• 4 ein Blockschaltbild des erfindungsgemäßen Steuergeräts und
• 5 ein Flussdiagramm des erfindungsgemäßen Verfahrens.

Show it

• 1 a first block diagram of the drive train according to the invention;
• 2 a second block diagram of the drive train according to the invention;
• 3 a third block diagram of the drive train according to the invention;
• 4th a block diagram of the control device according to the invention and
• 5 a flow chart of the method according to the invention.

1 shows the drive train according to the invention in a block diagram. An external energy source, for example a direct current or alternating current connection, for example via a wallbox XE is connected to a charging electronics LE connected. In the charging electronics LE a rectification or a conversion to the high-voltage voltage can take place at 650 V, for example. This charging electronics LE , which can also be referred to as an onboard charger or DC connection or both, is controlled by the control unit eDCU controlled. The charging electronics are responsible for providing the high-voltage DC voltage LE to the high-voltage network HVN connected. Ultimately, this is a high-voltage intermediate circuit. The control line from the central control unit eDCU to power electronics LE is with ST1 designated. To the high-voltage network HVN is still the converter SR1 connected to an AC voltage from the generator G which it rectifies and converts to high-voltage DC voltage. The generator G is mechanical and electrical with the internal combustion engine VM connected, for example via a so-called power take-off. The generator then converts the energy that comes from the internal combustion engine into electrical energy and an alternating voltage. The converter SR1 is also via the central control unit eDCU via the control line ST3 controlled. In the present case, the control lines can be a data bus, for example a CAN bus. Furthermore to the high-voltage network HVN is the high-voltage battery HVB connected to energy for battery charging HVB to be taken or made available. These modes are controlled by the battery control unit B-SG set. This battery control unit too B-SG is from the central control unit eDCU controlled via the control line ST4. Furthermore to the high-voltage network HVN is the second converter SR2 connected, which converts the high-voltage DC voltage to an AC voltage for the electric motor CMe generated. This converter too SR2 is controlled by the central control unit via the control line ST2.

The electric motor CMe is with a reduction gear RG connected and then to the mixer drum MT to ultimately drive the drum.

According to the invention, the battery HVB only charged from a component that provides energy. Consequently, either the charge can be obtained from the external energy source XE or the generator G respectively. Since no switch is provided in the present case to switch only one energy source to the battery in order to charge the battery, the energy is provided logically. That is, it ensures that only those from the generator G electrical energy provided for charging the battery HVB is used. The other energy source, for example the external energy source here, then supplies the energy for other components, such as the electric motor CMe to drive the mixer drum MT . The provided direct currents are superimposed on the high-voltage direct voltage network HVN , but logically they are assigned to the respective applications. Alternatively, as I said, a circuit is possible so that only one line is then between the generator and the converter SR1 and the high-voltage battery or just for the charging electronics and the high-voltage battery. Then there is a kind of mediation which then switches physical lines between the necessary components. It is then a kind of channel switching. Additional components can be connected to the high-voltage DC voltage network HVN be connected.

2 now shows in the block diagram how the energy flows run separately. The energy from the generator G that ultimately from the internal combustion engine VM is provided, is via the first converter SR1 and the line 21st to the battery HVB transferred to the battery HVB to charge. In contrast, the energy comes from the external power source XE about the power electronics LE and the line 20th to the second converter SR2 which then transfers the alternating voltage for the electric motor CMe so that it can rotate. This then uses the reduction gear RG the mixer drum MT driven.

3 shows the upside down case. Now supplies the external energy source XE about the power electronics LE and the line 30th the battery with electricity to charge it. In contrast, the energy from the combustion engine is now VM about the generator G and the first converter SR1 to the second converter SR2 passed to the AC voltage for the electric motor CMe to generate. Again is between the electric motor CMe and the mixer drum MT the reduction gear RG intended.

4th shows the control device according to the invention in a block diagram eDCU , which is usually located in a housing. Only the components necessary for understanding the invention are shown here. Via a bus interface CAN-IF for the so-called CAN bus data is received and sent. The microcontroller μC is connected to this interface, on which functions F1, F2 and F3, for example, as shown above are available and which it uses on the basis of the data flowing to it. As shown above, one of the most important functions is the flow of energy over the high-voltage DC voltage network HVN to control. As shown above, the controller is eDCU also connected to an input interface via which, for example, an operator can enter instructions regarding the drum behavior and other components. These are then implemented here according to the sensor values and existing functions.

5 shows the flow diagram of the method according to the invention. In method step 500, a first AC voltage is output from a generator to a first converter, the first converter being connected to a high-voltage DC voltage network. In process step 501 becomes the electric motor CMe to drive the mixer drum MT with a second AC voltage through a second converter SR2 connected to the high-voltage network. In process step 502 a high-voltage battery HV-BAT is provided, which is connected to the high-voltage DC voltage network. In process step 503 a connected external AC voltage is rectified and converted to the high-voltage DC voltage by an onboard charger XE . In process step 504 the conversion of an external direct voltage to the high-voltage direct voltage takes place through a direct voltage connection XE connected to the high-voltage direct voltage network HVN connected. In process step 505 is the control of an energy flow via the high-voltage direct voltage network HVN by a control unit eDCU , that with the first and the second converter SR1 , 2 of the high-voltage battery HV-BAT, HVB , the onboard charger XE and the DC voltage connection XE connected is. The high-voltage battery is then charged in method step 506 HVB either through the generator G or the onboard charger XE or the DC voltage connection XE depending on a signal from the control unit eDCU .

List of reference symbols

XE

external energy source, DC voltage connection, onboard charger

LE

Power electronics or inverters or power converters

ST1-4

Control lines

HVN

High-voltage direct voltage network

eDCU

central control unit

SR1, SR2

Power converter

VM

Internal combustion engine

G

generator

HVB

High voltage battery

B-SG

Battery control unit

CMe

Electric motor

RG

Reduction gear

MT

Mixer drum

20,21,30,31

physical or logical connection for energy transfer

MC

Microcontroller

CAN-IF

Bus interface

500-506

Procedural steps

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• EP 2807007 B1 [0002]
• EP 2719510 A1 [0002]

Claims (9)

Drive train for a mixer drum (MT) with: - A generator (G) which delivers a first AC voltage to a first converter (SR1), the first converter (SR1) being connected to a high-voltage DC voltage network (HVN); - A second converter (SR2) which is connected to the high-voltage direct voltage network (HVN) and which supplies an electric motor (CMe) for driving the mixer drum (MT) with a second alternating voltage; - a high-voltage battery (HVB) that is connected to the high-voltage direct voltage network (HVN), - an onboard charger (OC) is connected to the high-voltage direct voltage network (HVN), the onboard charger (OC) rectifying a connected external alternating voltage and converting it to the high-voltage direct voltage, - a direct voltage connection (GA) is connected to the high-voltage direct voltage network (HVN) and converts an external direct voltage to the high-voltage direct voltage, - a control unit (eDCU) that is connected to the first and second converter (SR1, 2), the onboard charger (XE) and the DC voltage connection (XE) and the battery (HVB) and thus an energy flow (eDCU) via the high-voltage DC voltage network HVN), the control device being configured in such a way that the high-voltage battery (HVB) is charged either via the generator (G) or the onboard charger (XE) or the DC voltage connection (XE). Drive train after Claim 1 , characterized in that a DC voltage converter (GW) is connected to the high-voltage DC voltage network (HVN), which derives a low voltage from the high-voltage DC voltage to supply additional components. Drive train after Claim 2 , characterized in that the further components are a chute adjustment and / or a drum cover and / or a cooling system. Drive train according to one of the preceding claims, characterized in that the control unit (eDCU) furthermore has at least the following functions: a speed control for the mixer drum (MT), a first monitoring of a maximum speed of the mixer drum (MT), a second monitoring of a predetermined one Direction of rotation of the mixer drum, holding the mixer drum (MT), compensating for an uneven distribution of a material in the mixer drum (MT), regulating the torque of the mixer drum (MT). Drive train after Claim 4 , characterized in that the second converter (SR2) transmits data to the control unit (eDCU), the data being derived at least from the following values: a first temperature value of the electric motor (CMe) and / or a second temperature value of the second converter (SR2) and / or a speed of the electric motor (CMe). Drive train according to one of the preceding claims, characterized in that the first and second power converters (SR1, 2) and the DC voltage converter (GW) are housed together in a switch cabinet. Drive train according to one of the preceding claims, characterized in that at least one pilot contact is provided, which connects components of the drive train on the tractor (ZM) and the trailer (A). Control unit (eDCU) for a drive train according to one of the Claims 1 to 7th . Process for operating a drive train for a mixer drum with the following process steps: - Output of a first alternating voltage from a generator (G) to a first converter (SR1), the first converter (SR1) being connected to a high-voltage direct voltage network (HVN), - Supply of an electric motor (CMe) for driving the mixer drum (MT) with a second alternating voltage by a second converter (SR2) which is connected to the high-voltage direct voltage network (HVN), - Provision of a high-voltage battery (HVB) that is connected to the high-voltage DC voltage network, - Rectification of a connected external AC voltage and conversion to the high-voltage DC voltage by the onboard charger (XE), which is connected to the high-voltage DC voltage network (HVN), - Conversion of an external direct voltage to the high-voltage direct voltage through the direct voltage connection (XE), which is connected to the high-voltage direct voltage network (HVN), - Control of an energy flow via the high-voltage direct voltage network (HVN) by a control unit (eDCU) that is connected to the first and second power converters (SR1,2), the high-voltage battery (HVB), the onboard charger (XE) and the direct voltage connection, - Charging the high-voltage battery (HVB) either via the generator (G) or the onboard charger (XE) or the DC voltage connection (XE) depending on a signal from the control unit (eDCU).

Images