DE102012019236A1 - Control device for power supply system e.g. block-type thermal power station, measures electrical variables at electrical machine, and connects separating element with torque forming function block and monitoring function block - Google Patents

Abstract

The control device (7) has a torque-forming function block (13) that is provided for controlling an electric machine such as electric motor or generator (4) to cause a non-abrupt torque curve. A monitoring function block (14) is provided for disconnecting a power supply (6) in case of failure. A measurement unit (9) is provided for measuring electrical variables at electrical machine. The separating element (8) is connected with torque forming function block and monitoring function block.

Description

Technical area

The invention relates to control units for combined heat and power plants, in particular devices that perceive protective functions of the power supply system and control power generation with a generator.

State of the art

Autonomous power systems, such as combined heat and power plants or the like, have various control and switching devices for controlling the individual components and monitoring the grid connection. In particular, various devices are used for motor protection functions, network protection functions, network disconnection and monitoring functions. This variety of devices requires a large amount of space and performs functions in a redundant manner, without thereby increasing the overall reliability of the power system.

From the publication DE 10 2009 011 778 A1 a power supply system with a control / regulator unit is known. The power supply system includes a heat storage and a charging station to provide an indication of the amount of energy stored in the heat storage in the control unit.

Also from the publication DE 10 2009 040 227 A1 is known a combined heat and power plant, which is operated by means of a control device.

The publication DE 291 714 885 U1 discloses a control unit for a combined heat and power plant, which provides the control and monitoring of connected aggregate elements.

The publication US 4,802,100 discloses a control system for a power supply unit.

Autonomous power systems often include internal combustion engines that provide motive power to drive a generator to generate electrical power. To start the internal combustion engine, the generator is often operated as a starter. In order to limit a current consumption of the generator operated as a starter, a soft starter is often provided for starting the internal combustion engine, which continuously increases the torque during starting.

Furthermore, a mains protection device may be provided, which has a separating device in order to disconnect a power grid from the generator. These and other modules are typically provided separately in a power system.

It is an object of the present invention to reduce the number of modules required for controlling and monitoring a power supply system.

Disclosure of the invention

This object is achieved by the control unit for a power supply system according to claim 1 and by the power supply system according to the independent claim.

Further advantageous embodiments of the present invention are specified in the dependent claims.

• – einen Momentenformungsfunktionsblock zum Ansteuern einer elektrischen Maschine, um einen nicht sprunghaften Momentenverlauf zu bewirken;
• – einen Überwachungsfunktionsblock zum Trennen eines Netzanschlusses im Fehlerfall; und
• – mindestens eine Messeinheit zum Messen einer elektrischen Größe und/oder ein Trennelement, die sowohl mit dem Momentenformungsfunktionsblock als auch mit dem Überwachungsfunktionsblock in Signalverbindung stehen.

According to a first aspect, a control unit for a power supply system is provided, comprising:

• A torque-shaping function block for driving an electric machine to effect a non-erratic torque curve;
• A monitoring function block for disconnecting a network connection in the event of a fault; and
• - At least one measuring unit for measuring an electrical variable and / or a separating element, which are in communication with both the torque-shaping function block and with the monitoring function block.

One idea of the above controller is to combine the otherwise separately performed monitoring function or network protection function and a realizable by the torque shaping function block soft starter function for towing the engine in a control unit and thus previously performed twice functions such as the measurement of required electrical variables and / or Disconnecting a network connection, just having to realize it. By combining the soft starter function and the network protection function in one unit, it is sufficient to simply perform the voltage and current measurement and / or the isolating element and to share the corresponding measured values. As a result, the hardware complexity for implementing a control system for a power supply system can be significantly reduced.

Furthermore, the measuring unit may be included in a voltage and current detector unit for measuring an electrical quantity on the electric machine.

According to one embodiment, the torque-shaping function block may be provided with a Kommutierungsblock be connected to cause the moment characteristic of the electric machine by means of a Kommutierungsmusters for driving the electric machine.

It can be provided that the torque-shaping function block is connected to the separating element in order to disconnect the electric machine from a power network.

According to one embodiment, an electromotive operation of the electrical machine can be carried out by providing a three-phase current directly via the mains connection, wherein the torque-shaping function block is equipped with a current limiting function, in order to carry out a current limitation during an electromotive operation of the electrical machine.

• – einen Verbrennungsmotor;
• – eine elektronisch kommutierte elektrische Maschine, die mechanisch mit dem Verbrennungsmotor gekoppelt ist; und
• – das obige Steuergerät.

According to another aspect, there is provided a power supply system comprising:

• An internal combustion engine;
• - An electronically commutated electric machine, which is mechanically coupled to the internal combustion engine; and
• - the above control unit.

Furthermore, the electric machine can be connected via an inverter to a power grid.

In particular, a separating element can be arranged between the inverter and the electrical machine.

It may further be provided that the electric machine is operated both as a generator and as an electric motor.

Brief description of the drawings

Preferred embodiments of the present invention will be explained in more detail with reference to the accompanying drawings. Show it:

1 a schematic representation of a power supply system with a generator, an internal combustion engine for driving the generator and a control unit; and

2 a more detailed representation of the functional units of the control unit of the power supply system of 1 ,

Description of embodiments

1 shows a schematic representation of a combined heat and power plant 1 as an energy supply system in the sense of this invention. The combined heat and power plant 1 includes an internal combustion engine for providing mechanical energy 2 that about a wave 3 with a generator 4 is coupled. The combined heat and power plant 1 is used to generate electrical power via an inverter 5 in a power grid 6 can be fed.

The internal combustion engine 2 can be designed as a conventional four-stroke engine, in particular as a diesel engine or gasoline engine. In particular, the internal combustion engine 2 be designed as an internal combustion engine for operation with conventional fuels or as a gas-powered internal combustion engine.

The internal combustion engine 2 is via a control unit 7 operated in a known manner by engine actuators, such as. As a throttle valve, injectors and the like, for providing one of the control unit 7 predetermined drive torque can be provided.

The generator 4 is preferably designed as an electronically commutated electric machine, so that it can be removed in the driven state by a suitable tap electrical energy. Furthermore, the generator 4 be operated by an electric motor. In particular, for starting the internal combustion engine 2 is preferably dispensed with a separate starter motor and the generator 4 so driven that this over the shaft 3 the internal combustion engine 2 comes up with.

The starting of the internal combustion engine 2 can via the control unit 7 be controlled, which is the commutation of the generator 4 according to a predetermined Kommutierungsschema makes. For starting energy is from the mains 6 taken from the inverter 5 in an appropriate manner by the control unit 7 is provided with the commutation scheme is provided.

Alternatively, the starting of the internal combustion engine 2 also by direct connection of the generator 4 (electrical machine) to the mains 6 take place when this provides an at least three-phase alternating current. This can be done by the inverter 5 be bridged and driven only for the realization of a current limiting function or operated.

In connecting lines 10 between the inverter 5 and the generator 4 can separators 8th be arranged, which may be formed, for example, as a contactor or power semiconductor switch. The separating elements 8th serve to power the generator from the inverter 5 to be galvanically separated.

Furthermore, voltage and current sensors 9 provided, which are arranged to voltages and currents the output side of the generator 4 to measure and corresponding information in the control unit 7 to provide.

In 2 is the structure of the control unit 7 shown in more detail. The control unit 7 is designed as a multifunction device and combines different functional blocks. An engine control block 11 serves to control the internal combustion engine 2 so that it provides a desired mechanical drive power in the form of a drive torque to the generator 4 to drive in regenerative mode.

A commutation block 12 serves to the generator 4 using the inverter 5 to operate as a generator or alternatively to control it so that via its connection lines 10 provided electrical energy in kinetic energy for towing the engine 2 over the wave 3 can be provided. The commutation block 12 still stands with the separating elements 8th in connection to the generator in case of failure 4 from the inverter 5 to be able to separate galvanically.

It is a moment shaping function block 13 provided the commutation block 12 so controls that when starting the engine 2 with a towing by the electric motor driven generator 4 is started. The torque shaping function block 13 includes a soft starter function, which is the commutation block 12 so controls that in the starter motor operated generator 4 the current flow on the connecting cables 10 of the generator 4 does not exceed a certain predetermined threshold, so as to avoid an erratic course of the provided torque. The momentum shaping function block receives this 13 in the voltage and current measuring unit 9 corresponding current flows on the connection lines 10 ,

Alternatively, for starting the internal combustion engine 2 on the use of the inverter 5 be waived. It may then merely be provided that the torque-shaping function block 13 in the case of direct connection of the electrical machine to a three-phase current provided by the power supply, a current limitation is carried out in the context of the soft starter function. The current limit can be controlled by a corresponding control of the inverter 5 or by a separate current limiting unit (not shown).

Furthermore, a network protection control unit 14 provided that with the separating elements 8th to disconnect if it is determined that there is an error. An error can be detected, for example, by monitoring the voltage and current values on the connecting cables 10 be determined. This is the monitoring block 14 also with the voltage and current measuring units 9 connected.

Furthermore, for the torque-shaping function block 13 be provided that this also with the separating elements 8th in order to activate or deactivate them in order to be able to exercise a disconnection on the network side. By combining the monitoring block 14 and the torque-shaping function block 13 integrated in a multifunction device, the voltage and current measuring units 9 as well as the separating elements 8th be used for both functions simultaneously, without compromising the reliability of the overall system.

LIST OF REFERENCE NUMBERS

1

CHP

2

internal combustion engine

3

wave

4

generator

5

inverter

6

power grid

7

control unit

8th

separating element

9

Voltage and current detector unit

10

connecting cables

11

Engine control block

12

commutation block

13

Moment shaping function block

14

monitoring block

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been 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.

Cited patent literature

• DE 102009011778 A1 [0003]
• DE 102009040227 A1 [0004]
• DE 291714885 U1 [0005]
• US 4802100 [0006]

Claims (9)

Control unit ( 7 ) for a power supply system ( 1 ), comprising: - a torque-shaping function block ( 13 ) for driving an electric machine to cause a non-erratic torque curve; A monitoring function block ( 14 ) for disconnecting a mains connection in the event of a fault; and at least one measuring unit ( 9 ) for measuring, an electrical variable and / or a separating element ( 8th ) associated with both the torque shaping function block ( 13 ) as well as with the monitoring function block ( 14 ) are in signal connection. Control unit according to claim 1, wherein the measuring unit ( 9 ) in a voltage and current detector unit for measuring an electrical quantity on the electric machine ( 4 ) is included. Control device according to claim 1 or 2, wherein the torque-shaping function block ( 13 ) with a commutation block ( 12 ) is connected to the torque curve of the electric machine ( 4 ) by means of a commutation pattern for driving the electric machine ( 4 ) to effect. Control unit according to one of claims 1 to 3, wherein the torque-shaping function block ( 13 ) with the separating element ( 8th ) is connected to the electrical machine ( 4 ) to be disconnected from a power grid. Control unit according to claim 1 or 2, wherein an electromotive operation of the electric machine by providing a rotary current is carried out directly via the mains connection, wherein the torque-shaping function block ( 13 ) is equipped with a current limiting function to perform a current limiting in an electric motor operation of the electric machine. Energy supply system ( 1 ), comprising: - an internal combustion engine ( 2 ); An electronically commutated electric machine ( 4 ) mechanically connected to the combustion engine ( 2 ) is coupled; and a control device ( 7 ) according to one of claims 1 to 5. Energy supply system ( 1 ) according to claim 6, wherein the electric machine ( 4 ) via an inverter ( 5 ) with a power grid ( 6 ) connected is. Energy supply system ( 1 ) according to claim 7, wherein between the inverter ( 5 ) and the electric machine ( 4 ) a separating element ( 8th ) is arranged. Energy supply system ( 1 ) according to claim 7 or 8, wherein the electric machine ( 4 ) is operable both generator and electric motor.

Images