DE102005042817B3 - Combined power supply and air conditioner operating method for vehicle, involves controlling speed of prime mover and providing control mechanisms to ensure that mechanisms bring required power with adjusted consumption-optimized speed - Google Patents

Abstract

The method involves determining instantaneous engine power required by an operating machine so that an instantaneous total power requirement is resulted. The speed of a prime mover (10) is controlled based on the total power requirement in such a manner that fuel consumption of the mover is minimized. Control mechanisms are provided to ensure that the mechanisms bring the required power with an adjusted consumption-optimized speed.

Description

The The invention relates to a method for operating a combined Energy supply and air conditioning, comprising one or more Variable speed engines, preferably diesel engines and with these coupled mechanically or electrically driven machines for power generation and air conditioning.

With Increasing fuel and personnel costs worldwide (operation, maintenance, Repair) for the operation of self-sufficient energy supply and air conditioning systems (sanitary facilities, emergency shelters, Construction sites, military Facilities) it is becoming increasingly clear that the operating costs across from the procurement costs become the decisive cost factor. These Expenses increase, the more remote the location is and the more extreme the local climatic conditions are.

Around the fuel consumption behavior of the engine were Diesel generator sets with performance-based variable speed developed. To make electric AC power more constant Frequency is then a power conditioning (AC / DC / AC) required, the fuel economy due to their efficiency diminishes, Investment costs and equipment weight increased.

With the patent applications WO 98/28832 A1 and WO 03/028187 A1 very complex control systems proposed that meet the requirements independently of fluctuating energy supply and demand. through a regulated energy exchange with a storage tank (accumulator, flywheel) is the adaptation time to positive and negative load jumps with great shortened design effort.

Next these consumption-optimized systems for providing electrical Energy belong in refrigeration analogous concepts to the state of the art. For building air conditioning are refrigeration compressors used with variable speed of the electric drive motor. While Here is the electrical grid is the primary energy source is in the case of vehicle air conditioning, the internal combustion engine. The current, strongly fluctuating driving conditions dictate its Rotation speed. With the use of refrigeration compressors in the suction pressure controlled swash plate design can not correlated requirements of driving and air conditioning are sufficient.

The DE 103 54 103 A1 describes a method for consumption-optimized control of ancillary units, in particular of a generator, in a motor vehicle. In the process, the electric generator load currently applied to the generator while driving is varied as a function of certain operating conditions that are relevant for fuel consumption.

In preferably self-sufficient combined power supply and Air conditioning systems with consumption-optimized operation management combine the requirements purely electrical and mechanical systems. It is therefore the task the invention, a management for systems from one or more engines and coupled therewith several To create working machines to the variable in a wide range and independent of each other Demand for electrical and mechanical power with near minimum Fuel consumption of the engine (s) to meet.

These The object is achieved with the subject of claim 1. advantageous Executions of the Invention are the subject of dependent claims.

According to the invention in the scheme for minimizing the fuel consumption of the engine (s) the sum of the currently required benefits of all Working machines (in particular generator, refrigeration compressor) included.

In addition will be Control mechanisms for the individual work machines provided so that the work machines under the boundary condition of the determined fuel-optimized system speed can provide the required benefit.

The operating map of an engine, eg diesel engine, represents the context of mechani Characteristics of the working machines combine the parameters net power P _N , eg current / voltage or flow rate, speed n and efficiency η. The system optimum operating speed results from the minimum of the losses of all work machines and the minimum fuel demand B for providing the sum of all drive _powers P _mech .

und dem System-Wirkungsgrad

Analytically, the following results for the optimum system operating point in the system map:
With

and the system efficiency

Of the Denominator of the term of the right side of (3) is the criterion of Optimization. Not the individual efficiencies of secondary energy converters (Work machines) are authoritative but the converter with the larger power component. In the optimization, it is assumed that the speeds of Power machines and work machines rigidly coupled with each other are.

The according to the invention everyone Working machine associated with regulation, which e.g. at the generator on its excitement, the refrigeration compressor on the piston stroke of the refrigeration compressor the swash plate type is effective (adjustment of the swash plate angle), can be ensured that the individual work machines at the given fuel-optimized speed in each case the meet the required power requirements.

• 1. Die Änderung der Leistungsanforderungen erfolgt sprunghaft und in relativ hoher Frequenz. Die gesteuerte Verbrauchsoptimierung stützt sich auf die gespeicherten Kennfelder von Kraftmaschine(n) und Arbeitsmaschinen. Wenn diese nicht vom Hersteller zu beschaffen sind, sind sie in Versuchen zu bestimmen. Bauartbedingte Abweichungen werden durch Einzelmessungen erfasst und in die Kennfelder umgesetzt. Aus den Änderungen des Leistungsbedarfs resultieren dann gezielt die gesteuerte und berechnete Einstellung des neuen Betriebspunktes, nämlich Drehzahl und Kraftstoffbedarf der Kraftmaschine, Erregung des Generators, Frequenzanpassung des Wechselrichters und Kolbenhub (ggf. auch Zylinderzu- bzw. -abschaltung oder Bypass) des Kälteverdichters.
• 2. Die Anpassung an geänderte Lastanforderungen kann langsam erfolgen, das Zeitintervall konstanter Betriebsbedingungen ist groß.

There are two variants to realize the control task:

• 1. The change in the power requirements occurs abruptly and in relatively high frequency. The controlled fuel consumption optimization is based on the stored maps of engine (s) and work machines. If these can not be obtained from the manufacturer, they must be determined in tests. Design-related deviations are recorded by individual measurements and converted into the maps. From the changes in power requirements then result in a targeted manner the controlled and calculated setting of the new operating point, namely speed and fuel demand of the engine, excitation of the generator, frequency adjustment of the inverter and piston stroke (possibly also Zylinderzu- or shutdown or bypass) of the refrigeration compressor.
• 2. The adaptation to changed load requirements can be slow, the time interval of constant operating conditions is large.

The fuel supply of the engine (eg internal combustion engine with control rod) is superimposed on a control technology search movement (+/- a kontinuierli chen value) to adjust to the minimum fuel demand, with the benefits can be met. The subsystem controls follow the control of the engine to keep the AC frequency constant as the speed fluctuates, or to adjust the flow rate of the refrigeration compressor, so the cooling capacity to the new value and then to keep constant.

With a breakdown of mechanical power to two with the same Speed-driven power engines can improve fuel economy be achieved. Such a configuration may also be prescribed for redundancy be. Preference is given to identical type engines with the same rated power and the same operating map used.

The optimal ratio the power distribution on two identical motors is one relationship of 50% / 50% with the optimal power requirement Rotation speed. In the case of the split on two engines of unequal nominal power shifts the relationship slightly. In the case of motors of different rated power results the optimal power distribution from the two maps.

A However, splitting on two or more engines should be beneficial to a power range of approximately 60% to 100% of the total power limited remain because the savings advantage then disappears when the two Engines working in the partial load range. This variant is therefore only for Paying for plants that are mainly operated with high performance.

Becomes the functionally reasonable lowest part-load threshold of a power branch, electric or mechanical, undershot, subsystems or also the primary energy converter in the beat mode over.

low electrical power (emergency supply) or short-term energy contributions with fast performance leaps can deliver a battery pack. The charge is another DC consumers and operational management parameters.

In an advantageous embodiment can Working machines are used, which consist of two or more Units exist, the drive side or secondary side are connected. These subunits can be energetic as a subsystem be assigned to separate consumer groups.

Next Consumption minimization can also operating and environment dependent Controlled variables influence on the management as mentioned in the publications mentioned above. Of the operational reliability and plant life can be temporarily given a higher priority, as the momentary minimization of primary energy consumption. In the the software of the management fixed limits of the various operating parameters, e.g. ambient equal combustion and cooling air temperature, Exhaust gas and cooling water temperature, Generator temperature, high and low pressure in the refrigerant circuit, then restrict Consumption minimization.

• – Der Generatorausgang wird mit dem Fremdnetz verbunden und treibt mittels eines Frequenzumrichters im motorischen Betrieb drehzahlgeregelt den Kälteverdichter an.
• – Wird eine galvanische Trennung vom Verbundnetz gefordert, muss ein weiterer Synchrongenerator für die Spannungsversorgung eingesetzt werden.
• – Auch eine Netztrennung mittels Trenntrafo kann zweckmäßig sein.

If it is possible locally to operate the energy supply and air conditioning system by connecting to the electrical grid, the regulation to minimize the primary energy demand remains. For the construction of the system, there are the following variants:

• - The generator output is connected to the external network and drives by means of a frequency converter in motor operation speed-controlled to the refrigeration compressor.
• - If galvanic isolation is required from the grid, another synchronous generator must be used for the power supply.
• - A network separation by means of isolation transformer may be useful.

With the management of the invention can be independent of the operating time compared to conventional Systems, preferably at high partial load, 30% to 40% fuel be saved. Only with COTS components (COTS: commercial off the shelf) systems remains viable a modest additional Software and hardware effort, with faster between control systems and slow reaction time must be distinguished.

The The invention will be described with reference to specific embodiments closer to figures explained. Show it:

1 The operating map of a diesel engine is supplemented by the curves of the absolute fuel consumption and the curve of an exemplary specific power requirement.

2 The block diagram of an energy supply and air conditioning system according to the invention, which is set up for both self-sufficient and external power fed operation.

3 A diagram for the structure of the demand and environment controlled control of the system.

4 The AC and DC provision of the system with electrical energy storage.

1 shows the operating map of an internal combustion engine in the known representation, abscissa motor speed n, mean effective pressure in the combustion chamber p _me as ordinate.

Further describe:

1

lines constant specific fuel consumption b (g / (W, h)), messtech

cally determined

2

lines constant fuel consumption B (g / h), calculated

3

Constant power lines P _mech (W)

4

rotation speed- and demand-based Sum of the momentary demand mechani

shear power Σ (P _{N, i} / η _i ) (W)

x

currently optimal operating point

At operating point x, a fuel curve is affected 2 the demand curve 4 ie

The is currently the operating point with minimal fuel consumption. All right and left operating points would provide more fuel need the same net power.

With the simplified block diagram, 2 , will the interaction of engine 10 (eg diesel engine) and the two working machine generator 11 and refrigeration compressors 12 shown. With 13 is the generator excitation and with 14 the stroke adjustment of the refrigeration compressor 12 Designated by means of an angle-adjustable swash plate. combustion engine 10 and generator 11 are by means of clutches 15 and 16 connected. The belt drive 17 forms the connection to the refrigeration compressor 12 as an energetically more favorable solution compared to the electric drive, which is associated with the proportion of generator losses and losses of the drive motor.

The control / regulation 20 supplies the signals to the excitation 13 and the adjusting actuator of the swash plate 14 according to the electrical power requirement, determined by the power conditioning 21 and the setpoint deviation of the room temperature - in the case of a chiller also the temperature of the cold water return.

The transition to foreign network operation, supply line 22 , is done by switching the switch 23 for feeding into the DC line 24 and the switch 25 for the AC string 26 , About the frequency converter 27 becomes the generator 11 motor operated. With the clutch 16 the connection of the refrigeration compressor takes place 12 ,

• – die Dosierung des Kraftstoffs des Dieselmotors 10,
• – den Sollwert der Erregungsspannung für den Generator 11,
• – die Winkelstellung der Taumelscheibe des Kälteverdichters 12.

The inventive control / regulation 20 for the engine 10 and for example generator 11 and refrigeration compressors 12 as work machines is composed of the control unit 30 and the connected demand recording 35 . 3 , In the control 30 are the operating maps of the engine 10 and the working machines 11 and 12 stored in order to supply the signals dependent on the utility power requirement:

• - The dosage of the fuel of the diesel engine 10 .
• - The setpoint of the excitation voltage for the generator 11 .
• - The angular position of the swash plate of the refrigeration compressor 12 ,

• – 36 für den elektrischen Leistungsbedarf, AC und DC,
• – 37 für den Kühlungs- bzw. Heizungsbedarf im Arbeitsraum oder in einem Gerätekühlkreis,
• – 38 für Parameter der Umgebungsbedingungen, die den Anlagenbetrieb im Sinne der Betriebszuverlässigkeit beeinflussen können, z.B. Umschalten auf Stand-By-Betrieb in Ruhezeiten, Vorwärmung Dieselmotor, Ölsumpfheizung des Kälteverdichters u.ä.

The net power requirement is determined by the computer 35 from the signals of the sensors:

• - 36 for electrical power requirements, AC and DC,
• - 37 for the cooling or heating demand in the work space or in a device cooling circuit,
• - 38 for parameters of the environmental conditions that can influence the plant operation in terms of operational reliability, eg switching to stand-by mode during rest periods, preheating diesel engine, oil sump heating of the refrigeration compressor, etc.

One Means of increase the operational reliability is for mobile systems the creation of a partial redundancy by means of division the required nominal power to several units. space, Weight and plant complexity increase yourself. Full redundancy is required only in exceptional cases. A change of the Rule concept is not necessary with such an extension. Power supply and cooling circuits can be interconnected. Alternatively, the drive side be formed switchable. The controller switches at lower Part load off a strand, then if the total useful power more economical can be supplied by a strand.

A detailed illustration of the AC and DC deployment is shown 4 , The motor-generator unit 10 and 11 follows the energy preparation for the strands 24 and 26 , The rectifier 41 and 42 supply the required voltage, the inverter 43 supplies the 50Hz alternating current, if necessary 60Hz. The stores 44 and 45 buffer large load jumps and form an energy reserve for short interruptions. In order to increase the life of the buffer batteries, the control takes into account the charge and charge retention according to the current-voltage characteristic when the DC link voltage is selected. With low power requirements of the DC consumers, the DC supply from the DC link is optionally implemented via the electronic DC-DC converter 46 (Battery Charging and Battery Management) or another AC / DC converter (optional).

Claims (11)

Method for operating a combined power supply and air conditioning system, comprising one or more engines each having a variable approachable speed and coupled to these machines for power generation and air conditioning, characterized in that - are determined by means of sensors currently required by the working machines benefits, so that there is an instantaneous total utility demand; - Based on the current total useful power, the speed of the engine (s) is controlled such that its or their fuel consumption is minimal, with control mechanisms are provided for the work machines to ensure that these at the so set consumption-optimized speed each required benefits can provide. Method according to claim 1, characterized in that that the consumption-optimized speed by a scheme, the on stored operating maps of the engine (s) and of the working machines, he follows. Method according to claim 1, characterized that preferably with little change in total utility demand the consumption-optimized speed through a slow search movement is regulated in the form of a fluctuating fuel supply. Method according to one of the preceding claims, characterized characterized in that as a working machine in a swash plate design trained refrigeration compressor an air conditioner is used, wherein to adjust the required Net power of the refrigeration compressor and at a given consumption-optimized speed, the angle of Swash plate is adjusted. Method according to one of the preceding claims, characterized characterized in that used as a working machine, a generator is, where to adjust the required power of the generator and at a given consumption-optimized speed, the excitation of the generator is set. Method according to one of the preceding claims, characterized characterized in that working machines are used, which consist of two or more units, the drive side or secondary side are connected. Method according to one of the preceding claims, characterized characterized in that there are exactly two engines. A method according to claim 7, characterized in that the two engines identical Nenn have performance and operating characteristics and the required mechanical power is equally divided between the two engines. Method according to one of the preceding claims, characterized characterized in that individual power or working machines off if the needed Efficiency more fuel efficient from the remaining machines can be delivered. Method according to one of the preceding claims, characterized characterized in that with rapid increase in the load of the short-term Lack of electrical power due to energy storage for the DC and / or AC string is covered. Method according to one of the preceding claims, characterized characterized in that at low loads the supply from the Energy storage and its state of charge monitoring with start for recharging he follows.