Speed changing diesel generator
[technical field]
The present invention relates to diesel engine generator, particularly relate to the economic scene steady operation of a kind of may command diesel engine in the big torque of the slow-speed of revolution, thus the speed changing diesel generator of the requirement that the power source voltage of assurance system output and frequency meet load.
[background technology]
Diesel generating set belongs to one type that provides AC power station equipment for oneself, is a kind of middle-size and small-size independent generating equipment.Because it has maneuverability, invest lessly, characteristics such as can start at any time, thereby the oil recovery drilling platforms that is widely used in digging up mine, build the road field construction, defence engineering and mobile power supply unit such as diesel locomotive, harbour tire type gantry container crane and even factory and enterprise, big institutional settings etc.
Most of power loads by diesel-electric set electric supply all change continuous, and are also different in different load in some time, and work under the light load of being everlasting.Especially at drilling platforms, harbour hoisting equipment etc. are in the system of basic load with the motor, multiple motors generally not can with the time move, the generating set load variations is very big.In addition at the potential energy load equipment, in hoisting equipment, the motor start-up electric current is very big, often reach 1.5~2 times of motor rated current, in order to start fast, to increase work efficiency, the capacity of diesel generating set need strengthen, otherwise can stop because of overload causes serious over-emitting black exhaust even arrives the diesel generating set stall, cause a serious accident.
The power source of diesel generating set is a diesel engine, and the oil consumption rate when its key property is low-speed running is low during than high speed.The relation of oil consumption rate and rotating speed is illustrated by Fig. 1, and Fig. 1 is the universal characteristic curve of a kind of exemplary diesel engine (4100QB type, rated power are 60KW).As shown, if diesel engine is operated in about 3000 rev/mins, its oil consumption rate g
eBe every kilowatt-hour of 320g, per hour factor G
TBe 6400g.When load is about 1/3, during the 20KW of generator output just power, if speed is dropped to 1400r/min, export 20KW power equally, oil consumption rate g at this moment
eBe every kilowatt-hour of 230g, per hour oil consumption is G
T=230 * 20=4600g, when being operated in 3000r/min, rate of economizing gasoline is about 30%.If load factor is lower, oil-saving effect is taller.This is because of the increase along with rotating speed, and volumetric efficiency reduces, and incomplete combustion causes effective thermal efficiency to descend oil consumption rate g
eRise thereupon.After load is increased to 90%, increase load again, fuel delivery significantly increases, and burning condition extremely deteriorates into diesel engine and begins over-emitting black exhaust, causes environmental pollution, and makes piston and combustion chamber deposit easily.Because afterburning increases, also easily make engine overheat and cause fault.Be to reduce oil consumption, modern diesel engine all is provided with variable speed governor, regulates continuously between from the idling to full speed by controlling its rotating speed artificially, so that can be with alap rotating speed operation when underloading, thereby obtains best economy most effectively.
Yet concerning existing diesel engine generator, its diesel engine must be fixed on operation under the maximum speed, and this is because the required AC supply voltage and the frequency of power consumption equipment of various countries all is changeless.The power standard of the most power consumption equipments of China all is 3 phase 380V/50Hz or single-phase 220V/50Hz, also is 3 phase 380V so require the voltage standard of diesel engine generator output, 50Hz or single-phase 220V, 50Hz, otherwise power consumption equipment just can't use.This also just requires motor hand to make speed will be stabilized in a rotating speed, and its fluctuation range has strict standard.National standard according to the diesel power generation unit: gradual change or when sudden change in loading on the 0-100% scope, the voltage fluctuation of I-III class diesel generating set must not be greater than ± 1~± 3%, the unit output frequency must not fluctuate greater than 0.5~3%, the output voltage of IV class unit and frequency fluctuation must not surpass ± 5%, and the voltage and the frequency of generator output directly depend on its rotating speed, so the rotating speed of diesel engine must be stabilized in this index, its working speed must strictly be stabilized in a rotating speed that is associated with power frequency in other words, as bipolar machine is 3000 rev/mins, four utmost point motors are 1500 rev/mins, and 6-pole motor is 1000 rev/mins or the like.For guaranteeing the peak load ability of diesel engine, this working speed must be the maximum speed of this diesel engine operate as normal, and the oil consumption rate of this moment is very high, and economy is very poor.And existing unit all is to adopt diesel engine and the coaxial of synchronous generator to be connected, and the voltage of generator electricity and the unprocessed electrical appliance that directly outputs to of frequency, so diesel engine also can only be operated near the maximum speed.As shown in Figure 1, when diesel engine work during in high velocity, when promptly being in large load operation, diesel engine work is in the economic work zone.When diesel engine work during at little load area, its work is then extremely uneconomical, and especially diesel engine power is big more, and its energy consumption is high more, this be since high-power diesel engine when little load operation, its mechanical efficiency and the heat efficiency all sharply descend.Have only diesel-generator set control under the operating state of the big torque of little rotating speed, diesel engine just can be operated in the high efficiency economic work state of little load.But this operating state is fatal to unallowed for traditional diesel generating set, because diesel engine is when tick-over, the electromotive force that synchronous generator produces is that voltage is too low, and frequency is low too, and power consumption equipment can't use at all.
[summary of the invention]
The present invention is intended to address the above problem, and provide a kind of economic scene steady operation that makes diesel engine in the big torque of the slow-speed of revolution, thereby the requirement that the power source voltage of assurance system output and frequency meet load, and reduce fuel consume, reduce the speed changing diesel generator of toxic emission.
For achieving the above object, the invention provides a kind of speed changing diesel generator, this diesel engine generator comprise be provided with working speed can be from the idling to full speed between the diesel engine and the synchronous generator of coaxial connection with it of variable speed governor of continuous speed adjustment, it is characterized in that, this speed changing diesel generator is provided with also that an AC energy from low-frequency and low-voltage to the rated frequency rated voltage that generator is produced is transformed into available direct current energy and by the detection to the required actual power of load, control the power conversion controller of the generated output of generator, this power conversion controller is connected with diesel engine and synchronous generator respectively.
The power conversion controller comprises that the AC power from low-frequency and low-voltage to the rated frequency rated voltage that generator is produced is transformed into the dc power converter of available DC power supply, be used for intermediate dc energy storage and buffering unit to load short time overload makeup energy, become the intermediate dc power source transition AC power transducer and the intelligent energy of the power supply that can use for any power consumption equipment to manage and control unit, wherein, dc power converter respectively with synchronous generator, AC power transducer and intelligent energy management and control unit connect, the intermediate dc energy storage is connected with dc power converter with the buffering unit, and the AC power transducer links to each other with dc power converter and ac bus respectively.
The dc power converter of power conversion controller comprises three-phase bridge circuit and torque vector control circuit, wherein, three-phase bridge circuit is to be made of HF switch K1~K6 and antiparallel with it sustained diode 1~D6 that three-phase bridge connects, the control utmost point of each HF switch is connected with the torque vector control circuit, and be connected with the inductance L of generator in the incoming line, sustained diode 1~D6 and HF switch K1~K6 are mutually and connect; Described torque vector control circuit is the stator current of alternating current motor is divided into exciting current and changes apart from electric current and control to reach the circuit with the equal control performance of DC motor.Also have only the torque control of having adopted vector control method could realize motor, thus the control generated output.
Intermediate dc energy storage and buffering unit are energy storage buffer capacitor C 1, and it is connected with the outlet side of the bridge circuit of dc power converter.
Described AC power transducer comprises power inverse transformation circuit, voltage detecting circuit, automatic voltage regulating circuit and pulse generating circuit, wherein, power inverse transformation circuit is made up of a plurality of HF switch K7~K12 that connects according to the three phase inverter bridge mode and sustained diode 7~D12, voltage detecting circuit is connected between automatic voltage regulating circuit and the ac bus L2, pulse generating circuit is connected with power inverse transformation circuit, the power inverse transformation circuit input connects dc bus L1, and output is connected with ac bus L2.
Intelligent energy management and control unit comprise power sensing module and intelligent control module, and wherein, the power sensing module is connected with dc bus L1, gather direct voltage and current signal, as the foundation of power control; Intelligent control module stores the Mathematical Modeling of the performance data of this diesel engine, be connected with torque vector control circuit, power sensing module, diesel engine and the synchronous generator of dc power converter respectively, according to the control method of detected load actual power according to optimum, control the rotating speed of diesel engine, the commentaries on classics distance of dc energy source transducer, thereby controlled the generated output of generator.
Near problems such as contribution of the present invention is, it efficiently solves the conventional diesel generator and can only be operated in the maximum speed and cause the energy consumption height, and efficient is low, thereby have following distinguishing feature:
One, power conversion controller of the present invention can make the situation of diesel oil function according to its operating characteristic and load, all the time operate in most economical operating mode, thoroughly eliminated existing diesel also operates in high oil consumption poor efficiency when middle-low load high-revolving disadvantage, therefore can reduce fuel consume greatly, to intermittent loads, perhaps load that load variations is bigger and potential energy load, can save at most and surpass 50% fuel consumption, and regulate as energy snubber by super capacitor, energy-conservationly may reach 70%.
Two, owing to avoided under the high speed of poor efficiency, moving, thereby significantly reduce fume emission, obviously reduced noise pollution.
Three, owing to avoided moving under high speed for a long time, make diesel engine each several part working strength reduce, wearing and tearing and failure rate greatly reduce, and have therefore prolonged the useful life of diesel engine greatly and have reduced the workload of keeping in repair.
Four, owing to be provided with intermediate dc energy storage and buffering unit, can effectively reduce the diesel engine generator capacity, can reduce half at most, therefore reduce equipment investment significantly and improved the machine utilization ability.
Five, intelligent energy management and control unit have been guaranteed the high efficiency of using.
[description of drawings]
Fig. 1 is the universal characteristic curve that reflects a kind of diesel engine of oil consumption rate and rotation speed relation in the prior art.
Fig. 2 is the overall structure block diagram of embodiments of the invention 1.
Fig. 3 is the power conversion controller circuitry schematic diagram of embodiments of the invention 1.
Fig. 4 is the circuit theory diagrams of a phase of the dc power converter of power conversion controller.
Fig. 5 is the dc power converter course of work schematic diagram of power conversion controller.
[embodiment]
The following example is to further explanation of the present invention and explanation, and the present invention is not constituted any limitation.
Consult Fig. 2, speed changing diesel generator of the present invention comprises diesel engine 10, synchronous generator 20 and power conversion controller 30, wherein, diesel engine 10 and 20 coaxial connections of synchronous generator, and diesel engine be can be commercially available the diesel engine that has variable speed governor, the working speed that its variable speed governor can make diesel engine is regulated between from the idling to full speed continuously.Variable speed governor is by signal of telecommunication control carrying out automatic speed regulation.Synchronous generator 20 can stable operation in from the idling to the full speed range under Diesel Driven, produces the AC power of different voltages, different frequency, and it is outputed to the energy conversion controller.For example, the idling of supposing diesel engine is 750 rev/mins, and rated speed is 1500 rev/mins, and synchronous generator is 4 utmost points, generator rated voltage 400V, rated frequency 50HZ.During sub-load, diesel engine can be under any rotating speed between 750-1500 rev/min steady running and can regulating by the variable speed governor continuous stepless.
Main points of the present invention are, this speed changing diesel generator also is provided with a power conversion controller 30, this power conversion controller can be transformed into the AC energy from low-frequency and low-voltage to the rated frequency rated voltage that generator produces available direct current energy and by the detection to the required actual power of load, control the generated output of generator.More specifically, as shown in Figure 3, power conversion controller 30 comprises dc power converter 31, intermediate dc energy storage and buffering unit 32, AC power transducer 33 and intelligent energy management and control unit 34, wherein, dc power converter 31 structures such as Fig. 3, the work principle of equal effects as shown in Figure 4, it comprises three-phase bridge circuit 311 and torque vector control circuit 312, in this example, three-phase bridge circuit 311 is to be made of HF switch K1~K6 and antiparallel with it sustained diode 1~D6 that six three-phase bridges connect, in this example, HF switch adopts the high-power insulated gate bipolar transistor, the control utmost point of HF switch K1~K6 is connected with torque vector control circuit 312, and be connected with the inductance L (see figure 6) of generator in the incoming line, inductance L is the inductance of generator unit stator winding.Sustained diode 1~D6 and HF switch K1~K6 are anti-and connect.This three-phase bridge circuit 311 is used for the AC power from low-frequency and low-voltage to the rated frequency rated voltage that generator produces is transformed into available DC power supply.The input of three-phase bridge circuit is connected with the generator alternating current power supply, and output is connected with dc bus.Described torque vector control circuit 312 is the stator current of alternating current motor is divided into exciting current and changes apart from electric current and control to reach the circuit with the equal control performance of DC motor, and it is realized by vector control algorithm.It is used for the vector control to alternating current motor.Vector control is to realize the control mode of the high-speed responseization of alternating current motor.This mode is divided into exciting current to the stator current of alternating current motor and changes apart from electric current and control respectively to reach the mode with the equal control performance of DC motor.This mode is applicable to needs high-speed response, and high-precision purposes then uses this control mode to realize changeing apart from control in the present invention, reaches the purpose of control generated output.Just by generated output to the adjusting control generator of the controlling depth of HF switch K.Its equivalent operation principle such as Fig. 4, among Fig. 4, the K1~K6 in the K representative graph 3, the D1~D6 in the D representative graph 3.Because the generator unit stator winding is an inductance element, when the voltage U of generator generation
iWhen moving by HF switch K, switch disconnects at a high speed suddenly from closure state, produces a very high induced voltage U on inductance
L, the size of this voltage is U
L=LdI/dt, this voltage are by freewheeling circuit, and both sustained diode made the voltage U on the electric capacity to the charging of intermediate dc energy storage buffer capacitor C
CRise, no matter U
iVoltage low again, we can be upgraded to its pump greater than U by high-frequency switch circuit
CVoltage, to electric capacity charging, buffer capacitor voltage is raise, we can be by the controlling depth to HF switch K in addition, control has just been controlled the generated output of generator to the size of electric capacity charging current, the operation principle of Here it is energy converter.Fig. 5 has provided the wherein course of work of a phase of the course of work in the side circuit, path of current when solid line is HF switch K5 conducting among Fig. 5, and dotted line is HF switch K5 path of current when disconnecting suddenly.C1 among Fig. 4 is the electric capacity of intermediate dc energy buffer, and it is connected with dc power converter 31.Described AC power transducer 33 structures as shown in Figure 3, it comprises power inverse transformation circuit 331 and voltage detecting circuit 332, wherein power inverse transformation circuit 331 is made of automatic voltage regulating circuit 3311 and SPWM pulse generating circuit 3312, described power inverse transformation circuit 331 is identical with the three-phase bridge circuit 311 of dc power converter, it is made up of a plurality of HF switch K7~K12 that connects according to the three phase inverter bridge mode and sustained diode 7~D12, be input as DC power supply, be output as AC power, the power inverse transformation circuit input is connected with dc bus L1, and output is connected with ac bus L2.Voltage detecting circuit 332 is connected between automatic voltage regulating circuit 333 and the ac bus L2, output bus L2 gathers output voltage signal and signal is after treatment delivered to automatic voltage regulating circuit 3311 as the virtual voltage feedback signal from exchanging, the automatic voltage regulating circuit is according to virtual voltage value of feedback and set-point, through the control computing, deliver to the SPWM pulse generating circuit.The SPWM pulse generating circuit is the Sine Wave Pulse Width Modulation circuit in this example, and it is connected with the control utmost point of the HF switch K7~K12 of power inverse transformation circuit.Described automatic voltage regulating circuit 3311 is equivalent to the inversion part of ups power, and its effect is the middle dc voltage DC450V-780V, converts stable AC power to by inverter circuit, uses for load.The voltage of AC power transducer 33 and frequency are that three-phase 380V (considers line loss, the generator output 400V that has), 50Hz, also single-phase 220V, 50Hz also can provide the AC power of required voltage and frequency by countries in the world or various special installation, to adapt to the needs of this area's power consumption equipment.Described voltage detecting circuit 332 can adopt custom circuit, and it is connected between automatic voltage control circuit 3311 and the ac bus L2.Described intelligent energy management and control unit 34 comprise power sensing module 341 and store the intelligent control module 342 of the performance data of this diesel engine, as Fig. 3, power sensing module 341 is connected with dc bus L1, gather direct voltage and current signal, as the foundation of power control, intelligent control module 342 is connected with torque vector control circuit 312, power sensing module 341 and diesel engine 10 and the synchronous generator 20 of dc power converter respectively.The size of the actual power that management of this intelligent energy and control unit 34 record according to the performance data and the power sensing module of described diesel engine is regulated the working speed of diesel engine, thereby the generated output of generator has been controlled in the torque of regulating the dc energy transducer, it is worked under alap rotating speed satisfying under the prerequisite of demanded power output, thereby guarantee to obtain minimum oil consumption rate and the highest economy.Specifically, this intelligent energy management and control unit are by the detection to the required actual power of load, control the generated output of generator, when bearing power increases, can cause that middle dc voltage descends, can pass through the size of the generated output of control energy switching controller, make the intermediate dc energy storage stable with the voltage maintenance on the buffering accumulated energy electric capacity that cushions unit 32, make diesel engine under this power, characteristic curve according to diesel engine, the rotating speed of control diesel engine makes it be operated in most economical operating mode.Because the characteristic of every diesel engine is all inequality, want to make the resonable economic work state of thinking of diesel engine work, need be converted into different diesel engine characteristics the digital information of being convenient to control computing is input in the intelligent control module 342, intelligent energy manages and control unit calculates power demand from the performance data of diesel engine and the minimum rotating speed of oil consumption rate sends regulating command as working speed to diesel engine, carry out by variable speed governor, realize best and most economical control this speed changing diesel generator.So corresponding each different diesel engine, intelligent energy management control unit all have a cover to Mathematical Modeling software that should diesel engine characteristic and finish that the control diesel generating set starts, stops, the Control Software of safe operation and protection.
Although by above embodiment the present invention is disclosed, scope of the present invention is not limited thereto, do not departing under the condition of the present invention design, more than each member can replace with the similar or equivalent element that affiliated technical field personnel understand.