WO2017041752A1

WO2017041752A1 - Intermittent operation continuous power supply diesel generator power saving system

Info

Publication number: WO2017041752A1
Application number: PCT/CN2016/098624
Authority: WO
Inventors: 安同会; 贾凯
Original assignee: 深圳市安顺节能科技发展有限公司
Priority date: 2015-09-11
Filing date: 2016-09-09
Publication date: 2017-03-16
Also published as: CN204928358U

Abstract

An intermittent operation continuous power supply diesel generator power saving system, comprising: a generator set, a system controller (1), an AC/DC rectifier (6), a DC/AC inverter (3), a transformer (2), a battery pack (4), and a two-way DC/DC converter (5). The power saving system adds, on the basis of the generator set, the battery pack (4) of which the charging/discharging power is greater than or equal to the power of a load. The energy demand of the load can be provided for independently by the battery pack (4). The discharging power of the battery pack (4) fully matches the power demand of the load. When the battery pack (4) is low in power, the generator set is controlled and turned on to work at the optimal economic energy consumption, to provide directly the load with energy, and to charge the battery pack (4) with any surplus energy. When the power level of the battery pack (4) is raised to a set value, the generator set is shut off, and energy demand is provided for by the battery pack (4), thus implementing intermittent and high efficiency operation of the generator set and uninterrupted power supply. The greater the load fluctuations and the longer the time of operating at a low load, the higher the power saving rate of the power saving system in such working conditions.

Description

Diesel generator energy-saving system with intermittent operation and continuous power supply

Technical field

The utility model belongs to the field of energy application, and particularly relates to an energy-saving system for a generator set with intermittent operation and continuous power supply.

Background technique

Generator sets are widely used. Conventional generator sets must ensure constant output of standard frequency and voltage. The unit speed must be constant (the domestic generator set usually has a speed of 1500 rpm and a frequency of 50 Hz). When the load has power demand, the unit must be constant regardless of the demand. The speed continues to run. The installed capacity of the generator set must meet the maximum load demand. When the load is small, the “large horse-drawn carriage” has low energy efficiency. Especially when it is applied to equipment with energy feedback such as variable frequency driven crane, each working cycle has a short time. Negative power (energy feedback), even when negative power is generated, the generator set will continue to operate and still consume energy.

The reasons for the in-depth analysis of conventional generator sets (here we use diesel engines) are as follows:

The best economical fuel consumption of diesel engines: Figure 1 is a graph showing the typical characteristics of a certain type of rated power 100kW diesel engine. As shown in the shaded part of Figure 1, the diesel engine outputs a power consumption of about 206 g/kWh at a power of about 70 kW at a speed of about 1250 rpm, which is called "optimal economic fuel consumption." The diesel engine used as the generator set has an engine speed of 1500 rpm and a minimum fuel consumption of 208 g/kWh. When the load power demand is lower than 5 kW, the fuel consumption rate is as high as 350 g/kWh, which is the lowest fuel consumption rate at 1500 rpm. 1.68 times, which is 1.7 times the best economic fuel consumption.

Diesel engine fuel consumption: diesel engine cooling fan and other self-consumption power of 6 to 8%, diesel engine speed used as generator engine is constant at 1500 rpm, self-consumption power and load size have little relationship. As shown in Figure 2, assume that a load is cycled once per hour, power demand 5kW (running 0.75 hours) → 75kW (running 0.25 hours) cycle alternating, working 20 hours energy demand total 450kWh; assuming power system power factor 0.8, diesel engine The self-consumption power is 6kW, then the corresponding output power of the diesel engine is 12.25kW. Turning 0.75 hours) → 100 kW (running for 0.25 hours), the diesel engine runs for 20 hours and consumes a total of 684 kWh of energy. Among them, the energy consumption is 184 kWh for 15 hours at 12.25 kW, and 500 kWh for 5 hours at 100 kW. As shown in Fig. 1, the diesel engine is operated at 1500 rpm, the fuel consumption is about 325 g/kWh at a power of 12.25 kW, and the fuel consumption is 240 g/kWh at a power of 100 kW. Then, corresponding to the above working conditions, the fuel consumption of the diesel engine is 60kg and 120kg respectively, and the total fuel consumption is 180kg.

The ideal fuel consumption of diesel engine: Assume that the control diesel engine always works at the ideal fuel consumption - the best economic fuel consumption rate (206g / kWh), that is, the speed of 1250rpm, the power of 70kW, the power factor of the power system is 0.8 and the diesel engine power consumption is 6kW. Under the condition, when the output energy demand is 450kWh, the diesel engine's self-consumption energy is 615kWh (450×0.8÷64), the total fuel consumption is 126.7kg (615×206÷1000); the diesel engine only takes 3.79 hours (615÷). 70). Compared with the actual fuel consumption of conventional diesel generator sets, fuel economy is 30%.

However, the conventional diesel generator set has no energy storage device. When the load has energy demand, the generator set must work continuously, and the output energy of the unit must be consumed in real time. That is, the output power of the generator set must be adjusted and matched according to the load size in real time, and the diesel engine cannot be always realized. Operating in the best economic fuel consumption area, the ideal energy efficiency cannot be achieved. The unevenness of the load seriously affects the energy efficiency of the diesel generator set. Some loads such as cranes, the diesel generator set must be matched according to the maximum power, and the rated power is more than three times larger than the average power of the load, which is larger than the minimum waiting power. Eight times more than ten times, energy efficiency is very low.

Summary of the invention

In order to overcome the above drawbacks, the object of the present invention is to provide an energy-saving system for a generator set which is operated with an optimal economical energy consumption and has high energy efficiency and intermittent operation and continuous power supply.

The purpose of the utility model is achieved by the following technical solutions:

The utility model relates to an energy-saving system for a generator set with intermittent operation and continuous power supply, comprising: a generator set, a system controller, an AC/DC rectifier, a DC/AC inverter, a transformer, a battery pack, a bidirectional DC/DC converter The generator set includes an engine and a generator connected to the engine. After the generator set is connected with the AC/DC rectifier, it is divided into two paths through the DC bus, one is connected to the DC/AC inverter and the transformer in turn, and the other is connected to the bidirectional DC/DC converter and the battery pack in sequence, and the system is controlled. The device performs signal control on the battery pack, the bidirectional DC/DC converter and the generator set, and the transformer is connected to the load, and the charge and discharge power of the battery pack is greater than or equal to the load power.

Further, the transformer outputs 50 Hz alternating current.

The utility model provides an energy-saving system for a generator set with intermittent operation and continuous power supply. The energy-saving system adds a battery pack with a charge and discharge power greater than or equal to the load power on the basis of the original generator set, and the load energy demand can be from the battery pack. Independently provided, the battery pack discharge power is fully matched to the load power demand. When the battery pack is low, the control starts the generator set to work with the best economical energy consumption, and directly supplies energy to the load. The surplus energy charges the battery pack. When the battery pack power rises to the set value, the generator set is turned off, and the energy demand is turned. It is provided by the battery pack to realize intermittent high-efficiency operation of the generator set without interruption. The energy-saving system has higher energy-saving rate when the load fluctuates more and the low-load working time is longer.

DRAWINGS

For ease of explanation, the present invention is described in detail by the following preferred embodiments and the accompanying drawings (herein, we exemplify a diesel engine).

Figure 1 is a graph showing the typical characteristics of a diesel engine;

Figure 2 is a map of load power demand and diesel fuel consumption;

3 is a circuit connection block diagram of an energy-saving system of a generator set with intermittent operation and continuous power supply according to the present invention;

The reference numerals are: 1, system controller; 2, transformer; 3, DC / AC inverter; 4, battery pack; 5, bidirectional DC / DC converter; 6, AC / DC rectifier; 8, engine.

detailed description

In order to make the objects, technical solutions and advantages of the present invention more comprehensible, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the description here The specific embodiments described are merely illustrative of the invention and are not intended to limit the invention.

Referring to FIG. 3, an energy-saving system for a generator set with intermittent operation and continuous power supply includes: system controller 1, transformer 2, DC/AC inverter 3, battery pack 4, bidirectional DC/DC conversion The AC 5 , the AC/DC rectifier 6 and the generator set are composed of an engine 8 and a generator 7 connected to the engine 8 .

The connection of each component is as follows:

The engine 8 is mechanically connected with the generator 7 to form a conventional generator set. The current output end of the generator 7 is connected to the AC input end of the AC/DC rectifier 6, is rectified by the AC/DC rectifier 6, and output to the DC bus, DC/AC inverter. The DC input terminal of 3 is connected to the DC bus, the DC/AC inverter 3 outputs 50Hz AC and the input of the transformer 2, and the transformer 2 outputs 50Hz AC to supply the load. The battery pack 4 is connected to the DC bus through a bidirectional DC/DC converter 5, and the system controller 1 monitors the battery pack 4 and controls the charging and discharging of the battery pack 4 by controlling the bidirectional voltage of the bidirectional DC/DC converter 5, according to the battery pack. The SOC (State of Charge) of 4 controls the engine 8 to start, run or shut down.

The working principle and energy management control of this system are described in detail as follows:

According to the load demand, the generator set with appropriate power and voltage level can be selected, and the capacity of the generator assembly machine can be configured according to the average power demand. In order to improve the reliability of the power supply, the generator set can be configured according to the maximum power demand of the load. The working principle of the utility model determines the The fuel consumption of the optional generator set has little to do with the installed capacity. It is related to the selected engine 8 characteristics, and the speed and maximum output power are set according to the optimal economic energy consumption of the selected engine. The characteristic group is equipped with a battery pack 4 that is suitable for charging and discharging power and working voltage, and sets the working range of the battery pack 4SOC.

Start system controller 1, self-test battery pack 4, etc. The system is normal before it is put into operation. After the load is turned on, when the SOC capacity of the battery pack 4 is within the set operating range, the load energy demand is provided by the battery pack 4, and the genset is turned off. The battery pack 4 energy supplies a constant voltage direct current to the DC bus through the bidirectional DC/DC converter 5, the DC bus is connected to the DC/AC inverter 3, and the DC/AC inverter 3 converts the direct current into a standard 50 Hz alternating current to the transformer. 2. Transformer 2 delivers regulated, constant-frequency AC to the load.

When the system controller 1 detects that the SOC capacity of the battery pack 4 falls to the set low position, the system controller 1 controls the engine 8 to start, and operates at a constant speed according to the set speed (frequency), and the generator 7 is at a fixed frequency. (Depending on the set engine 8 speed and the number of pole pairs of the generator 7 winding), the AC power is output. The AC power is rectified and converted to DC power by the AC/DC rectifier 6 and sent to the DC bus, which in turn passes through the DC/AC inverter 3 and the transformer. 2 power supply to the load; when the load power demand is greater than the set genset output power, the system controller 1 controls the discharge of the battery pack 4 by controlling the DC bus terminal voltage of the bidirectional DC/DC converter 5 to make up the load demand; when the load power When the output power of the genset is less than the set, the system controller 1 charges the battery pack 4 by controlling the voltage of the battery terminal of the bidirectional DC/DC converter 5, so that the output power of the genset is always maintained near the set optimal operating condition. Ensure that the engine 8 is operating at optimum economical fuel consumption.

When the system controller 1 detects that the SOC capacity of the battery pack 4 rises to the set high level, the system controller 1 issues a command to the genset, and the genset decelerates according to the inherent program of the unit - idle speed - flameout.

In summary, the utility model provides an energy-saving system for a generator set with intermittent operation and continuous power supply for different working load characteristics, and the energy-saving system protects various components and their connection relationships, and does not involve software. Innovative, the energy-saving system uses a battery pack 4 power supply. The battery pack 4 can meet the short-term power supply requirements of the load, and achieve full matching of output power and load power demand to improve energy efficiency; the engine 8 is either working in the optimal economic fuel consumption area. Either turn off the flame to achieve the highest energy efficiency; control the engine 8 never overload, do not smoke black; shorten the running time of the generator set, extend the maintenance cycle.

The utility model has the following characteristics:

1. The battery pack 4 meets the maximum power demand of the load, and can be independently powered for a short time, so that the power supply and the load power are completely matched; the engine 8 works intermittently, and once the engine 8 is put into operation, it is controlled to work in the optimal working condition, the fuel Highest efficiency;

2. The system is widely used, such as cranes, pumping units, oil platforms, ship auxiliary machines, etc. It is especially suitable for working conditions with uneven load, the more uneven the load, the higher the fuel economy; the crane is used for variable frequency drive. When there is energy feedback device, the DC bus is directly connected to the DC terminal of the inverter. Supply or recycle energy to the frequency converter and reuse it;

3. When the system is applied to energy-saving renovation, the original conventional generator set can be replaced, and the high fuel economy rate can be realized without changing the original load demand, thereby reducing the transformation cost.

The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the present invention. The scope of protection of utility models.

Claims

An energy-saving system for diesel generators with intermittent operation and continuous power supply, comprising: generator set, system controller, AC/DC rectifier, DC/AC inverter, transformer, battery pack, bidirectional DC/DC conversion The generator set includes an engine and a generator connected to the engine. The generator set is connected to the AC/DC rectifier and split into two paths through a DC bus, and one circuit is sequentially connected with a DC/AC inverter and a transformer, and the other is connected. All the way is connected to the bidirectional DC/DC converter and the battery pack in sequence, and the system controller performs signal control on the battery pack, the bidirectional DC/DC converter and the generator set, the transformer is connected to the load, and the charging and discharging power of the battery pack Greater than or equal to the load power.
The intermittently operated continuously powered diesel generator energy saving system according to claim 1, wherein the transformer outputs 50 Hz alternating current.