电动力学论文英文短篇

电动力学论文英文短篇

用于分布式在线UPS中的并联逆变器的一种无线控制器
A Wireless Controller for Parallel Inverters in Distributed Online UPS Systems
Josep M. Guerrero', Luis Garcia de Vicufia", Jose Matas'*, Jaume Miret", and Miguel Castilla"
. Departament #Enginyeria de Sistemes, Automatica i Informhtica Industrial. Universitat Polithica de Catalunya
C. Comte d'Urgell, 187.08036 -Barcelona. Spain. Email: .. Departament #Enginyeria Electrbnica. Universitat Polit6cnica de Catalunya
AV. Victor BaLguer s/n. 08800I - Vilanova i la Geltrh. Spain
Absiract - In this paper, a novel controller for parallelconnected
online-UPS inverters without control wire
interconnections is presented. The wireless control technique is
based on the well-known droop method, which consists in
introducing P-oand Q-V schemes into the inverters, in order to
share properly the power drawn to the loads. The droop method
has been widely used in applications of load sharing between
different parallel-connected inverters. However, this method
has several drawbacks that limited its application, such as a
trade-off between output-voltage regulation and power sharing
accuracy, slow transient response, and frequency and phase
deviation. This last disadvantage makes impracticable the
method in online-UPS systems, since in this case every module
must be in phase with the utility ac mains. To overcome these
limitations, we propose a novel control scheme, endowing to the
paralleled-UPS system a proper transient response, strictly
frequency and phase synchronization with the ac mains, and
excellent power sharing. Simulation and experimental results
are reported confirming the validity of the proposed approach.
1. INTRODUCTION
The parallel operation of distributed Uninterruptible Power
Supplies (UPS) is presented as a suitable solution to supply
critical and sensitive loads, when high reliability and power
availability are required. In the last years, many control
schemes for parallel-connected inverters has been raised,
which are derived from parallel-schemes of dc-dc converters
[I], such as the master-slave control [2], or the democratic
control [3]. In contrast, novel control schemes have been
appeared recently, such as the chain-structure control [4], or
the distributed control [ 5 ] . However, all these schemes need
control interconnections between modules and, hence, the
reliability of the system is reduced since they can be a source
of noise and failures. Moreover, these communication wires
limited the physical situation ofthe modules [6].
In this sense, several control techniques has been proposed
without control interconnections, such as the droop method.
In this method, the control loop achieves good power sharing
making tight adjustments over the output voltage frequency
and amplitude of the inverter, with the objective to
compensate the active and reactive power unbalances [7].
This concept is derived from the power system theory, in
which the frequency of a generator drops when the power
drawn to the utility line increases [8].
0-7803-7906-3/03/$17.00 02003 IEEE. 1637
However, this control approach has an inherent trade-off
between voltage regulation and power sharing. In addition,
this method exhibits slow dynamic-response, since it requires
low-pass filters to calculate the average value of the active
and reactive power. Hence, the stability and the dynamics of
the whole system are hardly influenced by the characteristics
of these filters and by the value of the droop coefficients,
which are bounded by the maximum allowed deviations of
the output voltage amplitude and frequency.
Besides, when active power increases, the droop
characteristic causes a frequency deviation from the nominal
value and, consequently, it results in a variable phase
difference between the mains and the inverter output voltage.
This fact can be a problem when the bypass switch must
connect the utility line directly to the critical bus in stead of
its phase difference. In [9], two possibilities are presented in
order to achieve phase synchronization for parallel lineinteractive
UPS systems. The first one is to locate a particular
module near the bypass switch, which must to synchronize
the output voltage to the mains while supporting overload
condition before switch on. The second possibility is to wait
for the instant when phase matching is produced to connect
the bypass.
However, the mentioned two folds cannot be applied to a
parallel online-UPS system, since maximum transfer time
ought to be less than a % of line period, and all the modules
must be always synchronized with the mains when it is
present. Hence, the modules should be prepared to transfer
directly the energy from the mains to the critical bus in case
of overload or failure [lo].
In our previous works [11][12], we proposed different
control schemes to overcome several limitations of the
conventional droop method. However, these controllers by
themselves are inappropriate to apply to a parallel online-
UPS system. In this paper, a novel wireless control scheme is
proposed to parallel different online UPS modules with high
performance and restricted requirements. The controller
provides: 1) proper transient response; 2) power sharing
accuracy; 3) stable frequency operation; and 4) good phase
matching between the output-voltage and the utility line.
Thus, this new approach is especially suitable for paralleled-
UPS systems with true redundancy, high reliability and
power availability. Simulation and experimental results are
reported, confirming the validity of this control scheme.
Fig. 1. Equivalenl cimuif ofan invener connecled 10 a bus
t"
Fig. 2. P-odraop function.
11. REVlEW OF THE CONVENTIONAL DROOP METHOD
Fig. 1 shows the equivalent circuit of an inverter connected
to a common bus through coupled impedance. When this
impedance is inductive, the active and reactive powers drawn
to the load can be expressed as
EVcosQ - V2 Q=
where Xis the output reactance of an inverter; Q is the phase
angle between the output voltage of the inverter and the
voltage of the common bus; E and V are the amplitude of the
output voltage of the inverter and the bus voltage,
respectively.
From the above equations it can be derived that the active
power P is predominately dependent on the power angle Q,
while the reactive power Q mostly depends on the outputvoltage
amplitude. Consequently, most of wireless-control of
paralleled-inverters uses the conventional droop method,
which introduces the following droops in the amplitude E
and the frequency U of the inverter output voltage
u = w -mP (3)
E = E ' - n Q , (4)
being W* and E' the output voltage frequency and amplitude
at no load, respectively; m and n are the droop coefficients
for the frequency and amplitude, respectively.
Furthermore, a coupled inductance is needed between the
inverter output and the critical bus that fixes the output
impedance, in order to ensure a proper power flow. However,
it is bulky and increase:; the size and the cost of the UPS
modules. In addition, tho output voltage is highly distorted
when supplying nonlinezr loads since the output impedance
is a pure inductance.
It is well known that if droop coefficients are increased,
then good power sharing is achieved at the expense of
degrading the voltage regulation (see Fig. 2).
The inherent trade-off of this scheme restricts the
mentioned coefficients, which can be a serious limitation in
terms of transient response, power sharing accuracy, and
system stability.
On the other hand, lo carry out the droop functions,
expressed by (3) and (4), it is necessary to calculate the
average value over one line-cycle of the output active and
reactive instantaneous power. This can be implemented by
means of low pass filters with a smaller bandwidth than that
of the closed-loop inverter. Consequently, the power
calculation filters and droop coefficients determine, to a large
extent, the dynamics and the stability of the paralleledinverter
system [ 131.
In conclusion, the droop method has several intrinsic
problems to be applied 1.0 a wireless paralleled-system of
online UPS, which can he summed-up as follows:
Static trade-off between the output-voltage regulation
(frequency and amplitude) and the power-sharing
accuracy (active an4d reactive).
2) Limited transient response. The system dynamics
depends on the power-calculation filter characteristics,
the droop coefficients, and the output impedances.
Lost of ac mains synchronization. The frequency and
phase deviations, due to the frequency droop, make
impracticable this method to a parallel-connected
online UPS system, in which every UPS should be
continuously synchronized to the public ac supply.
1)
3)
111. PROPOSED CONTROL FOR PARALLEL ONLINE UPS
INVERTERS
In this work, we will try to overcome the above limitations
and to synthesize a novel control strategy without
communication wires that could be appropriate to highperformance
paralleled industrial UPS. The objective is to
connect online UPS inverters in parallel without using
control interconnections. This kind of systems, also named
inverter-preferred, should be continuously synchronized to
the utility line. When an overload or an inverter failure
occurs, a static bypass switch may connect the input line to
the load, bypassing the inve:rter [14][15].
Fig. 3 shows the general diagram of a distributed online
UPS system. This system consists of two buses: the utility
bus, which is connected lo the public ac mains; and the
secure bus, connected to the distributed critical loads. The
interface between these buses is based on a number of online
UPS modules connected in parallel, which provides
continuously power to the: loads [16]. The UPS modules
include a rectifier, a set of batteries, an inverter, and a static
bypass switch.
1
1638
Q ac mains
utility bus
I I I
j distributed loads !
Fig. 3. Online distributed UPS system.
syposr /
I 4
(4
Fig. 4. Operation modes of an online UPS.
(a) Normal operation. (b) Bypass operation. (c) Mains failure
The main operation modes of a distributed online UPS
1) Normal operation: The power flows to the load, from
the utility through the distributed UPS units.
2) Mains failure: When the public ac mains fails, the
UPS inverters supply the power to the loads, from the
batteries, without disruption.
Bypass operation: When an overload situation occurs,
the bypass switch must connect the critical bus
directly to the ac mains, in order to guarantee the
continuous supply of the loads, avoiding the damage
of the UPS modules.
For this reason, the output-voltage waveform should be
synchronized to the mains, when this last is present.
system are listed below (see Fig. 5):
3)
Nevertheless, as we state before, the conventional droop
method can not satisfy the need for synchronization with the
utility, due to the frequency variation of the inverters, which
provokes a phase deviation.
To obtain the required performance, we present a transient
P-w droop without frequency-deviation in steady-state,
proposed previously by OUT in [ 111
w=o -mP (5)
where is the active power signal without the dccomponent,
which is done by
. -
I t -1s
P= p ,
( s + t - ' ) ( s + o , )
being zthe time constant of the transient droop action.
The transient droop function ensures a stable frequency
regulation under steady-state conditions, and 'at the same
time, achieves active power balance by adjusting the
frequency of the modules during a load transient. Besides, to
adjust the phase of the modules we propose an additional
synchronizing loop, yielding
o=w'-m%k,A$, (7)
where A$ is the phase difference between the inverter and the
mains; and k, is the proportional constant of the frequency
adjust. The steady-state frequency reference w* can be
obtained by measuring the utility line frequency.
The second term of the previous equality trends to zero in
steady state, leading to
w = w' - k4($ -@'), (8)
being $and $* the phase angles of the output voltage inverter
and the utility mains, respectively.
Taking into account that w = d $ / d t , we can obtain the
next differential equation, which is stable fork, positive
d$ *
dt dt
- + km$ = - + k,$' . (9)
Thus, when phase difference increases, frequency will
decrease slightly and, hence, all :he UPS modules will be
synchronized with the utility, while sharing the power drawn
to the loads.
IV. CONTROLLIEMRP LEMENTATION
Fig. 5 depicts the block diagram of the proposed
controller. The average active power P , without the dc
component, can be obtained by means of multiplying the
output voltage by the output current, and filtering the product
........................................................................................
io
",.
L
Sj'nchronirorion loop
.......................................................................................
Fig. 5. Block diagram of the proposed controller.
using a band-pass filter. In a similar way, the average
reactive power is obtained, hut in this case the output-voltage
must be delayed 90 degrees, and using a low-pass filter.
In order to adjust the output voltage frequency, equation
(7) is implemented, which corresponds to the frequency
mains drooped by two transient-terms: the transient active
power signal term; and the phase difference term, which
is added in order to synchronize the output voltage with the
ac mains, in a phase-locked loop (PLL) fashion. The outputvoltage
amplitude is regulated by using the conventional
droop method (4).
Finally, the physical coupled inductance can be avoided by
using a virtual inductor [17]. This concept consists in
emulated an inductance behavior, by drooping the output
voltage proportionally to the time derivative of the output
current. However, when supplying nonlinear loads, the highorder
current-harmonics can increase too much the outputvoltage
THD. This can be easily solved by using a high-pass
filter instead of a pure-derivative term of the output current,
which is useful to share linear and nonlinear loads [I 1][12].
Furthermore, the proper design of this output inductance can
reduce, to a large extent, the unbalance line-impedance
impact over the power sharing accuracy.
v. SIMULATION AND EXPERIMENTARELS ULTS
The proposed control scheme, (4) and (7), was simulated
with the parameters listed in Table 1 and the scheme shown
in Fig. 6, for a two paralleled inverters system. The
coefficients m, n, T, and kv were chosen to ensure stability,
proper transient response and good phase matching. Fig. 7
shows the waveforms of the frequency, circulating currents,
phase difference between the modules and the utility line,
and the evolution of the active and reactive powers. Note the
excellent synchronization between the modules and the
ACmiiinr 4 j. ...L...I.P...S...1... ..........................B...u...n...r.r..r..e..s... ................................... i
Fig. 6. Parallel operation oftwa online UPS modules,
mains, and, at the same time, the good power sharing
obtained. This characteristik let us to apply the controller to
the online UPS paralleled systems.
Two I-kVA UPS modules were built and tested in order to
show the validity of the proposed approach. Each UPS
inverter consisted of a single-phase IGBT full-bridge with a
switching frequency of 20 kHz and an LC output filter, with
the following parameters: 1. = 1 mH, C = 20 WF, Vi" = 400V,
v, = 220 V, I50 Hz. The controllers of these inverters were
based on three loops: an inner current-loop, an outer PI
controller that ensures voltage regulation, and the loadsharing
controller, based on (4) and (7). The last controller
was implemented by means of a TMS320LF2407A, fixedpoint
40 MHz digital sigrial processor (DSP) from Texas
Instruments (see Fig. 8), using the parameters listed in Table
I. The DSP-controller also includes a PLL block in order to
synchronize the inverter with the common bus. When this
occurs, the static bypass switch is tumed on, and the droopbased
control is initiated.
1640
big 7 Wa\cfc)rms for r, ;mnectcd in parallel. rpchrontred io Ihc ac mdnl.
(a) Frequencics ufhoth UPS (b) Clrculattng currcni among modulcs. (CJ Phmc d!Nercn;: betucen ihc UPS a#>dth e ai mum
(d) Ikiril uf the phze diNmncc (e) md (0 Activc and rcactlw pouerr "I ooih UPS
Note that the iimc-acs arc deliheratcly JiNercni due in thc disiinct timuion*uni) ofthe \ inrblrr
1641
TABLEI.
PARAMETEROSF THE PARALLELESDYS TEM.
Filter Order I I
Filter Cut-off Frequency I 0, I 10 I rags
Fig. 8 shows the output-current transient response of the
UPS inverters. First, the two UPS are operating in parallel
without load. Notice that a small reactive current is circling
between the modules, due to the measurement mismatches.
Then, a nonlinear load, with a crest factor of 3, is connected
suddenly. This result shows the good dynamics and loadsharing
of the paralleled system when sharing a nonlinear
load.
Fig. 8. Output current for the two paralleled UPS, during the connection of B
common nonlinear load with a crest factor of 3. (Axis-x: 20 mddiv. Axis-y:
5 Mdiv.).
VI. CONCLUSIONS
In this paper, a novel load-sharing controller for parallelconnected
online UPS systems, was proposed. The controller
is based on the droop method, which avoids the use of
control interconnections. In a sharp contrast with the
conventional droop method, the controller presented is able
to keep the output-voltage frequency and phase strictly
synchronized with the utility ac mains, while maintaining
good load sharing for linear and nonlinear loads. This fact let
us to extend the droop method to paralleled online UPS.
On the other hand, the proposed controller emulates a
special kind of impedance, avoiding the use of a physical
coupled inductance. Th.e results reported here show the
effectiveness of the proposed approach.

谁有关于电力系统方面的英文论文？

An electric power system (or simply power system) is a network of electrical components used to supply, transmit and utilise electric power. The quintessential example of an electric power system is the network that supplies a region's homes and industry with power - for sizable regions, this power system is known as the grid and can be broadly divided into the generators that supply the power, the transmission system that carries the power from the generating centres to the load centres and the distribution system that feeds the power to nearby homes and industries. Smaller power systems are also found in industry, hospitals, commercial buildings and homes. The majority of these systems rely upon three-phase AC power - the standard for large-scale power transmission and distribution across the modern world. Specialised power systems that do not always rely upon three-phase AC power are found in aircraft, electric rail systems, ocean liners and automobiles.

求一电动力学论文题目

先给你一些建议： 1．论文写作应建立在丰富的材料的基础上，正式撰写论文之前，应当围绕选题广泛收集资料，并对材料进行整理提炼，写出一篇反映本论题的各种观点的综述性文章 2．论文写作要按照选题、收集资料、编写提纲、撰写初稿、修改初稿、定稿的顺序进行。定稿前论文要多次修改。 3．定稿后的论文应包括下列内容: (1)题目 （2）提纲 （3）中文摘要、关键词 （4）正文 （5）参考文献 （6）英文摘要、关键词 下面就是一些题目，不知有没有适合你的。希望对你有帮助吧！ 1、库仑定律的实验及其应用 2、正负粒子相互环绕产生的辐射 3、用麦克斯韦理论谈电磁波在介质界面上的入射角、反射角、折射角的关系 4 ~用麦克斯韦理论谈电磁波在介质界面上的反射、折射振幅和位相的关系 5、矩形波导中TE10波的最大功率 6、麦克斯韦方程组的建立探讨 7、对电磁场的能量和动量深入的认识 8、电磁场的能量和动量在狭义相对论条件下的表达形式 9、电磁场和介质相互作用分析 10、矩形波导的发展过程 11、“惟一性定理”的应用 12、电动力学方程的洛仑兹协变性 13、论证矩形波导内不存在TEm0或T Eon波 14、电磁波辐射初探 15、电动力学基本方程四维协变形式的推导

希望采纳

求一篇关于电动力学的论文

Abstract:变数分离法在不同坐标系下解Laplace-equation

Keywords:泊松 亥姆霍兹 勒让德 贝塞尔

依据数学的定理：一个关于时间和空间的函数总可以分离为一个只于时间有关的函数和另一个只于空间有关的两个函数的乘积，即 。利用变数分离就可以将一个 的复杂函数分离为 和 的两个单变量函数，从而使问题得到简化，所以变数分离在数学物理中都是解决问题的一种重要方法。
电动力学里的曾多次用到变数分离法：求电势时，给出了一个泊松方程；在谐振腔和波导管中的亥姆霍兹方程；高斯光束；光学空间孤子等。解决这些问题的一种相同的方法就是变数分离，下面讨论两种具体的形式在这些问题的解法。
无论是高斯光束还是光孤子，还是泊松方程，其实质都是亥姆霍兹方程，以下就从拉普拉斯开始推导一般的解。

（1）.直角坐标系下
泊松方程的统一方程为 ，其中 ，所以只要解的 的通解在加上泊松的特解就可以得到泊松方程的通解。下面用变量分离的方法解拉普拉斯方程。
，代入 ，得：
， ，即 ，将此式两边同时以 ， ，移项有，
。此式的左边是一个关于 的函数，而右式仅是 的函数，要两边相等那么就只有一种可能，两边等于一个常数或者为零，不妨设此常数为 ，则 ， ，同理令 ； ，整理得：

；
于是拉普拉斯方程就化到了以上的六个公式，其形式为 其中 取 , 取 ：，诺令 ，那么解得 显然 都满足以上的方程 ，于是

（2）.柱坐标下的变数分离
，

（3）.
，在关于极对称下化为 。

在波导管和谐振腔中电磁波的传播满足亥姆霍兹方程 ，依据上面的解法，不难知道其解的表达式与（4）相似，那么其解与（5）有相同的形式。

由上面的过程可知在解决问题时应该视问题的具体形式而选用适合的坐标系下解析，以使计算尽量变得的简单，一般当一个问题具有球对称时用球坐标系下的解比较简单。当一个波导管不是矩形是那么用直角坐标解析就十分复杂。球电势的拉普拉斯方程就是利用在球坐标系下,而且选取极轴并利用（7）式的结论使求解简单。实际的问题中往往都具有边界条件，再根据边界来确定各方程中的系数。显然一般的方程中都有六个待定的系数，理论上也就需要六个边界来确定。

参考文献： 梁昆淼.《数学物理方法》,第三版，229.236

求热能动力工程的英文论文一篇，中英文都要，英文单词5000左右，谢谢。

近二十年来，以振动为主要原因造成的恶性事故相继发生，给国家造成了巨大经济损失。而且，振动问题目前仍是新投运大机组不能按期并网、正常投运的主要原因，在机组正常运行期间，振动问题连续不断，影响到正常生产，经常出现机组减负荷和带病运行的情况，甚至使机组被迫停机处理，这些事故屡见不鲜。本系统基于LabVIEW虚拟仪器软件平台，对汽轮机振动信号进行读取加窗，并进行谱分析及自相关分析。LabVIEW虚拟仪器就是在以通用计算机为核心的硬件平台上，由用户设计定义、具有虚拟前面板、测试功能由测试软件实现的一种计算机仪器系统。本系统主要完成了对汽轮机振动信号进行读取，对信号进行矩形窗、汉宁窗、海明窗的加窗选择，然后分别进行信号的幅值谱、功率谱、相位谱分析及自相关分析，并且具有图形操作及显示界面。系统运行结果证明，本系统能够完成对信号的读取，并进行三种窗函数及各种分析的动态选择，并用图形显示结果。
Over the last 20 years, mainly due to the vibration caused by the fatal accidents occurred one after another, inflicting huge economic losses. Furthermore, the vibration is still new to large units shipped impossible grid, the normal operation for the main the crew during normal operations, continuous vibration problems affecting the normal production, Units often reduced load and operation of the sick, and even the unit was forced to stand, these incidents not uncommon. The system based on LabVIEW virtual instrument software platform for turbine vibration signal window read, and spectral analysis and correlation analysis. LabVIEW virtual instrument is a common core of computer hardware platform, defined by the user, with virtual front panel, the test function test software from a computer equipment system. The system completed the turbine vibration signal read, the signal rectangular window Hanning, Hamming window window choice, and then the signal amplitude spectrum, power spectrum and phase spectrum analysis and correlation analysis, and operating with graphics and display interface. The result of running the system proved that the system can accomplish the signal read, and three window function and the dynamic analysis of the various options and graphical display with the results.

专业前景 本专业以工程热物理学科为主要理论基础，以内燃机和正在发展中的其它新型动力机械及系统为研究对象，运用工程力学、机械工程学、自动控制、计算机、环境科学、微电子技术等学科的知识和内容，研究如何把燃料的化学能和液体的动能安全、高效、低（或无）污染地转换成动力的基本规律和过程，研究转换过程中的系统和设备的自动控制技术。随着常规能源的日渐短缺，人类环境保护意识的不断增强，节能、高效、降低或消除污染排放物、发展新能源及其它可再生能源成为本学科的重要任务，在能源、交通运输、汽车、船舶、电力、航空宇航工程、农业工程和环境科学等诸多领域获得越来越广泛的应用，在国民经济各部门发挥着越来越重要的作用。 培养目标 本专业方向培养具备热能与动力工程专业方面的基本理论、基本知识和基本技能，能在国民经济各部门从事热力发动机和其它新型动力机械及设备的设计、制造、管理、教学和科研等方面的高级工程技术人才。 培养特色 本专业在加强学生基础理论和综合素质教育的同时，加强计算机及自动控制技术的应用，强化专业实践教学，注重全能训练，全面提高学生的实践动手能力和科学研究潜力，使毕业生具有较强的择业竞争能力和较宽的就业适应能力。 主干课程 机械制图、机械原理、机械设计、理论力学、材料力学、工程材料、电工技术、电子技术、计算机软件基础、液压技术、液力传动、内燃机构造、内燃机原理、内燃机设计、内燃机试验、发动机电子技术、工程热力学、流体力学、传热学、自动控制理论、现代测试技术等。 就业方向 毕业后可从事能源与动力设备的行政管理、内燃机及新型动力设备的开发研制、内燃机排放控制、新能源利用、汽车工业、兵器工业、环保工业、交通运输业、船舶、电力、航空宇航工业等方面的工作。
The prospect of major works of the major hot in physics as the main theoretical basis to the internal combustion engine and the other is the development of new machinery and power systems for the study, the use of engineering mechanics, mechanical engineering, automation, computers, environmental science, microelectronics technology disciplines, such as content knowledge and to study how the chemical energy of fuel and liquid kinetic energy security, high-performance, low (or none) of pollution to the power into the basic law and the process of research in the conversion process of the automatic control systems and equipment technology . With the growing shortage of conventional energy, human the growing awareness of environmental protection, energy saving, high efficiency, reduce or eliminate polluting emissions, the development of new energy and other renewable sources of energy has become an important task for the subjects in the energy, transportation, automotive, ships, electricity, aviation aerospace engineering, agricultural engineering and environmental science in many fields such as access to more and more widely used, the department in the national economy is playing an increasingly important role. Cultivate cultivate goal with the direction of the major thermal power projects with the major aspects of the basic theory, basic knowledge and basic skills, to engage in various departments in the national economy and other heat engines power the new machinery and equipment design, manufacture, management, teaching and scientific research aspects of advanced engineering and technical personnel. Cultivate major characteristics of the students in strengthening the basic theory and the overall quality of education, to strengthen the computer and automatic control technology, and strengthen the teaching of professional practice, pay attention to all the training, students enhance the practice of comprehensive practical ability and scientific research potential, so that graduates have strong competitiveness and a wide choice of employment adaptability. Mechanical Drawing trunk curriculum, mechanical principles, mechanical design, theoretical mechanics, mechanics of materials, engineering materials, electrical technology, electronics technology, computer software foundation, hydraulic technology, hydraulic transmission, the internal combustion engine structure, the principle of internal combustion engines, internal combustion engine design, the internal combustion engine testing, engine electronic technology, engineering thermodynamics, fluid mechanics, heat transfer, automatic control theory, modern test technology. Employment after graduation can be engaged in the direction of energy and power equipment, administration, internal combustion engines and new development of power equipment, internal combustion engine emission control, new energy use, the auto industry, the weapons industry, industrial environmental protection, transport, shipping, electricity, air space industrial job.

Motor vehicles are not the only air polluters. Coal and oil, used to heat homes and factories and to generate electricity, contain small amounts of sulfur. When the fuels are burned, sulfur dioxide, a poisonous gas, is produced. It is irritating to the lungs. Some cities have passed laws that allow coal and oil to be burned only if their sulfur content is low.
汽车不是唯一的空气污染。煤炭和石油，用于家庭取暖和工厂，并产生电力，含有少量的硫。当燃料燃烧，二氧化硫，一种有毒气体，就产生了。它是刺激到肺部。一些城市已通过法律，允许煤炭和石油只有在其被烧毁硫含量低。
Most electricity is generated by steam turbines. About half of the sulfur dioxide in the air comes from burning fuel to make steam. Nuclear power plants do not burn fuel, so there is no air pollution of the ordinary kind. But the radioactive materials in these plants could present a danger in an accident. Also, there is a problem in disposing of the radioactive wastes in a way that will not endanger the environment.
大部分电力是由蒸汽涡轮机。关于空气中的二氧化硫，使蒸汽一半来自燃料燃烧。核电厂不烧燃料，所以不存在的那种普通的空气污染。但是，在这些植物的放射性物质可能会提出一个意外的危险。此外，还有一个在放射性废物处置的方式，不会危害环境的问题。
Another type of pollution, called thermal (heat) pollution, is caused by both the fuel-burning and nuclear plants. Both need huge amounts of cold water, which is warmed as it cools the steam. When it is returned to the river, the warm water may stimulate the growth of weeds. It may also kill fish and their eggs, or interfere with their growth.
另一种污染类型，称为热（热）污染，是造成双方的燃料燃烧和核电厂。双方都需要的冷水，这是温暖，因为它大量的蒸汽冷却。当返回到河边，温暖的水会刺激杂草生长。它也可以杀死鱼，它们的卵，或干扰他们的成长。
Physicists are studying new ways of generating electricity that may be less damaging to the environment. In the meantime, many power plants are being modernized to give off less polluting material. Also, engineers try to design and locate new power plants to do minimum damage to the environment.
物理学家们正在研究发电对环境损害较小的新方法。与此同时，许多发电厂也在实现现代化以减少污染物质。此外，工程师们尝试设计并找到对环境的损害最小的新的发电厂。

Thermal energy and power engineering
This program is to cultivate both master thermal energy and power engineering professional basic theoretical knowledge, computing skills, but also the ability in various forms of generating power plant, refrigeration and air conditioning, new energy related fields in need of economic management knowledge and ability, can be engaged in the electric power industry related to areas of science and technology application, research, development and management of a senior talents. According to the national construction and talents needs, set up the professional direction includes: thermal power engineering, power plant set control operation, refrigeration and air conditioning engineering, gas power engineering, advanced energy engineering etc.
Major courses: theoretical mechanics, mechanics of materials, engineering thermodynamics, engineering fluid mechanics, heat transfer, turbine principle, boiler principle, thermal power plants, the pump and fan, automatic control theory, motor learning, circuit theory, the control system, unit unit operation principle, thermal process detection technology, engineering graphics, mechanical design basis, electrician technical basis, electronic technology base, refrigeration and cryogenic principle, refrigeration compressor, refrigeration automation and testing technology, gas turbine principle, gas gas-steam combined cycle power plant, gas turbine combined-cyde operation and maintenance, nuclear reactor theoretical basis, nuclear system and the maintenance, the PWR nuclear power plant system and equipment, wind power generation principle, professional class.
Employment place to go: large-scale modernized electric power enterprise, power equipment manufacturing enterprises and energy class enterprise engaged in production, operation and management work, Government departments at all levels and institution engaged in energy, power, energy saving, environmental planning, design, construction, operation, consultation and supervision work; etc. Research institutes, universities in energy and power related research and development, teaching, management, etc.