80 early, the first Japanese Toshiba AC variable speed technology used in the air conditioner. 1997, its share has reached more than 70% of the Japanese home air conditioning. The advantages of comfort, energy saving inverter air conditioner with ordinary air conditioning is difficult to do. Domestic inverter air conditioner began in the early 1990s,Grid tie inverter, many colleges and universities, the factory, the once invested a lot of manpower and resources to develop, but basically did not reach the target. Until the second half of 1996, the inverter air conditioner products heavily in the introduction of the production line before entering the market, to break the stagnant situation of the research and development of domestic inverter air conditioner. After just more than a year, a succession of introduction of similar products from multiple vendors, and gradually formed a development and production of inverter air conditioner hot.
examine domestic inverter air conditioner development process, there are a few points worth noting:
(1) the inverter air conditioner is not equal to the ordinary air conditioning plus variable frequency power supply. Inverter air conditioner is a mechatronic product also requires, in addition to the variable frequency power supply, compressor motors suitable for frequency control. Domestic development of inverter air conditioner early, due to the limitations of the sources of the compressor, the majority focused on the existing single-phase capacitor motors or two-phase motors. A single phase motor (capacitor or resistor divider phase), the structure of the variable frequency power supply for single-phase input and single phase output (SISO) does not change the existing compressor to reduce investment in principle, but because of the motor field is not round shape, the motor capacitance and frequency changes changes, low switching losses, the efficiency of the system, operating performance and energy saving effect is not ideal. http://www.gridtieinverter.de/
two-phase motors, variable frequency power supply for single into a double out strict 90 ° of phase, remove a capacitor or resistor, the motor just re-winding can. Same winding, two-phase process is simple, the costs are very low, and to ensure a circular magnetic field. However, this method voltage serious losses, low utilization rate of the core, the efficiency is not high. Despite a number of reports of this method [1,2], but in fact is not great value.
mature inverter on the theory and practice structure is a single into three forms,Grid tie inverter. Divided into three-phase alternating current variable frequency power supply, the single-phase AC electric drive three-phase asynchronous motor with smooth speed control technology is relatively mature, control methods varied motor operating characteristics, higher efficiency advantages.
(2) the inverter air conditioner problems not just a the VVVF problem. For example, since the compressor to change the rotational speed caused flow problems. Inverter under the conditions of ordinary air conditioning capillary throttling element is no longer applicable.
(3) Air conditioning variable frequency power supply has its own special conditions of use compared with the general general-purpose inverters [3]. Lack of knowledge of this particularity, to follow the development of the general-purpose inverters thinking to develop the air-conditioning variable frequency power supply, and inevitable difficult to have practical value.
present, the inverter air conditioner as a new generation of air-conditioning products in the country is gradually expected to reach a peak around 2000. Ancillary variable frequency power supply, in addition to the introduction of production, the development of domestic production is also available on the track [4]. Optimal control strategy, the selection of functional components, is a further development of the direction of the air conditioner inverter power developed.
air conditioner inverter power
air conditioner inverter power supply design should consider the following:
(1) volume. Variable frequency power supply only air conditioning is a feature, which determines its stringent requirements on the volume. This requirement is consistent with the direction of the development of power electronic devices. Intelligent power module (IPW), for example. Reduce the leakage inductance of the plate-wiring with the current board, as well as high-performance cooling system, not only greatly improve the performance of the inverter, and 0,power inverter.75kW inverter volume is reduced to less than ten years 10% of the original.
(2) voltage regulator. Domestic residents electricity voltage fluctuations. Design variable frequency power supply voltage regulation capability ill-considered, practical occurs torque ripple serious impact on the overall performance. The voltage regulator implementation depends mainly on the PWM method.
(3) the low frequency performance. Although the governor of the air conditioner inverter power than small, but because of the work of most of the time in the low-frequency insulation segment, thus its low frequency PWM characteristics require a higher, especially the power switch interlock time should be as small as possible, the time on the low-frequency performance impact.
(4) reliability. Continuous variable frequency power supply for many years to work outdoors, and reliability requirements is self-evident.
In addition, the switching losses, the feedback signal interface and cost, there are some special requirements. Some problems belong to the control level to do the work; software and control circuit power level, will have to do the work in the selection of modules, components.
3 integrated power stage
only
intelligent power module (IPM) is to solve the integration of the inverter bridge drive circuit as variable frequency power supply applications, need to reprovision the rectifier bridge, not only the system volume increase, between the bridge rectifier with the IPM Miscellaneous scattered inductance is difficult to overcome, in the application of the inconvenience.
integrated power stage
International Rectifier (IR) introduced in recent years (IntegratedPowerStage, registered the name POWIRTRAIN) for AC motor drive provides a full range of power conversion solutions, indicators from its specifications, it is suitable for air-conditioning variable frequency power supply power level. Integrated power stage, including the two complement each other part of a power module, including single-phase or three-phase bridge rectifier and three-phase inverter bridge; another driver board, including high-voltage drive board power; possess overcurrent overheating and grounding protection, and gives the voltage and current feedback signal control circuit interface,power inverter. The power module is a direct plug-in driver board contains filter capacitor, including the entire system size (0.75kW products, for example the) only 71mm × 71mm × 57mm, we can see the extent of its compact. The system has been specifically optimized to use it can be put into the main effort of the developers to strategy.
as instance variable frequency power supply applications in air conditioning, and its parameters are listed in the following example) (0.75kW motor POWIRTRAINIRPT1059.
input voltage single phase 220V, 50Hz ~ 60Hz
output voltage 0 ~ 230V
motor power 1HP (150% overload 1min)
overcurrent protection value 30A ± 10%
grounding protection value 36A ± 10%
overheating protection value 100 ℃ ± 5%
interlock time typically 0.8μs
IGBT short circuit capacity 10μs, 16A
rose time tr a typical value of 42ns (16A, Udc = 480V)
decline time tf maximum of 120ns (16A, Udc = 480V)
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