AC Drive Solutions

Remarks on the AC Drive Solutions Feature

Michihiko Zenke

Corporate Vice President,
General Manager, Drives Div.
Michihiko Zenke

The signing of the COP21 (The 21st Conference of the Parties to the United Nations Framework Convention on Climate Change) Paris Agreement by 175 countries from around the world is still fresh in our memories. This was the first framework in history that had the participation of all countries, including the countries that are the greatest emitters of greenhouse gases, and it was described as a breakthrough moment. It has been predicted that if no action is taken regarding our emissions of greenhouse gases, then there will be a rise in average global temperatures of around 5°C and an accompanying rise in sea levels of nearly one meter. The agreement defined targets for the greenhouse gases reduction in order to prevent this outcome. CO2 makes up just over 70% of those greenhouse gases and just over 70% of that CO2 comes from electricity related sources, such as energy conversion, industry, other work and households. Furthermore, around half of all electricity consumption is by motors, so the reduction of energy consumption on motors is a major issue for the world of industry. As one of the solutions to this issue, high motor efficiency regulations that are equivalent to IE3 have also been introduced in Japan as the Top Runner Program. In another area, AC drives are devices which control the rotational speed of motors. In addition to achieving smoother and higher performance movement on machinery and equipment, they can also make a great contribution to productivity improvements and energy-saving in factories. The inclusion of AC drives is also becoming widespread in air conditioning equipment such as home air conditioners. I believe that examples such as these will give you an idea of how AC drives are products that are found close to us and simultaneously achieve both user comfort and energy saving.

The AC drive market is expected to continue to grow steadily from now onwards due to factors such as the global reduction of CO2 emissions as described above, the advances in machinery and equipment in the advanced countries and the growth and development of the emerging nations. As this market growth continues, AC drives will be required to realize further environment adaptability, advances in energy-saving technologies, and higher efficiency. AC drives make it possible to control the rotational speed of a motor to the speed appropriate for the load, so it is possible to obtain large energy-reducing effects. However, there are also demands for technology to control the speed to achieve the maximum possible motor efficiency in response to the situation of each rotational speed and load and also demands for improved power conversion efficiency on the AC drives themselves. One key point when working to improve the efficiency of an AC drive is the switching elements in the main circuits. At the current time, the majority of these are IGBT. However, the development of high power density drive systems using silicon carbide (SiC) and gallium nitride (GaN) is being actively progressed. These materials are attracting attention for the next generation of devices. The use of these switching elements makes it possible to greatly reduce losses and there are expectations not only for energy saving, but also for the realization of equipment that is smaller and has higher performance. In another issue, guidelines for the suppression of harmonics were established in 1996. These guidelines were introduced as restrictions when the harmful effects of the harmonics included in electrical currents became apparent. However, even today, many general purpose AC drives include harmonics in the input current. The suppression of these harmonics eliminates the harmful effects on peripheral equipment and also contributes to the reduced consumption of energy. In addition, there are obviously also requirements to conform with the WEEE directive, which is related to the 3R (Reduce, Reuse, Recycle) and the RoHS directive, which restricts the use of harmful substances, both of which are directives that were introduced by Europe ahead of the world.

Our company supplies products to the global market. Power electronics is one of our core technologies and we are working to further advance it in order to convert the comments and requests of customers around the world into reality and also to aim to construct a safe and sustainable society. We will offer new value to society by proceeding with the development of environmentally friendly products that can contribute to the solution of serious social problems such as global warming and the unbalance in energy supply and demand.

Regarding specific AC drive products, we have now completed the preparations for the launch on the market of a new series of products that fully updates our products for the first time in ten years. As the first stage to this, we launched the GA700 in April 2016. This is a general-purpose, high performance vector control AC drive for industrial use. This GA700 was developed with the concepts of “versatility,” “ease of use,” and “peace of mind” and offers value that will change the equipment of customers in a groundbreaking way. It achieves productivity improvements, energy saving, reduced system costs, and improved environmental adaptability. Furthermore, the U1000 that applies matrix converter technology is ideal for harmonics-free applications such as fans, pumps, and compressors and for regenerative applications such as elevators. It achieves total cost reductions on equipment and machinery due to achievements such as more compact and simpler control panels, the elimination of harmonics and no requirements for regeneration resistance. Furthermore, we will actively promote the proposal of a mix of the GA700 and U1000 products to give high added value to machinery such as cranes, compressors, injection molding equipment, extruders, and presses.

This special feature introduces the latest AC inverter drives from Yaskawa and the application technologies for them, which contribute to the protection of the environment and to the advancement of customer machinery. In addition, using this feature as a reference for consumers from now onwards, I would also be happy if it gives you an understanding of some of the efforts being undertaken in our AC drive business.

AC drive trends and the initiatives in Yaskawa

Ever since 1974, when the VS-616T was sent out into the world from Yaskawa as the world’s first transistor inverter, we have repeatedly developed innovative AC drive technologies and have continued to lead the market as a pioneer of motor control. We have maintained a firm position throughout that time, for example in 2014, when Yaskawa was the first company in the world to reach a total cumulative production of 20 million AC drives for industrial use.
The current 1000 series has been very well received, but it is now nearly ten years since it was launched on the market. During that time, the high efficiency regulations for motors have been strengthened in response to the increasing concern regarding global environmental problems. Also, the requirements for AC drives from the market have become increasingly varied and increasingly sophisticated.
To respond to these changes, we have now reformed our AC drive product series and launched the GA700 as the first model of this series. This article primarily introduces the concepts of the new series.

Zero series and the positioning of the GA700

Zero series and the positioning of the GA700

Development of the GA700 high performance vector control AC drive for general-purpose industrial use

GA700

GA700

High efficiency regulations are currently being strengthened in an attempt to suppress the consumption of electricity by motors, which are said to account for more than 40% of the electricity consumed globally. In response to this situation, we updated our previous series of AC drive products with the concepts of “versatility,” “ease of use,” and “peace of mind” and have now launched the GA700 general-purpose, high performance vector control AC drive for industrial use. This GA700 is a general-purpose product for industrial use that is ideal for use for general industrial machinery and equipment applications.
This one GA700 unit is not only able to drive all of the motors in a wide range encompassing IM, IPMSM, SPMSM, and SynRM, it can also control each of these with and without PG. In addition to this, we made improvements to the reduction of energy consumption, the network connectivity and the durability and also achieved easy customization, miniaturization, reduced set-up time, reduced down time, and compatibility with international standards.
This article refers to the development concepts used for the GA700 and the advantages and specifications of the product.

Crane application technology

U1000 matrix converter for cranes

U1000 matrix converter for cranes

In the sector of loading and transportation machinery such as cranes, in addition to requirements for performance aspects such as accuracy and efficiency, there are also increasing requirements for aspects related to environmental protection, such as energy saving and CO2 emission reductions. In response to these requirements, Yaskawa developed a drive system for cranes using the matrix converter U1000 and also aimed for further improvement with the inclusion of new functions in the software for the crane control. Cranes are an ideal application for the collection and use of regenerative energy and this makes it possible to fully exploit the superb advantages of the U1000.
This article refers to the advantages of the U1000 and the current status of crane application technologies.

HVAC application technology

Z1000

Z1000

Efforts to prevent global warming are increasing internationally, but the uncertainty in the global economy and the friction between the advanced and the emerging nations are meaning that progress based on international cooperation is not necessarily proceeding as it might. However, despite this situation, Japan has set the target for greenhouse gases reduction to a 3.8% reduction compared to FY2005 levels by FY2020 and has made a commitment to the world to achieve this. If we consider the current situation of strong feelings of caution regarding the restarting of nuclear power stations, this target is by no means a low hurdle to overcome.
In order to further advance the energy saving, it is desirable that we see results in the consumer sector in addition to results in industry. One urgent task is therefore to save the energy on air conditioning, which is a large consumer of power. To achieve this, there has been progress in the introduction of inverter control and the use of synchronous motors. However, there are still issues that need to be solved in the consumer sector due to factors particular to that sector such as the strict regulations on harmonics.
This article refers to some of our efforts to find solutions to these issues by giving an introduction to the latest Yaskawa models for HVAC.

U1000L matrix converter specifically for elevators

U1000

U1000L

In recent years, the requirements for energy saving and miniaturization of apparatus on elevators have meant that gearless drives using synchronous motors with built-in permanent magnets (PM motors) have become the most common selection for everything from low speed models to high speed models. This applies to both new installations and for the renewal of existing elevators. In addition to the requirements for the improvement of the comfort and safety of the ride, the increasing height of buildings has also meant that elevators have become faster, so there are requirements for the use of regenerative energy and for higher performance motor drives. Furthermore, on elevators for facilities such as condominiums, office buildings, data centers, and nursing homes, it is becoming particularly necessary to give consideration to the surrounding environment.

This product was developed as a single unit that can respond to the requirements described above and it is based on the matrix converter U1000 that received the “Minister of Economy, Trade and Industry Award” in the “Energy Conservation Grand Prize” in FY2015. This article refers to an overview and advantages of the matrix converter U1000L specifically for elevators.

Simulation technology

Thermal fluid simulation

Thermal fluid simulation

In Yaskawa, we have further raised the level of the simulation technologies that we have been using for some time and are now using them in our next generation AC drive development. We have prepared remote operation from our development bases and also HPC (High Performance Computers) that can perform high speed operations, so we are able to execute high efficiency simulations. The use of simulations in front end processes such as development and design makes it possible to minimize the actual verification and therefore greatly improves the efficiency of product development.
This article refers to some of the simulation technology in Yaskawa and gives examples of it applied to vibration simulations, thermal simulations and resin flow simulations.

All-SiC high efficiency motor drive systems for automobiles

Efforts for the greenhouse gases readuction and energy saving have become common issues around the world for the protection of the global environment. As one solution to this issue, in Japan, there has been a promotion and acceleration of research and development for the motorization of the drive systems of items such as automobiles, construction machinery, and marine vessels. In the area of automobiles in particular, as the exhaust gas regulations of each country are made ever stricter, there have been rapid advances in the development and spread of high efficiency motor drive systems to support the move to the mass production of electric vehicles (EV) and hybrid electric vehicles (HEV).
Yaskawa has developed a new electronic winding changeover system using silicon carbide (SiC) power devices. These devices are more efficient than the conventional silicon (Si) devices and make it possible to produce lighter and more compact systems. We achieved good results when we applied this new system to an all-SiC high efficiency drive system for automobile use and performed prototype evaluations. This article refers to an overview of this new system.

Results of system efficiency measurements

Results of system efficiency measurements

Development of matrix converter using input and output sine wave filter and use of SiC for reduced filter size

Matrix converter with input and output voltage and current sine wave

Matrix converter with input and output voltage and current sine wave

The problem of harmonics on matrix converter input currents is normally solved by using an input filter. However, the PWM output of matrix converters still has problems remaining such as EMI and motor axis degradation.
In this development, we considered the use of LC filters on the outputs of matrix converters as a solution to these problems. We also considered the miniaturization of the LC filters through the use of high frequency SiC switching elements, which offer high frequency switching and low loss characteristics. Furthermore, we developed a prototype model and evaluated it.
This article refers to the development of the world’s first next-generation matrix converter with a full SiC power semiconductor module built in. It also describes the results obtained in the achievement of the ultimate drive performance of “input and output, voltage and current sine wave.”

PAGE TOP