3.Power factor improvement

Booster coil reactor and PFC rectify AC to DC and control its voltage.

In the motor drive system of sine wave control, power factor can be improved by reducing harmonics. PFC and reactor stabi- lize the voltage of DC supplied to inverter circuit and make its waveform smooth.

4.Power transistor module

IPM consists of the following components.

· Power Transistors (x6) : Converts DC waveform to three-phase AC waveform and outputs it.

· Drive Circuit

: Drives transistors.

· Protection circuit

: Protects transistors from over current.

Since the above components are all integrated in IPM, IPM has a merit that can get the control circuit simplified and miniatur- ized.

5.Elimination of electrical noise

NOISE FILTER CIRCUIT, which is formed by *CMC COILS and capacitors placed on the noise filter P.C. board, eliminates electrical noise of AC power that is supplied to main power supply circuit. In short, common mode noise is absorbed in this circuit.

Moreover, normal mode noise is absorbed in another NOISE FILTER CIRCUIT which is formed by *NMC COILS and capaci- tors.

Both NOISE FILTER CIRCUIT exists for preventing the electrical noise generated in the inverter circuit from leaking out. *CMC COILS; Common mode choke coils

*NMC COILS; Normal mode choke coils

3-1-3. Sine wave control

In these air conditioners, compressor equips brushless DC motor which doesn't have Hall element.

In short, the motor is sensorless. However, it's necessary to locate the polar direction of rotor in order to drive brushless DC mo- tor efficiently. The general detection method of the polar direction for such a DC motor is to locate it from the voltage induced by unenergized stator.

Therefore, it is necessary to have a certain period of time in which the stator is being unenergized for the rotor position detection when the voltage of supplied power is impressed.

So the motor has been driven by square wave control (the conventional motor drive system) which energizes the motor only when the range of electrical angle is within 120° because it is forced to be unenergized within 30° at start & end of one heap in one waveform cycle (180°) when the voltage is impressed.

However, torque pulsation occurs at rotation in this method when the current-carrying phases are switched over to other phases in sequence. Therefore, sine wave control system is adopted for these air conditioners because it can make the phase-to-phase current waveform smoother (sine wave) in order to drive the motor more efficiently and smoothly.

3-1-4. Characteristics of sine wave control in case of brushless DC motor

●Although ordinary three-phase induction motor requires energy to excite the magnetic field of rotor, brushless DC motor doesn't need it. So, higher efficiency and torque are provided.

●This control provides the most efficient waveform corresponding to the rotation times of compressor motor.

●The rotation can be set to higher compared to the conventional motor drive system. So, the time in which air conditioner can be operated with energy saved is longer than conventional models. This can save annual electric consumption.

●Compared to square wave control, the torque pulsation is reduced at rotation so that the motor operates more quietly.

●Since response and efficiency are enhanced in sine wave control, finer adjustment can be provided.

 

DC Motor

AC Motor

 

 

 

Rotor

Permanent magnet is embedded

Excited by magnetic field of stator

 

 

 

Rotor Position Signal

Necessary

Unnecessary

 

 

 

In brushless DC motor, permanent magnet is embedded in the rotor. Therefore, it doesn't require energy to excite the rotor like AC motor does. However, it's necessary to control the frequency of three-phase AC current supplied to the stator accord- ing to the polar direction of magnet embedded in the rotor so as to drive the motor efficiently. Controlling 3 phase AC current frequency also means controlling the timing to switch the polarity of stator. Therefore, the polar direction of rotor needs to be detected.

3-1-5. Control Method of Rotation Times

Sine wave control makes the current transformers conduct real time detection of the value of the current running into the mo- tor, locates the rotor position from the detected value and decides if voltage should be impressed and if frequency should be changed.

Compared to the conventional control and rotor position detection method, sine wave control can provide finer adjustment of the voltage of supplied power. The value of the current running into the motor is determined by each motor characteristic.

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Mitsubishi Electronics MS-AWA, MUZ-ANA - U, MUY-ANA, MU-AWA, MSY-ANA, MSZ-ANA manual Protects transistors from over current
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MSZ-FDNA, MUZ-FDNA - U, MUZ-FDNA, MUZ-ANA - U, MUY-ANA specifications

Mitsubishi Electronics has long been a leader in the HVAC (heating, ventilation, and air conditioning) industry, consistently delivering cutting-edge technology and innovative solutions. The MUZ-ANA, MUZ-ANA - U, MU-AWA, MUZ-FDNA, and MS-AWA models exemplify the company's commitment to efficiency, comfort, and advanced engineering.

The MUZ-ANA series is designed for residential and light commercial applications, offering powerful cooling and heating performance. One of the key features is its inverter technology, which allows for variable-speed operation. This means that the system can adjust the compressor speed according to the temperature demands, leading to significant energy savings and consistent comfort levels throughout the space. Additionally, the MUZ-ANA series operates quietly, ensuring a pleasant indoor environment.

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The MU-AWA series is specifically tailored for larger spaces, making it suitable for commercial settings. Its robust design ensures reliability even under the most demanding conditions. Key features include advanced filtration systems that improve indoor air quality by trapping particulates and allergens, preferred by businesses aiming for a healthier environment.

The MUZ-FDNA model stands out for its sleek, compact design that fits seamlessly into various installation contexts, making it flexible for diverse architectural styles. It also features a built-in drain pan that helps in moisture removal, preventing mold growth and enhancing system longevity.

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In summary, the Mitsubishi Electronics MUZ-ANA, MUZ-ANA - U, MU-AWA, MUZ-FDNA, and MS-AWA models feature state-of-the-art technology geared towards maximizing efficiency, comfort, and reliability. From inverter technology to smart connectivity, these units are designed to meet modern consumer demands while emphasizing sustainability and performance. With Mitsubishi Electronics, you can be assured of exceptional quality and technological advancement in HVAC solutions.
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