Drive device for motor and air conditioner using same

A technology of motor drive and current detection device, which is applied in the direction of electronic commutator, single motor speed/torque control, application, etc., which can solve the problems of efficiency reduction and increase of motor iron loss, so as to improve work efficiency and reduce voltage Effect

CN1655439AInactive Publication Date: 2005-08-17PANASONIC CORP
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
Publication Date
2005-08-17
Estimated Expiration
Not applicable · inactive patent

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Abstract

To accurately detect phase current using a simple system constitution, to achieve high-quality driving from a low-speed rotation zone to a high-speed rotation zone, and to enable a motor to be driven at high efficiency. This motor drive unit comprises an induction voltage estimating means 17 that estimates the induction voltage of the motor from the input voltage, the output voltage, and the output current of an inverter; a rotator position and speed estimation means 18 that estimates the magnetic pole position and a rotational speed of the motor, on the basis of the estimated induction voltage; a PWM signal generation means 9 that generates a PWM signal for controlling the inverter, on the basis of the information of the estimated rotator magnetic pole position; a duty correction means 19 that corrects the duty of the generated PWM signal; and a boosting and step-down means 21 that calculates the voltage saturation rate, that is the degree of voltage saturation from the input voltage and a voltage command value applied to the motor, and varies the input voltage of the inverter according to the voltage saturation rate.
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Description

technical field

[0001] The present invention relates to a motor driving device for a compressor, which can drive motors used in compressors such as brushless DC motors at any rotational speed; and also relates to an air conditioner using the device. Background technique

[0002] In recent years, in a motor drive device for driving a motor in a compressor or the like of an air conditioner, it is very important to reduce power consumption from the viewpoint of protecting the global environment. Among them, technologies such as inverters capable of driving high-efficiency compressor motors such as brushless DC motors at arbitrary frequencies have been widely used as energy-saving technologies. In addition, among various drive techniques, sine wave drive technique is attracting attention because of its higher efficiency and lower noise than the rectangular wave drive technique of driving with a rectangular wave current.

[0003] In the case of driving the motor in the compresso...

Examples

Embodiment 1

[0030] figure 1 It is a structural block diagram of the motor driving device in Embodiment 1 of the present invention. Among them, the DC voltage supplied from the variable DC power supply 1 is first converted into an AC voltage having a desired frequency and voltage by the inverter 2 , and then supplied to the brushless motor 3 . The frequency converter 2 is controlled on and off by a control part 6 .

[0031] The brushless motor 3 is provided with a stator 4 and a rotor 5. The stator 4 is equipped with three-phase windings 4u, 4v and 4w connected in a Y shape around the neutral point, and the rotor 5 is equipped with magnets. U-phase terminal 8u is connected to a non-connecting end of U-phase winding 4u, V-phase terminal 8v is connected to a non-connecting end of V-phase winding 4v, and W-phase terminal 8w is connected to a non-connecting end of W-phase winding 4w.

[0032]The frequency converter 2 has three series circuits in which a pair of switching elements are respec...

Embodiment 2

[0110] In this example, in figure 1 The set value of the boost voltage saturation rate and the set value of the step-down voltage saturation rate are stored in the step-up and step-down device 21, which are determined by the rotational speed of the brushless motor 3 estimated by the rotor position and speed estimation device 18. switch. Specifically, in such switching based on the rotation speed, when the rotation speed of the brushless motor 3 estimated by the rotor position speed estimation device 18 is greater than a preset value, it is determined that the load of the brushless motor 3 is light, Even if the estimation error of the rotor position is larger, out-of-step is less likely to occur, so the set value of the boost voltage saturation rate and the set value of the step-down voltage saturation rate are increased. Since the variable DC power supply 1 is not prone to step-up, the high-efficiency working range of the motor can be expanded.

Embodiment 3

[0112] when figure 1 When the phase currents (iu, iv, iw) flowing in the windings of each phase detected by the current detection device 11 are very small, it can be concluded that the load of the brushless motor 3 is very light, and the estimation error of the rotor position will not appear even if it is larger. out of step. Therefore, in this embodiment, according to the phase currents (iu, iv, iw) flowing in each phase winding detected by the current detection device 11, the set value of the boost voltage saturation rate and the set value of the step-down voltage saturation rate are set to switch. In this way, the same effect can also be obtained.