A brushless DC motor driver employing a bridgeless standard switching unit

Abstract

This utility model relates to the field of brushless DC motor technology for household appliances, specifically a brushless DC motor driver using a bridgeless standard switching unit. It includes an AC power supply, a bridgeless power standard switching converter, a voltage source inverter, a PI controller and a PWM generator, two brushless DC motors, a Hall sensor, a reference voltage generator, and a multiplier. The bridgeless power standard switching converter includes Sw1, Sw2, diodes D1, D2, Dn, and Dp, capacitors C1, C2, and Cd, and inductors Li1 and Li2. Compared to traditional technologies, this brushless DC motor improves the power factor and reduces harmonic energy of the power current. Diode bridge rectifiers often reduce the power factor of brushless DC motors. The proposed brushless DC motor based on a bridgeless standard switching unit converter can improve the power factor from 0.7 to 0.9.

Description

Technical Field

[0001] This utility model relates to the field of brushless DC motor technology for household appliances, and in particular to a brushless DC motor driver that uses a bridgeless standard switching unit. Background Technology

[0002] Today, brushless direct current (BLDC) motors are gaining popularity in the industry due to their advantages such as improved efficiency, high reliability, robustness, reduced electromagnetic interference, and excellent performance over a wide speed range. These advantages make BLDC motors suitable for both low-power and medium-power applications, such as medical equipment, home appliances, position controllers, air conditioning, motion controllers, heating, ventilation, and traction. However, existing BLDC drivers can negatively impact the power factor. Traditional BLDC drive power supplies consist of a diode bridge rectifier, followed by a DC-link capacitor and a voltage source inverter. This arrangement draws peak current from the power supply and injects harmonics, resulting in a low power factor. Utility Model Content

[0003] The purpose of this utility model is to solve the technical problems mentioned in the background art.

[0004] The present invention adopts the following technical solution: a brushless DC motor driver using a bridgeless standard switching unit, comprising an AC power supply, a bridgeless power standard switching converter, a voltage source inverter, a PI controller and a PWM generator, two brushless DC motors, a Hall sensor, a reference voltage generator and a multiplier, characterized in that: the bridgeless power standard switching converter includes Sw1, Sw2, diodes D1, D2, Dn, Dp, capacitors C1, C2, Cd, and inductors Li1 and Li2.

[0005] Preferably, the output terminals of the AC power supply, PI controller, and PWM generator are electrically connected to the input terminal of the bridgeless power standard switching converter.

[0006] Preferably, the output terminal of the bridgeless power standard switching converter is electrically connected to the input terminal of the voltage source inverter.

[0007] Preferably, the output terminal of the brushless DC motor is electrically connected to a master-slave structure, and the output terminal of the master-slave structure is electrically connected to the input terminal of the Hall sensor.

[0008] Preferably, the output terminal of the Hall sensor is electrically connected to an electronic commutator, and the output terminal of the electronic commutator is connected to the input terminal of a voltage source inverter. The live wire of the AC power supply is connected to one end of inductor Li1, and the neutral wire of the AC power supply is connected to one end of inductor Li2. The other end of inductor Li1 is connected to the drain of switching transistor Sw1 and the anode of diode D1, and the other end of inductor Li2 is connected to the drain of switching transistor Sw2 and the anode of diode D2. The sources of switching transistors Sw1 and Sw2 are connected to the negative terminal of capacitor Cd, and the cathodes of diodes D1 and D2 are connected to the positive terminal of capacitor Cd. The anode of diode Dp is connected to the neutral wire of the AC power supply, and the cathode is connected to the positive terminal of capacitor Cd. The cathode of diode Dn is connected to the live wire of the AC power supply, and the anode is connected to the negative terminal of capacitor Cd. Capacitor C1 is connected in parallel between the drain and source of switching transistor Sw1, and capacitor C2 is connected in parallel between the drain and source of switching transistor Sw2.

[0009] Compared with the prior art, the advantages and positive effects of this utility model are as follows: In this invention, the DC motor employs a master-slave technology, where Hall sensor signals from the master motor are used to generate inverted PWM pulses for the voltage source. The operating speed of the brushless DC motor is controlled by changing the DC link voltage. Unlike traditional driving methods that use diode bridge rectifiers on the power supply side, this circuit uses a bridgeless standard switching unit converter. Compared to traditional solutions, this brushless DC motor improves the power factor and reduces harmonic energy of the power supply current. Diode bridge rectifiers often reduce the power factor of brushless DC motors; the proposed brushless DC motor based on a bridgeless standard switching unit converter can improve the power factor from 0.7 to 0.9. Attached Figure Description

[0010] Figure 1 This utility model presents a system diagram of a brushless DC motor driver using a bridgeless standard switching unit; Figure 2 This invention provides a circuit diagram for a bridgeless power standard switch converter for a brushless DC motor driver that employs a bridgeless standard switch unit. Detailed Implementation

[0011] To better understand the above-mentioned objectives, features, and advantages of this utility model, the present utility model will be further described below with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0012] Many specific details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention may also be implemented in other ways than those described herein, and therefore the present invention is not limited to the specific embodiments disclosed in the following specification. Example

[0013] Please see Figure 1-2 This utility model provides a technical solution: a brushless DC motor driver using a bridgeless standard switching unit, including an AC power supply, a bridgeless power standard switching converter, a voltage source inverter, a PI controller and a PWM generator, two brushless DC motors, a Hall sensor, a reference voltage generator and a multiplier. The DC motors adopt master-slave technology, and the Hall sensor signal from the master motor is used to generate the inverted PWM pulse of the voltage source. The operating speed of the brushless DC motor is controlled by changing the DC link voltage. Unlike the traditional driving method that uses a diode bridge rectifier on the power supply side, this circuit uses a bridgeless standard switching unit converter. The advantage of this is that it operates in discontinuous current conduction mode, for example, the inductor currents i1 and i2 are discontinuous. The bridgeless power standard switching converter includes Sw1, Sw2, diodes D1, D2, Dn, Dp, capacitors C1, C2, Cd, and inductors Li1 and Li2. The specific operating modes are as follows: Mode 1: Switch Sw1 is turned on, inductor Li1 is charged through diode Dp, and current flows through Li1, increasing the current in inductor Li1. In Mode 1, switch Sw2 is turned on, inductor Li1 discharges through diode D1 to capacitor Cd, and capacitor Cd is charged in this mode. In Mode 2, switch Sw1 is turned off, inductor Li1 discharges through diode D1 to capacitor Cd, and capacitor Cd is charged in this mode. In Mode 3, capacitor Cd in the DC link supplies power to the load, capacitor C1 remains charged, and switch Sw2 will repeat a similar operation, except that switch Sw1 operates in the positive half-cycle, while switch Sw2 operates in the negative half-cycle. In Mode 1, switch Sw2 is turned on, inductor Li2 is charged through diode Dn, and current flows through Li2, increasing the current in Li2. Capacitor C2 begins to discharge through switch Sw2 and charges capacitor Cd in the DC link. In Mode 2, switch Sw2 is turned off, inductor Li2 discharges through diode D2 to capacitor Cd, and capacitor Cd is charged in this mode. In Mode 3, capacitor Cd in the DC link supplies power to the load, capacitor C2 remains charged, and the outputs of the AC power supply, PI controller, and PWM generator are electrically connected to the input of the bridgeless power standard switching converter. The output of the bridgeless power standard switching converter is electrically connected to the input of the voltage source inverter; The output of the brushless DC motor is electrically connected to a master-slave structure. The output of the master-slave structure is electrically connected to the input of the Hall sensor. The output of the Hall sensor is electrically connected to electronic commutation. The output of the electronic commutation is connected to the input of the voltage source inverter.

[0014] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments for application in other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present utility model without departing from the technical solution of the present utility model shall still fall within the protection scope of the technical solution of the present utility model.

Claims

1. A brushless DC motor driver employing a bridgeless standard switching unit, comprising an AC power supply, a bridgeless power standard switching converter, a voltage source inverter, a PI controller and a PWM generator, two brushless DC motors, a Hall sensor, a reference voltage generator and a multiplier, characterized in that: The bridgeless power standard switching converter includes Sw1, Sw2, diodes D1, D2, Dn, Dp, capacitors C1, C2, Cd, and inductors Li1 and Li2. The live wire of the AC power supply is connected to one end of inductor Li1, and the neutral wire of the AC power supply is connected to one end of inductor Li2. The other end of inductor Li1 is connected to the drain of switching transistor Sw1 and the anode of diode D1, and the other end of inductor Li2 is connected to the drain of switching transistor Sw2 and the anode of diode D2. The sources of switching transistors Sw1 and Sw2 are connected to the negative terminal of capacitor Cd, and the cathodes of diodes D1 and D2 are connected to the positive terminal of capacitor Cd. The anode of diode Dp is connected to the neutral wire of the AC power supply, and the cathode is connected to the positive terminal of capacitor Cd. The cathode of diode Dn is connected to the live wire of the AC power supply, and the anode is connected to the negative terminal of capacitor Cd. Capacitor C1 is connected in parallel between the drain and source of switching transistor Sw1, and capacitor C2 is connected in parallel between the drain and source of switching transistor Sw2.

2. The brushless DC motor driver using a bridgeless standard switching unit according to claim 1, characterized in that: The outputs of the AC power supply, PI controller, and PWM generator are electrically connected to the input of the bridgeless power standard switching converter.

3. The brushless DC motor driver using a bridgeless standard switching unit according to claim 1, characterized in that: The output terminal of the bridgeless power standard switching converter is electrically connected to the input terminal of the voltage source inverter.

4. The brushless DC motor driver using a bridgeless standard switching unit according to claim 1, characterized in that: The output terminal of the brushless DC motor is electrically connected to a master-slave structure, and the output terminal of the master-slave structure is electrically connected to the input terminal of the Hall sensor.

5. The brushless DC motor driver using a bridgeless standard switching unit according to claim 1, characterized in that: The output terminal of the Hall sensor is electrically connected to an electronic commutator, and the output terminal of the electronic commutator is connected to the input terminal of a voltage source inverter.

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