Invention and impact of the three phase motor

Most DC motors are small permanent magnet PM types. A commutated DC motor has a set of rotating windings wound on an armature mounted on a rotating shaft. The shaft also carries the commutator, a long-lasting rotary electrical switch that periodically reverses the flow of current in the rotor windings as the shaft rotates. Thus, every brushed DC motor has AC flowing through its rotating windings.

Invention and impact of the three phase motor

This application claims priority of Taiwanese application no. Field of the Invention The present invention relates to a motor driver circuit and a three phase direct current brushless motor. Three phase coils Lu, Lv, Lw of the three phase brushless DC motor are electrically connected to each other in a Y circuit configuration, wherein terminals on one end of the three phase coils Lu, Lv, Lw are electrically connected to each other contact nand the terminals on the other end contacts U, V, W are electrically connected with the drive circuit 1.

Driver circuit 1 has three bridge arms coupled in parallel with a DC power supply Vdc hereinafter referred to as the U-phase, V-phase and W-phase bridge arms. This protects the power supply Vdc from the instantaneous high voltage attributed to back electromotive forces eu, ev.

Although such an approach may suppress the high voltage attributed to back electromotive forces, power of the power supply Vdc is dissipated by the dissipating resistor R in vain and consumption of power of the power supply VDC is accelerated.

Since the back electromotive forces cannot be stored by the power supply Vdc as it has an alternating current form, the energy dissipated will cause temperature to rise in the driver circuit 1, and such high temperature will shorten the service life of the power supply Vdc usually a battery.

History - The invention of the electric motor

In addition, as compared to the delta circuit configuration, the currents in the Y circuit configuration are smaller and thus the mechanical power outputted by the motor is smaller. However, if the delta circuit configuration is used, the back electromotive forces produced will be greater than that of the Y circuit configuration, which is unfavorable for the driver circuit 1.

Therefore, the conventional driver circuit 1 is not suited for the delta circuit configuration. According to one aspect of the present invention, there is provided a driver circuit for a three phase direct current DC brushless motor.

The three phase DC brushless motor includes a stator having three phase coils that are electrically connected to each other in a delta circuit configuration.

The delta circuit configuration has three contacts and each of the phase coils has a center tap.

Invention and impact of the three phase motor

The driver circuit is adapted to be electrically coupled with a DC power supply and includes: Another object of the present invention is to provide a three phase direct current DC brushless motor that includes the driver circuit of this invention.

According to another aspect of the present invention, a three phase direct current DC brushless motor is configured to be driven by a DC power supply, and includes: As shown in FIG. Each first diode D1 has a cathode electrically coupled with the positive terminal of the DC power supply Vdc, and an anode electrically coupled with a cathode of the corresponding second diode D2.

Each second diode D2 has an anode electrically coupled with the negative terminal of the DC power supply Vdc. Therefore, as shown in FIG. As a result, the currents generated by the back electromotive forces do not flow through the DC power supply Vdc, preventing damage to the DC power supply Vdc.

Works Cited

Moreover, the energy of the back electromotive forces is stored in the capacitors Cd1, Cd2 for future use.

Since the capacitors Cd1, Cd2 are capable of storing the energy of the back electromotive forces, the temperature rise in the driver circuit 2 can be regulated, preventing shortening of the lifespan of the DC power supply Vdc due to high temperature.

The driver circuit 2 turns the switches of the U-phase, V-phase and W-phase bridge arms on and off for sequentially connecting the three phase coils Lu, Lv, Lw the DC power supply for driving the rotor, and whenever the switches are switched from an on state to an off state, the back electromotive forces produced in one of the three phase coil Lu, Lv, Lw charges the first and second capacitors Cd1, Cd2 of the capacitor arm connected thereto.

When the driver circuit 2 is in operation, the back electromotive forces produced by each of the three phase coils Lu, Lv, Lw will charge the capacitors Cd1, Cd2 in sequence, maintaining the electrical energy stored in the capacitors Cd1, Cd1.

Thus, when the DC power supply Vdc is a rechargeable battery, and a series voltage across the first capacitor Cd1 and the second capacitor Cd2 of one of the capacitor arms is higher than a voltage across the DC power supply Vdc, the first capacitor Cd1 and the second capacitor Cd2 of the one of the capacitor arms may charge the rechargeable battery, prolonging the battery life of the DC power supply Vdc.

Moreover, the driver circuit 2 in this embodiment does not require a dissipating resistor R used in the prior art as shown in FIG. For instance, a bridge rectifier filter circuit 20 that filters an alternating current AC signal from an AC power source may serve as the DC power source of the driver circuit 2.

In summary, each of the first capacitors Cd1 that is electrically coupled between the corresponding center tap Un, Vn, Wn and the positive terminal of the DC power supply Vdc and each of the capacitors Cd1 that is electrically coupled between the corresponding center tap Un, Vn, Wn and the negative terminal of the DC power supply Vdc are charged by the back electromotive forces through the corresponding first and second diodes D1, D2 to prevent the DC power supply Vdc from high voltage impacts from the back electromotive forces.

This invention can be implemented in the three phase DC brushless motor stator having the delta circuit configuration, and the electrical energy stored in the capacitors Cd1, Cd2 can provide power to the DC power supply Vdc for prolonging battery life or power boosting when the motor is outputting a high amount of torque.

While the present invention has been described in connection with what is considered the most practical and preferred embodiment, it is understood that this invention is not limited to the disclosed embodiment but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.

A driver circuit for a three phase direct current DC brushless motor, the three phase DC brushless motor including a stator having three phase coils that are electrically connected to each other in a delta circuit configuration, the delta circuit configuration having three contacts, each of the phase coils having a center tap, the driver circuit being adapted to be electrically coupled with a DC power supply and comprising: The driver circuit as claimed in claim 1, the DC power supply being a rechargeable battery, wherein the first capacitor and the second capacitor of one of the capacitor arms are configured to charge the rechargeable battery when a series voltage across the first capacitor and the second capacitor of said one of the capacitor arms is higher than a voltage across the rechargeable battery.

A three phase direct current DC brushless motor configured to be driven by a DC power supply, the three phase DC brushless motor comprising: The three phase DC brushless motor as claimed in claim 3, the DC power supply being a rechargeable battery, wherein the first capacitor and the second capacitor of one of the capacitor arms are configured to charge the rechargeable battery when a series voltage across the first capacitor and the second capacitor of said one of the capacitor arms is higher than a voltage across the rechargeable battery.The 3 phase rotating magnetic field was invented by Tesla.

Nikola Tesla's 3 great inventions were: 1. Tesla is standing atop an AC motor, one of the inventions he patented. Tesla Monument at Goat Island, Niagara Falls, New York. A gift of Yugoslavia to the United States in Ferraris invented an AC three phase motor without commutator.

Tesla and Oliver Shallenberger also were working on the motor a couple of months behind Ferraris. To learn about important early sites and installations of AC power please see our History of Power Transmission and Electrification page. Chapter 1 INDUCTION MACHINES: AN INTRODUCTION ELECTRIC ENERGY AND INDUCTION MOTORS environmental impact where the motor works and lower thermal and chemical Three-phase induction motors are sometimes built with aluminum frames for general purpose applications below 55 kW (Figure ).

3-phase motors will also vibrate less and hence last longer than motor of the same power used under the same conditions. Large air conditioning, etc.

AC Power History

equipment use motors for reasons of efficiency, economy, and longevity. The electric motor's world impact before light bulbs: Trolleys and the connected power systems were very expensive to build but transported millions of people to work in the s.

Until the growth of the power grid in the s most people (middle and low classes) even in . Serbian-American, engineer and inventor; having worked independently from Ferraris, presented a paper in May, to AIEE describing three patented two-phase four-stator-pole motor types: one with a four-pole rotor forming a non-self-starting reluctance motor, another with a wound rotor forming a self-starting induction motor, and the third a true synchronous motor with separately-excited DC supply to rotor .

AC motor - Wikipedia