Brushless dc motor and circuit for controlling the same

• US 20050007043A1
• Filed: 11/28/2002
• Published: 01/13/2005
• Est. Priority Date: 11/29/2001
• Status: Active Grant

• Current Assignee: G & W Technologies Incorporated
• Original Assignee: G & W Technologies Incorporated
• Inventors: Kim, Sang Uk
• Granted Patent: US 6,934,468 B2
• Time in Patent Office: Days
• US Class Current: 318/400.280
• CPC Class Codes: H02K 3/28 Layout of windings or of connections between windings windings for pole-changing H02K17/06, H02K17/14, H02K19/12, H02K19/32

Abstract

Disclosed is a multiphase brushless DC motor of a concentrated winding type having shunt connection, and a control circuit. The brushless DC motor includes a rotor made up of a permanent magnet with M number of poles, and a stator operating in K number of phases by means of windings wound on N number of teeth, wherein the plurality of windings having the same excitation phases wound on the teeth, are each maintained in shunt connection so as to improve driving torque and a rotational speed. A brushless DC motor includes a switching section having a plurality of upper switching devices and a plurality of lower switching devices connected with each other in series. Each of the windings is connected between a common joint between the upper and lower switching devices, and a common joint between a lower power supply voltage and a plurality of upper power supply voltages.

Claims

1. (cancelled)

2. In an apparatus in which a switching part allows a power of a DC power part to be applied to a brushless DC motor comprising a rotor comprised of a permanent magnet of M pole, a stator provided with N number of teeth wound by coils and operated in K-phase,

a control circuit of an independent multi-phase brushless DC motor being characterized in that the stator is constructed of which windings of K-phase wound on the teeth are independently connected,

the DC power is comprised of a power Vd+, Vo that is voltage-divided by an upper condenser (C) for applying a power to upper switching devices and a resistance and correspond to the half of the DC power, and a power Vo, Vd−

that is voltage-divided by a lower condenser for applying a power to lower switching devices and a resistance and correspond to the half of the DC power, K number of independent ground terminals Vo corresponding to common connection points of the cathode of the upper condenser and the anode of the lower condenser are provided,

the switching part is comprised of an upper switching device of which one end is connected to the power Vd+, Vo, and a lower switching device of which one end is connected to the power Vo, Vd−

, the upper switching device and the lower switching device being connected in series, the windings of respective phases are independently connected between a serial connection point of the two switching devices and the ground and the ground terminal Vo, and

when the upper switching device is turned on, a current by the voltage of Vd−

flows to Vo via the turned-on upper switching device and a corresponding winding, and when the lower switching device is turned on, the voltage of Vo flows to Vd−

through the lower switching device.

3. (cancelled)

4. (cancelled)

5. (cancelled)

6. In an independent multiphase brushless DC motor constructed to be independently controllable by a switching part and comprising a rotor comprised of a permanent magnet of M pole, a stator having K-phase windings formed by coils wound on N number of teeth and independently connected with each other, in which the windings of independent exciting phase are respectively connected in parallel,

when assuming that j is number of excitation phases for applying current to the stator at the same time and k is an arbitrary natural number, an optimal ratio of pole number of the rotator to pole number of the stator is 2*k to 3*j, and 3*j is greater than 2*k.