摘要:
The invention relates to a control circuit for an electronically commuted motor (120) with a power stage (122), comprising at least two semiconductor switches (216, 218) for control of the motor current. The semiconductor switches may be controlled by commuting signals. The control circuit comprises a current measuring body (170) for the generation of a motor current control parameter (I), dependent on the motor current, a base diode (240), arranged in series with the current measuring body and between the current measuring body and the at least two semiconductor switches and a motor current adjuster (180), which may be influenced by the commutation signal depending on the motor current control parameter.
摘要:
The invention relates to a method for limiting the current in a direct current motor, acting on a full bridge circuit (137) by which means the stator winding configuration (102) of said motor is supplied with a current. When the current limitation responds, the energy supply from the direct current network to the stator winding configuration (102) is interrupted. The stator winding configuration is then operated essentially in short circuit by means of static switches of the full bridge circuit, and the flowing, decaying current is essentially used to continue to drive the motor. When said current reaches a lower value, the energy supply from the direct current network to the motor is reactivated. Preferably, the effective value of the current flowing to the motor is thus reduced when the current limitation responds. The length of time during which said current flows in the form of blocks of current is then increased in a compensatory manner.
摘要:
The invention relates to a control circuit for an electronically commuted motor (120) with a power stage (122), comprising at least two semiconductor switches (216, 218) for control of the motor current. The semiconductor switches may be controlled by commuting signals. The control circuit comprises a current measuring body (170) for the generation of a motor current control parameter (I), dependent on the motor current, a base diode (240), arranged in series with the current measuring body and between the current measuring body and the at least two semiconductor switches and a motor current adjuster (180), which may be influenced by the commutation signal depending on the motor current control parameter.
摘要:
The invention relates to a method for controlling a physical variable in an electronically commutated motor, according to which the current is supplied to the stator winding arrangement (102) of the motor in the form of current blocks. The distance (BW) between switch-on command and cut-off command for controlling said current blocks, that is the length (BW) of the control signals, is influenced by a control device, and the current effective value of said current blocks is influenced by adjusting a duty factor (pwm). Upper and lower limits are set to the length (BW) of the control signals. When the control signal becomes shorter than a predetermined lower limit value, the duty factor (pwm) is reduced, thereby reducing the effective value of the current and increasing the length (BW) of the current blocks. When the control signal becomes longer than a predetermined upper limit value, the duty factor (pwm) is increased, thereby increasing the effective value of the current and reducing the length (BW) of the current blocks in compensation thereof.
摘要:
The invention relates to an electronically commutated motor (20) operated on a direct current source (UB), for example, a direct current intermediate circuit (46). The motor has a permanent magnetic rotor (28) and a stator having a stator winding phase (26) in which an alternating voltage is induced during operation by the permanent magnetic rotor (28). The motor further has an H-bridge circuit (22) comprising power semiconductors (T1 to T4). The circuit (22) has an upper bridge half (38) that is connected during operation to a pole (46) of the direct current source (UB) and a lower bridge half (56) that is connected during operation to the other pole (50) of the direct current source (UB). The stator winding phase (26) is disposed in the diagonal (24) of the H-bridge circuit (22) and, during operation, a current pulse flows through it, first in one direction and then in the other. One commutation process each occurs between two consecutive current pulses (i1, i1'). At the beginning of a commutation process, the currently conducting semiconductor switch of the one bridge half (38) is switched off in order to interrupt the energy supply from the direct current source (UB) such that a circulating current (i*; -i*) flows through the stator winding phase (26) in the other bridge half (56), the semiconductor circuit, which continues to be controlled in a conductive fashion, and a free-wheeling diode (58; 60) associated with the closed semiconductor circuit of this other bridge half. Said circulating current converts the energy stored in the magnetic circuit of the motor (20) at least partially into drive energy for the permanently magnetic rotor (28), thus adjusting to zero. Said current-free state of the stator winding phase (26) is detected in a sensor-free fashion by measuring the voltage (uind) that is induced in the stator winding phase (26) by the rotor (28). The previously conducting semiconductor circuit of the other bridge half (56) is blocked. The commutation process is completed in that a current is supplied to the stator winding phase (26) from the direct current source (UB) in a direction opposite to the direction in which the current was flowing before the commutation process. The invention further relates to a motor for performing such a method.