Abstract:
In a method for controlling a physical variable in an electronically commutated motor, current is supplied to the stator winding arrangement (102) of the motor in the form of current blocks. The interval (BW) between the switch-on command and switch-off command for controlling those current blocks, i.e. the length (BW) of the control signals, is influenced by a control apparatus, and the effective current value of those current blocks is influenced by setting a pulse duty factor (pwm). The length of the control signals is limited in both directions. If a control signal becomes shorter than a specified lower limit, the pulse duty factor (pwm) is decreased, so that the effective value of the current falls and the length (BW) of the current blocks is increased by the control system. If a control signal becomes longer than a specified upper limit, the pulse duty factor is increased, so that the effective value of the current rises and the length of the current blocks decreases in compensatory fashion.
Abstract:
The invention concerns a method for nonvolatile storage of at least one operating data value of an electric motor (32). The latter comprises a microprocessor or microcontroller (23) that controls its commutation, and it comprises a nonvolatile memory (74). In this method, when the motor (32) is switched on, an old operating data value is transferred from the nonvolatile memory (74) into a volatile memory (97) associated with the microprocessor (23) and saved there as a variable. The variable is updated by the microprocessor in the time intervals between the commutation operations (FIG. 13). At intervals of time, the operating data value saved in the nonvolatile memory (74) is replaced by the updated operating data value corresponding to the present value of the variable. A motor for carrying out this method is described.
Abstract:
An electronically commutated motor has at least two winding phases (112, 114) which are wound together or otherwise inductively coupled. Current in each phase is controlled by a respective power transistor (124, 128). An integrated circuit controller (146) receives signals from a Hall sensor (118) and generates rotor position output signals (OUT1, OUT2) which are oppositely phased and are applied to the bases of the respective power transistors (124, 128) so that the power transistors never both conduct at the same time. Further, a pair of latching transistors (162, 172) and a pair of base drain resistors (164, 174), connected to respective bases of the power transistors (124, 128) are provided, in order to assure “soft” switching of the power transistors at low RPM, yet prompter switching and higher efficiency at high RPM. These additional components also ensure a sufficiently long current gap between switch-off of one power transistor and switch-on of the other power transistor.
Abstract:
An electronically commutated claw pole motor has an external rotor (42) with a shaft (40) and a rotor magnet (62). The claw pole motor contains a stator (64) which has a first soft ferromagnetic stator pole piece (74) located on its side facing away from the external rotor (42). The stator pole piece is provided with first claw poles (82, 84) projecting toward the external rotor (42). The stator has a second soft ferromagnetic stator pole piece (76) located on its side facing the external rotor (42). The second soft ferromagnetic pole piece is provided with second claw poles (88, 90) extending from the external rotor (42) and having a larger axial extension (h2) than the first claw poles (82, 84) and projecting into gaps (92) between the first claw poles (82, 84). An axial bearing (44, 46) supports the end (44) of the shaft (40) which faces away from the external rotor (42). In order to generate a magnetic force (F) acting on this bearing, the rotor magnet is displaced, relative to the stator (64), in a direction away from the axial bearing (40, 44).
Abstract:
An electronically commutated motor (10) has a permanent-magnet external rotor (58) and an inner stator (20) with claw-poles (30,32; 44,46). Preferably, the claw-poles extend axially from opposite directions along the outside of the stator (20) and are interdigited. A galvanomagnetic sensor (14) generates a rotor position signal, based upon measurement of a stray or cross-flux field (.phi..sub.1) of the rotating permanent-magnet external rotor (58,66). Between the claw-poles of the stator (20) are a plurality of neutral field zones (52). The motor turns in a predetermined direction (72) and the galvanomagnetic sensor (14) is positioned adjacent the stator (20) at a location which is circumferentially displaced with respect to a neutral field zone (52), in order to trigger early commutation of current to windings (22,24) of the motor (10). The stator structure includes a soft ferromagnetic element (28) which is formed with a cutout (76,76') adjacent the sensor (14) in order to increase the effective flux exerted on the sensor by the field of the rotor, and to thereby improve the precision of the rotor position signal generated by the sensor (14) during operation of the motor (10). The motor includes a control circuit actuated by the sensor output signal (86) which commutates current through the motor windings (22, 24).
Abstract:
An improved motor for driving a variable-speed fan used, for example, to prevent overheating of electronic equipment, features an electronic controller which sends current pulses through the stator winding(s) of the motor, and varies the slope of trailing edges of these pulses in accordance with at least one sensed operating parameter of the motor, such as temperature of the power semiconductors which control the motor current. The slopes are steepened at high motor speeds to reduce electrical losses, and flattened at low motor speeds to minimize noise. Another feature of the improved motor provides for fail-safe, high-speed operation of the fan when the sensed value of the operating parameter is implausible, for example when a lead from a temperature-dependent sensing resistor breaks. In a preferred embodiment, a bridge circuit is used, which includes a transistor in one diagonal of the bridge circuit. Currently marketed personal computers use central processor chips containing several million transistors, which generate heat, and adequate, reliable cooling is absolutely essential to their proper operation. The present invention improves reliability.
Abstract:
A two-stranded electronically commutated DC motor has a permanent-magnet rotor (36), power supply terminals (28, 30) for connecting the motor to a current source (22) and a stator (102) having a winding arrangement which includes first and second winding strands (52, 54). The latter are controlled by respective first and second semiconductor switches (70, 80). The motor also has a third controllable semiconductor switch (50), arranged in a supply lead from one of the terminals (28, 30) to the winding strands (52, 54), which third switch is alternately switched on and off by applying to it a PWM (Pulse Width Modulated) signal 24. During switch-off intervals, magnetic flux energy stored in the motor causes a decaying loop current (i2) to run through the windings, continuing to drive the rotor. This facilitates conformal mapping of temperature information in the PWM signal onto a target motor rotation speed.
Abstract:
A control circuit for an electronically commutated motor (120), having a power stage (122) that comprises at least two semiconductor switches (216, 218) to influence the motor current. The semiconductor switches are controllable by way of commutation signals. The control circuit comprises a current measuring element (170) to make available a motor current control variable (I) dependent on the motor current, a base diode (240) that is arranged in series with the current measuring element and between the current measuring element and the at least two semiconductor switches, and a motor current setting element (180) with which the commutation signals can be influenced as a function of the motor current control variable.
Abstract:
The invention relates to a sensorless electric motor and a method of controlling such an electric motor, which motor comprises a permanently magnetic rotor, a stator having at least one winding, and a power stage for influencing the current flowing through the winding. As a function of a predetermined commutation duration (T_K), a commutation period is defined, during which period the direction of the magnetic field generated by current flow through the winding is not modified, during which period a commutation completion operation (107) and a commutation initiation operation (109) take place, and which period starts at a first commutation instant (t_KN) and ends at a second commutation instant (t_KN+1); preferably, commutation timing is adjusted, based upon a value of induced voltage picked up at a currently non-energized one of the winding strands, during a plateau portion (108) of a winding voltage trace, located temporally between commutation instants.
Abstract translation:本发明涉及无传感器电动机和控制这种电动机的方法,该电动机包括永磁转子,具有至少一个绕组的定子和用于影响流过绕组的电流的功率级。 作为预定换向持续时间(T_K)的函数,定义了换向周期,在此期间,通过绕组的电流产生的磁场的方向不被修改,在此期间,换向完成操作(107)和 进行换向启动操作(109),并且哪个时段在第一换向时刻(t_K N N N)开始,并在第二换向时刻(t_K N + 1)结束。 优选地,在时间上位于换相时刻之间的绕组电压迹线的高原部分(108)期间,基于在当前未通电的绕组线圈拾取的感应电压的值来调整换向定时。
Abstract:
In an electronically commutated motor (M), rotor position signals are generated by means of a galvanomagnetic rotor position sensor (40). A timer (CNT_HL) brings about an advanced commutation which occurs only once the motor has reached a specific rotation speed, and whose magnitude is a function of the rotation speed.