Direct current machine with a controllable arrangement for limiting current

The direct current machine according to one of the preceding claims,

• wherein the current limiting arrangement (131, 161) influences the switching definition signal (PWM1) so that the driving current (i_2) in the stator winding arrangement (114) is limited to a first limiting current (I_max+), which first limiting current is controllable by means of a first signal (PWM_I+) conveyable to the current limiting arrangement (131, 161).

The direct current machine according to one of the preceding claims,

• wherein the current limiting arrangement (131, 161) influences the switching definition signal (PWM1) so that a braking current (i—2′) in the bridge circuit is limited to a second limiting current (I_max−), which latter is controllable by means of a second signal (PWM_I−) conveyable to the current limiting arrangement (131, 161).

The direct current machine according to one of the preceding claims,

• wherein the current limiting arrangement (131, 161) influences the switching definition signal (PWM1) so that the driving current (i_2) in bridge circuit is limited to a first limiting current (I_max+) and so that the braking current (i_2′) in the bridge circuit is limited to a second limiting current (I_max−), the first limiting current (I_max+) and the second limiting current (I_max−) being controllable respectively by means of first and second signals conveyable to the current limiting arrangement (131, 161).

The direct current machine according to one of the preceding claims, which comprises a controller (24) for regulating the rotation speed (n) to a specified rotation speed value (n_s), which controller (24) outputs a switching definition signal (PWM1) as a control input (n_CTRL via U_CTRL).

The direct current machine according to one of the preceding claims,

• wherein the switching definition signal (PWM1) is adjustable to a value which substantially continuously activates the current limiting arrangement (131) that limits the driving current (i_2).

The direct current machine according to one of the preceding claims,

• wherein the switching definition signal (PWM1) is adjustable in such a way that the current limiting arrangement (161) limiting the braking current (i_2′) is substantially continuously activated.

The direct current machine according to one of the preceding claims, comprising a digital control element (23) serving for motor control, such as a microprocessor or microcontroller,

• wherein the signal (PWM_I+ or PWM_I−) conveyable to the current limiting arrangement (131, 161) is controllable by means of the digital control element (23).

The direct current machine according to one of the preceding claims, comprising an arrangement for monitoring the voltage (Us) at the direct current source (73, 74), which arrangement blocks all the semiconductor switches of the full bridge circuit (78) when a specified upper limit value (U_MAX_OFF) of that voltage (Us) is exceeded.

The direct current machine according to one or more of the preceding claims, comprising a digital control element (23) serving for motor control such as a microprocessor or microcontroller, which, in operation, furnishes output signals for controlling the full-bridge circuit (78), each bridge arm having associated with it a commutation module (50, 52, 54) for alternatingly switching on its upper semiconductor switch and its and lower semiconductor switch, which commutation module comprises at least two signal inputs (e.g. IN1, EN1) that are controllable by means of separate signal outputs of the digital control element (23),

• the PWM signal (PWM2) being conveyable to one of those signal inputs (IN1, IN2, IN3),
• and a signal output (IN1, IN2, IN3), associated with that signal input, of the digital control element (23) being switchable into a high-resistance state in order to activate, from the digital control element, an alternating switching-on of the semiconductor switches of that bridge arm by means of the PWM signal (PWM2).

The direct current machine according to one or more of the preceding claims, comprising a digital control element (23) serving for motor control such as a microprocessor or microcontroller, which serves to regulate the rotation speed of the direct current machine and provides, at at least one output, a signal (PWM1) for influencing the rotation speed of the direct current machine,

• and comprising an arrangement for limiting that signal to a rotation-speed-dependent value.

Use of a direct current motor according to one of the preceding claims to drive a fan.