Loading patent…
AssigneeTelefonaktiebolaget L M Ericsson
InventorPer Ingvar M. Back
Estimating the term…
The invention relates to a method and a controlling apparatus for controlling the magnitude and direction of a current (I) through a winding (L). The method and controlling apparatus are based on a drive circuit (TR.sub.1, D.sub.1, TR.sub.2, D.sub.2, TR.sub.3, D.sub.3, TR.sub.4, D.sub.4) which is controllable such as to enter into three different types of operational state. In a first type of operational state the current is normally increasing in magnitude. In a second type of operational state the current is normally decreasing in magnitude comparatively slowly. In a third type of operational state the current magnitude is normally decreased comparatively rapidly. When the drive circuit is in the first type of operational state it is controlled either to remain in this state or to change to the second type of operational state in response to the result of at least one comparison between the actual value of the current and a desired value (I*) carried out during the time the drive circuit was in the first type of operational state. When the drive circuit is in the third type of operational state it is controlled either to remain in this state or to change to the second type of operational state in response to the result of at least one comparison between the current actual value and a desired value carried out during the time the drive circuit was in the third type of operational state. The method and apparatus are primarily intended for microstepping a two-phase stepping motor with a permanent magnetized rotor.
A method of controlling the magnitude and direction of a current (I) through a winding (L), which winding is connected to an electrical energy source (2) via a drive circuit (3), this drive circuit having at least three types of operational state and can be controlled to change between different types of operational states, wherein the drive circuit in a first type of operational state can supply electrical energy to the winding from the energy source, wherein the drive circuit in a second type of operational state neither supplies any substantial electrical energy to the winding from the energy source nor feeds back any substantial energy from the winding to the energy source, wherein the drive circuit in a third type of operational state does not supply any substantial electrical energy from the energy source but can feed back substantial electrical energy from the winding to the energy source, in which method the current through the winding is sensed and an actual value representing the sensed current is formed, and the actual value is compared with at least one desired value (I*) for the current, comprising the steps of:
A regulating apparatus for controlling the magnitude and direction of a current (I) through a winding (L), which controlling appartus comprises a drive circuit (3) for connecting the winding to an electrical energy source (2), this drive circuit having at least three types of operational state and being controllable to change between different types of operational states, which drive circuit in a first type of operational state can supply electrical energy to the winding from a connected energy source, which drive circuit in a second type of operational state neither supplies any substantial electrical energy from the energy source to the winding nor feeds back any substantial energy from the winding to the energy source, which drive circuit in a third type of operational state does not supply any substantial electrical energy from the energy source to the winding but can feed back substantial electrical energy from the winding to the energy source, said controlling apparatus including actual value means (5) for sensing the current to the winding and forming an actual value representing the sensed current, said controlling apparatus including comparison means (7) for comparing the actual value with at least one desired value (I*) for the current, said controlling apparatus including control means (4) connected to the drive circuit (3) and to the comparison means (7) for controlling the drive circuit to enter into different types of operational states in response to the result of the comparison, characterized in that when the drive circuit is in the first type of operational state the control means are adapted to control the drive circuit so that it either maintains the first type of operational state or changes to the second type of operational state in response to at least one comparison carried out by the comparison means during the time the drive circuit is in the first type of operational state, in that when the drive circuit is in the third type of operational state the control means are adapted to control the drive circuit so that it either maintains the third type of operational state or changes to the second type of operational state in response to at least one comparison carried out by the comparison means during the time the drive circuit is in the third type of operational state, and in that when the drive circuit is in the second type of operational state the control means are adapted to control the drive circuit so that it changes to the first or the third type of operational state or maintains the second type of operational state in response to at least one comparison carried out by the comparison means during the time the drive circuit is in the second type of operational state.
Dependencies are inferred from the claim text.