Excitation device for electromagnetic actuator
First Claim
1. A device for the electrical excitation of the coil or coils of an electromagnetic actuator, said device capable of causing a shift of said actuator in either direction, said device comprising a bridge consisting of two pairs of transistors, said bridge electrically connected to and capable of directly supplying electrical current to said coil(s) in either direction to obtain said shift of said actuator in either direction, said device further comprising means for measuring an error voltage, said error voltage being the difference between a reference voltage representing the current to be applied to said coil(s) and a voltage proportional to a current actually flowing through said coil(s), said error voltage consisting of an absolute value and a sign positive or negative;
- said device further comprising means which, in response to one sign of said error voltage, turns off a first pair of said two pairs of transistors of said bridge and turns entirely on one transistor of a second pair of said two pairs of transistors, while simultaneously the other transistor of said second pair of transistors is caused to operate in a substantially linear mode, causing a current proportional to said error voltage to flow through said coil(s) in a first direction, and, conversely, in response to the opposite sign of said error voltage, turns off said second pair of said two pairs of transistors of said bridge and turns entirely on one transistor of said first pair of said two pairs of transistors, while simultaneously the other transistor of said first pair of transistors is caused to operate in a substantially linear mode, causing a current proportional to said error voltage to flow through said coil(s) in a second direction.
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Accused Products
Abstract
A device for the electrical excitation of the coil or coils of an electromagnetic actuator, especially that of a linear motor, the coil of which has a low self-inductance. This coil is supplied by a bridge of transistors. The error between a reference voltage and a voltage proportional to the current in this coil is used to turn off a pair of transistors of the bridge, and simultaneously saturate a transistor of the other pair and make the other transistor work in linear mode. Two electronic switches and one sign discriminator are used to this end.
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Citations
6 Claims
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1. A device for the electrical excitation of the coil or coils of an electromagnetic actuator, said device capable of causing a shift of said actuator in either direction, said device comprising a bridge consisting of two pairs of transistors, said bridge electrically connected to and capable of directly supplying electrical current to said coil(s) in either direction to obtain said shift of said actuator in either direction, said device further comprising means for measuring an error voltage, said error voltage being the difference between a reference voltage representing the current to be applied to said coil(s) and a voltage proportional to a current actually flowing through said coil(s), said error voltage consisting of an absolute value and a sign positive or negative;
- said device further comprising means which, in response to one sign of said error voltage, turns off a first pair of said two pairs of transistors of said bridge and turns entirely on one transistor of a second pair of said two pairs of transistors, while simultaneously the other transistor of said second pair of transistors is caused to operate in a substantially linear mode, causing a current proportional to said error voltage to flow through said coil(s) in a first direction, and, conversely, in response to the opposite sign of said error voltage, turns off said second pair of said two pairs of transistors of said bridge and turns entirely on one transistor of said first pair of said two pairs of transistors, while simultaneously the other transistor of said first pair of transistors is caused to operate in a substantially linear mode, causing a current proportional to said error voltage to flow through said coil(s) in a second direction.
- View Dependent Claims (2, 3)
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4. A device for the electrical excitation of at least one coil of an electromagnetic actuator for shifting in either direction a current flow in said coil comprising:
- a bridge of transistors connected to directly supply current to said coil, in either direction;
means for measuring an error between a reference voltage representing current to be applied to said coil and a voltage proportional to a current flowing through said coil and providing an error signal in accordance with said measurement;
means for providing, when said error signal is of one sense, a turn off of a pair of transistors of the bridge which, if they were on, would make the current flow in a first direction in said coil and, a turn on of the transistors of the other pair;
said transistors of said other pair working in a substantially linear mode, whereby the current flowing through said other pair of transistors and therefore flowing through said coil is in the second direction varies practically linearly with said error signal; and
said means for providing when said error signal is of an opposite sense, a turn off of the two transistors of said other pair and a turn on of the two transistors of the first pair, with one transistor of said first pair being totally on while the other transistor of said first pair works in a substantially linear mode so that the current, which then flows through the coil in said first direction varies, practically linearly with the error signal. - View Dependent Claims (5, 6)
- a bridge of transistors connected to directly supply current to said coil, in either direction;
Specification