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US 10,901,003 B2Granted
Current measuring device
AssigneeIsabellenhuette Heusler GmbH & Co. KG
InventorUllrich Hetzler
Life of this patent
Estimating the term…
Abstract
The invention concerns a current measuring device for measuring an electric current (Ip, In) according to the four-wire technology with a low resistance current measuring resistor (RCu1, RCu, R0). The invention also provides for a compensating resistor (Rp) consisting of a fixed resistor connected in parallel with the resistor element (R0) of the low-resistance current measuring resistor (RCu1, RCu, R0) in order to at least partially compensate for the temperature dependence of the resistance value, so that the current measuring device has two current paths, namely a main current path through the resistor element (R0) on the one hand and a secondary current path through the compensating resistor (Rp) on the other hand.
Claims17
Current measuring device for measuring an electric current according to a four-wire technique, comprising:
- a) a current measuring resistor with
- a1) a first current connection part made of a conductor material for introducing the current into the current measuring resistor,
- a2) a second current connection part made of a conductor material for discharging the current from the current measuring resistor,
- a3) a resistor element made of a resistor material, the resistor element being arranged in the current flow direction between the first current connection part and the second current connection part,
- a4) a first voltage measurement terminal made of a conductor material for measuring an electric voltage dropping across the resistor element, and
- a5) a second voltage measurement terminal made of a conductor material for measuring the electric voltage dropping across the resistor element, and
- b) a compensating resistor including a fixed resistor which is electrically connected between the two voltage measurement terminals in parallel with the resistor element in order to at least partially compensate for the temperature dependence of the resistance value, so that the current measuring device has two current paths, namely a main current path through the resistor element on the one hand and a secondary current path through the compensating resistor on the other hand, wherein
- c) a printed circuit board is mounted on the current measuring resistor and is electrically connected to the current measuring resistor.
- d) the compensating resistor is mounted on the printed circuit board,
- e) the printed circuit board contains the compensating resistor intergrated or has pads on its upper side for mounting and contacting the compensating resistor,
- f) the printed circuit hoard has through-connections in order to connect the solder pads on the underside of the printed circuit board to the pads for the compensating resistor on the upper side of the printed circuit board, board,
- g) the voltage measuring terminals are arranged on the upper side of the printed circuit board, and
- h) at least one conductor track is arranged on the upper side of the printed circuit board or on one of the inner layers of the printed circuit board, which track connects one of the pads for the compensating resistor to one of the through-connections and forms the conductor element in the secondary current path.
10 more elements
Current measuring device for measuring an electric current according to a four-wire technique, comprising:
- a) a current measuring resistor with
- a1) a first current connection part made of a conductor material for introducing the current into the current measuring resistor,
- a2) a second current connection part made of a conductor material for discharging the current from the current measuring resistor,
- a3) a resistor element made of a resistor material, the resistor element being arranged in the current flow direction between the first current connection part and the second current connection part,
- a4) a first voltage measurement terminal made of a conductor material for measuring an electric voltage dropping across the resistor element,
- a5) a second voltage measurement terminal made of a conductor material for measuring the electric voltage dropping across the resistor element;
- and
- b) a compensating resistor including a fixed resistor which is electrically connected between the two voltage measurement terminals in parallel with the resistor element in order to at least partially compensate for the temperature dependence of the resistance value, so that the current measuring device has two current paths, namely a main current path through the resistor element on the one hand and a secondary current path through the compensating resistor on the other hand, wherein
- c) the current measuring resistor has a resistance value of at least 1 μΩ and at most 10 mΩ,
- d) the current measuring resistor has a current carrying capacity of at least 1A,
- e) the current measuring resistor has a length in the main current flow direction of not more than 20 mm,
- f) the current measuring resistor has a thickness of at most 5 mm,
- g) the current measuring resistor has a width transverse to the main flow direction not exceeding 200 mm,
- h) the current measuring resistor has a resistance value with a temperature coefficient not exceeding 500 ppm/K,
- i) the conductor material is one of copper and a copper alloy,
- j) the conductor material has a lower resistivity than the resistor material,
- k) the two current connection parts are welded to the resistor element,
- l) the resistor material is a copper-manganese-nickel alloy,
- m) the two current connection parts are plate-shaped,
- n) the resistor element is plate-shaped.
17 more elements
Current measuring device for measuring an electric current according to a four-wire technique, comprising:
- a) a current measuring resistor with
- a1) a first current connection part made of a conductor material for introducing the current into the current measuring resistor,
- a2) a second current connection part made of a conductor material for discharging the current from the current measuring resistor,
- a3) a resistor element made of a resistor material, the resistor element being arranged in the current flow direction between the first current connection part and the second current connection part,
- a4) a first voltage measurement terminal made of a conductor material for measuring an electric voltage dropping across the resistor element,
- a5) a second voltage measurement terminal made of a conductor material for measuring the electric voltage dropping across the resistor element, and
- b) a compensating resistor including a fixed resistor which is electrically connected between the two voltan measurement terminals in parallel with the resistor element in order to at least partially compensate for the temperature dependence of the resistance value, so that the current measuring device has two current paths, namely a main current path through the resistor element on the one hand and a secondary current path through the compensating resistor on the other hand, wherein the compensating resistor has a resistance value Rp which is calculated according to the following approximation formula:
- Rp=RCupg·TKcu/TK
- with:
- Rp:
- Resistance value of the compensating resistor,
- RCupg:
- Sum of the resistance values of the conductor loops in the secondary current path,
- TKCu:
- Temperature coefficient of the resistance value of the conductor material, preferably copper,
- TK:
- Temperature coefficient of the current measuring resistor without the compensating resistor,
- and with a tolerance of less than ±30%.
15 more elements
Dependencies are inferred from the claim text.