Pre-charge circuits on both low-side switch and high-side switch
AssigneeCaterpillar Inc.
InventorGowan J. Woolley
Life of this patent
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Abstract
Techniques to extend the working life of an electrically controllable switch that is coupled in a parallel configuration with a pre-charge circuit. A pre-charge strategy includes both a high side switch (HSS) and low side switch (LSS). This design allows sharing the operational life across all HV contactors as opposed to just the one as in existing designs. In addition, the additional HSS/LSS pre-charge circuit may be used to safely confirm the working condition, e.g., welded, of an opposing contact.
Claims20
A battery system configured to improve contactor life, the battery system comprising:
- a battery pack electrically coupled with a first voltage bus and a second voltage bus including:
- a first battery string having at least one first battery cell, wherein the first battery string is electrically coupled between the first voltage bus and the second voltage bus;
- a first side coupled with the first voltage bus;
- and
- a second side coupled with the second voltage bus;
- at least one contactor including:
- a first contact electrically coupled with the first voltage bus, wherein the first contact is configured to selectively isolate the first side of the battery pack from a load, wherein the first contact divides the first voltage bus into a first side and a second side, wherein the first side of the first voltage bus is coupled with the battery pack and the second side of the first voltage bus is configured to be coupled with the load;
- a second contact coupled with the first battery string between the second side of the battery pack and the second voltage bus, wherein the second contact is configured to selectively isolate the first battery string from the load;
- a first pre-charge circuit coupled in a parallel configuration with the first contact;
- and
- a second pre-charge circuit coupled in a parallel configuration with the second contact.
A method for improving a working life of an electrically controllable switch, the method comprising:
- coupling a first pre-charge circuit in a parallel configuration with a first electrically controllable switch;
- coupling a second pre-charge circuit in a parallel configuration with a second electrically controllable switch;
- and
- selectively enabling the first pre-charge circuit or the second pre-charge circuit when a power source is coupled with a load.
A method for determining whether an electrically controllable switch in a circuit configured to couple a power source to a load of a machine is operational, the method comprising:
- selectively enabling either:
- a first pre-charge circuit coupled in a parallel configuration with a first electrically controllable switch;
- or
- a second pre-charge circuit coupled in a parallel configuration with a second electrically controllable switch, while ensuring that the other remains disabled;
- measuring an electrical parameter associated with the load of the machine;
- and
- determining, based on the measured electrical parameter, whether the first electrically controllable switch or the second electrically controllable switch is operational.
Dependencies are inferred from the claim text.