Vehicle or environment-controlled unit having a multiphase alternator with a protected high-voltage bus
A mobile environment-controlled unit, such as an over-the-road compartment trailer, having an environmental-control system, such as a refrigeration unit, powered by an alternator and having a high-voltage alternating current (AC) bus. The unit incorporates a high resistance ground scheme and can incorporate a solid-state input module to detect phase-chassis faults. This combination provides an improvement in protection for mobile applications that cannot have a voltage reference (or neutral point) solidly connected to earth ground.
1. A mobile environment-controlled unit comprising:
a ground potential contact;
a multiphase alternator configured to supply electrical power, the alternator having phase windings and a neutral point for the phase windings; and
a high-resistance resistor electrically coupling the neutral point for the phase windings to the ground potential contact.
2. The mobile environment-controlled unit of claim 1 , further comprising:
a solid-state module electrically coupling the neutral point for the phase windings to the ground potential contact, the module being configured to monitor a voltage from the neutral point to the ground potential contact, and to provide an output when the monitored voltage indicates a possible phase-to-ground potential contact fault.
3. The mobile environment-controlled unit of claim 1 , wherein the high-resistance resistor has a value in a range sufficient to limit current in a possible phase-to-ground potential contact fault and to dissipate parasitic current during a possible intermittent phase-to-ground potential contact fault.
4. The mobile environment-controlled unit of claim 1 , wherein the high-resistance resistor has a value between 1 kΩ and 1 MΩ.
5. The mobile environment-controlled unit of claim 1 , wherein the high-resistance resistor has a value between 10 kΩ and 100 kΩ.
6. The mobile environment-controlled unit of claim 1 , wherein the high-resistance resistor has a value between 30 kΩ and 70 kΩ.
7. The mobile environment-controlled unit of claim 1 , wherein the alternator is a three-phase alternator with the phase windings configured in a wye arrangement, and wherein the neutral point is the center of the wye arrangement.
8. A mobile environment-controlled unit comprising:
a chassis;
a three-phase alternator configured to supply electrical power, the alternator having phase windings in a wye arrangement and a neutral point for the phase windings;
a high-resistance resistor electrically coupling the neutral point for the phase windings to the chassis.
9. The mobile environment-controlled unit of claim 8 , wherein the range of the high-resistance resistor is between 30 kΩ and 70 kΩ.
10. The mobile environment-controlled unit of claim 1 , further comprising:
a compartment; and
an environmental-control system in environmental communication with the compartment, the environmental-control system being configured to control an environmental parameter of the compartment.
11. The mobile environment-controlled unit of claim 1 , wherein the ground potential contact is a chassis.
12. The mobile environment-controlled unit of claim 8 , further comprising:
a compartment; and
an environmental-control system in environmental communication with the compartment, the environmental-control system being configured to control an environmental parameter of the compartment.
13. The mobile environment-controlled unit of claim 8 , wherein, the high-resistance resistor having a value in a range sufficient to limit current in a possible phase-to-chassis fault and to dissipate parasitic current during a possible intermittent phase-to-chassis fault.
14. The mobile environment-controlled unit of claim 8 , further comprising a solid-state module electrically coupling the neutral point for the phase windings to the chassis, the module being configured to monitor a voltage from the neutral point for the phase windings to the chassis, and to provide an output when the monitored voltage indicates a possible chassis fault.
15. A mobile environment-controlled unit comprising:
a ground contact portion;
a high voltage AC generator configured to supply AC electrical power for one or more components of the mobile environment-controlled unit, the high voltage AC generator having phase windings and a neutral point for the phase windings; and
a high-resistance resistor electrically coupling the neutral point for the phase windings to the ground contact portion.
16. The mobile environment-controlled unit of claim 15 , further comprising:
a solid-state module electrically coupling the neutral point for the phase windings to the ground contact portion, the module being configured to monitor a voltage from the neutral point to the ground contact portion, and to provide an output when the monitored voltage indicates a possible phase-to-ground contact portion fault.
17. The mobile environment controlled unit of claim 15 , further comprising:
a compartment; and
an environmental-control system in environmental communication with the compartment, the environmental-control system being configured to control an environmental parameter of the compartment.
18. The mobile environment-controlled unit of claim 17 , wherein the environmental-control system further includes
a controller configured to control the environmental-control system for affecting the environment of the compartment.
19. The mobile environment-controlled unit of claim 10 , wherein the environmental-control system further includes
a controller configured to control the environmental-control system for affecting the environment of the compartment.
20. The mobile environment-controlled unit of claim 12 , wherein the environmental-control system further includes
a controller configured to control the environmental-control system for affecting the environment of the compartment, to receive an output from a solid-state module, and to control the environment-control system based on the output.