POWER SWITCHING DEVICE FOR AN ELECTRICAL POWER DISTRIBUTION SYSTEM, IN PARTICULAR FOR AN AIRCRAFT, WITH METERING OF THE CONSUMED ELECTRICAL POWER

Abstract

A power switching device for an electrical power distribution system. The power switching device is configured for supplying an electrical load with power, having switching means and means for protecting the loads. The device includes current measurement means and voltage measurement means delivering current and voltage measurement signals to a driver stage of the device. The device includes processing means that are capable of formulating information relating to the electrical power consumed by the loads on the basis of the voltage and current measurement signals.

Claims

1. A power switching device for an electrical power distribution system, the power switching device being configured for supplying at least one electrical load with power, the power switching device comprising: switching means; means for protecting the at least one load; current measurement means; voltage measurement means delivering current and voltage measurement signals to a driver stage of the device, and processing means that are configured for formulating information relating to the electrical power consumed by the at least one load based on the voltage and current measurement signals.

2. The device of claim 1, further comprising means configured for formulating a RMS value of a current and a voltage delivered to the at least one load.

3. The device of claim 1, wherein the processing means include means for calculating a phase shift between the voltage and current.

4. The device of claim 3, comprising means for calculating a cosine of an angle of said phase shift.

5. The device of claim 1, wherein the processing means include means for calculating an active power consumed by the at least one load.

6. The device of claim 1, wherein the processing means include means for calculating a reactive power consumed by the at least one load.

7. The device of claim 1, wherein the processing means include means for driving the switching means based on a value of the measured voltage.

Description

DESCRIPTION OF THE DRAWINGS

[0031] The power switching device illustrated in the FIGURE is in particular intended to be incorporated within a primary electrical power distribution system or in a secondary distribution system of an onboard network of an aircraft.

[0032] It is intended to provide the power-switching and the protection of the loads and of the cables of the power supply network.

DETAILED DESCRIPTION

[0033] This device, denoted by the general numerical reference 1, is intended to be connected between a power input 2 and a power output 3 of a power line and includes a switching member 4 for distributing electrical power and protecting the loads and/or the power supply cables, and an auxiliary safety member 5, of the fuse type, for example placed between the switching member 4 and the power output 3.

[0034] The switching member 4 is driven by a computing and processing unit 6 on the basis of current and voltage measurement signals.

[0035] The power switching device is thus supplemented by a current sensor 7, placed for example between the safety member 5 and the power output 3, and voltage sensors 8a and 8b, placed at the power input and at the power output and measuring the voltage conveyed over the power line. The voltage value delivered by the voltage sensors 8a and 8b is advantageously the phase-to-neutral voltage of the power supply line.

[0036] The measurement signals from the current and voltage sensors are delivered to conditioning stages 9a and 9b used for conditioning and shaping the signals delivered by the sensors with a view to their processing by the processing unit 6. They perform in particular the sampling of the measurement signals at a frequency that is substantially high with respect to the frequency of the power supply network.

[0037] It may additionally be seen that the processing unit 6 communicates with a bus for communicating and transmitting data and is also capable of communicating with a digital input and output E/S.

[0038] The computing unit incorporates all of the hardware and software means that are capable of driving the switching member on the basis of the signals from the sensors and for calculating information relating to the electrical power consumed by the loads on the basis, in particular, of the measurements of current and voltage conveyed over the power line.

[0039] The computing unit additionally receives the state of the power switch of the switching member 4, namely open, closed, not in use, etc., and information pertaining to the state of the protections put in place by the switching member and the safety member 5, namely active or inactive.

[0040] First and foremost, the processing unit 6 ensures that the measured input voltage meets the conditions for the power switch to be able to be closed. To this end, the input voltage is compared with minimum and maximum admissible values.

[0041] With regard to the voltage conveyed over the power line, the processing unit 6 acquires the phase-to-neutral voltage value, determines the time of zero crossing of the voltage, for example by interpolation or estimation on the basis of an acquired direct value, and also calculates the RMS value of the voltage.

[0042] With regard to the current distributed to the load, the processing unit 6 acquires the value of the line current or that delivered to the load, calculates the RMS value of this value and determines the time of zero crossing of the current.

[0043] To avoid introducing overly large measurement errors or making the processing overly complex, the voltage and the current are acquired substantially synchronously.

[0044] The processing unit 6 additionally calculates the phase shift between the voltage and the current, by measuring the time difference between the voltage and the current, calculates the value of the cosine of the phase-shift angle Phi between the voltage and the current, and also calculates the value of the sine of this angle.

[0045] The active power consumed by the load is calculated by calculating the product:

VrmsIrmsCosinus(Phi)(1)

[0046] The consumed reactive power is calculated by calculating the product:

VrmsIrmsSinus(Phi)(2)

[0047] where

[0048] Vrms and Irms denote the RMS voltage and the RMS current, respectively.

[0049] The power switching device thus formulates, on the basis of the signals delivered by the current and voltage sensors, information relating to the electrical power consumed by the loads on the basis of current and voltage values. These signals were used, in the prior art, for the protection of the loads and power-switching.

[0050] The power metering implemented by the power switching device makes it possible to improve the management of the electrical power distribution, by virtue of the metering and of the power management, to track the variation in the loads and to size the elements of the distribution system.