This article will introduce the design challenges that the energy collection source is facing the design challenge of the power supply node in high reliability vital industrial automation. The text will explore how energy from temperature and vibration is combined with battery systems and wireless links to ensure that sensor nodes are exactly placed in a suitable location while maintaining the highest reliability.
Energy collection techniques can be used to enhance the reliability and availability of industrial systems. Such techniques can be positioned in the desired position without considering the power supply or communication link, thereby providing data of quality. This in turn provides trend data for technologies such as Kalman algorithms, which helps identify problems that may have, and prevent preventive maintenance or put into spare equipment before the failure.
Energy collection techniques can overcome the challenges faced by the sensor nodes that are powered by a single battery. Maintenance and replacement batteries are a cost-effective task for production workshops throughout thousands of nodes. However, it is believed that the energy collecting source is unstable, and the reliability is low, so it usually does not consider it for the production application. The combination of energy collection sources such as vibration, high temperature or solar energy is not lost as the policy of two full beauty. Separate sensor nodes can be easily placed in a difficult location, while the rechargeable battery system can make thousands of charge and discharge, which makes the node service life significantly.
However, this combination requires a new power management device that provides reliable power supply from irregular weak current sources. Such devices use lifting pressure architecture to specifically manage electrical energy captured from different sources.
The energy generated by Midé's Volture V25W or similar devices collect vibration is a valuable power source in factory automation. .
This piezoelectric device uses a full-closed structure for harsh environments. It can be used as a sensor or directly integrate with the power management chip and thin film battery to provide a reliable power source. By converting the energy generated by converting motor vibration, this device is specifically used to supply power to the sensor node of the industrial network and the wireless high voltage air conditioner (HVAC) sensor in the industrial automation device. In addition, the status of HVAC can also be monitored, which ensures that the temperature of the production workshop is strictly controlled, thereby ensuring reliability.
The sensor is installed in the vibration source and tunes to the resonant frequency of the vibration source. Typically, 120 Hz AC motor or 60 Hz devices will be obvious, tuning is therefore more easy, but most applications require certain vibration-characterized forms to ensure that the vibration source operates in resonance frequency.
V25W can be connected to a power management device such as MaxIm's MAX17710. This complete system allows energy to collect the source as a micro-power battery charging while protecting the battery. It can manage the output level between 1 fW to 100 mW. At the same time, this device also includes a boosting regulator circuit that allows the energy collection source of as low as 0.75 V (typical value) to charge.
The internal regulator prevents excessive charging of the battery; the output voltage supplied to the target application is adjusted by a low pressure difference (LDO) linear regulator, and the optional voltage is 3.3 V, 2.3 V or 1.8 V. Output regulators can choose low power or ultra-low power operating mode to minimize battery consumption. Internal voltage protection prevents excessive discharge of batteries.
Even in indoor production workshops, solar cells are also a feasible power supply. Spansion's MB39C831 is an efficient synchronous rectifier to boost DC / DC converter, which can effectively provide energy from a single or multi-section solar cell or thermoelectric generator (TEG) to a lithium ion battery.
It tracks the maximum power point of the solar cell to control the DC / DC converter output by using the maximum power point tracking (MPPT) algorithm to control the DC / DC converter output, and the lithium ion battery is safely charged with the protection function.
In general, solar cell voltages varies with load current, and therefore works at the maximum power point is the key. The control algorithm tracks the optimal work point on the basis of the contrast without load release point, and achieves the highest power conversion efficiency.
Using a low pressure design (Figure 3), it is possible to start with a voltage of 0.35 V. The device is suitable as an input application with a single solar cell, and provides 3.0 V to 5.0 V output at 41 μA static current to power the sensor node. One key feature of the device is that it can be automatically switched between the pulse frequency mode (PFM) and the pulse width mode (PWM), so power conversion efficiency can be optimized during low output power.
This adaptive solution is also suitable for thermal energy electrical energy. It can be applied to production workshops and utilize heat differences. Laird WPG-1 and other thermal engines provide useful output power up to 1.5 mW to process wide range load resistance (Figure 4). The device integrates an ultra-low pressure boost converter that outputs useful power under small temperature difference conditions less than 20 ° K. Output power can be adjusted to accommodate three voltage set points (3.3 V, 4.1 V or 5.0 V), and then powered by sensor nodes or more devices.
This device is a self-sufficient film thermoelectric power generator that collects waste heat and converts it to the DC output power available for wireless sensor networks. Custom design services can be accommodated for alternating heat absorption and heat dissipation mechanisms for different heat differences or output voltages.
One way to further enhance energy collection source is that the capacitor group is collected using a capacitor group in front of the energy consumption or stored in a self-supplied battery. Advanced Linear Devices EPAD Energy Collection Module Accepts energy from multiple sources, providing 3.3 V and 5.0 V traditional output, suitable for low-power sufficient duty cycle sampling data, state-based monitoring and extremely high Use life requirements. The module is completely powered and always in active mode, so an instantaneous input voltage supplied from 0.0 V to +/- 500 VAC or DC, and input current from 200 Na to 400 mA can be accepted. , Energy collecting sources are sometimes stable, sometimes intermittent, irregular, and source impedance changes.
Each module is set to work between two supply voltage thresholds, namely + V_LOW DC, and + V_High DC, respectively, corresponding to the minimum (VL) and maximum (VH) power supply voltage of the sensor node, respectively.
These charge packages are collected and stored, accumulated and stored to internal energy storage capacitor banks when the energy source was sent to the module input. For the most common energy collection applications, the power charge package appears in the form of uncontrollable and unpredictable input voltage spikes. These charge packs typically cover various voltages, currents, and timing waveforms, so it is difficult to handle. For example, the EH300 module can complete the cycle within 4 minutes of 10 μA, or only the cycle is completed in 40 minutes only at a average input current of 1.0 μA.
Summarize
Energy Collection is an effective way to provide power supplies for sensor networks and are not limited by power cable. Place the sensor at the desired position, power supply through the device vibration or upper lighting - the useful data obtained by this innovative method ensures reliable factory system. The installed rechargeable battery greatly prolongs the maintenance and replacement cycle while providing a flexible and efficient way - reliable monitoring of the equipment via wireless sensor network.
Be
Be
Article source network
Our other product:
