The voltage output waveform shown in Figure 1 can be easily achieved by programming the power supply. V1, V2, T1, T2, dv, and dt can all be set via programming. The output voltage range is 0–16 V, and the maximum output current is 10 A. The output voltage accuracy is 0.1 V, and the current accuracy is 10 mA. The current setting refers to the maximum allowable output current, and it can also be programmed to have the same waveform as the output voltage.
Alternatively, the power supply can also operate in lead-acid battery charger mode (referred to as "LBC mode"). Based on the characteristics of lead-acid batteries, when the power supply operates in LBC mode, it will initially output a large charging voltage and current V1/I1, maintaining this for at least 10 seconds. When the charging current drops below the set value I2, the power supply will output a smaller charging voltage and current V2/I2. If, by the set time T1, the charging current has not yet dropped below I2, the power supply output will also decrease to V2/I2. When the output current exceeds I2 again, the power supply will output V1/I1 for charging again. The set value of V2 must be less than 14 V. If set to greater than 14 V, the power supply will automatically set it to 14 V. The value of I2 must be greater than 1/8I1; otherwise, it will be automatically set to 1/8I1. The LBC mode is shown in Figure 2.
Users can configure the power supply output in three ways:
① Program via the buttons on the power panel. The output voltage, current limit, time, and other parameters can be set using the buttons.
② Programming via PC serial port. Connect the PC's RS232 serial port to the power supply's serial port, and then run serial communication software on the PC to program the power supply.
③ Inter-power supply programming. This method involves connecting two power supplies via their serial ports and programming the other power supply by pressing buttons on its control panel. The power supply being programmed is called the "master power supply," and the power supply being programmed is called the "slave power supply." In this programming method, the slave power supply's parameters can only be set to be identical to the master power supply's; individual parameter settings are not possible. Each power supply can only provide 100W of power. This method is suitable for applications requiring higher power outputs, as two or more power supplies with identical settings can be connected in parallel to easily expand power capacity.
With the rapid advancements in electronic technology and the continuous development of research, production, quality control, and industrial testing, power supply and AC power supply testing equipment, including programmable DC power supplies, AC power supplies, and electronic loads, have been recognized as categories of power electronic measurement instruments due to their wide range of applications. As fundamental testing and measurement tools in the power electronics field, they play a crucial foundational role. They are widely used in traditional and emerging industries such as national defense, aerospace, satellite radar, power electronics, automotive parts, new energy, industrial automation testing, electrochemical energy storage, battery testing, and passive and active component testing.
A programmable DC power supply is a high-frequency switching DC power supply employing PWM technology. It features a modular design and advanced DSP digital control technology, offering constant voltage, constant current, and constant power output modes with automatic crossover switching. This device not only boasts high power but also high precision. In particular, its voltage accuracy can reach up to 0.05%, and current accuracy is approximately 0.1%. The power supply also exhibits very high stability, operating continuously and stably from 0℃ to 40℃. Current measurements using this device are highly accurate.
Programmable DC power supplies offer stable DC output and a wider voltage and current range, with a single unit providing a current range of up to 200A and a voltage range of up to 800V. One unit can replace multiple rectangular power supplies in various applications. It can be remotely controlled via a panel or host computer to output diverse voltage and current combinations, features configurable timed output, and provides OVP/OCP/OPP/OTP/short-circuit protection. It also supports list waveform editing. This simplifies operation for test engineers, ensuring simple, fast, and accurate testing.
(1) Application of inductive loads
When we turn the programmable DC power supply on or off, or change the output voltage, the inductive load will generate a reverse electromotive force that affects the operation of the programmable DC power supply. In severe cases, it can even damage the programmable DC power supply. Therefore, we should connect a diode in series between the output terminal of the programmable DC power supply and the load, and connect a resistor and a capacitor in parallel at the load. This can effectively protect the programmable DC power supply.
(2) Battery-based load applications
When a programmable DC power supply is charging a battery-type load, we can prevent damage to the power supply caused by incorrect battery polarity. Therefore, a diode is connected in series between the power supply and the battery to protect the programmable DC power supply for safe use.
(3) Pulse-type load applications
Even if the peak current of a pulsed load is within the rated current range of the programmable DC power supply, or if the waveform of a pulsed circuit or motor is within the nominal value indicated by the metering equipment, the current will still reach the rated current range. This will cause the output voltage to drop or become unstable. The solution is to connect an inductor between the power supply and the load, which will effectively solve the problem.
(4) Capacitive load application:
Because capacitive loads often cause the output voltage to rise, especially when adjusting the output voltage from high to low, the output voltage will drop slowly. Therefore, when using it, a power resistor is connected in parallel at the output of the DC power supply, and a diode is connected in series between the output and the load to achieve better performance.
Foreign brands that started early in the field of programmable source device testing have accumulated some advantages, such as EA (Germany), Keysight (USA), and Chroma (Taiwan). In recent years, with the rise of domestic brands and the increasingly fierce competition in the Chinese market, including the influence and guidance of national policies, market demand has undergone differentiated changes, and various fields are facing specific needs for source device testing equipment. In particular, China's aerospace, automotive, new energy, energy storage, and higher education industries have triggered huge market demand potential.
With the rapid advancement of the new energy and energy storage industries, the demand for test power supplies and loads is becoming increasingly diversified, including bidirectional DC power supplies, high-power DC power supply test systems, and energy recovery electronic load systems. As the technological gap between domestic and international manufacturers narrows, and domestic technology is increasingly balancing with and surpassing foreign technology, a number of power supply brand manufacturers with technological advantages and customization capabilities have emerged in the market, such as ITECH, LONGi Technology, and AGCO. Compared with some mainstream international manufacturers, they have strong competitive advantages in terms of cost-effectiveness and product quality. In addition to high power density and series-parallel module solutions in hardware, they also offer standard test curves and customized solutions in software. LONGi Technology, in particular, has developed high-power density, high-current DC power supplies with single-module currents reaching 1000A and up to 20000A. These are mainly used in the research and testing of photovoltaic/energy storage grid-connected inverters/energy storage converters; new energy vehicles on-board chargers/DC-DC modules and automotive components; medium and high-power motors in electric vehicles, aircraft/ships/aerospace motors; and batteries in cells, battery modules, and capacitors. In the field of automotive sensor testing, it is also known as a dedicated test power supply, creating a differentiated competitive advantage over traditional programmable DC power supplies.
As fundamental equipment for laboratory and industrial testing, power supply devices (programmable AC/DC power supplies and electronic loads) are increasingly valued by the government in recent years due to the escalating international trade war. Domestically produced equipment is considered essential for national development, and its production has benefited from favorable policies and support for leading domestic manufacturers. In particular, domestic brands with strong technological foundations are receiving increasing attention.
From the perspective of product categories:
ITECH is a professional manufacturer of precision test and measurement instruments. Always customer-oriented, ITECH is committed to researching and developing testing solutions for related industries, with power electronics products at its core, providing competitive testing solutions to industry clients. Its product range covers AC/DC power supplies, electronic loads, automatic test systems, and more, offering a complete product line.
As a technology innovation-driven enterprise, LONGi Technology is a leading brand in the power control instrument field, known for its quality, precision, and innovation. LONGi Technology focuses on advanced global testing technologies, developing, manufacturing, and selling reliable testing products and providing high-quality technical services. LONGi offers innovative testing solutions in the field of laboratory AC/DC power supplies and electronic loads. Meanwhile, LONGi also focuses on standard AC/DC power supplies and electronic loads, developing upgraded and differentiated products to meet the diverse needs of research institutions and enterprises beyond the conventional requirements. Notable examples include small-volume DC power supplies, multi-channel DC power supplies, low-temperature DC power supplies, and high-density DC power supplies for the research field.
Programmable power supplies have a wide range of applications, and one device can function as multiple devices. Electronic design engineers use power supplies of various specifications for debugging. Planning your power supply products from the initial purchase stage will undoubtedly expand their applications. This article uses the SP-1U/2U series of all-day programmable DC power supplies as an example, providing a detailed explanation of their reverse current protection, series and parallel connection, software, and communication interface functions. We hope this will be helpful to those who need it.
Anti-reverse current function of battery charging power supply
The SP-1U/2U series of all-day programmable DC power supplies features reverse backflow prevention and energy absorption functions, adapting to reverse backflow prevention during battery charging.
The reverse current protection function cuts off the backflow of battery current to the power source under certain conditions, preventing damage to the power supply hardware. Similarly, the SP-1U/2U series also features energy absorption to handle motor loads.
When the power supply needs to absorb the spikes of the device under test to ensure operational safety, the energy absorption mode is activated (by opening the chassis and connecting the short-circuit copper plate), and this energy is absorbed by the power supply's internal output capacitor and other circuits.
The system power software and communication interface can be downloaded free of charge, along with local monitoring software.
*When communication is only powered by one device, enter the standalone interface. The standalone interface includes basic voltage and current settings and measurement functions.
*When the number of power supplies connected to the communication network exceeds one, enter the multi-machine interface. The multi-machine interface supports switching control or displays the current control power settings.
The SP-1U/2U series of all-day programmable DC power supplies offer communication interfaces including USB, RS-485, RS-232, LAN, and GPIB; external analog control outputs are also provided. When the free software cannot meet customized needs, free SCPI and MODBUS communication protocols are available for secondary development and system integration.
You can control the process through your browser if you don't want to download software.
You can remotely control the power supply by entering its IP address into your browser.
Series and parallel connection of power supplies enables positive and negative output and current sharing functions.
The SP-1U/2U series of all-day programmable DC power supplies supports master-slave mode and current sharing function in parallel mode to balance the power output, ensuring expanded power without affecting the power supply's performance.
CAN parallel mode enables master-slave synchronous response with no delay.
Two 600W/60A power supplies connected in parallel equal one 1200W/120A high-power power supply.
Two 600W/20V power supplies connected in series equal one 1200W/40V high-power power supply.
Two power supplies achieve synchronous output of positive and negative polarities.
These two extended functions can address current and future testing needs. If they still don't meet your current testing requirements, please contact Boyu Xunming Integration Business Unit for customized services to help you solve your testing challenges.
