In areas such as home power, industrial equipment, “variant frequency” and “ straight-flow frequency” are technical terms that appear to be high frequency, and many users may confuse them and even consider “direct-flow frequency” as an upgrade of “variant frequency”. In practice, however, the rationale, structure design and application of the two are fundamentally different. The paper will address the four dimensions of conceptual definition, technology, key differences, application scenarios and provide targeted options。
I. Concepts first: clear definitions of “variant frequency” and “direct flow frequency”
In order to understand the difference between the two, it is necessary first to clarify the broad and narrow concept of “variance frequency”, which is a generic term, and “direct flow frequency” is a subdivision of the “variant frequency” technology, but the drivers and control logic of the two are completely different。
Broadly defined "variable frequency": control techniques to change frequency
The "variable frequency" is essentially an electrical rate control technique, the logic of which is to change the power frequency of the power input by changing the frequency of the "frequency converter" (which, according to the electrical method, is proportional to the frequency of the power)。
In terms of technology classification, the broad term "variable frequency" can be divided into two main directions:
Ac variable frequency: drives the "communicator" (e. G., a different pacer) and the "transformation current" (e. G.), which is the dominant form of early modulation technology, which is commonly referred to as the "ordinary frequency"。
Direct current frequency (dc variable frequency): drives a “direct current power machine” (e. G., a constant magnetic synchronous current), which is required to fix the communication current into a direct current, then to transform the direct current reverse into a modifiable frequency “pulse current” (simulating the replacement effect of the exchange), thereby controlling the speed of the direct current generator — which is a narrow “direct current frequency” — and is the dominant technology for current electrical, precision equipment。
Key to confusion: "synthetic current frequency" and " straight current power"
Special attention needs to be paid to the fact that " straight current frequency" is not "pure straight current power." early “pure current generators” (e. G., toy and small fans) do not need a frequency transformer to control speed directly by regulating the direct current voltage, but there is a problem of low rate stability and high energy consumption; and “ straight current variant” is “control of the current generator by using variable frequency technology” to achieve smooth control of current frequencies and bands through precision regulation, balancing energy efficiency with stability。
Technology dismantling: differences in nature from "electricity type" to "control logic"
The fundamental difference between the two stems from the different types of motors, which in turn leads to a range of differences in the structure of the variable, energy consumption performance, and operational stability. The following is an analysis of the two dimensions of electrical structure and control process。
1. Difference 1: type and rationale of the driver
The electric power is the "transformation frequency" and the "direct flow-transformation frequency" of the heart, both of which are structured to determine their performance limit:
(1) "communicated variable frequency": drive "communicated heap machines"
Interchange is a traditional variable frequency technology with a simple structure and low cost, but there are problems of “rotation loss” and “turn speed lag”:
Structural characteristics: the electrons consist of the "sent" (input exchange) and "rotor" (closed conductor, which produces the current through the indentation of the magnetic field and is thus subject to electromagnetic rotation), which is always rotated at a slower rate than the rate of the fixed magnetic field (which is known as the "distant")。
Deficiencies: the rotor's factor “sensitized current” produces “copper damage” (heating loss of the current overconductor), while the fixed iron core produces “iron damage” (magnetic decomposition due to magnetic field changes, vortex loss), both of which result in less efficient electric power (usually 70-85 per cent) and visible heat at high speed。
(2) "strength": driven "annual magnetic synchronized straight streaming machine"
The direct current frequency is the long-magnetic-synthetic-synthetic-synthetic-sync-sync-sync
Structural characteristics: electrons are fixed in a similar way to transients (invertable currents), but rotors are no longer a closed conductor, but are embedded in a "magnetic permagnetic" (e. G., cerium permagnetic material) - – the rotation magnetic field generated by the tranquoise will be associated with the constant magnetic field of the rotor “sync attracting/exclusion”, which will drive the transcript rotation (the rate of rotation is fully consistent with that of the transcript magnetic field, which gives the name)。
Advantages: the rotor is insensitive to currents, so there is no rotor copper loss; at the same time, the magnetic field strength of the permagnetic is stable, and the stat need not produce “magnetic currents” (the exchange engine needs to use part of the current to magnetize the rotor), which further reduces the fixed losses. The total efficiency of the electric power is 85-95 per cent, with low heat and low noise。
2. Difference 2: control processes and structures of the variable
The difference between the two "energy consumption" and "speed accuracy" is the key to the difference:
(1) control process for "ordinary frequency": direct frequency
An ordinary variable frequency (known as a "turn-turner" or "voltage-type transformer") is a "changed communication frequency" which is simple but deplete:
(a) holistic chain: exchange of municipal electricity 220v/380v and conversion of direct current electricity through a two-polar bridge (but without filtering or simple filtering, the voltage is unstable)
(a) inverted chain: the "reverse" of unstable direct currents of electrical communication (output voltage and frequency synchronized changes, known as "v/f control") through switches such as the igbt (insulation grid bipolar transistor)
Drivers: the modifiable electro-input internacional (tei) is an arcade machine, which changes the rotation speed of the fixed magnetic field and adjusts the velocity of the electric machine。
Deficiencies: direct currents after the current has not passed "filtration wave energy" and the reverse output is close to "square wave" (rather than a swirl wave) and produces "harmonic loss"; and, at the same time, the "show properties" of the exchange aniso power result in low speed control accuracy (usually 5-10 per cent-10 per cent error rate)。
(2) a secondary conversion of the control process for " straight current frequency": "communication of straight current pulse straight flow"
There are more direct stream filters, more precise controls:
(a) holistic chain: in line with normal variability, the municipal electricity exchange is being converted to direct current
(a) leach storage chain: “left to flat current” (low voltage fluctuations, providing a stable power source for subsequent reversals) through large capacity capacity or perception
Inverted chain: the smooth flow of electrical retrogents is replaced by "pulse-widening (pwm) pulse straight currents" through a three-way reverser of igbt. - this pulse wave simulates the "replacement effect" of communication electricity, precisely controlling the magnetic field direction and rotation of the straight current electrons
(b) drivers: pulse direct currents input permanent magnetic synchronous straight currents, fixed magnetic fields rotate simultaneously with rotor permagnetics, achieving precision control of rotation speed (which can be as low as 0. 1 to 1%)。
Advantages: a smooth direct current reduces the loss of the rhythm, and pwm controls achieve a dynamic match of “turn-load” not only to lower energy consumption but also to avoid “flow shocks” (e. G., peaks of power consumption when air conditioners are activated)。
Key dimensions comparison: across-the-board differences from performance to cost
To show the difference more clearly, we compare it directly with the five dimensions of "energy consumption, noise, speed accuracy, lifetime, cost":
Energy consumption performance: direct current frequency is significantly more energy-efficient
Normal variant frequency: the ratio of rotor copper damage to the exchange arcade power plant, the percentage of inverted magnetic loss, and the proportion of inverted magnetic loss to the frequency transformer, combined with the total energy efficiency ratio (e. G., apf values for air conditioners) is usually between 3. 0 and 4. 0 (near the lower limit of the energy efficiency standard); under low load conditions (e. G., air conditioner heating phase), the speed of the motor is not accurate enough to match the load and is prone to “frequent start” to increase energy consumption。
Direct current frequency: the non-rotor loss of the long-magnetic synchronous electric power, the reduction of the frequency filters, the reduction of the wave loss, the energy efficiency of which is easier to achieve 4. 5-5 (high energy efficiency standards); the rate of rotation can be reduced to extremely low when the load is low (e. G., air conditioners need only to maintain room temperature, the speed of the electric power is reduced from 1500rpm to 300rpm), without frequent start-up, and the energy consumption is only 50-70 per cent of the normal frequency。
2. Noise and vibration: more quiet current frequency steady
Normal variable frequency: the rotor of the exchange aniso walker has a "reverse differential" with the stationary magnetic field, which produces "electromagnetic noise" when run; at the same time, the electrical current shock is high on the start-up of the power plant, which can easily cause the equipment to vibrate (e. G., dithering of the external air conditioner), and noise is usually at 55-65 db。
Direct current frequency: the fixed and rotor "synchronous rotation" of the long-magnetic synchronous electric power plant, which is free of electromagnetic velocity differentials and very low electromagnetic noise; combined with the smoothing of electrical currents (no impact) at start-up, the equipment has a small vibration and the noise can be contained at 40-50 db, close to background noise (e. G. About 30-40 db in the bedroom)。
3. Resizing accuracy: straight current frequency with high demand scenario
Normal variant frequency: due to the control logic limits of the communicators' “isoverse properties” and v/f, the speed adjustment is low and can only achieve a “blank retrench” (e. G., three-to-five slots for fans) and cannot be adapted to scenarios that require high speed stability (e. G., transfer belts for industrial equipment, electric drive for precision household appliances)。
Straight current frequency: based on pwm precision control, the velocity can achieve "ungraded velocity" (e. G., air conditioner speed from 300rpm to 1800rpm continuous velocity) with minimal rate fluctuations (in error)
4. Useful life: a more durable straight-flow variable frequency structure
Normal variant frequency: the rotor copper loss of the exchange arcade power plant causes the generator to heat for long periods, accelerating the ageing of the insulation material; at the same time, frequent outages of current shocks reduce the bearing life of the generator, usually designed to be 8-12 years (home electric scene)。
Direct current frequency: long-magnetic synchronous electrons are less hot and the insulation materials are ageing slowly; low loads do not require frequent activation, the bearings are less worn, and the stability of the permagnetic body (the life of the cylindrium permagnetic is more than 20 years old) can lead to an overall life of 15-20 years, which is more than 50% longer than the normal frequency。
5. Cost and maintenance: ordinary frequencies are more price-driven
Normal variant frequency: simple (never-magnetic) communication power sets, no filtering wave energy components, low production cost, usually 20-30 per cent less than direct current frequency equipment of the same power (e. G. 1. 5 air conditioners, approximately 2000 ordinary frequency, approximately 2,500 direct frequency); easy access to spare parts for electrical and frequency transformers and low maintenance costs (e. G., approximately 300-500 for the replacement of the frequency)。
Straight current frequency: the nsp is required to use a high-cost cerium permagnetic, and the rv is required to increase the volume of filtering capacitors at a higher cost of production; during maintenance, the dismantling and replacement of the rmb is difficult and the maintenance of the precise chip of the rmb is costly (e. G. Replacement of the rmu is approximately $800-1200)。
Application of scene selection: matching technology to demand to avoid "blind selection"
They don't have "good or bad" but "suitable or not." the logic chosen is to match the corresponding technology according to the “energy consumption sensitivity, noise requirements, precision requirements, budget ranges” of the use scene。
Preference given to the " straight current frequency" scenario
When the scene meets the "long-use, high energy consumption / noise / precision" requirement, the "high input" of the current frequency can be translated into "long-term benefits" and typical scenarios include:
In the field of household electricity:
Air conditioning (especially in bedrooms and living rooms for long-term use): low noise (no sleep impact) and high energy efficiency (no electricity savings for long-term use, three-to-five-year recoverable differentials) associated with straight-flow frequencies are advantages
Refrigerators / laundry machines: refrigerators require 24 hours to run, and low energy consumption of straight-flow frequency can significantly reduce electricity costs; direct-flow frequency generators of washing machines can achieve “ungraded velocity” and avoid entanglement of clothing while dehydrating with lower noise。
Industry and precision equipment:
Precision conveyor belts (e. G. Electronic component assembly lines): need for precision control of rotation speed (in error)
Medical equipment (e. G., air current-driven machines in breathing machines): need to be low-noise and high-stable to avoid compromising patients ' rest and equipment accuracy。
Commercial scene:
Central air conditioning in malls / writing buildings: long-term high load operation, with the energy-saving advantage of direct-flow frequency significantly reducing operating costs
Elevator drive: direct-to-flow frequency generators can reduce passenger discomfort, with a smooth start and low noise。
Preference given to the “ordinary frequency” scenario
When the scene meets the “short-term use, low energy consumption/noise requirements, limited budget”, the “low-cost” of the common variable frequency is more cost-effective and typical scenarios include:
Short-term or transitional household electricity:
Small-scale air conditioners for rental housing (1 and below): short life cycle (3-5 years), low cost of common variable frequency can reduce initial input without a premium on direct current frequency
Industrial fans / ventilators used on an ad hoc basis: only in the summer or during the production season, with low energy consumption and noise requirements, and sufficient common variability to meet demand。
Equipment with low load and low precision requirements:
Domestic exhaust fans, mini-pumps: rotation does not require precision regulation, but only a "yes/ none" or "high/low" set of speeds, which can be met by simple control of normal frequencies
Entry-level runners: users have low precision requirements for speed adjustments (e. G., 5-10 slot speeds only) and the cost advantage of a common fm machine can reduce the price of the whole machine。
Maintenance cost sensitive scene:
(a) alteration of old equipment (e. G. Old transmission belts at the plant): the original equipment is structured to fit the normal variable frequency electric power plant without the need to replace the electrical support and control system, which can significantly reduce the cost of the conversion
Outdoor environmental equipment (e. G., temporary ventilation units for site use): the environment is dusty and vibrating, the structure of the common variable frequency power is simple and spare parts are readily available for maintenance without fear of damage to sophisticated components。
Keywords: straight flow frequency
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Buyer service line: 0571-85317607
Seller service line: 0571-85317607
