Re: AC amplitude modulation for inductive loads


"Marcel Baum" <privat@xxxxxxx> wrote in message
news:471e0fc6$0$30782$91cee783@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
I have got a linear pump which needs a sinusoidal excitation.
The pumpflow is controlled by the amplitude of the AC to the coils
The amplitude is controlled via a DC input signal which on itself can
change
very fast.
So far I have used a 24VAC pump, which is no longer available, the actual
pumps have 230VAC (50hz). The rated power is roughly 150W.

My present design is powered from 24V DC and utilises a full (H-) Mosfet
bridge.
The bridge is controlled by a MC 33035 which is a PWM motor controller
with
an analogue input and a direction signal. The analogue input gets a sine
have wave with variable amplitude, the DIR input sees a 50hz TTL signal
in
phase with the sinus.
To go on with this design I would have to rectify the 230V, change to a
500V
Mosfet bridge and to add some HV photocouplers to feed the hi side Fets
of
the bridge.

Does anyone have better suggestion how to directly modulate the mains AC
instead of synthesising the AC from a DC source?
I probably should mention that the pump wants to see a sinus like (or
trapezoid) excitation which limits the use of a triac .

Any ideas are welcome.


Google for "AC Chopper". There's 2 very useful papers out there (I can't be
arsed looking). They handle the AC directly.
ST also have a useful application note


.

Relevant Pages

  • Small village and IBM
    ... Pump pressure controller failed. ... So I bike to the local village ... the IBM sales ...
    (comp.os.vms)
  • observer pattern - message handling/passing interface
    ... My system consists of a platform, a controller and pumps. ... controller to pump. ... void SetData() ...
    (comp.object)
  • AC amplitude modulation for inductive loads
    ... I have got a linear pump which needs a sinusoidal excitation. ... The bridge is controlled by a MC 33035 which is a PWM motor controller with ... an analogue input and a direction signal. ...
    (sci.electronics.design)
  • Re: AC amplitude modulation for inductive loads
    ... My present design is powered from 24V DC and utilises a full Mosfet bridge. ... The bridge is controlled by a MC 33035 which is a PWM motor controller with an analogue input and a direction signal. ... The analogue input gets a sine have wave with variable amplitude, the DIR input sees a 50hz TTL signal in phase with the sinus. ... I probably should mention that the pump wants to see a sinus like excitation which limits the use of a triac. ...
    (sci.electronics.design)
  • Re: AT&T Usenet Netnews Service Shutting Down
    ... degrees controlling when the pump ran. ... Never had a problem with the controller at all. ... That was one of my requirements when buying a house: No HOA. ... It's difficult to impossible to buy a new house without an HOA ...
    (sci.electronics.design)